JOYLYN CRIS L.

AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

ULO 1a
Let’s Analyze

1. Classify the bridge’s superstructures according to the materials of constructions, span length,
interspan relation, deck location, geometric shape span types, usage, and structural forms.

Materials of Construction:
Concrete Bridges: Bridges primarily constructed using reinforced or prestressed concrete.
Steel Bridges: Bridges made predominantly from steel or structural steel elements.
Wooden Bridges: Bridges constructed with wood as the primary material.
Span Length:
Short Span Bridges: Typically have a span length of less than 50 feet (15 meters).
Medium Span Bridges: Span lengths ranging from 50 feet (15 meters) to 250 feet (75 meters).
Long Span Bridges: The concept of “super-long span bridges,”defining a bridge with a span much
longer than any existing bridges, was also proposedin recent years

Interspan Relation:
Simple Span Bridges: Supported at both ends with no intermediate supports.
Continuous Span Bridges: Supported by multiple piers or abutments, creating multiple spans.
Cantilever Bridges: Supported at one end and project outwards with unsupported ends.

Deck Location:
Deck Bridges: The bridge is defined as a deck bridge when the deck is placed on the top of the main
structure.
Through Bridges: If the deck is located on the bottom of the main structure, it is a through bridge.
Half-trough Bridges: If the deck is located on the middle of the main structure, it is a half-through
bridge.

Geometric Shape:
Straight Bridges: If the bridge axis follows a straight line, then it is a straight bridge. The bridges
should be constructed in straight to avoid the extra force ssuch as torsions and to simplify the bridge
design, analysis, and construction.
Skewed bridges: are designed and constructed to accommodate specific site conditions and
geometric constraints. They are used in situations where the road or waterway alignment does not
intersect the bridge at a right angle. The degree of skew, or the angle at which the bridge is skewed,
can vary depending on the project and site requirements.
A curved bridge: is a type of bridge that features a curved or arched alignment as it spans across a
river, road, railway, or any other obstacle. Instead of having a straight, linear design, curved bridges
have a curved or arched profile, which can be aesthetically pleasing and can also offer certain
structural and functional advantages.

Span Types:
Single Span Bridges: Consist of a single main span.
Multi-Span Bridges: Comprise multiple spans supported by piers.
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

Usage:
Road Bridges: Designed for vehicular traffic, including cars and trucks.
Railway Bridges: Specifically designed for trains and other rail vehicles.
Pedestrian Bridges: Intended for foot traffic and non-motorized modes of transportation.
Pipeline Bridges: Constructed to support pipelines for the transportation of fluids.

Structural Forms:
Truss Bridges: Constructed using a framework of connected elements.
Cantilever Bridges: Supported on one end with projecting arms.
Suspension Bridges: Supported by cables and towers.
Arch Bridges: Shaped like an arch for support.

2. Describe the structural characteristic of Girder Bridge, rigid-frame bridge, truss bridge, arch
bridge, cable-stayed bridge, and suspension bridge, respectively.

Girder Bridge: Girder bridges are among the simplest bridge designs. They consist of one or more
horizontal beams, known as girders, supported by piers at regular intervals. Girders are typically
made of steel, concrete, or a combination of both. Girder bridges are suitable for short to medium-
span applications.

Rigid-Frame Bridge: are characterized by a continuous frame structure. They consist of horizontal
beams and vertical supports that are rigidly connected to each other. They are commonly constructed
using steel or reinforced concrete. Rigid-frame bridges are used for short to medium spans, and their
rigidity allows them to handle heavy loads.

Truss Bridge: Truss bridges have a framework of triangular truss elements, which provide strength
and stability. These trusses can be above, below, or within the bridge deck. Truss bridges can be
made from steel or occasionally timber. They are versatile and can span short to long distances,
depending on the design.

Arch Bridge: Arch bridges have a curved structure, resembling an arch, which carries the load. They
rely on the compressive strength of the arch to support the weight. Arch bridges are often built using
stone, brick, concrete, or steel. They can span medium to long distances, with longer spans
achievable with advanced materials and engineering.

Cable-Stayed Bridge: Cable-stayed bridges have towers that support the bridge deck through cables
that radiate from the towers to the deck. The cables are often arranged in a fan-like pattern. The
towers are typically made of concrete or steel, and the cables are usually steel. Cable-stayed bridges
can cover medium to long spans, with multiple variations in design.

Suspension Bridge: Suspension bridges have main cables that hang from tall towers and support the
bridge deck through vertical suspenders. The main cables bear most of the load. Main cables are
typically made of steel, while the deck may be constructed with various materials. Suspension
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

bridges are known for their ability to span extremely long distances and are commonly used for
iconic, long-span crossings.

3. Describe the following terminologies: (a) superstructure,(b) substructure,(c) piers,(d) abutments,(e)

Superstructure: The superstructure of a bridge refers to the upper portion of the bridge that carries the
load, including the road or rail deck and any other components that support it, such as beams,
girders, or trusses. It is the visible part of the bridge that people and vehicles use.

Substructure: The substructure of a bridge refers to the underlying support system that bears the load
of the superstructure and transfers it to the ground. This includes the foundation, piers, abutments,
and any other components that provide stability and strength to the bridge.

Piers: Piers are vertical support structures that are typically built within a body of water or across a
valley to provide support to the bridge's superstructure. Piers help distribute the weight of the bridge
and the loads it carries to the ground or the waterbed.

Abutments: Abutments are the supports at the ends of a bridge that resist the horizontal forces and
moments generated by the superstructure. They anchor the bridge to the ground, providing stability
and preventing the superstructure from moving or rotating.
Span Length: The span length is the distance between two adjacent supports, such as piers or
abutments. It measures the length of the bridge between its points of support and is a critical factor in
determining a bridge's overall design and capacity.

Total Length: The total length of a bridge is the overall length from one end of the superstructure to
the other, including the approach spans, the main span, and any additional components like transition
spans or ramps. It provides an assessment of the bridge's size and how much area it covers.

Bridge Width: The bridge width is the horizontal measurement of the bridge from one side to the
other. It indicates how wide the road or rail deck is and can affect the number of lanes or tracks the
bridge can accommodate, as well as the available space for pedestrians or other features.

Clearance: Clearance refers to the vertical space or distance between the lowest point of the bridge's
superstructure (such as the underside of a beam or girder) and the surface below, which might be the
ground, water, or a road. It is essential for ensuring that there is adequate space for vehicles, ships, or
other objects to pass safely under the bridge without colliding with it. Clearance is a critical
consideration in bridge design to prevent obstructions and accidents.

4. List more than three types of moveable bridges, and describe their characteristics.

Bascule Bridges are characterized by a counterweight system that allows the bridge deck to pivot
upward along a horizontal axis to create an opening for water traffic. They typically have a seesaw-
like appearance when in the open position. Bascule bridges are commonly used in locations with
moderate waterway traffic.
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

Swing Bridges have a central pivot point, allowing the bridge to swing horizontally to one side,
perpendicular to the traffic flow. These bridges are often used over narrow or shallow waterways and
require less vertical clearance compared to some other types of moveable bridges.

Drawbridges are hinged at one end and can be raised or drawn horizontally to provide clearance for
water vessels. They often have a vertical clearance limitation due to their design. Drawbridges are
common on both roadways and railways, especially in areas with lower water traffic.

Vertical lift bridges have one or more towers with counterweights and a lifting mechanism. The
bridge deck is raised vertically to create an opening for water vessels. Vertical lift bridges are known
for their efficient use of vertical clearance, making them suitable for locations with high-masted
ships.

Floating bridges consist of interconnected floating sections that can be detached or moved aside to
allow water traffic to pass. These bridges are often used in temporary or military settings and can be
quickly assembled or disassembled.
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

In a Nutshell
Reflective Journal Writing

I. What have I learned from this chapter?

I learned about the bridge superstructures can be classified based on materials of construction, span length,
interspan relation, deck location, geometric shape, span types, usage, and structural forms. For example,
bridges can be made of concrete, steel, or wood, have short, medium, or long spans, and be either simple
span, continuous span, or cantilever. They can have a deck on top (deck bridge), below (through bridge), or
in the middle (half-trough bridge) of the main structure. Their shape can be straight, skewed, or curved, and
they can consist of single spans or multiple spans supported by piers. Bridges can be designed for road,
railway, pedestrian, or pipeline use and can take structural forms such as truss, cantilever, suspension, or
arch. Also, I have learned about the different bridge types, such as girder bridges with horizontal girders
suitable for short to medium spans, or rigid-frame bridges featuring a continuous frame structure for short to
medium spans and heavy loads, exhibit specific structural characteristics.

I was able to know the truss bridges that it utilize triangular truss elements for strength and are adaptable for
various spans. Arch bridges, with their curved arch shape, are ideal for medium to long spans, while cable-
stayed bridges feature tower-supported decks with radiating cables, covering medium to long spans.
Suspension bridges, with main cables hanging from towers, are suitable for long-span crossings.
Moveable bridge types include bascule bridges, which pivot upward with counterweights and are suitable
for moderate waterway traffic. Swing bridges swing horizontally on a central pivot point and are used in
narrow or shallow waterways. Drawbridges raise or draw horizontally and often have vertical clearance
limitations, making them common on roads and railways. Vertical lift bridges employ a vertical lifting
mechanism with efficient vertical clearance use, ideal for high-masted ships. Floating bridges consist of
floating sections and are easily assembled or disassembled, often used in temporary or military settings.

II. Explain briefly the significant ideas that enlightened you as a future engineer?

As a future engineer, several significant ideas from the classification of bridge superstructures and the
characteristics of different bridge types have enlightened me. About the material selection, span length, deck
location, structural forms, moveable bridges and clearance. These ideas emphasize the need for engineers to
be versatile in their design and construction approaches, considering factors such as materials, structural
forms, and practical requirements. The classification and characteristics of bridges provide valuable insights
into the considerations that future engineers must address to create safe, efficient, and aesthetically pleasing
infrastructure.

III. How will these concepts influence my future work?

Understanding the characteristics and applications of different construction materials (concrete, steel, wood)
is crucial. Recognizing the different categories of span lengths and design requirements is essential for
tailoring your bridge designs to specific project needs. These concepts will influence our ability to create
aesthetically pleasing and functional bridge designs that align with the project's goals. Knowledge of various
structural forms, such as truss, cantilever, suspension, and arch, allows us to choose the most suitable design
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

for a given project, taking into account factors like span length, terrain, and environmental conditions. In
summary, these concepts will serve as the building blocks for my career as future engineer, enabling me to
make informed decisions, design structurally sound and aesthetically pleasing bridges, and ensure that the
work complies with safety and regulatory standards. They are fundamental to the successful design and
construction of bridges, which are essential elements of our infrastructure.

ULO 1b
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

Let’s Analyze

Describe the “earthquake ground motions” and “seismic performances requirement” used in the
standard specifications of highway bridges.

"Earthquake ground motions" and "seismic performance requirements" play a critical role in maintaining the
safety and integrity of these structures during seismic occurrences, according to the standard specifications
for highway bridges. In earthquake-prone areas, these requirements are often produced by pertinent
engineering authorities and agencies to serve as a reference for the design, building, and maintenance of
highway bridges. Earthquake ground motions refer to the complex patterns of ground shaking and
movement that occur during an earthquake. While, Seismic performance requirements specify the expected
performance levels of highway bridges during an earthquake.

In a Nutshell
JOYLYN CRIS L.AUXILLO
BCET 6 / 5016
ULO WEEK 1-3

Reflective Journal Writing

I. What have I learned from this chapter?

In this chapter, I learned that engineers carefully take into account loads in bridge constructions when
planning and building bridges. Dead loads and live loads are the two basic categories into which these loads
can be broadly divided. The weight of a bridge's permanent parts, such as the superstructure, foundation, and
any utilities, as well as the weight of the bridge itself exert significant static stresses on it. These forces are
known as "dead loads." These loads constitute a basis for the bridge's structural stability because they are
essentially constant over time. On the other hand, live loads are dynamic forces that bridges need to
withstand. They are caused by the cyclical weight of moving objects like cars and people, as well as by the
wind and seismic activity in the environment. Additionally, safety is another primary concern when it comes
to bridges. The loads a bridge will experience can vary widely based on its location, purpose, and anticipated
traffic. These loads include dead loads (the weight of the bridge itself), live loads (traffic, pedestrians, and
cargo), and environmental factors like wind, seismic activity, and temperature variations. By factoring in
these loads, engineers can determine the appropriate materials, dimensions, and construction methods to
ensure the bridge remains safe for use over its intended lifespan.

II. Explain briefly the significant ideas that enlightened you as a future engineer?

As a future engineer, several significant ideas from this chapter have enlightened me about the critical
considerations in bridge construction. For me, understanding the differentiation between dead loads and live
loads is crucial. This insight highlights the need to factor in both the intrinsic and extrinsic forces that
bridges must withstand. It emphasizes that engineering isn't just about the design but also about predicting
how structures will interact with their environment. The mention of safety as a primary concern underscores
the responsibility of engineers in ensuring that bridges are not just functional but also safe for the people
who use them. The awareness of potential hazards, such as wind and seismic activity, is crucial for the
longevity and safety of bridges. The loads that is being discussed in this chapter underscores the importance
of selecting appropriate materials, dimensions, and construction methods. As an engineer, this concept is
pivotal because it shows that the choices made in the planning stage have a direct impact on a structure's
safety and durability.

III. How will these concepts influence my future work?

This concepts will serve as a foundation for my career, ensuring that the structures I design are not only safe
but also well-suited to their intended purpose, capable of withstanding the challenges posed by
environmental factors and traffic loads over their operational life.