What is the estimated weight of a single track wooden truss bridge with a span of 120 feet, including floor timbers and bracing?
- 1/3 ton per foot run
- 1.33 tons per foot run
- 10 tons per panel
- 240 tons
Correct Answer: 1/3 ton per foot run
Correct Answer Explanation: This is a key finding from the treatise on bridge building. The weight of a bridge is crucial for determining the strain on its components, particularly with longer spans.
What is the estimated maximum load that a single track wooden truss bridge with a span of 120 feet can withstand, assuming it’s solely loaded with locomotives?
- 1/3 ton per foot run
- 1.33 tons per foot run
- 10 tons per panel
- 240 tons
Correct Answer: 1.33 tons per foot run
Correct Answer Explanation: The maximum load that a bridge can handle is essential for its safety and stability. This information was used in the treatise to determine the necessary strength of the bridge’s components.
What is the estimated load per panel of a single truss bridge with a span of 120 feet and 12 panels, considering both the weight of the bridge and the maximum load?
- 1/3 ton per foot run
- 1.33 tons per foot run
- 10 tons per panel
- 240 tons
Correct Answer: 10 tons per panel
Correct Answer Explanation: The treatise discusses the importance of understanding the load distribution across panels of a truss, which is a crucial element in designing a strong and stable bridge structure.
What is the estimated total weight of a bridge and its load for a 120-foot span, assuming a load of 1.33 tons per foot run?
- 1/3 ton per foot run
- 1.33 tons per foot run
- 10 tons per panel
- 240 tons
Correct Answer: 240 tons
Correct Answer Explanation: This is calculated by multiplying the load per foot run by the span length. It demonstrates the importance of accurately calculating the total load that a bridge must support.
What is the estimated tension on one lower chord of a 120-foot bridge, assuming a total weight of 240 tons?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 160 square inches
Correct Answer: 268800 lbs
Correct Answer Explanation: The treatise discusses the calculation of tension on bridge components, a crucial factor in designing a safe and stable structure. This information is needed to determine the necessary strength of the bridge’s lower chord.
What is the minimum area required for one lower chord to safely withstand a tension of 268800 lbs, assuming a working strength of 2000 lbs per square inch for wood?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 160 square inches
Correct Answer: 134.4 square inches
Correct Answer Explanation: The treatise delves into the calculation of required area for bridge components based on their working strength. This calculation helps ensure that the bridge’s lower chord is strong enough to handle the tensile forces.
What is the actual area of a lower chord composed of three 8″ x 12″ timbers?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 160 square inches
Correct Answer: 288 square inches
Correct Answer Explanation: This is a demonstration of the practical application of the calculations discussed in the treatise. By calculating the actual area of a bridge component, engineers can ensure that it meets the required strength for its intended purpose.
What is the effective area of the lower chord after accounting for allowances for splicing, foot blocks, bolts, and washers?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 160 square inches
Correct Answer: 160 square inches
Correct Answer Explanation: The treatise highlights the importance of considering practical aspects of bridge construction, such as allowances for connections and fittings, which can affect the effective area of bridge components.
What is the minimum area required for one upper chord to safely withstand a compression of 268800 lbs, assuming a working strength of 1000 lbs per square inch for wood?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 268.8 square inches
Correct Answer: 268.8 square inches
Correct Answer Explanation: The treatise explains how to calculate the required area for bridge components based on their compressive strength. This information is vital for ensuring that the upper chord of the bridge can withstand the compressive forces.
What is the area required for a single tie rod to safely withstand a strain of 67200 lbs, assuming a working strength of 15,000 lbs per square inch for wrought iron?
- 268800 lbs
- 134.4 square inches
- 288 square inches
- 4.48 square inches
Correct Answer: 4.48 square inches
Correct Answer Explanation: The treatise discusses the use of iron in bridge construction, particularly for tie rods, and provides methods for calculating the required area based on the material’s working strength.
What is the estimated maximum load per lineal foot of a bridge for moving loads, which is used to calculate the strains on counter braces?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 45000 lbs
Correct Answer: 2000 lbs per lineal foot
Correct Answer Explanation: The treatise addresses the importance of considering moving loads when designing bridges. This load is used to calculate the strains on critical components like counter braces, ensuring that the bridge can handle dynamic forces.
What is the load supported by a 150-foot arch-brace truss model?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 45000 lbs
Correct Answer: 2,500 lbs at the centre
Correct Answer Explanation: This is an example from the treatise on arch-brace trusses, highlighting the load distribution and the ability of this design to support significant weight.
What is the movable load used to test the 150-foot arch-brace truss model?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 45000 lbs
Correct Answer: 150 lbs
Correct Answer Explanation: This demonstrates how dynamic testing was used in the 19th century to evaluate the stability of bridge designs under real-world conditions.
What is the weight supported by each set of braces in the 150-foot arch-brace truss model, calculated based on a load of 3000 lbs per foot run?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 45000 lbs
Correct Answer: 45000 lbs
Correct Answer Explanation: This shows how the treatise provides detailed calculations for specific bridge designs, demonstrating the importance of understanding load distribution and brace strength.
What is the weight supported by each stick of the brace in the 150-foot arch-brace truss model, assuming 4 sticks per brace?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 5625 lbs
Correct Answer: 5625 lbs
Correct Answer Explanation: The treatise provides practical examples of how to calculate the load supported by individual components within a truss, demonstrating the importance of understanding the internal forces at play within the bridge structure.
What is the compressional strain on the first brace of the 150-foot arch-brace truss model, accounting for its inclination?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 7031 lbs
Correct Answer: 7031 lbs
Correct Answer Explanation: The treatise explains the importance of considering the inclination of bridge components, as it affects the strain they experience under load.
What is the compressional strain on the last brace of the 150-foot arch-brace truss model, accounting for its inclination?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 21937 lbs
Correct Answer: 21937 lbs
Correct Answer Explanation: This demonstrates the treatise’s focus on understanding how strain varies across different components of a truss, due to factors like inclination and load distribution.
What is the maximum load that a highway bridge can safely withstand, based on the area of the bridge deck?
- 2000 lbs per lineal foot
- 2,500 lbs at the centre
- 150 lbs
- 120 lbs per square foot
Correct Answer: 120 lbs per square foot
Correct Answer Explanation: The treatise provides guidance on determining the maximum load that a bridge can safely handle, based on the area of the bridge deck, ensuring safety for both the bridge and the people using it.
What is the estimated weight of a single track wooden truss bridge with a span of 25 feet?
- 0.266 tons per foot run
- 0.792 tons per foot run
- 1/3 ton per foot run
- 1.33 tons per foot run
Correct Answer: 0.266 tons per foot run
Correct Answer Explanation: The treatise highlights how the weight of a bridge varies with its span length. This information is crucial for calculating the necessary strength of bridge components for different spans.
What is the estimated weight of a single track wooden truss bridge with a span of 200 feet?
- 0.266 tons per foot run
- 0.792 tons per foot run
- 1/3 ton per foot run
- 1.33 tons per foot run
Correct Answer: 0.792 tons per foot run
Correct Answer Explanation: The treatise provides data on the weight of bridges with varying spans, showcasing how the weight of a bridge is a significant factor in determining its stability and strength.
What is the simplest type of bridge, suitable for spans of 20 feet or less?
- Single beam
- Inclined beam
- Howe truss
- Pratt truss
Correct Answer: Single beam
Correct Answer Explanation: This type of bridge is the most basic, using a single beam to support the load. It’s suitable for short spans but becomes impractical for larger structures.
What is the name of a bridge design with two inclined braces supporting a single beam?
- Single beam
- Inclined beam
- Howe truss
- Pratt truss
Correct Answer: Inclined beam
Correct Answer Explanation: This design, described in the treatise, is suitable for slightly larger spans than a single beam bridge.
What is the name of a bridge with diagonal braces for compression and vertical rods for tension, widely used for spans under 150 feet?
- Single beam
- Inclined beam
- Howe truss
- Pratt truss
Correct Answer: Howe truss
Correct Answer Explanation: The Howe truss is a common and reliable design for bridges, offering a good balance of strength and cost-effectiveness.
What is the name of a bridge with diagonal rods for tension and vertical posts for compression, allowing for adjustments and offering a more compact structure?
- Single beam
- Inclined beam
- Howe truss
- Pratt truss
Correct Answer: Pratt truss
Correct Answer Explanation: The Pratt truss is another popular design, offering advantages in terms of adjustability and space efficiency.
What is the name of a bridge with braces extending directly from the abutments to the head of each vertical, eliminating the need for multiple web members?
- Single beam
- Inclined beam
- Howe truss
- Arch-brace truss
Correct Answer: Arch-brace truss
Correct Answer Explanation: This design, discussed in the treatise, utilizes the direct transfer of load from the deck to the abutments, offering potential advantages in stability and efficiency.
What is the name of a bridge supported by piles driven into the ground, ideal for marshy or shallow areas?
- Single beam
- Inclined beam
- Howe truss
- Pile bridge
Correct Answer: Pile bridge
Correct Answer Explanation: Pile bridges are cost-effective and efficient for crossing unstable terrain, as they transfer the load to the ground through piles.
What is the name of a structure of posts, caps, and braces used for temporary or permanent support?
- Single beam
- Inclined beam
- Howe truss
- Trestle work
Correct Answer: Trestle work
Correct Answer Explanation: Trestle work is used for various purposes in bridge construction, offering flexibility for temporary support, permanent support, or even creating a walkway.
What is the name of the bridge on the Vermont Central R.R. that is a Howe truss?
- South Royalton Bridge
- White River Bridge
- Cheshire Bridge
- Passumpsic Bridge
Correct Answer: South Royalton Bridge
Correct Answer Explanation: This bridge is an example from the treatise, showcasing the practical application of the Howe truss design in the 19th century.
What is the name of the bridge on the Passumpsic R.R. that is a Howe truss bridge strengthened by an arch?
- South Royalton Bridge
- White River Bridge
- Cheshire Bridge
- Passumpsic Bridge
Correct Answer: White River Bridge
Correct Answer Explanation: This example from the treatise highlights the use of arches as a reinforcement method for bridges, increasing their structural stability.
What is the name of the Howe truss bridge with a span of 175 feet?
- South Royalton Bridge
- White River Bridge
- Cheshire Bridge
- Passumpsic Bridge
Correct Answer: Cheshire Bridge
Correct Answer Explanation: This bridge serves as an example of the adaptability of the Howe truss design for larger spans, showing its versatility and popularity in the 19th century.
What is the force that pulls or stretches a material?
- Compression
- Tension
- Detrusion
- Neutral axis
Correct Answer: Tension
Correct Answer Explanation: This is a fundamental concept in bridge design, as it’s one of the main forces that bridge components must be able to withstand.
What is the force that pushes or squeezes a material?
- Compression
- Tension
- Detrusion
- Neutral axis
Correct Answer: Compression
Correct Answer Explanation: Compression is another critical force that bridge components experience, particularly in the upper chords and braces.
What is the force that shears or crushes a material against a fixed point?
- Compression
- Tension
- Detrusion
- Neutral axis
Correct Answer: Detrusion
Correct Answer Explanation: This force is also important to consider in bridge design, as it can affect the strength of connections and joints.
What is the point within a beam where there is neither tension nor compression?
- Compression
- Tension
- Detrusion
- Neutral axis
Correct Answer: Neutral axis
Correct Answer Explanation: This axis is crucial for understanding how beams bend under load and how the material distribution affects their strength.
What is the ratio of the ultimate strength of a material to its working strength?
- Compression
- Tension
- Detrusion
- Factor of safety
Correct Answer: Factor of safety
Correct Answer Explanation: The factor of safety is a vital concept in bridge design, as it ensures that the bridge has enough strength to withstand unexpected loads or stresses.
What is the resistance offered by the fibers of a material to sliding past each other?
- Compression
- Tension
- Detrusion
- Lateral Adhesion
Correct Answer: Lateral Adhesion
Correct Answer Explanation: This force is critical for maintaining the integrity of joints and connections between bridge components, preventing them from slipping or separating under load.
What is the slight upward curvature of a bridge’s chords, designed to prevent sag?
- Compression
- Tension
- Detrusion
- Camber
Correct Answer: Camber
Correct Answer Explanation: Camber is a common design element in bridges, helping them maintain their intended shape and preventing excessive deflection under load.
What is a structural frame made of interconnected members that support loads through a combination of tension and compression?
- Compression
- Tension
- Detrusion
- Truss
Correct Answer: Truss
Correct Answer Explanation: This type of structure is fundamental to bridge design, offering efficiency and stability through the combination of tension and compression in its members.
What is a section of a truss between two adjacent vertical members?
- Compression
- Tension
- Detrusion
- Panel
Correct Answer: Panel
Correct Answer Explanation: Panels are important units within a truss, as they allow for the distribution of load and the effective transfer of forces through the structure.
What is a system of diagonal members used to stiffen bridges and reduce vibrations?
- Compression
- Tension
- Detrusion
- Diagonal bracing
Correct Answer: Diagonal bracing
Correct Answer Explanation: Diagonal bracing is crucial for the stability and stiffness of bridges, particularly under dynamic loads like moving trains or vehicles.
What type of strain primarily affects a bridge’s lower chord?
- Compression
- Tension
- Detrusion
- Shear
Correct Answer: Tension
Correct Answer Explanation: The lower chord of a bridge is primarily subjected to tension due to the downward forces from the load, which pull on the chord.
What type of strain primarily affects a bridge’s upper chord?
- Compression
- Tension
- Detrusion
- Shear
Correct Answer: Compression
Correct Answer Explanation: The upper chord of a bridge experiences compression as it pushes against the load and tries to maintain the shape of the bridge structure.
What is the term for the vertical members in a bridge truss?
- Posts
- Braces
- Chords
- Web members
Correct Answer: Posts
Correct Answer Explanation: These members are crucial for transferring the load from the deck of the bridge down to the abutments or foundation.
What is the term for the diagonal members in a bridge truss?
- Posts
- Braces
- Chords
- Web members
Correct Answer: Braces
Correct Answer Explanation: Braces are essential for providing stability and stiffness to a bridge truss, resisting forces from both tension and compression.
What is the term for the horizontal members in a bridge truss?
- Posts
- Braces
- Chords
- Web members
Correct Answer: Chords
Correct Answer Explanation: The upper and lower chords of a truss form the main structural elements that carry the load and shape the overall geometry of the bridge.
What is the term for the members that connect the upper and lower chords of a truss?
- Posts
- Braces
- Chords
- Web members
Correct Answer: Web members
Correct Answer Explanation: Web members, including braces and posts, provide the internal structure of a truss, helping it to transfer load effectively and maintain stability.
What is the name of the bridge component that is designed to prevent buckling under compressive forces?
- Counter brace
- Web member
- Chord
- Post
Correct Answer: Counter brace
Correct Answer Explanation: Counter braces are specifically designed to resist buckling under compressive forces, ensuring stability and preventing failure of the bridge structure.
What is the primary function of counter braces in a bridge truss?
- Transferring load
- Reducing vibrations
- Preventing buckling
- Providing stability
Correct Answer: Preventing buckling
Correct Answer Explanation: Counter braces are crucial for preventing buckling in the truss, especially under compressional loads, which could lead to instability and collapse.
What is the term for the force that a bridge experiences from its own weight?
- Dead load
- Live load
- Impact load
- Shear force
Correct Answer: Dead load
Correct Answer Explanation: The dead load of a bridge is a crucial factor in design, as it contributes to the overall load that the bridge must support.
What is the term for the force that a bridge experiences from the weight of vehicles or other moving objects?
- Dead load
- Live load
- Impact load
- Shear force
Correct Answer: Live load
Correct Answer Explanation: Live loads are dynamic forces that vary with the weight and movement of vehicles or other objects using the bridge, making it essential to consider them in bridge design.
What is the term for the additional force that a bridge experiences due to the impact of moving loads?
- Dead load
- Live load
- Impact load
- Shear force
Correct Answer: Impact load
Correct Answer Explanation: Impact loads occur due to the dynamic forces created by moving objects on the bridge, which can cause additional stresses on the structure.
What is the term for the force that causes a bridge to slide or shift horizontally?
- Dead load
- Live load
- Impact load
- Shear force
Correct Answer: Shear force
Correct Answer Explanation: Shear forces act parallel to the surface of a material, causing it to slide or shift. They are a critical consideration in bridge design, as they can impact the stability and strength of the structure.
What is the term for the process of adjusting the tension in the tie rods of a bridge truss?
- Cambering
- Splicing
- Tensioning
- Bracing
Correct Answer: Tensioning
Correct Answer Explanation: Tensioning is a crucial process in bridge construction, ensuring that the tie rods in the truss are properly tightened to maintain their tension and support the bridge effectively.
What is the term for the process of joining two pieces of timber together to create a longer member?
- Cambering
- Splicing
- Tensioning
- Bracing
Correct Answer: Splicing
Correct Answer Explanation: Splicing is a common technique in bridge construction, allowing engineers to create longer members by joining shorter pieces of timber together, often with bolts or other fasteners.
What is the term for the process of creating a slight upward curvature in the chords of a bridge?
- Cambering
- Splicing
- Tensioning
- Bracing
Correct Answer: Cambering
Correct Answer Explanation: Cambering is a technique used to ensure that the bridge deck has a slight upward curve, preventing sag and maintaining the intended shape of the bridge.
What is the term for the process of adding additional diagonal members to a bridge truss to increase its stiffness?
- Cambering
- Splicing
- Tensioning
- Bracing
Correct Answer: Bracing
Correct Answer Explanation: Bracing is essential for adding stiffness and stability to a bridge truss, particularly under dynamic loads or strong winds.
What is the term for the vertical supports that transfer the load from the bridge deck to the foundation?
- Abutments
- Piers
- Foundations
- Falsework
Correct Answer: Piers
Correct Answer Explanation: Piers are vertical supports that transfer the load from the bridge deck to the foundations, often used in multi-span bridges where there are intermediate supports.
What is the term for the structures at the ends of a bridge that anchor the bridge to the ground?
- Abutments
- Piers
- Foundations
- Falsework
Correct Answer: Abutments
Correct Answer Explanation: Abutments are crucial for anchoring the bridge to the ground, providing stability and preventing the bridge from moving horizontally.
What is the term for the structures that support the bridge deck during construction?
- Abutments
- Piers
- Foundations
- Falsework
Correct Answer: Falsework
Correct Answer Explanation: Falsework provides temporary support for the bridge deck during construction, allowing workers to safely build the bridge before it is fully supported by its permanent structures.
What is the term for the process of driving piles into the ground to provide support for a bridge?
- Piling
- Splicing
- Cambering
- Tensioning
Correct Answer: Piling
Correct Answer Explanation: Piling is a common technique for constructing bridges, especially in marshy or unstable terrain, where piles driven into the ground provide solid support for the bridge structure.
What is the term for the material that is used to fill the space between the bridge deck and the top of the truss?
- Deck
- Planking
- Flooring
- Paving
Correct Answer: Planking
Correct Answer Explanation: Planking is the material used to create the walking surface or the roadway of the bridge, providing a solid base for vehicles or pedestrians to traverse the structure.
What is the term for the process of applying a protective coating to the wood members of a bridge to increase its lifespan?
- Waterproofing
- Preserving
- Staining
- Painting
Correct Answer: Preserving
Correct Answer Explanation: Preserving wood is a crucial step in bridge construction, using special treatments to protect the wood from decay, insects, and weather damage, extending the lifespan of the bridge structure.