4.

5 Target Bridge Management Level

Project and Network Level Analysis

A BMS can either function using a project and/or network level analysis approach. Project level
analysis concerns itself with individual structures and the remedial measures that are to be taken
to correct any deficiencies. Associated costing and predicted ramifications of various measures
can be performed in an effort to determine which method of repair offers the best solution, both
in terms of economy and safety.

Network level analysis concerns itself with a group of bridges and makes its decisions based not
only on the needs of an individual bridge, but that of the network as a whole. An example of this
would be in one bridge requiring deck repair and another suffering extensive scour damage. With
finite funds available, the BMS could assist in the decision making process which identifies
correcting the scour problem, with the ultimate impact of structure failure, to be more pressing
than fixing the deck, which should not be ignored but at least can be deferred until later. This is
but one example of a network level decision making scenario.

A well rounded BMS provides the functionality of examining bridges using both of the methods
described above. Although the theoretical image of a BMS is one that produces a list of bridges
with appropriate measures to be taken, the reality is much different. A BMS is not so much a
decision making tool as it is a decision assisting tool. Engineers must absorb this information and
with the aid of the BMS arrive at a logical plan of attack for maintaining a network’s structures.
There are simply too many factors outside of the BMS analysis process that influence project
selection for the system to function as a “black box.” It is difficult to imagine the coding of a
routine in a BMS which accounts for the political pressure employed by a legislator with a
deteriorating bridge in his or her community A way to view the network level–project level
relationship is that of the macroscopic database to the microscopic one. The macroscopic
database provides a view of the entire set of bridges, in essence acting as a bird’s-eye view from
far away. From such a view, maintenance personnel can gain an appreciation of the magnitude
and scope of the problems they are facing. This can be called the pie chart view. For example, a
typical network analysis product is to show the percentage of bridges which can be classified as
poor, good, or excellent. A well-established BMS can perform network level optimization
analysis—determining the optimal time to take improvement actions on various bridges in the
network, under the constraints of the limited budget.

The microscopic project level analysis provides a detailed snapshot of an individual structure.
This snapshot includes information on specific elements, the present condition, and possible
ramifications if left untouched. The project level view of a bridge can be used to refine the
selection process and weed out final candidates for various levels of repair. Where the network
analysis methods can be used to determine which bridges make the final round of consideration,
a project level approach can be used to select the winning candidates, and be used to define the
rehabilitation scope. This two-step approach provides a coherent basis for project selection
which takes advantage of both methodologies.

Predicting the Condition of Bridges

Predicting the future condition of a highway bridge is an important factor in determining the type
and scope of repair a bridge should receive. This prediction is usually made based on one of the
following possible scenarios where:

 No work is performed
 Partial, interim measures are taken
 Full repair to correct all deficiencies is made
A basic tool in making these predictions is the so-called deterioration model. A deterioration
model takes the present condition of an element and extrapolates the condition of an element
based on certain remedial measures. The following is an example of how a deterioration model
can work. A structure’s bearings and pedestals show evidence of corrosion and deterioration
causing them to rate a 3 out of a possible 7. If no work is performed, a deterioration model may
indicate that the bearings could fall to a 1 in 2 years. If partial work is done to correct failing
deck joints and provide surface repair to the pedestals, the rating may hold at a 3 for 3 more
years. If the structure is jacked and the deteriorated bearings replaced, the resulting rating would
be a 7. The resulting rating is then used to determine an overall rating for the entire structure, so
that the picture becomes a little bit more complicated when weighting all of the various
alternatives. Maybe the bearings will be repaired and an existing pier problem left alone, or vice
versa. These are the type of questions which a deterioration model is supposed to address.

The answers produced by a deterioration model are based in large part on the wealth of
knowledge already present in a transportation department and then incorporated into the model.
These projections should take into account historical data on bridges in the same geographic
region and of a similar type.

Variations in geography, climate, and structure type will obviously have a great impact on the
answers generated by a deterioration model. For example, if a structure is in a marine
environment or constantly exposed to deicing agents, the corresponding effects on concrete
components should be accounted for in the model. In a way, building a deterioration model can
be considered more of an art than a science. Because there are so many factors that may affect a
bridge’s future condition, most BMSs use probabilistic models to give future deterioration
predictions.

Miscellaneous Decision Assisting Criteria

In conjunction with the results generated by the deterioration modeling of a structure, there are a
variety of decisions assisting criteria which are used to arrive at a general recommendation for
work to be done. One such criterion is the level of service criterion. The level of service criterion
is similar in concept to the Importance Classification (IC) used in determining the effects of
earthquake loading on a structure. In essence, the level of service criterion defines whether or not
a structure can be considered essential.

Examples of essential bridges would be structures that carry emergency vehicles and school
buses. This model should relate structure functionality to various characteristics of the structure
such as deck width, vertical clearance, and load carrying capacity.

Other decision assisting criteria are used to account for the impact of factors ranging from future
traffic conditions to deterioration of a structure. These models are used to optimize the
expenditure of a transportation department’s resources to address conditions that may exist
several years into the future.

4.5.1. Bridge Management Indicator

For the bridge management, “Health Index (HI)” will be used as the bridge management
indicator. HI is the quantified value of evaluation result of conditions of a bridge member from
the perspective of “soundness”, incorporating all the effects of various types of damage occurred
thereon. Evaluation value is basically calculated for each bridge member; however, it can be
calculated for each component, a span and a bridge.

Commonly-Recognized (CoRe) Elements

The AASHTO Guide for Commonly Recognized Structural Elements, often called the AASHTO
CoRe Element Manual, introduces the definition of each element and the unit of measurement
for as many as 108 elements (Thompson and Shepard, 2000). Most states have successfully used
the AASHTO CoRe elements as the basis for data collection, performance measurement,
resource allocation, and management decision support. State agencies may supplement the
AASHTO CoRe Element Manual with their own element definitions.

Condition States

The AASHTO CoRe Element Manual defines each structural and nonstructural element and the
descriptions for associated condition states (CSs). The definitions and descriptions reflect the
most common processes of deterioration and the effect of deterioration on serviceability.
AASHTO CoRe element manual generally defines the levels of deterioration of each CoRe
element as follows.

The levels shown below in Table II.1 are denoted Condition State 1 (CS1) through Condition
State 5 (CS5) respectively and each CoRe element has a set of 3-5 CSs. The element level
inspection supplies the total quantity of each element and the quantity of the element in each
respective CS. With this information, the severity of the deterioration and the quantity of the
deterioration can be determined for an individual element. Table II.2 is an example of CSs for a
structural element: Steel-Open girder-Painted.

Table II.1 Levels of deterioration of each CoRe element

Table II.2 CSs of steel open girder-painted

Bridge Health Index

BHI is a single number indicator of the structural health of a bridge. They go on to say that it is
an integral measure which meets bridge management engineers’ need for measuring bridge
health condition. This indicator is expressed as a percentage ranging from 0% (worst condition)
to 100% (best condition).

The premise of the BHI is that each bridge element has an initial asset value representing the best
condition state when the bridge is new. When the bridge deteriorates with age, the asset value of
each bridge element reduces and represents a lower condition state. After repair, maintenance, or
rehabilitation, the asset value of each bridge element increases and represents an improved
condition state.

In the Pontis BMS, the BHI is calculated by a series of formulas in two steps. Step one calculates
the element health index (EHI) according to the condition rating distribution from the element-
level inspection information. Step two computes the entire BHI based on the weighted EHI. The
Pontis system uses two weighting methods: the failure cost-based weighting method and the
repair cost-based weighting method. Each weighting method is dependent on cost.

Pontis Bridge Health Index Methodology

According to AASHTO (2003), the health index of an individual element (He) is the ratio of the
summation of the quantities in each condition state multiplied by a corresponding coefficient to
the total quantity of the element. It can be calculated by the following formula:

Equation II.1

Where

He is the health index of an individual element (EHI),

s is the index of the condition state,

qs is the quantity of the element in the sth condition state,

ks is health index coefficient corresponding to the sth condition state.

The health index coefficients of the CSs ks are fractional values calculated as follows:

Equation II.2

Where

ks is the health index coefficient for the sth condition state,

n is the number of applicable condition states ( n=3, 4, and 5),

s is the index of the condition state (s =1, 2, ..., n).

The health index coefficients ks take the following values shown in Table II.3.

Table II.3 Health index coefficients ks of the CSs

The health index (H) of the entire bridge can be evaluated as a weighted average of the health
indexes of bridge elements based on element total quantity and relative importance. According to
AASHTO (2003), it can be calculated by the following formula:

Equation II.3

Where

H is the health index of the entire bridge (BHI),

e is the index of an element,

Qe is the total quantity of element e,

We is the weighting factor of that element, and determined by either the element’s failure cost or
an empirically assigned value as relative importance (AASHTO, 2003).

Failure Cost-based BHI

In the Pontis system, one of the element weighting options that adopts element failure cost as
weighting factor is the failure cost-based weighting method. According to AASHTO (2003), the
corresponding failure cost-based BHI is calculated by following formula:
Equation II.4

Where

FCe is total element failure cost calculated as a sum of its agency and user failure cost
components (AASHTO, 2003).

Equation II.4 was applied to the 162 major CCD bridges which have complete inspection data
from 2000 to 2006. The results are shown in Appendix B. Among these results, 10 bridges were
selected to be shown in Table II.4. This is because their BHIs during 2000 to 2006 are all
between 90% and 100% and have extremely minimal decrease with age. In fact, with the
exception of three inspections, all inspection conditions are above 97%. This is despite the fact
that they all have severe element damage. In addition, these 10 major bridges will be also used
for repair cost-based BHI and DBHI.

Table II.4 Failure cost-based BHI for 10 major sample bridges

4.5.2Target Management Level

Target management level shall be set up with the use of Health Index (HI), as a bridge
management indicator. It is noted, however, that such target management level is not uniquely
determined from the health index; but shall be determined in consideration of availability of
budget to achieve such level.

In general, when the target management level is set up as high, necessary costs of repair of the
current damages on bridges will be increased. Therefore, target management shall be determined
in consideration of the available budget

4.6 Understanding and Evaluation of Present Conditions

4.6.1 Investigation and Inspection

In any consideration of the strength or load-carrying capacity of a bridge, it is necessary to have a

complete description of the bridge as it was first built, as it may have been modified, and its present
condition. Of these, the first two are generally available from drawings, which if unavailable or
incomplete must be reproduced by means of complete measurements taken in the field. The present
condition and changes that may occur in the future must be determined from regular inspections.

The main functions of bridge inspections are as follows:

 To indicate modifications (such as changes in dead load).

 To determine the extent of deterioration so that due allowance can be made for reduced strength or repairs
can be made to restore sections.
 To note signs of distress and so safeguard against danger of collapse.
 To provide a basis for comparing alternate forms of construction, experience in service being often the best
measure of relative advantages.
 Identify visible signs of deterioration or damage.
 Safety Assurance: Ensure the structural integrity of the bridge and the safety of users by
identifying potential hazards or deteriorations.
  Early Detection: Identify visible signs of wear, damage, or distress early, allowing for
timely maintenance and preventing further deterioration.
 Condition Assessment: Provide a preliminary assessment of the overall condition of the
bridge components, including superstructure, substructure, and safety features.
 Documentation: Create a detailed record of the current state of the bridge, including
photographs and notes on any observed issues, which aids in future evaluations and
maintenance planning.
 Maintenance Planning: Inform maintenance strategies and budget allocations by
identifying areas that require immediate attention or long-term repairs.
 Compliance: Ensure adherence to regulatory standards and guidelines by conducting
routine inspections as mandated by local and federal authorities.
 Monitoring Trends: Establish a baseline for ongoing monitoring, allowing for the analysis
of trends in deterioration over time.
 Community Trust: Build public confidence in infrastructure safety through regular
inspections and transparent reporting of conditions.
These objectives collectively contribute to maintaining the safety, functionality, and longevity of
bridge structures.

Key Areas to Inspect:

- Superstructure (girders, beams, deck)

- Substructure (piers, abutments)
- Deck (surface condition, drainage)
- Expansion joints and bearings
- Approach roadways
1. Structural Assessment

 Load Capacity Evaluation: Determine if the bridge can safely support current and
anticipated traffic loads.
 Material Integrity: Assess the condition of materials (concrete, steel, etc.) for signs of
corrosion, cracking, or fatigue.
  Deflection Measurements: Measure any deformation under load to evaluate structural
performance.
2. Advanced Testing Techniques

- Non-Destructive Testing (NDT):

- Ultrasonic testing to detect internal flaws.
- Magnetic particle testing for surface cracks in steel.
- Load Testing: Apply controlled loads to evaluate real-time structural response.
- Vibration Analysis: Assess dynamic characteristics to identify anomalies.
3. Condition Rating Systems

- National Bridge Inventory (NBI): Uses a scale (0-9) to rate various components
based on condition.
- Inspection Frequency: Based on condition ratings, inspections may be scheduled
annually, biennially, or at longer intervals.
4. Documentation and Reporting

- Maintain comprehensive records of inspections, assessments, and repairs.

- Use findings to prioritize maintenance and funding for bridge projects.
5. Regulatory Standards

- Follow guidelines set by agencies like the Federal Highway Administration

(FHWA) and local governing bodies.
- Ensure compliance with safety regulations and engineering best practices.
The frequency required for bridge inspections depends on particular circumstances. When no
data are available a very thorough first inspection is required. Supplementary inspections are
required at regular intervals to note changes. The most common interval suggested is 12 months,
although if a bridge is in poor condition, or posted due to low strength, intervals as short as one
month may be desirable. All inspections concerned with the behavior of the bridge as a structure
should be made by the bridge department to ensure careful attention to relevant details. Local
highway maintenance patrols should note such sources of danger as broken or damaged
members, scour around footings, and accumulation of debris in river channels.
Structural inspections of bridges need to be thorough and accurate. Although it is possible to set
up standard data sheets for recording:-

(1) there is such a variation in bridge types and in possible sources of trouble that a check list of
items that may be of concern is probably more satisfactory

(2). In any case, inspections must cover waterway, piers, abutments, superstructure, and
"geometric" condition or alignment.

Inspections are generally simply visual in nature, with accurate measurements of such things as
wastage due to rusting and abutment movements. Occasionally, actual physical inspection may
be necessary, as in probing timber or concrete to determine the extent of deterioration.

The results from bridge inspections, ratings, etc., are most useful if kept in the form of an
inventory. Ready reference can then be made to determine condition, strength, or clearances.
Inventories are usually kept on visible card filing systems where items of particular significance
(such as postings) can be displayed. Some authorities in the United States and England have
carried the recording of data one step further and use punch-card systems.

Effective bridge maintenance has such an important effect on prolonging the life of most bridges
that it should at least be mentioned here. Although cleaning and painting, etc., which are routine
functions of maintenance divisions, are most important, maintenance staffs can undertake minor
repairs on such things as bracing systems and floors. Because the need for such work will usually
arise out of the regular inspections by bridge department personnel, it is desirable to co-ordinate
maintenance work with inspections.

Basis for Analyses

Vehicle Loads. There are, of course, a great variety of vehicles in actual use on the roads. They
are regulated by law as to maximum size and weight, although it is possible to obtain special
permission to transport loads in excess of the legal limits. In rating bridges it is necessary to
determine whether a particular vehicle can safely cross a given bridge. In practice there are two
aspects to this problem.
Old or weakened bridges that cannot safely carry legal loads which might be encountered should
be posted to restrict their use. The posting generally takes the form of a safe load definition
displayed at the approaches to the bridge; therefore, the posting description must be easily
interpreted by vehicle operators.

In the case of bridges that can carry legal loads, but over which it may be desired to carry heavier
loads, there must be some convenient method for comparing the bridge's strength with the
proposed loading. In both cases a common scale to measure both the strength of the bridge and
the effect of the vehicle is essential.

It would be most convenient if some such simple measure as gross vehicle weight could be used.
Unfortunately this is not practicable, for the actual stress-producing effect of a vehicle on a
bridge depends not only on the gross weight, but also on the load length, the number and spacing
of the axles, and the distribution of load between the axles. A bridge that can carry a given load
on two axles can generally carry a much larger load spread over several axles. If postings were
based only on gross load, all loads would have to be restricted to the capacity reckoned in terms
of a two-axle truck, and multi-axle vehicles would be seriously and unreasonably restricted. To
obtain the greatest benefit from limited bridge capacities it obviously is necessary to have some
fairly exact method of comparing the effects of actual vehicles with rated bridge strengths. This
is a difficult problem, which is further complicated by in congruencies between legal load limits
and the loads on which new designs are based.

New bridges are designed according to standard specifications to carry so-called design loads.
These are intended to represent, in effect, the maximum anticipated loads. The development of
design standards has been typical of practice in most parts of the world. At first, more than 50
years ago, when roads were little more than tracks and heavy traffic moved by water or rail, road
bridges were designed for the more critical of a 5- or 10-ton wagon or a distributed load
representing cattle (see Fig . 1).

There is a certain unreality in design. Several alternatives are set, with the most critical to
govern. Notwithstanding the trouble and time spent in considering different cases, such things as
the fact that the concentrated load to be taken with the distributed load varies in magnitude
depending on the function being studied (see Fig . 1), shows that loading standards are set up not
so much to approximate actual effects as to produce desired results. This is also revealed in the
way separate design loading standards must be used for long-span bridges (S). The object of
legal load limits is to prevent the use of heavy vehicles which would damage roads and bridges.
At first only gross weight limits were set; but as it became apparent that heavier loads could be
carried safely if they were distributed over a number of axles, regulations were modified to
permit increased loads on multi-unit vehicles.

Figure 1. Design load standards.

Although these procedures may be necessary to give required proportions, the purpose would
perhaps be better served by dispensing with the myth of "truck" loads and alternate conditions
and designing for specified axle loads, and maximum moments and shears simply tabulated for
various spans. At any rate, "design" trucks (such as the H series) cannot be used to measure the
effect of actual vehicles, because 'the H equivalent of a given truck depends on the bridge span as
well as the details of the truck and its load. Thus, although H loadings may be used as a measure
for bridge capacities, the posted capacity of a bridge could not be simply its H rating, for drivers
would have no simple way of knowing the H equivalent of their vehicles for the particular span
involved.
 Figure 2. Maximum bending moments for various loads for spans up to 200 ft

4.6.1.1 Bridge Inspection

Bridge inspection is an essential element of any BMS particularly for aged and deteriorated
bridges and a path way to condition rating. The accuracy of condition assessment is relied
heavily on the quality of the inspection. Historically, bridge inspection of existing bridges has
been assumed as a secondary priority of a semi-random nature. The inspections were usually
done as a consequence of warnings received from sources very often outside the bridge network
system, or as a result of an obvious inadequacy of the bridge that did not allow it to fulfill the
expected function.

To reduce fixed costs and to enhance efficiency, an inspection system must be planned at the
bridge network level and not at the single bridge level. The routine inspection schedule should
not be changed frequently and must be performed at fixed period of time. The quality of the
inspection is strongly related to the knowledge and experience of the inspectors and compliance
with prescribed procedures The functionality of the management system is based on a
standardized inspection plan. It includes a periodic set of inspections based on a fixed timetable
in which some flexibility is allowed to take into account a reasonable global allocation of
inspection resources complemented by special inspections when something serious is detected or
suspected. A variety of inspections may be required on a bridge during its service life. The main
types of inspection are addressed in the following sections.

Initial (Inventory) Inspection

Initial inspections are performed on new bridges or when existing bridges are first entered into
the database. This inspection provides a basis for all future inspections or modifications to a
bridge. Inventory inspections provide structural inventory and appraisal data along with bridge
element information and baseline structural conditions.

Inventory inspections usually start in the office with the construction plans and route information
then proceed to the field for verification of the as-built conditions. Initial defects are noted which
might not have been present at the time of construction. Changes in the condition of the site,
such as erosion, scour and re-grading of slopes should also be noted.

Routine Inspection

The routine inspection is a diagnostic method with the greatest potential and is generally based
on direct visual observation of a bridge’s most exposed areas. It relies on subjective evaluations
made by the bridge inspectors. During an inspection, no significant structural defect is expected
and the work recommended falls within the range of maintenance.

A period of fifteen months between routine inspections is recommended so that the influence of
the weather on the general condition and degradation of the bridge can be assessed. A routine
inspection must be planned in advance to facilitate the best assured conditions (e.g., weather
conditions and traffic) that may permit detection of defects.

Detailed Inspection

Easy and fast nondestructive in situ tests are performed in detailed inspection in addition to
direct visual observation as a way of exploring every detail that may potentially lead to future
problems. There is a possibility that special means of access may be used if such is considered
indispensable. The period recommended for a detailed inspection is five years and replaces a
routine inspection if the inspector’s calendars agree. A preliminary visit to the bridge site may be
useful to evaluate existing conditions. If there is a need to follow up the evolution of certain
defects with greater frequency, however, the period between visits may be reduced to one year,
especially for local areas of the bridge.

Planning a detailed inspection includes a careful study of a bridge dossier to get to know the
reasons and evolution of the defects detected in the previous inspections and the specific points
to be assessed closely. Based on inspection forms and a preliminary visit to the site, the eventual
special means of access needed are planned. The following files must be brought to the site
and/or prepared beforehand: a list of all single points to be checked, schematics with reference
grids of the most relevant elements, and the last periodic inspection form and the inspection
manual.
According to the outcomes obtained, the inspection may possibly have one of the following
consequences: the organization of a structural assessment or of complementary surveillance
measurements, the preparation of a list with particular aspects to follow especially carefully in
the next inspection, the organization of maintenance work needed and the establishment of a
medium-term maintenance plan.

Structural Assessment

A structural assessment is normally the consequence of the detection of a major structural or

functional deficiency during a routine or detailed inspection. It may also be necessary if
widening the deck or strengthening the structure is under consideration. The expected results
from this inspection are: the characterization of the structural shortcomings, the remaining
service life estimation by using degradation mathematical models, and also evaluation of its
present load-bearing capacity. It is not easy to predict the required means because a wide range
of situations can initiate a structural assessment

The static and dynamic load tests and laboratory tests can be valuable complements to the
information collected in situ. Nevertheless, they must be used with some parsimony since, as
well as being expensive, they force the total interruption of traffic over the bridge for uncertain
periods of time.

The final report of the structural assessment must include the index, structural identification
form, schematic drawing of the bridge, structure general condition standard form, summary of
the most significant results, equipment used and calibration sheets, photos and schematic
representations of the cores, identification and description of the cores, identification and
description of the asphalt surface samples, photos and drawings. All the data collected are dated
and appended to the bridge dossier.

Special Inspection

This could be undertaken to cover special conditions such as occurrences of earthquakes, unusual
floods, passage of high intensity loading, etc. These inspections should be supplemented by
testing as well as structural analysis. For that reason the inspection team should include an
experienced bridge design engineer.

Underwater Inspection

An underwater inspection is performed on bridges with structural elements partially located

under water that are not easily accessible for inspection, and generally the inspection interval
should not exceed sixty months. Underwater inspections are undertaken by experienced divers to
assess the material condition specific material type and take under water photographs/videos as
necessary.

Qualifications and Responsibilities of Bridge Inspectors

The primary purpose of bridge inspection is to maintain the public safety, confidence, and
investment in bridges. Ensuring public safety and investment decision requires a comprehensive
bridge inspection. To this end, a bridge inspector should be knowledgeable in material and
structural behavior, bridge design, and typical construction practices. In addition, inspectors
should be physically strong because the inspection sometimes requires climbing on rough, steep,
and slippery terrain, working at heights, or working for days.

Some of the major responsibilities of a bridge inspector are as follows:

 Identifying minor problems that can be corrected before they develop into major repairs;
 Identifying bridge components that require repairs in order to avoid total replacement;
 Identifying unsafe conditions;
 Preparing accurate inspection records, documents, and recommendation of corrective
actions; and
 Providing bridge inspection program support.
The field team leader should be either a professional engineer or a state certified bridge
inspector, or a Level III bridge inspector certified through the National Institute for Certification
of Engineering Technologies. It is the responsibility of the inspection team leader to decide the
capability of individual team members and delegate their responsibilities accordingly. In
addition, the team leader is responsible for the safety of the inspection team and establishing the
frequency of bridge inspections.
Tools for Inspection

In order to perform an accurate and comprehensive inspection, proper tools must be available. As
a minimum, an inspector needs to have a 2-m (6-ft) pocket tape, a 30-m (100-ft) tape, a chipping
hammer, scrapers, flat-bladed screwdriver, pocketknife, wire brush, field marking crayon,
flashlight, plumb bob, binoculars, thermometer, tool belt with tool pouch, and a carrying bag.
Other useful tools are a shovel, vernier or jaw-type calipers, lighted magnifying glass, inspection
mirrors, dye penetrant, 1-m (4-ft) carpenter’s level, optical crack gauge, paint film gauge, and
first-aid kits. Additional special inspection tools are survey, nondestructive testing, and
underwater inspection equipment.

Inspection of a bridge prompts several unique challenges to bridge inspectors. One of the
challenges to inspectors is the accessibility of bridge components. Most smaller bridges can be
accessed from below without great effort, but larger bridges need the assistance of accessing
equipment and vehicles. Common access equipment are ladders, rigging, boats or barges, floats,
and scaffolds.

Common access vehicles are man lifts, snoopers, aerial buckets, and traffic protection devices.
Whenever possible, it is recommended to access the bridge from below since this eliminates the
need for traffic control on the bridge. Setting up traffic control may create several problems, such
as inconvenience to the public, inspection cost, and safety of the public and inspectors.

Safety during Inspection

During the bridge inspection, the safety of inspectors and of the public using the bridge or
passing beneath the bridge should be given utmost importance. Any accident can cause pain,
suffering, permanent disability, family hardship, and even death. Thus, during the inspection,
inspectors are encouraged to follow the standard safety guidelines strictly.

The inspection team leader is responsible for creating a safe environment for inspectors and the
public. Inspectors are always encouraged to work in pairs. As a minimum, inspectors must wear
safety vests, hard hats, work gloves, steel-toed boots, long-sleeved shirts, and long pants to
ensure their personal safety. Other safety equipment are safety goggles, life jackets, respirator,
gloves, and safety belt. A few other miscellaneous safety items include walkie-talkies, carbon
monoxide detectors, and handheld radios.

Field clothes should be appropriate for the climate and the surroundings of the inspection
location. When working in a wooded area, appropriate clothing should be worn to protect against
poisonous plants, snakes, and disease-carrying ticks. Inspectors should also keep a watchful eye
for potential hazardous environments around the inspection location. When entering a closed
bridge box cells, air needs to be checked for the presence of oxygen and toxic or explosive gases.
In addition, care should be taken when using existing access ladders and walkways since the
ladder rungs may be rusted or broken. When access vehicles such as snoopers, booms, or rigging
are used, the safe use of this equipment should be reviewed before the start of work.

Reports of Inspection

Inspection reports are required to establish and maintain a bridge history file. These reports are
useful in identifying and assessing the repair requirements and maintenance needs of bridges. It
is required that the findings and results of a bridge inspection be recorded on standard inspection
forms. Actual field notes and numerical conditions and appraisal ratings should be included in
the standard inspection form. It is also important to recognize that these inspection reports are
legal documents and could be used in future litigation.

Descriptions in the inspection reports should be specific, detailed, quantitative, and complete.
Narrative descriptions of all signs of distress, failure, or defects with sufficient accuracy should
be noted so that another inspector can make a comparison of condition or rate of disintegration in
the future. One example of a poor description is, “Deck is in poor condition.” A better
description would be, “Deck is in poor condition with several medium to large cracks and
numerous spalls.”

The seriousness and the amount of all deficiencies must be clearly stated in an inspection report.
In addition to inspection findings about the various bridge components, other important items to
be included in the report are any load, speed, or traffic restrictions on the bridge; unusual
loadings; high water marks; clearance diagram; channel profile; and work or repairs done to the
bridge since the last inspection.
When some improvement or maintenance work alters the dimensions of the structure, new
dimensions should be obtained and reported. When the structure plans are not in the history file,
it may be necessary to prepare plans using field measurements. These measurements will later be
used to perform the rating analysis of the structure.

Photographs and sketches are the most effective ways of describing a defect or the condition of
structural elements. It is therefore recommended to include sketches and/or photographs to
describe or illustrate a defect in a structural element. At least two photographs for each bridge for
the record are recommended.

Other tips on photographs are

 Place some recognizable items that will allow the reviewer to visualize the scale of the
detail;
 Include plumb bob to show the vertical line; and
 Include surrounding details so one could relate other details with the specific detail.
After inspecting a bridge, the inspector should come to a reasonable conclusion. When the
inspector cannot interpret the inspection findings and determine the cause of a specific finding
(defect), the advice of more-experienced personnel should be sought. Based on the conclusion,
the inspector may need to make a practical recommendation to correct or preclude bridge defects
or deficiencies. All instructions for maintenance work, stress analysis, posting, further
inspection, and repairs should be included in the recommendation. Whenever recommendations
call for bridge repairs, the inspector must carefully describe the type of repairs, the scope of the
work, and an estimate of the quantity of materials.

4.6.1.2 Evaluation of Bridge Conditions

Introduction to Structural Element Condition Ratings

Structural element condition ratings provide a detailed condition evaluation of the bridge by
dividing the bridge into separate elements, which are then rated individually based upon the
severity and extent of any deterioration. This rating system was developed by the American
Association of State Highway and Transportation Officials (AASHTO), and is outlined in the
“AASHTO Manual for Bridge Element Inspection”.

Structural element condition ratings provide input data for a Bridge Management System (BMS)
which allows computer projections of deterioration rates, providing cost-effective options for
bridge maintenance, rehabilitation, or replacement. Bridge Management Systems are intended to
be a source of information (and qualitative backing) for engineers and managers responsible for
long-range bridge improvement programs.

An “element” refers to structural members (beams, pier columns, decks, etc.), or any other
components (railings, expansion joints, approach panels, etc.) commonly found on a bridge.

Structural Element Types

AASHTO defines 2 basic element types:

• National Bridge Elements (NBEs) represent the primary structural components of a bridge or
culvert (bearings and railings are also included).

• Bridge Maintenance Elements (BME’s) include components of the bridge such as joints,
wearing surfaces, and protective coating systems that might be managed by agencies using
Bridge Management Systems. The condition rating language for BME’s can be altered by states
to best suit their bridge management practices.

Structural elements are also classified into five groups, depending upon structural function:

• Deck Elements: decks, slabs, wearing surface, deck joints, railings, and approaches.

• Superstructure Elements: girders, beams, arches, trusses, and bearings.

• Substructure Elements: abutments, piles, columns, pier caps, pier walls, and footings.

• Culvert Elements: culvert barrels, culvert end treatments, and roadway above culvert.

• Miscellaneous Elements: bridge components that do not fall under the other groups

Structural elements are also divided into six material groups (Miscellaneous Elements do not
apply to a specific material).
• Steel Elements

• Reinforced Concrete Elements

• Pre-stressed (including Post-Tensioned) Concrete Elements

• Timber Elements

• Masonry Elements

• Other Material Elements (includes Aluminum, Plastic or Composite Materials)

Structural Element Ratings

Structural elements are all rated on a scale of 1-4. Condition state 1 is the best condition, with
condition state 4 being the worst condition \.

If the severity of deterioration varies within a particular element, it should be rated using more
than one condition state. For example, on a bridge with 500 LF of beams, 250 LF could be rated
as condition state 1, 150 LF could be rated as condition state 2, and 100 LF could be rated as
condition state 3. Elements expressed as an “Each” (EA) quantity can also be rated using more
than one condition state (but only if the total quantity is greater than one). For example, on a
bridge with 9 columns, five could be rated as condition state 1, three could be rated as condition
state 2, and one could be rated as condition state 3.

Critical Deficiencies & Safety Hazards

A critical deficiency is any structural condition that, if not promptly corrected, could result in
collapse (or partial failure) of a bridge or culvert. This is not limited to findings observed during
a scheduled inspection, and can include traffic impact damage or flood damage. It may be
necessary to restrict traffic until further evaluation can be made or until the situation is corrected.

A critical deficiency should be thoroughly documented, and the Engineer (and Bridge Owner)
must be notified immediately.

A serious safety hazard refers to a non-structural condition that poses a significant safety hazard
and must be addressed immediately. Examples include severely damaged railings or guardrails,
or loose concrete above traffic or a pedestrian walkway. Serious safety hazards should be
immediately reported to the Inspection Program Administrator and Bridge Owner.

Deck & Slab Elements

Rating Procedures for Decks & Slabs

A typical deck or slab will be rated using two structural elements. The underside is rated using
one of the deck or slab elements, and the top is rated using (Wearing Surface).

The square feet (SF) quantity should include the full width of the deck (out-to-out dimensions)
over the length of the bridge. If segments of a bridge deck are comprised of different material
types, more than one deck (or slab) element should be used. If the roadway and sidewalk decks
are comprised of different materials, they should be rated under separate deck (or slab) elements.

The SF quantities may be broken up into multiple conditions states. In most situations, the deck
(or slab) element rating will be based upon the underside condition. In this manual, the condition
rating descriptions for deck and slab elements are divided into four material groups.

- Concrete Decks & Slabs

- Prestressed Concrete Decks & Slabs
- Timber Decks & Slabs
- Steel Decks
(Wearing Surface) is used to rate the top surface on bridge decks or slabs – this element includes
any wearing surface type or material. The wearing surface type, depth, and year of installation
are displayed on the Minnesota Structure Inventory Report. The inspector should note any
changes in the type or depth of the wearing surface - any significant increase in dead load will
 require a new load rating. On decks with bituminous or gravel wearing surfaces, the wearing
surface depth may build up over time.

- On roadway bridges, the SF wearing surface quantity includes only the roadway surface area
(curb to curb. Sidewalks, curbs, and raised medians are excluded.
- On pedestrian bridges, the SF wearing surface quantity includes the entire top deck surface
area (curb-to-curb or rail-to-rail).
- For bridge decks that carry only rail traffic, does not have to be rated. There is no need for a
roadway agency to inspect the top of the deck on an active railroad. An appropriate deck
element should be selected and rated (based upon the underside condition). The inspection
report notes should indicate if the railroad is active and how many tracks are present.
- Element does not need to be rated for bare timber decks (such as a timber plank deck without
wearing planks), or bare steel decks (such as an open grid steel deck).
Concrete Wearing Surface - Cracking & Sealing must be rated for all bridges with a concrete
wearing surface. This element is optional for other agencies. It tracks the total length of cracks
in the deck wearing surface and indicates if they are sealed.

Concrete Protective Coating is intended only for concrete bridge decks that have been “flood
sealed” with a waterproof sealant.

Reinforced Concrete Decks & Slabs

These elements describe the underside condition of reinforced concrete decks or slabs. The deck
overhangs and vertical fascia edges should also be considered in this rating. The top surface of
the deck or slab is rated using Wearing Surface.

- (Reinforced Concrete Top Flange refers to the upper horizontal “flange” of box girders, cast-in-
place concrete T-girders, or precast concrete channel beams.
- If shear cracking is present on reinforced concrete slabs, Shear Cracking must be added and rated
When determining condition states for the cracking defect, the inspector should consider width,
spacing, location, orientation, and structural (or non-structural) nature of the cracking. Cracks less
than 0.012" can be considered “minor”, cracks from 0.012" to 0.05" wide can be considered
“moderate”, and cracks wider than 0.05" can be considered “wide”.

Transverse or longitudinal cracks on the underside of concrete decks (or slabs) are typically
documented as a Linear Feet (LF) quantity. When determining condition states for square feet (SF)
deck elements, the LF crack quantity should be multiplied by the estimated width of the affected
concrete adjacent to the crack (a minimum crack width of 0.1 ft. should be assumed).

For example, on a concrete deck with 200 LF of light transverse leaching cracks, the 200 LF crack
quantity is multiplied by 0.1 ft., and 20 SF of the deck element is rated condition state 2. Map
cracking on the underside of a concrete deck is typically documented as a SF quantity, which would
correlate directly with SF deck element condition ratings.

Prestressed Concrete Decks & Slabs

 These elements describe the underside condition of prestressed (or post-tensioned) concrete
decks or slabs. The deck overhangs and vertical fascia edges should also be considered in this
rating. The top surface of the deck or slab is rated using Element #510 (Wearing Surface).

- Prestressed Concrete Top Flange) refers to the upper horizontal “flange” of prestressed box
girders or prestressed Bulb, Double, or Quad Tees.
- If shear cracking is present on prestressed concrete slabs, (Shear Cracking) must be added and
rated.

When determining condition states for the cracking defect, the inspector should consider width,
spacing, location, orientation, and structural (or non-structural) nature of the cracking. Cracks less
than 0.004" can be considered “minor”, cracks from 0.004" to 0.009" wide can be considered
“moderate”, and cracks wider than 0.009" can be considered “wide”.

Transverse or longitudinal cracks on the underside of concrete decks (or slabs) are typically
documented as a Linear Feet (LF) quantity. When determining condition states for square feet (SF)
deck elements, the LF crack quantity should be multiplied by the estimated width of the affected
concrete adjacent to the crack (a minimum crack width of 0.1 ft. should be assumed).

For example, on a concrete deck with 200 LF of light transverse leaching cracks, the 200 LF crack
quantity is multiplied by 0.1 ft., and 20 SF of the deck element is rated condition state 2. Map
cracking on the underside of a concrete deck is typically documented as a SF quantity, which would
correlate directly with SF deck element condition ratings.
Wearing Surface Elements

Deck Wearing Surface

For any bridge with a deck or slab element, this element is typically used to rate the condition of the
top (wearing) surface. This table includes specific condition rating criteria for low slump concrete,
plain concrete (bare decks), bituminous, epoxy chip seal, bituminous, timber plank, or gravel
wearing surfaces. For other deck wearing surfaces, use the “General” condition guidelines. In most
cases, this element does not need to be rated for bare timber decks, open grid steel decks, or decks
carrying only rail traffic.

Deck Wearing Surface - Low Slump Overlay (SF)

Low slump concrete overlays are the most common wearing surface on concrete bridge decks in
Minnesota (approximately 66% of the concrete bridge deck area). Low slump overlays are
intended to provide a high-density surface to protect the underlying deck from chlorides. This is
typically a 2” layer of concrete with high cement content, small course aggregate, and a ¾”
slump Low slump concrete is mixed at the bridge site, and is bonded to the deck with a grout
layer.
• Transverse or longitudinal cracking in a low slump concrete overlay is typically documented as
a Linear Feet (LF) quantity. When determining condition ratings, cracks must be converted to a
square feet (SF) quantity by multiplying by the estimated width of the affected concrete adjacent
to the crack (a minimum crack width of 0.1 ft. should be assumed). For example, on a low slump
concrete overlay with 1,000 LF of unsealed transverse cracks (with a typical crack width 1/16”),
the 1,000 LF crack quantity is multiplied by 0.1 ft.), and 100 SF of Element #510 would be rated
as condition state 3.

• Map cracking on a low slump overlay is typically documented as a square feet (SF) quantity, so
no conversion is required when determining the condition ratings.
Deck Wearing Surface - Plain Concrete SF

This element should be used for concrete wearing surfaces that are not low slump concrete. This
may include concrete decks without an overlay, monolithic decks that include a wearing surface
layer (poured with the underlying deck), or plain concrete wearing surfaces added to the deck.
Bridge decks (or slabs) are constructed without a low slump overlay when there are construction
time constraints or on bridges with a low traffic volume. Concrete bridge decks (or slabs)
constructed prior to the 1970’s are often bare.
• Transverse or longitudinal cracking in a concrete wearing surface is typically documented as a
Linear Feet (LF) quantity. When determining condition ratings for, cracks must be converted to a
square feet (SF) quantity by multiplying by the estimated width of the affected concrete adjacent
to the crack (a minimum crack width of 0.1 ft. should be assumed). For example, on a concrete
wearing surface with 1,000 LF of unsealed transverse cracks (with a typical crack width 1/16”),
the 1,000 LF crack quantity is multiplied by 0.1 ft.), and 100 SF of Element #510 would be rated
as condition state 3.

- Map cracking on a concrete wearing surface is typically documented as a square feet (SF)
quantity, so no conversion is required when determining the condition ratings.
Deck Wearing Surface - Bituminous (SF)

Bituminous wearing surfaces are mainly found on older (pre-1970’s) concrete bridge decks,
laminated timber bridge decks, or timber slab span bridges.
Concrete Wearing Surface - Cracking & Sealing
This element is intended to describe the quantity (and severity) of cracking on concrete wearing
surfaces, approach slabs, sidewalks, or medians, and to identify if crack sealing is required. If the
deck or approach slab has a bituminous or gravel wearing surface, there is no need to use this
element. Cracking of the top surface will eventually result in chloride contamination of the
underlying concrete deck or approach slab, and corrosion of the reinforcing steel - sealing these
cracks can extend the service life of the deck.

The inspector should first determine the total linear feet (LF) of sealed and unsealed cracks on
the concrete wearing surface, concrete sidewalks, and concrete medians. This should include all
transverse, longitudinal, diagonal, or random cracks that can be quantified in linear feet (LF).
The cracks should then be rated using the following criteria.

Deck Joint Elements

There are 8 structural elements for bridge deck joints:

- Strip Seal Deck Joint (LF)

- Plow Fingers (Each)
- Poured Deck Joint (LF)
- Compression Seal Deck Joint (LF)
- Modular Deck Joint (LF)
- Open Deck Joint (LF)
- Assembly Deck Joint (LF)
- Approach Relief Joint (LF)
Deck Joint Element Quantities
For most deck joints, the plan quantity (LF) will be entered as the element quantity. This will
typically include the roadway portion of the joint, but may also include portions of the joint that
extend through railings or under sidewalks and medians.

On bridge deck joints, steel cover plates are often present at the curbs, medians, sidewalks, and
railings. These cover plates are a component of the deck joint, and should be rated as part of the
deck joint element. If a sealed joint (such as a strip seal or modular joint) extends below a
sidewalk or median, that section should be rated under the strip seal or modular joint element. If
the seal does not extend below the sidewalk or median, that portion of the joint should be rated
under a separate deck joint element.

Inspection of Deck Joints

Deck joints should be inspected for leakage, as well as for proper function. Deck joint leakage is
a significant concern in Minnesota due to de-icing salt applied to roadways and sidewalks. Deck
joint leakage that results in damage to the superstructure or substructure below the joint should
result in a lowered condition rating, even if the joint is not designed or intended to be sealed.

Deck joints should be examined for skew, offset, or any evidence that the joint is restricted or is
beyond the limits of expansion or contraction. Note: deck expansion joints that are closed
tightly, offset vertically or horizontally, or have large gaps may indicate severe structural
problems (such as substructure movement).

Deck Joint Measurements

In order to confirm that deck expansion joints are properly functioning, periodic joint
measurements are recommended. Joint measurements should be taken at the same location, in a
consistent manner, and ideally under a wide range of temperatures. A common place to take
deck joint gap measurements is at the shoulder stripes. The gap between the inside vertical faces
of the joint is typically measured.

Measurements can also be taken at railing gaps or at sidewalk or curb cover plates. Note: recent
scrape marks along the edges of cover plates are a good indication that the joint is expanding
and contracting.
 Strip Seal Deck Joint – LF

This element applies to deck joints that utilize a single line “V” shaped neoprene gland, typically
held in place by a steel extrusion.

Strip seal deck joints are now the most common type of bridge deck expansion joint used in the
state.

- Type 4 joints are designed to accommodate 4” of movement (they are typically installed with a
2” gap).
- Type 5 joints are designed to accommodate 5” of movement. They are often used on skewed
joints.
The condition state language for

- (Strip Seal Deck Joint) is configured with the intent that joints requiring replacement (or
concrete/steel extrusion repairs) are rated as condition state 4, and that joints requiring gland
repair or replacement are rated as condition state 3
Chapter five: Development of Bridge Repair and Maintenance Plan

5.1 Estimate of Bridge Repair Costs

Cost configuration

The bridge works consist of various work items that are aggregated into a work package. The
total cost of any work package is structured in the formula shown in Figure 2-1.

TC = ∑ (Q × UP) × (1 + IWC) × (1 + OP) × (1 + VAT)

Figure 2.1: Cost Configuration

Direct work cost is the accumulation of all input costs for the execution of each work item. This
is a product of quantity by its unit price. The combination of unit work price (a pure work price
assuming that all the resources are on site) inclusive of the haulage cost constitute the Unit Rate.
Indirect Work Costs are costs related to management and administration. It is a percentage of
Direct Work Costs. Overheads and profit are a percentage of Direct and Indirect Work Costs.
Value-Added Tax (VAT) is a percentage determined by taxation regulations.

Price list and source The Unit Work Price consists of the Material, Labour and Machinery Unit
Rate. The material, labor and machinery rates used for cost estimation by procuring entities are
basically derived from official price indices given by government entities. They are open to the
public and are based on nation-wide market surveys, they can be assumed to be the average
prices in Kenya.

 Material Price: Material Price List from Kenya National Bureau of Statistics (KNBS).
 Labor Price: The Regulation of Wages (General) (Amendment) Order, The Labor
Institution Act, Ministry in charge of Labor.
 Machinery Price; Equipment Hire Rate List from Mechanical and Transport Department,
Ministry in charge of Roads.
For this case, labor, material and machinery prices are provided for the Nairobi/Central Region.

It is recommended that prices inputs for the other regions to be surveyed and included in the
manual. The recommended prices are revised every two years. The prices may be updated in an
adhoc basis when substantial changes take place. When some of material and machinery prices
are not covered in the recommended price indices, the average market prices acquired from the
survey by the cost estimate Engineer or provisional prices by referring to similar items are used.
Those prices should be revised immediately once the recommended prices are available. All
prices are to be coded based on RMS coding system. The prices of labour, material and
machinery used in the manual with their sources are shown in the Appendix II.

Methodology

Selection of the survey area

The survey area constituted of one region based on the unit rates are for the initial development
of the Cost Estimation Manual for Bridge Repair Works 2023.
Table 2-1: Survey Areas

Regions 1923
Nairobi/Central 1. Addis Ababa
2. Adama

Primary Data Collection

In each of the selected cities/town, information was obtained by visiting suppliers (whole sale
suppliers, major hardware shops, warehouses, contractors and manufacturers).

Secondary Data Collection

Table 2-2 shows the sources of official rates obtained from relevant government bodies and other
recognized organizations that were used to update the manual rates.

Unit price analysis

Labor

The contractors were selected based on the work contracted by the Road Agencies. The labour
unit rates selected were obtained from contractors. However, in cases where theaverage wage
rates from the contractors were comparatively lower, the minimum unit rates set in the
Regulation of Wages (General) (Amendment) Order, 2022 were used.

Table 2-3 Sources of Labor Unit Price

Material

The selection of suppliers in this category was done at random i.e. based on the availability of
the material. It was done through visits to contractors and Road Agencies regional offices, the
internet, phone and email communication and recommendations.

The procedure determining the material unit price was:

1. The price from the market survey was considered first;

2. The prices in the market survey were collected from a minimum of three suppliers, where
possible. The surveyed prices were averaged to provide one unit price from the market,

3. Comparison of the base indices and current indices was conducted to obtain the price
adjustment factor(s), and;

4. If an item was not available in the market; the international price was searched for and the cost
of transport, import duties and profits factored in.

Table 2-4: Sources of Material Unit Price

Priority Source of Data

1 Market Survey
2 Ethiopia National Bureau of Statistics
(ENBS)
3 Ethiopian Road Authority office
Equipment

The equipment lessors were selected at random; either through the internet, visits or
recommendations from the Regional RAs offices and contractors.

The prices were compared between the two sources of data. However, prices from the market
survey were prioritized.

The procedure determining the equipment unit price was:

1. The price from the market survey was considered first;

2. The prices in the market survey were collected from a minimum of three suppliers, where
possible. The surveyed prices were averaged to provide one unit price from the market;

3. Comparison of the market survey prices were compared by the rates of the equipment given
by Ethiopian Road Authority office; and,

4. If the equipment was not available in the market; the international price was searched for and
the cost of transport, import duties and profits factored in.

Table 2-5: Sources of Equipment Unit Price

Priority Source of Data

1 Market Survey
2 Ethiopian Road Authority office

Haulage cost

Site location is a major parameter to determine the Unit Rate so that haulage cost to transport
material or equipment should be carefully estimated. In this manual, haulage cost estimated
using the criteria in Table 2-6.

The calculated total haulage cost is divided by given quantity of the work item and added to unit
work price to get a Unit Rate of the work.
Table 2-6: Haulage Price Estimation

Unit quantity and productivity

Unit quantity of material (the amount of material used per unit of work), labour productivity (the
number of people required per unit of work), and machinery productivity (the number hours/days
of machinery operation needed per unit of work) are determined with the following references:

 Standard Specification for Road and Bridge Construction;

 Standard drawings; and,
 Average productivity rates from site surveys and site experiences
Indirect work costs

Indirect Work Costs are the costs related to management and administration. It is expressed as a
percentage of Direct Work Cost.

Indirect work costs include the following items;

 Human Resource Management costs (e.g. recruiting, staff welfare, transportation,

insurance, etc.);
 Site staff allowances;
 Management costs (e.g. site office maintenance, office equipment, communication,
transportation, etc.);
 Safety measures; and,
  Corporate Social charges/Statutory requirements (e.g. insurance, tax and welfare, etc.).
Overheads and profit

Overheads and profits are expressed as a percentage of the sum of Direct and Indirect Work
Costs. Overheads and profit include the following items:

 Head office staff salaries and allowances;

 Head office management costs (e.g. office maintenance, office equipment,
communication, transportation, etc.);
 Corporate Social charges//Statutory requirements (e.g. insurance, tax and welfare, etc.);
 Research and Development;
 Advertisement and publicity;
 Depreciation costs of fixed assets; and,
 Profit margin (bonuses, dividends to shareholders, internal reserves, etc.)

5.2 Establishment of Bridge Management Situations

Establishing a bridge management system is a comprehensive process designed to ensure the

safety, functionality, and longevity of bridge infrastructure. This involves multiple steps and
considerations to effectively oversee the entire lifecycle of bridges, from design and construction
to maintenance and eventual replacement.

1. Data Collection and Inventory Management

Detailed Approach:

- Inventory Creation: Start by creating a detailed inventory of all bridges within the
management area. This includes basic information such as location, age, design
specifications, dimensions, and materials used.
- Historical Data: Collect historical data on each bridge, including construction details, past
inspections, repairs, and maintenance activities. This data provides a baseline for
assessing current conditions and planning future interventions.
 - Digital Database: Utilize a digital database to store and manage this information
efficiently. Ensure that the database is regularly updated and accessible to all relevant
stakeholders.
2. Regular Inspections and Condition Assessment

Detailed Approach:

- Standardized Protocols: Implement standardized inspection protocols to ensure

consistency and thoroughness in assessments. This includes visual inspections, non-
destructive testing methods, and advanced technologies such as drones and sensors.
- Inspection Schedule: Develop a schedule for routine and in-depth inspections based on
the bridge's age, traffic volume, environmental exposure, and criticality. High-risk
bridges may require more frequent inspections.
- Documentation: Document all findings meticulously, including photographs, videos, and
detailed reports. Use this data to identify trends, prioritize maintenance needs, and plan
interventions.

3. Risk Analysis and Prioritization

Detailed Approach:

- Risk Assessment: Conduct a comprehensive risk assessment to identify potential threats

to bridge integrity. Consider factors such as structural weaknesses, environmental
impacts, traffic loads, and historical performance.
- Prioritization Criteria: Develop criteria for prioritizing bridges based on their risk levels
and importance within the transportation network. This ensures that resources are
allocated effectively to address the most critical issues first.
- Risk Mitigation Plan: Create a risk mitigation plan that outlines strategies for addressing
identified risks. This may include structural reinforcements, erosion control measures,
and emergency preparedness plans.
4. Maintenance and Rehabilitation Planning

Detailed Approach:
 - Preventive Maintenance: Establish a preventive maintenance program that includes
routine activities such as cleaning, painting, sealing, and minor repairs. Preventive
maintenance helps to address small issues before they escalate into major problems.
- Rehabilitation Projects: Plan and budget for major rehabilitation projects to extend the
lifespan of aging bridges. This may involve structural repairs, deck replacements, and
upgrading safety features.
- Resource Allocation: Allocate resources efficiently to ensure timely and effective
maintenance and rehabilitation activities. Consider factors such as budget constraints,
availability of skilled labor, and material procurement.
5. Asset Management System

Detailed Approach:

- System Implementation: Implement an asset management system to track all bridge-

related data, inspections, and maintenance activities. This system should provide real-
time updates and alerts for maintenance needs, generate reports for decision-making, and
support long-term planning.
- Integration: Ensure that the asset management system is integrated with other relevant
systems, such as GIS for spatial analysis and mapping, and predictive analytics for
forecasting maintenance needs.
6. Stakeholder Collaboration

Detailed Approach:

- Engagement: Engage all relevant stakeholders, including government agencies,

regulatory bodies, engineers, maintenance crews, local communities, and traffic
management authorities. Establish clear communication channels and regular meetings to
discuss inspection findings, maintenance plans, and potential issues.
- Collaboration: Foster collaboration among stakeholders to ensure that all perspectives are
considered and resources are used effectively. Collaborative decision-making enhances
the overall effectiveness of the bridge management system.
7. Technological Integration

Detailed Approach:
 - Advanced Technologies: Leverage advanced technologies to enhance bridge
management. Predictive analytics can forecast maintenance needs and identify potential
failures before they occur. Smart sensors provide continuous monitoring of bridge
conditions, and GIS allows for spatial analysis and mapping of bridge locations and
conditions.
- Data Utilization: Use the data collected from these technologies to inform decision-
making, prioritize maintenance activities, and improve overall bridge management.

8. Emergency Preparedness

Detailed Approach:

- Contingency Plans: Develop contingency plans for natural disasters, accidents, or sudden
bridge failures. These plans should outline specific actions to be taken in various
emergency scenarios, including evacuation routes, emergency contacts, and
communication protocols.
- Drills and Training: Conduct regular emergency drills and provide training for all
relevant personnel to ensure preparedness for emergency situations. Update emergency
plans and contact lists regularly.
9. Training and Development

Detailed Approach:

- Ongoing Education: Provide ongoing education and training for all personnel involved in
bridge management. Stay updated on the latest techniques, technologies, and best
practices in bridge inspection, maintenance, and repair.
- Knowledge Sharing: Encourage knowledge sharing and collaboration among teams to
continuously improve skills and expertise. This can be achieved through workshops,
seminars, and collaborative projects.
10. Continuous Improvement

Detailed Approach:
 - Review and Update: Regularly review and update management practices based on
lessons learned from past projects and maintenance activities. Incorporate feedback from
inspections, repairs, and stakeholders to refine strategies.
- Industry Advancements: Stay informed about industry advancements and integrate best
practices into the bridge management system. Continuous improvement ensures that
bridges remain functional, safe, and reliable over time.
By following these detailed steps, you can establish an effective bridge management system that
enhances the safety, reliability, and longevity of bridge infrastructure. This comprehensive
approach ensures that bridges remain functional and secure, meeting the needs of the community
now and in the future.

5.3 Development of Bridge Repair & Maintenance Budget Plan

Developing a bridge repair and maintenance budget plan is a critical aspect of ensuring the
longevity, safety, and functionality of bridge infrastructure. A well-structured budget plan helps
in allocating resources efficiently, prioritizing repairs, and managing costs effectively. Here's a
detailed note on how to develop a comprehensive bridge repair and maintenance budget plan:

1. Assessment of Current Condition

Detailed Approach:

Inspection Reports: Begin by gathering and reviewing recent inspection reports. These
documents provide a detailed account of the bridge's current condition, identifying areas of
concern such as structural damage, wear and tear, and potential risks.

Condition Rating: Assign a condition rating to each component of the bridge based on standard
criteria. This helps in prioritizing maintenance activities and allocating resources effectively.
Historical Data: Analyze historical data on past repairs and maintenance activities to identify
recurring issues and areas that may require more attention.

2. Identification of Maintenance and Repair Needs

Detailed Approach:

Categorize Needs: Categorize maintenance and repair needs into routine maintenance, preventive
maintenance, minor repairs, and major rehabilitation projects.

Priority Ranking: Rank these needs based on their urgency, potential impact on safety, and
overall importance. Use a risk-based approach to prioritize critical repairs that can prevent
significant structural failures.

Cost Estimates: Develop preliminary cost estimates for each maintenance and repair activity.
Consider factors such as materials, labor, equipment, and any additional costs associated with
specialized services.

3. Resource Allocation

Detailed Approach:

Budget Allocation: Determine the total budget available for bridge maintenance and repair
activities. This may involve securing funding from various sources, including government grants,
municipal budgets, and other financing options.

Resource Distribution: Allocate resources based on the priority ranking of maintenance and
repair needs. Ensure that high-priority activities receive adequate funding to mitigate risks
effectively.

Contingency Fund: Set aside a contingency fund to address unexpected repairs or emergencies
that may arise during the budget period.

4. Development of a Maintenance Schedule

Detailed Approach:
Annual Plan: Develop an annual maintenance plan that outlines the specific activities to be
performed each month. This plan should include routine inspections, preventive maintenance
tasks, and scheduled repairs.

Long-Term Planning: Create a long-term maintenance schedule that covers a period of 5-10
years. This schedule should include major rehabilitation projects and upgrades to ensure the
bridge remains in good condition over time.

Seasonal Considerations: Account for seasonal variations that may impact maintenance
activities. For example, plan for major repairs during favorable weather conditions and schedule
inspections in advance of harsh weather seasons.

5. Cost Management and Optimization

Detailed Approach:

Competitive Bidding: Use a competitive bidding process to select contractors and service
providers. This helps in obtaining the best value for money while ensuring high-quality work.

Bulk Purchasing: Consider bulk purchasing of materials and supplies to take advantage of
volume discounts and reduce overall costs.

Efficiency Measures: Implement efficiency measures such as optimizing work schedules, using
advanced technologies, and streamlining processes to minimize costs and enhance productivity.

6. Monitoring and Reporting

Detailed Approach:

Progress Tracking: Establish a system for tracking the progress of maintenance and repair
activities. Use project management software to monitor timelines, budgets, and milestones.

Regular Reporting: Prepare regular reports on the status of bridge maintenance and repair
activities. These reports should highlight completed tasks, ongoing projects, and any deviations
from the planned schedule or budget.
Performance Evaluation: Conduct performance evaluations to assess the effectiveness of
maintenance activities. Use key performance indicators (KPIs) such as cost variance, schedule
adherence, and quality of work to measure success.

7. Stakeholder Communication

Detailed Approach:

Communication Plan: Develop a communication plan to keep all stakeholders informed about
the maintenance and repair activities. This includes government agencies, regulatory bodies,
local communities, and project teams.

Public Engagement: Engage with the public to provide updates on bridge conditions, planned
maintenance activities, and any potential disruptions. Use various communication channels such
as newsletters, websites, and social media.

8. Continuous Improvement

Detailed Approach:

Feedback Mechanisms: Implement feedback mechanisms to gather input from stakeholders,

contractors, and project teams. Use this feedback to identify areas for improvement and enhance
the maintenance process.

Lessons Learned: Document lessons learned from past maintenance activities and use this
knowledge to improve future planning and execution.

Innovation: Stay informed about new technologies, materials, and best practices in bridge
maintenance. Incorporate innovative solutions to improve efficiency, reduce costs, and enhance
the quality of maintenance activities.

By following these steps, you can develop a comprehensive bridge repair and maintenance
budget plan that ensures the safety, reliability, and longevity of bridge infrastructure.

5.4 Degree of Relative Priority of Repair and Maintenance

Priority ranking

Ranking of bridge maintenance works is influenced by many factors, such as political influence,
differences in the importance of the road, condition of the bridges, the bearing capacity of the
bridges, etc. It is often necessary to choose between various strategies. Shall one choose an
expensive repair with a long service life or a cheaper repair with a short service life?

Another problem is the time at which the repair should be carried out. Should it be done as soon
as possible, can it be deferred, or can it wait until the structure is replaced?

Political influence can be more or less direct and can be impossible to predict. The focus can
within a very short time switch from maintenance of the transport sector to other areas within the
public sector such as health insurance, education etc., which of course depends on how the main
political currents are at the moment. The owners of the bridges sometimes demand higher
aesthetic standards and better condition of bridges in urban areas.

Some roads and railways are more important than others. A bridge carrying a main road is very
important and should function without any problems. Main traffic arteries often cross national
boarders and the transport sector is very dependent upon their functioning. But there are also
differences in the demand for quality when for instance comparing main roads with secondary
roads. Often there is a lower quality standard on the secondary roads despite the fact that it is
close to where people are living. In the following is described two different methods for ranking
bridges, the net present value method and the point ranking method. The first is a method that
results in cost information on the rehabilitation strategy for the whole bridge stock. The second
method can be a technical help or an alternative method to the economic method.

In the net present value method, the costs of repairs, traffic diversions, traffic noise and
pollution; operation and maintenance are calculated year for year within a chosen time-horizon;
the timing of each cost is based on the service life of each repair. The annual costs are then
discounted back to the initial year using a given discount rate. In this way the present value of
each year's expenditure is obtained.
By summing the present values, a value for the strategy in question is obtained that can be
compared with the corresponding value for other strategies. The strategy for which the
cumulative present value is lowest is the economic optimum for the structure considered in
isolation.

The cumulative net present value makes it possible to compare strategies in which the costs are
spread over varying periods, as all costs are converted to the initial year. The further in the future
a cost falls due, the lower is the present value of that cost. This effect is proportional to the
discount rate adopted. To put it simply, the present value is the amount that must be deposited in
the bank today to cover a cost that will fall due at the time the repair is carried out.

The present value is calculated by

Where In is the present value of a cost I in the year n

I is the cost in the yearn based on the chosen price level (normally current price)

n is the number of years until the cost falls due

r is the discount rate, decided by the management authority.

The net present value calculation is thus carried out in fixed prices (those of the initial year) with
a chosen price level and a chosen discount rate.
Parameters for Present Value

In an economic evaluation of alternatives, the most important parameters are:

 The costs of repairs and traffic inconveniences.

 The equal-value element in the repair strategies.
 The lifetime of the structural components.
 The time-horizon of the calculations.
 The residual value.
 The time at which the repair is carried out.
 The discount rate.
Costs

The cost of each repair strategy within a given time-horizon is calculated, the following items
being taken into account to the extent relevant:

- Repair costs, which include the costs of the contractor and the consultant.
- Client supply items and any railway costs that may be involved.
- Costs of inconvenience to road-users and other costs to society (e.g., relaying of cables
and pipes).
- Any operational costs that have an appreciable effect on the choice of repair strategy.
It should be noted that costs to society are not included in the budgets, but are used solely in
economic comparisons of strategies.

Repair Strategies

Several repair strategies should be investigated for each structure. To make an economic
comparison between strategies, they must result in the same increase in the value of the structure.
If a strategy involves a rehabilitation of the structure in the form of a strengthening or extension
(e.g., replacement of an old safety-barrier with a new one), the value of the improvement shall be
assessed, and a similar improvement must be included in the other strategies if they are to be
comparable.

Service Life

The service life of the structural components in question is estimated for each strategy. They are
estimated on the basis of experience with the various methods included in the strategies. The
estimated service life takes the expected maintenance of the component into account. Safety
considerations can reduce the service life relative to that estimated on the basis of repair and
maintenance; e.g., replacement of a functioning but obsolete safety-barrier by a new safety-
barrier.

Time-Horizon
The time-horizon is usually that of the repair with the longest service life. To make the various
repair strategies comparable from the economic point of view, the same time-horizon must be
used for all of them. The selected time-horizon should be long enough to make the present value
of expenditure beyond the h01izon insignificant. The normal time-horizon is 25 years. Time of
Repair the time at which the repair is to be carried out is determined on the basis of experience.
Postponement of a repair will usually result in further damage and consequently increased repair
costs later. The time of execution is thus based on the economic optimum service life of the
structural component, and is chosen so that the present value of each repair strategy is a
minimum. It is recommended to fix the times of execution of a number of related repairs; the
repairs should be considered as a group in order to reduce general costs, e.g., for traffic
diversions.

Budgetary limitations may require a postponement of the above-mentioned times of execution.

This means that the present value of the repair can increase, as the cost of repairing an increased
amount of damage and possibly also the cost of increased traffic inconvenience may outweigh
the economic gain resulting from the postponement.

Residual Value

A consequence of using the same time-horizon for several strategies will often be that when the
horizon is reached, there will be a residual value because the lifetime has not expired. If the
value declines linearly with time, it is easy to calculate the residual value.

Other forms of decline are possible, e.g., a parabolic curve, corresponding to a slow decline in
early years and a rapid decline later. However, this will normally have little influence on the
calculation, so that a linear decline can be used in most cases.

In present value calculations, the residual value is discounted and deducted from the cumulative
discounted cost.
Point Ranking Method

As described above the net present value method gives information on the cumulative costs over
a period, and these costs are based on the engineer's judgment from case to case and much
information is hidden in the cumulative costs of each rehabilitation strategy. If it is necessary to
have more detailed information on changes in condition, bearing capacity or possibility, the point
ranking method can be an alternative or supplementary method.

The point ranking method, which calculates the final priority-ranking point, PR, is based upon
the condition points, Pcon, the load capacity points, P cap, and the clearance points, Pcle, and can be
generally described as:

PR= Wrd,max * W con *Pcon+ W rd,overpass * Wcap * Pcap + W rd,underpass * Wcle * Pcle

The final ranking of the structures may-according to the current maintenance policy-be
influenced by the condition rating, determined by deterioration, malfunctioning, aesthetics; the
load capacity rating, determined by the safety level; and the clearance according to the
requirements for special transports.

This policy may be changed from year to year. Therefore, the decision must be reflected in
independent weighting factors for the condition, W com for the capacity, Wcap, and the clearance,
Wcle, of the structures.

It is not necessary to vary these factors from one area to another because the importance of the
road is given by its weight (W). Connected to the structure are the weights of the roads: the
maximum weight, W,rd,max which is based on the maximum weight of one of the roads allocated
to the structure, the general road weight of the road passing under the structure, W rd,undepass and
the weight of the road passing over the structure, w rd,overpass·

The road weights basically reflect the amount of traffic on specified parts of the roads, but also
the importance of the road, for instance, if the road is a main road carrying heavy traffic across
the border. Generally the weights are chosen by the management authority. When carrying out a
sensitivity analysis on the ranking of the structures for rehabilitation, the ranking is recalculated
with different weights, both at superior and lower bridge component level.
Condition Rating Point Model

Based upon the condition marks, Mcom, component, for components and the condition weight of
components, Wcon, components, the condition point, Pcon , is calculated as the maximum value of each
of the products:
Pcon= max value of {Mcon, eomponents * Wcon, components}

The condition marks are evaluated at the principal inspection and/or at the special inspection.
The condition marks are given to all major components of the bridge such as wing walls,
abutments, piers, bearings, superstructures;, parapets, road components etc. The range of the
condition mark is 0 to 5. A condition mark of 0 indicates a component with very little damage
and 5 indicates a component in very poor condition.

The condition mark reflects the following:

- The nature and degree of the damage.

- The extent of the damage.
- Whether the component can fulfill the requirements for its functioning.
- Whether the component has a negative influence on other components or users.
The importance of the different bridge components for the service life of the whole bridge has to
be taken care of by allocating a condition weight, W con,component, for each component. This means
that it is possible to have different weights for the different bridge components, for instance the
superstructure can be weighted higher than the wing walls. The weight of a component shall
always be less than or equal to the weight of the superior element.

Load Capacity Rating Model

This model calculates the load capacity point, Peaµ, based upon the load capacity mark,

Mcap,componens, and the component capacity weights, Wcap,component, of the bridge components. The load
capacity mark is calculated for each bridge on the basis of current load capacity and the current
loads. The marks 0, 3 and 5 are used according to the following:

- If the vehicle class is less than or equal to the inventory class of the bridge the load
capacity rating mark is 0.
- If the vehicle class is higher than the inventory class of the bridge but less than or equal
to the operating class of the bridge the load capacity rating mark is 3.
- If the vehicle class is higher than the operating class of the bridge the load capacity rating
is 5.
According to the above mentioned classes every bridge must be rated to two levels:

1. Operating class is the absolute maximum permissible load to which the structure may be
subjected.

2. Inventory class is the load level which can safely utilize the structure throughout its service
life.

The importance of the different components for the safety of the whole bridge shall also be taken
into account. This is carried out by the component capacity weights, W cap,component, determined for
each component. The weight of a component shall always be less than or equal to the weight of
the superior component. The load capacity point, P cap, is calculated as the maximum value of
each of the products:

Pcap =max.value of {Mcap,componens * Wcap,component}

5.5 Development of Bridge Repair & Maintenance Plan

The Development of a Bridge Repair & Maintenance Plan involves creating a comprehensive
strategy to ensure the safety, functionality, and longevity of bridge structures. Here’s how it
typically goes down:

1. Objectives and Goals

Detailed Approach:

Objective: The primary objective of a bridge repair and maintenance plan is to ensure the safety,
functionality, and longevity of bridge structures. This involves regular assessments, timely
interventions, and proactive maintenance to prevent structural failures and extend the lifespan of
the bridge.
Goals: Establish clear goals, such as reducing the frequency of major repairs, minimizing
disruption to traffic, and optimizing resource allocation. These goals guide the development and
implementation of the maintenance plan.

2. Data Collection and Analysis

Detailed Approach:

- Bridge Inventory: Create a comprehensive inventory of all bridges, including details such
as location, design, dimensions, materials, age, and load ratings.
- Historical Data: Gather historical data on inspections, repairs, and maintenance activities.
This information helps in identifying trends, recurring issues, and the effectiveness of
past interventions.
- Condition Assessment: Conduct regular inspections to assess the current condition of
each bridge. Use visual inspections, non-destructive testing, and advanced technologies
like drones and sensors to gather accurate data.
3. Risk Assessment and Prioritization

Detailed Approach:

- Risk Analysis: Perform a risk analysis to identify potential threats to bridge integrity,
such as structural weaknesses, environmental impacts, and traffic loads.
- Prioritization Criteria: Develop criteria for prioritizing bridges based on their risk levels,
importance within the transportation network, and potential impact of failure. High-risk
bridges should be prioritized for immediate attention.
- Mitigation Strategies: Create strategies for mitigating identified risks, such as
strengthening vulnerable components, implementing erosion control measures, and
improving drainage systems.
4. Maintenance and Repair Strategies

Detailed Approach:
 - Preventive Maintenance: Establish a preventive maintenance program that includes
routine activities such as cleaning, painting, sealing, and minor repairs. Preventive
maintenance helps address small issues before they escalate into major problems.
- Scheduled Inspections: Schedule regular inspections based on the bridge's age, traffic
volume, environmental exposure, and criticality. High-risk bridges may require more
frequent inspections.
- Emergency Repairs: Develop protocols for emergency repairs to address sudden damage
or failures promptly. Ensure that resources and materials are readily available for quick
response.
5. Budgeting and Resource Allocation

Detailed Approach:

- Cost Estimation: Estimate the costs of maintenance and repair activities, including labor,
materials, equipment, and overheads. Use historical data and industry benchmarks to
develop accurate cost estimates.
- Budget Planning: Create a budget plan that allocates funds for routine maintenance,
major repairs, emergency repairs, and contingency reserves. Prioritize high-risk bridges
and critical repairs in the budget.
- Resource Management: Ensure efficient allocation of resources, including skilled labor,
materials, and equipment. Develop a resource management plan that outlines the
availability and deployment of resources for maintenance activities.
6. Implementation and Scheduling

Detailed Approach:

Maintenance Schedule: Develop a detailed maintenance schedule that outlines the timing and
frequency of maintenance and repair activities. Use project management tools and software to
plan and track progress.

- Coordination: Coordinate maintenance activities with relevant stakeholders, including

government agencies, contractors, and local communities. Ensure clear communication
and minimize disruption to traffic and public services.
 - Quality Control: Implement quality control measures to ensure that maintenance and
repair activities meet established standards and specifications. Conduct regular audits and
inspections to verify compliance.
7. Monitoring and Evaluation

Detailed Approach:

- Performance Monitoring: Continuously monitor the performance of bridge structures and

maintenance activities. Use sensors, monitoring systems, and regular inspections to
gather data on structural health and maintenance effectiveness.
- Evaluation: Evaluate the effectiveness of the maintenance plan through performance
metrics, feedback from stakeholders, and analysis of inspection and repair data. Identify
areas for improvement and make necessary adjustments to the plan.
- Documentation: Maintain comprehensive records of all maintenance and repair activities,
including inspection reports, repair logs, and cost data. Use this documentation for future
planning and decision-making.
8. Stakeholder Collaboration

Detailed Approach:

- Engagement: Engage all relevant stakeholders, including government agencies,

regulatory bodies, engineers, maintenance crews, local communities, and traffic
management authorities. Establish clear communication channels and regular meetings to
discuss maintenance plans and progress.
- Collaboration: Foster collaboration among stakeholders to ensure that all perspectives are
considered and resources are used effectively. Collaborative decision-making enhances
the overall effectiveness of the bridge maintenance plan.
9. Training and Development

Detailed Approach:

- Ongoing Education: Provide ongoing education and training for all personnel involved in
bridge maintenance. Stay updated on the latest techniques, technologies, and best
practices in bridge inspection, maintenance, and repair.
 - Knowledge Sharing: Encourage knowledge sharing and collaboration among teams to
continuously improve skills and expertise. This can be achieved through workshops,
seminars, and collaborative projects.
10. Continuous Improvement

Detailed Approach:

- Review and Update: Regularly review and update the maintenance plan based on lessons
learned from past projects and maintenance activities. Incorporate feedback from
inspections, repairs, and stakeholders to refine strategies.
- Industry Advancements: Stay informed about industry advancements and integrate best
practices into the bridge maintenance plan. Continuous improvement ensures that bridges
remain functional, safe, and reliable over time.
By following these detailed steps, you can develop an effective bridge repair and maintenance
plan that enhances the safety, reliability, and longevity of bridge infrastructure. This
comprehensive approach ensures that bridges remain functional and secure, meeting the needs of
the community now and in the future.