FIELD VISIT REPORT TO THE: "ACCESS ROAD TO

RATAQUENUA ROADS IIFIC

NATIONAL UNIVERSITY

SANTIAGO ANTÚNEZ DE MAYOLO

Faculty of Mining Engineering, Geology and Metallurgy

PROFESSIONAL SCHOOL OF MINING ENGINEERING

BRIDGES (FRAMES)

COURSE: STATIC

TEACHER: Eng. BARRETO PALMA John

STUDENT: AGUIRRE JARAVladimir………101.0802.428

Huaraz, May 20, 2013

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INTRODUCTION

This report will deal with the truss bridge and more specifically about
Santo Toribio Bridge located in Huaraz–Palmira. There are many definitions.
About bridges, but more specifically, a bridge is a structure.
built with the purpose of allowing a communication route to cross a watercourse (river,
ravine, etcetera) or cross another communication route, without there being
mixing problems of both traffics.

In its construction, many important aspects must be taken into account, such as:
stability, resistance to displacement and breaking, etc.

I hope that this report will be very helpful to both me and the
receptors.

The Student

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INDEX

1 title 4

2 OBJECTIVES. 4

3 BIBLIOGRAPHIC REVIEW.- 4

3.1 HISTORICAL BACKGROUND.- 4

3.2 DEFINITION OF BRIDGE 5

3.3 ELEMENTS OF A BRIDGE: 5

3.4 MAIN TYPES OF BRIDGES: 6

3.5 USE OF BRIDGES: 7

4 TRUSS TYPE BRIDGES. 7

5 CONSTRUCTION PROCESS OF TRUSS TYPE BRIDGES. 8

5.1 Preliminary work 8

5.2 Earthmoving 9

5.3 Formwork 10

5.4 Concrete 10

5.5 Reinforcement armor 10

5.6 reticulated metal structure 11

5.7 Supports 11

5.8 Various 11

6 MODELING. 11

7 CURRENT TECHNOLOGY.- 15

8 BRIDGE ANALYSIS (STRUCTURES). 17

9 CONCLUSIONS. 21

10 BIBLIOGRAPHY 21

11 ANNEXES 22

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1 TITLE.-

BRIDGES (FRAME)

2 OBJECTIVES.-

2.1 GENERAL.-

Understand the construction process, the modeling, and the analysis of a bridge
armor type with the use of current technologies.

2.2 SPECIFIC.

To know the construction process of a truss bridge.

Knowing how to model and analyze this type of bridges.

How current technology is used in truss bridges.

3 BIBLIOGRAPHIC REVIEW.-

3.1 HISTORICAL BACKGROUND.-

The bridge is one of the constructions with the most ancient origins in History.
Nowadays, there are hanging bridges made in the Amazon rainforest with a
tangle of vines and grasses that may be similar to those that are
they would build in prehistory. From these, they would transition to those supported by wood

about trunks. Around the year 70 B.C., the first ones were built in China
suspension bridges (rope bridges equipped with planks that facilitate passage),
that were replaced by iron suspension bridges around the year 250 of our era
Era. The Roman civilization built numerous bridges for very
various; those made of stone stand out, and among the many built, the one that stands out is the one that

Cross the Tiber River in Rome, there are Romanesque stone bridges in Spain,
Mudejars, Gothic and Renaissance. In 1741, the first European bridge was built.
suspension bridge over the River Tees, in the northeast of England. In 1780, it
he built in England the first metal arch bridge, made of
foundry. Since this date, the "metal bridges" multiplied; it moved from
the foundry to rolled iron, and later to steel. In 1803 it was built in
Paris the first iron bridge in France. It was estimated, with the greatest of
possible precisions, the interplay of forces in this type of constructions
above-mentioned, and the corresponding values were also determined.

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materials through tensile, shear, and fracture tests. In 1804 the

British engineer Walter first conceived a rotating metal bridge

3.2 DEFINITION OF BRIDGE

It is a construction, generally artificial, that allows for overcoming an obstacle.

geographical or any other physical obstacle such as a river, a canyon, a valley, a
way, a railway, a body of water, or any obstruction. The design of
Each bridge varies depending on its function and the nature of the terrain over which it spans.

that the bridge is built. Its design and calculation belong to engineering
structural, with numerous types of designs that have been applied throughout
from history, influenced by the available materials, the techniques developed and
the economic considerations, among other factors.

3.3 ELEMENTS OF A BRIDGE:

3.3.1 Substructure or infrastructure

It is the part of the bridge that is responsible for transmitting the loads to the ground.
foundation, and is made up of:

. The piles: They are the intermediate supports of bridges with two or more spans.
They must support the load permanently and overloads without seats, be
insensitive to the action of natural agents (wind, floods, etc.).
. The abutments: Located at the ends of the bridge, they support the embankments.
that lead to the bridge. Sometimes they are replaced by driven piles that
allow the movement of the ground around them. They must withstand all kinds
of efforts for what is usually built in reinforced concrete and have shapes
various.
. The foundations: Also known as support for abutments and piers.
in charge of conveying all efforts to the ground. They are made up of the
rocks, ground or piles that support the weight of abutments and piers.

3.3.2 Superstructure

It is the part of the bridge where the moving load acts, and it is made up of:

. Main beams: They receive this name because they are the elements that
they allow to save the opening, being able to have a great variety of shapes like with
straight beams, arches, portals, reticulars, among others.
The secondary beams parallel to the main ones are called longitudinal beams.

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. Diaphragms: They are transverse beams to the previous ones and serve for their
bracing.
These perpendicular beams can receive other names such as
beams or in other cases bridge girders.
. Board: It is the structural part that is at the level of the subgrade and that
transmits both loads and overloads to the beams and main beams.

3.4 MAIN TYPES OF BRIDGES:

3.4.1 According to its structure:

3.4.1.1 Fixed bridges:

. Beam bridges
. Arch bridges
. Truss bridges
. Cantilever bridges
. Cable-stayed bridges
. Pontoon bridges

3.4.1.2 Movable bridges:

. Drawbridge
. Swing bridges
. Horizontal displacement bridges
. Vertical lift bridges
. ferry bridge

3.4.2 According to the material:

. String bridges
. Wooden bridges
. Masonry bridges
. Metal bridges:
Cast Iron Bridges
2. Wrought iron bridges.
3 Steel bridges.
. Reinforced concrete bridges.
. Prestressed concrete bridges.
. Mixed bridges.

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3.5 USE OF BRIDGES:

A bridge is designed for trains, vehicular traffic, pedestrian traffic, pipes

gas or water for its transportation or maritime traffic. In some cases there may be
restrictions on its use. For example, it can be a bridge on a highway and
to be prohibited for pedestrians and bicycles, or a pedestrian bridge, possibly
also for bicycles.

4 ARMATURE TYPE BRIDGES.

4.1 Definition

A truss bridge is a type of bridge based on different tensions.

in wood or metal pulling together when weight is applied to it. The bridge does not
it has many lower support elements, and much of the support comes from the
placement of different metal pieces above it. This type of bridge
it is designed to hold itself when weight is applied through tension
each of its pieces, causing it to be able to bear the load.

4.2 History

Truss bridges are one of the oldest types of large bridges.

in the United States. The first truss bridges were built
around the 1820s. These were made of wood in many cases and
they were used to transport heavy cars. When the railway became popular
in the 1880s and 1890s, this type of bridge began to be built from
iron and other strong metals. This allowed trains to go to many places that
otherwise they wouldn't have been able to go. Many famous bridges, such as the bridge
About the Kwan River and the Garden Bridge in Shanghai, they are truss bridges.

4.3 Identification

All truss bridges are built on the same principle

Basic. A flat bridge is placed over the opening and supports in arrangement
Horizontal and diagonal braces are added to each side of the bridge for support.
Then a structure is built over the bridge in the same horizontal pattern.
and diagonal to support the bridge from above. In this way, when it is applied
weight, all the pieces of the bridge are held together, which causes it to
can support almost any weight.

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4.4 Function

The purpose of this type of bridge is to enable the construction of these in places
that have unstable ground. When the soil supports are unable to be
built, the bridge has to be supported in some other way. Here it is
where this type of bridge comes into play. A truss bridge is also
capable of supporting large amounts of weight than a traditional bridge.

4.5

The truss bridges can be almost any size. There are some that
they are a few feet long, covering a small opening in the ground, or
helping to overcome an unstable patch of ground. However, there are some
truss bridges that are quite long. There is a truss bridge in
Japan that is used as an overpass and is almost a mile (1.6
kilometers) long. The longer the bridge, the greater its need for
support.

4.6Meaning:

The truss bridges have contributed greatly to the way the world
it works currently. Railways still use truss bridges
so that the trains can pass over it. Without the invention of this type of bridge, it is
unlikely that the train would have become so popular. This would mean that the
transport would be slower and goods would remain much more localized.
This type of bridge is also used for car traffic. While
that many other types of bridges are used for the passage of cars, this
bridge is still a popular option due to its strength and capacity to
to place oneself almost anywhere.

5CONSTRUCTION PROCESS OF TRUSS BRIDGES.

5.1 Preliminary works

Cleaning and deforestation: it consists of clearing and cleaning the land

natural in the areas that will be occupied by the project works and the zones or strips

lateral areas reserved for the road, which are covered with straw,
weeds, forest, grasslands, crops, etc. It is carried out by the staff.
qualified and the team.

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Trace and replanning: Based on the plans and topographic surveys of the
Project, the Contractor will proceed with the general layout of the work, in which
If necessary, the necessary adjustments will be made to the conditions.
real found on the ground. Through skilled and qualified technical personnel and
surveying equipment.

Additional building (guardhouse and/or storage): These are the constructions

necessary to install infrastructure that allows housing for workers,

supplies, machinery, equipment, etc.

Identification sign of the work: It is the preparation and placement of the sign.
which identifies the work. The location of it will be proposed by the Contractor and
approved by the Supervision.

Mobilization of machinery-tools for the work: This item

consists of the transfer of personnel, equipment, materials, camps, and others,
that are necessary to the place where the work will be developed before starting and to the

complete the work. The mobilization includes obtaining and paying for permits
and insurance.

5.2 Earth movement

Loose material cutting: This work consists of the set of the

activities of excavating, removing, loading, transporting to the haul limit
free and place in waste sites, the materials coming from the
required cuts for the land leveling and loose material loans,
indicated in the plans and cross sections of the project, with the
modifications ordered by the Supervisor.

Excavation of earth in saturated material and underwater: This work

it includes the execution of the necessary excavations for the foundation
of structures and walls. It also includes drainage, pumping, drainage,
shoring, bracing and construction of cofferdams, when applicable
necessary, as well as the supply of materials for such
excavations and the subsequent removal of shoring and cofferdams.

Rock excavation: It involves the excavation of medium rock masses.

or strongly lithified so that, due to their cementation and consolidation,
they require the systematic use of explosives.

Compacted fill for structures with own material: This work

it consists of layering, moistening or drying,

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formation and compaction of the suitable materials coming from the

same excavation, from the cuts or other sources, for fills along
of concrete structures.

Filling with loan material: This work consists of the filling, the
placement, the wetting or drying, the shaping and
compaction of suitable materials in accordance with the present
specification, the plans, and the Supervisor's instructions.

Removal of excess material: Under these items, the

material in general that needs to be eliminated.

5.3 Formwork

This item refers to the formwork and stripping of foundations, braces,

reinforced walls, solid slabs, and in general all concrete work that
specify in the plans.

Materials: The formwork may be made of wood or metal and must have the
sufficient resistance to contain the concrete mix, without the formation of
combats between the supports and avoid deviations of the lines and contours that
show the plans, nor can the mortar escape.

The wooden formwork may be made of planed boards or plywood, and must
to have a uniform thickness.

5.4 Concrete

This work consists of the supply of materials, manufacturing, transportation,

placement, vibrating, curing and finishing of Portland cement concrete
used for the construction of stirrups, retaining walls, deck of the
bridges and structures in general, according to the project plans, the
specifications and the instructions of the Supervisor.

Materials: Cement

5.5 Reinforcement Armor

This work consists of supply, transportation, storage, cutting,

bending and placing of steel bars within the different
permanent concrete structures, according to the project plans,
this specification and the instructions of the Supervisor.

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5.6 Reticulated metal structure

This work consists of the manufacture, transport, assembly, and launch of the
metal bridge.

5.7 Supports

This contract refers to the supply and installation of plates at the supports.
of the bridge.

5.8 Various

Permanent vertical signaling: This specification presents the Provisions

General guidelines to be followed for Vertical Signage work
Permanent.

Polished floor finish with mortar: This item refers to the floor finish.
of the slab or board, which will serve as the running surface of the bridge.

5.8.1 Riverbank Defense

Double twist gabions: This specification pertains to the provision and

placement of the gabions, as well as the filling of them with stone
selected and finishes.

6 MODELING.-

For its modeling, the sap 2000 v- 9.10 program is used.

Generation and Editing of the Model Using Typical Templates

6.1 DEFINITION OF UNITS

Work will be done in Ton-m units.

DATA ENTRY:

 Number of Divisions
 Length of the division
 Height

BRIDGE MODEL IN THE XZ PLANE

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WE OBSERVE THE SPATIAL MODEL OF THE TWO EXTREMES OF

BRIDGE:

Then we proceed to draw the two beams that support the slab, the
which transmit the loads to the framework.

Generation of the upper braces of the framework

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Generation of the beams that support the concrete slab and the braces.

Finished geometry of the structural model.

6.2 Design Specifications:

For this, we define the sections and the materials to be used.

We proceed to assign the sections to each of the elements by drawing to

each of them.

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For the analysis of the structure, the nodes of the truss are assigned.
like kneecaps:

6.3 Final Model

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7 CURRENT TECHNOLOGY.-

7.1 Rigid Frame Bridges

They combine the plates and stirrups of the plate bridges with the beams and
stirrups of the beam ones; this combination forms simple units without
joint connections between the pieces. They are built of reinforced concrete or
prestressed or steel reinforcements surrounded by concrete. Of very
recent, they are extremely useful for separating the crossings into levels
roads and railways. In these crossings, it is often advisable that the difference
of levels is minimal and the bridges of the class we are dealing with are susceptible
to receive lower height in the same section than the other types.

7.2 Simple truss bridges

The structures of modern bridges adopt very varied shapes. The

Pratt and Warren trusses, of upper or lower passage, are the most commonly used in
short span steel bridges. The Howe is only used in bridges of
wood; its vertical members, constructed with steel bars, are in
tension, just like the bottom cord, which is made of wood.

For long span bridges, the Parker truss is used, which has a chord.
curved superior, also called Pratt truss, and for long spans and beam
simple lattice structures with subdivided panels are used, such as the
Warren armor; the Petit with parallel laces, also called
Baltimore, the Petit with an inclined top cord, which is also called
Pennsylvania, and the truss beam in "K". In the Petit and the subdivided Warren,
short vertical organs that appear in the respective figures are usually
extend to the upper cord to serve as support. The frameworks for
long beams are subdivided in such a way that the length of the beams is not
excessive; as the width of the opening increases, the height must also increase.
armor both to prevent excessive bending and for reasons of
Economy. The subdivided Warren, Petit, and "K" can be of lower board.
superior and of various numbers of shelves in the framework according to the
needs of each case. The metallic members of the beam bridges.
Lattices are built in very diverse ways. Those made of wood adopt sections.
rectangular.

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Fig. 1. Simple Truss Bridge

Fig 2. Metal frame bridges.

Fig. 3. Truss Bridge

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8 BRIDGE ANALYSIS (FRAMES).-

8.1 AVERAGE REAL DIMENSIONS OF BRIDGE

The bridge to be developed is a scaled model of a real bridge of the following

characteristics.

Truss bridge: 20 m in length by 3 m in width.

One lane.

Maximum capacity 36 tons.

Young's modulus: E = 235 540.65 Kg/cm2

σinfluence = 1869.0784 Kg/cm2

σlast = 2806.9065 Kg/cm2

σBreak = 2753.42 Kg/cm2

8.2 SCALES

8.2.1 GEOMETRIC SCALE:

Scale at which the bridge will be designed in comparison to the actual dimensions
of a bridge 25 m long by 3 m wide and with a single lane:

8.2.2 LOAD SCALE:

For this, the actual load and the ultimate stress of a real bridge will be taken into account.

(approx. 4200 kg/cm)2), and the average last effort of the sample approximately
tested wire (2806.9065 kg/cm)2) and the geometric scale:

The equations are:

Where the subscripts

they indicate:
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BRIDGES (FRAME). STATICS.

.......... (1)

...........(2)

From the geometric scale we will have the relationship between the transverse areas:

From the test conducted on wire No. 16 it is obtained that:

Thus, from equations (1) and (2) it is obtained:

By replacing values, it will be:

So the load scale will be:

How will it be designed for a real mobile load of 48 tons (48,000 kg), the load
scale model is:

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8.3 ANALYSIS:

The behavior of our bridge under various types of load will be analyzed.
you will find the axial loads in each element and the displacements of points
of control.

The mobile load is located in different situations, at the entrance of the mobile; when
the centroid of the mobile is located at the centroid of the bridge, at the exit of
mobile, the distributed load at critical nodes will also be seen, all this with the
help from a computer software for Engineering: SAP 2000. Next
The method of load distribution in the nodes and in the trusses will be explained.

The load of 320 Kg will be evenly distributed among each of the 3.

trusses of the bridge; said load by truss will be

Load by truss: 320 divided by 3 106.6667 Kg

Distributed in the proportions shown in the figure:

According to the shown distribution, it is given:

9P = 106.66667 Kg 11.851852 Kg

The dead load (self-weight) of the bridge will be taken into account; that said,
will proceed to add the load and deformation tables for the previous cases
mentioned.

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8.4 CRITICAL LOAD:

From the theory of columns, the following is known:

Where Pcrindicates the maximum critical load that must be applied to an element a
compression to prevent the bulging of this, using wire No. 8 whose diameter
It is 0.4 cm.

According to the bridge design, three different lengths can be appreciated between
all the elements, these are the horizontals, the verticals, and the diagonals
whose measurements are as follows:

Length Modulus of Elasticity Moment of

Element
(cm) (Kg/cm2) Inertia (cm4)

Horizontal 16 235540.65 0.001256637

Vertical 20 235540.65 0.001256637

Inclined 25.6125 235540.65 0.001256637

Having these data and using the critical load formula, the loads will be determined.
maximums in each element:

P16 = 11.4113097 Kg

P20 = 7.303238206 Kg

P25.6125 4.45319297 Kg

These values will influence the bridge construction process, according to the
values obtained from load by element, those that are under compression and
they exceed the critical load values.

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9 CONCLUSIONS.-

Truss bridges have been installed in the country, generally by

critical causes, urgencies or emergencies, to develop or modernize
areas or zones, natural or man-made disasters, benefiting towns
production areas, etc.

Truss bridges are designed to support themselves when a load is applied.

weight through the tension of each of its parts, causing it to be able to
to support the load.

A truss bridge is a type of bridge based on different

tensions in wood or metal pulling together when weight is applied to it.

10 BIBLIOGRAPHY

Truss Bridge Project-130218090948-phpapp01

Applications of modular metal bridges in El Salvador

FINAL REPORT ON MATERIALS STRENGTH

TECHNICAL SPECIFICATIONS of a Bridge

typesofbridges-110302102144-phpapp02

Reevaluation of the construction processes of the Colima bridge, located over

northern trunk road, and reconstruction proposal using the method
of double cantilever

themetalbridges-100522121638-phpapp01

http://puentes.galeon.com/tipos/pontsstructs.htm

http://www.civilengineerinfo.com/2011/01/ridged-frame-bridges-and-
No text provided for translation.

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11 ANNEXES

11.1 SANTO TORIBIO BRIDGE:

Located 5 minutes from Huaraz. In the district of Palmira for the crossing to the village
from pickup. The holy Toribio bridge crosses the Santa river.

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