1. What are the primary types of beams based on their support conditions?
a) Cantilever and continuous beams
b) Simply supported and overhanging beams
c) Fixed and propped beams
d) Rolled and built-up beams
Answer: b) Simply supported and overhanging beams
Explanation: Beams can be classified based on their support conditions, with simply supported beams having supports at both ends and overhanging beams extending beyond their supports on one or both ends.
2. What is the critical parameter for assessing the lateral stability of beams?
a) Moment of inertia
b) Radius of gyration
c) Section modulus
d) Shear force
Answer: b) Radius of gyration
Explanation: The radius of gyration is crucial for determining the lateral stability of beams. It represents the distribution of the cross-sectional area about the axis of bending, influencing the beam’s resistance to lateral torsional buckling.
3. Lateral torsional buckling typically occurs in which type of beams?
a) Short and slender beams
b) Wide and shallow beams
c) Symmetric and asymmetric beams
d) Thick and heavy beams
Answer: c) Symmetric and asymmetric beams
Explanation: Lateral torsional buckling is a buckling mode where a beam, subjected to bending, twists laterally due to a combination of bending and torsional effects. It’s particularly pertinent to symmetric and asymmetric beams.
4. What is the design strength consideration for laterally supported beams in bending?
a) Yield strength
b) Ultimate strength
c) Buckling strength
d) Fatigue strength
Answer: a) Yield strength
Explanation: For laterally supported beams, the design strength is typically based on the yield strength of the material. This ensures that the beam remains within its elastic range under design loads.
5. Shear strength of steel beams primarily depends on which factor?
a) Beam span
b) Beam depth
c) Beam width
d) Beam material
Answer: c) Beam width
Explanation: The shear strength of steel beams is largely influenced by the beam’s width. A wider beam generally offers greater resistance to shear forces due to the increased area available to transmit shear.
6. Web buckling and crippling primarily affect which part of a beam?
a) Top flange
b) Bottom flange
c) Web
d) End connections
Answer: c) Web
Explanation: Web buckling and crippling refer to failure modes primarily affecting the web of a beam, where it may buckle under compressive loads or become locally deformed due to excessive stress.
7. What is a common method for designing built-up beams?
a) Moment distribution method
b) Plastic analysis
c) Lateral torsional buckling analysis
d) Section classification method
Answer: d) Section classification method
Explanation: The section classification method is commonly used for designing built-up beams, where the individual sections are analyzed and classified based on their capacity to resist bending and shear.
8. Plate girders are primarily composed of which structural elements?
a) Solid plates
b) Angles and channels
c) Reinforced concrete
d) Hollow tubes
Answer: b) Angles and channels
Explanation: Plate girders are constructed using plates along with angles and channels, which are welded or bolted together to form the structural framework capable of withstanding bending and shear forces.
9. What purpose do stiffeners serve in beam design?
a) Increase beam span
b) Enhance lateral stability
c) Reduce beam depth
d) Minimize beam weight
Answer: b) Enhance lateral stability
Explanation: Stiffeners are structural elements added to beams to enhance their lateral stability, particularly against buckling and torsional effects. They help distribute loads more evenly and prevent local buckling.
10. Flange and web splices are typically used for what purpose in beam construction?
a) Reinforcement against shear
b) Enhancement of bending capacity
c) Connection of beam segments
d) Reduction of beam weight
Answer: c) Connection of beam segments
Explanation: Flange and web splices are employed in beam construction to connect separate segments of beams, ensuring continuity and integrity along the length of the beam, especially in long-span or built-up beam configurations.
11. In the design of beam-columns subjected to combined tension and bending, what parameter is crucial for assessment?
a) Cross-sectional area
b) Elastic modulus
c) Section slenderness ratio
d) Radius of gyration
Answer: c) Section slenderness ratio
Explanation: The section slenderness ratio is a critical parameter in the design of beam-columns subjected to combined tension and bending. It helps determine the stability of the column under combined loading conditions.
12. Which of the following is not a type of built-up beam configuration?
a) Box girder
b) T-beam
c) I-beam
d) Warren truss
Answer: c) I-beam
Explanation: While “I-beam” is a common term, it refers to a specific type of beam with a distinctive cross-sectional shape. The other options represent various built-up beam configurations commonly used in structural engineering.
13. What is the primary advantage of using a cantilever beam?
a) Simple to construct
b) Economical use of materials
c) Allows for larger spans
d) Provides support at both ends
Answer: c) Allows for larger spans
Explanation: Cantilever beams offer the advantage of allowing larger spans compared to other beam configurations, as they are anchored at only one end while extending freely over space.
14. Which material property is crucial for determining the design strength of timber beams?
a) Modulus of elasticity
b) Ultimate tensile strength
c) Compressive strength parallel to grain
d) Shear strength
Answer: c) Compressive strength parallel to grain
Explanation: The compressive strength parallel to grain is a crucial material property for determining the design strength of timber beams, as timber is often subjected to compressive forces along the grain direction in beam applications.
15. What is the primary concern in the design of composite beams?
a) Lateral stability
b) Shear strength
c) Compatibility of materials
d) Uniform distribution of loads
Answer: c) Compatibility of materials
Explanation: In composite beams, which consist of different materials such as concrete and steel, ensuring compatibility between these materials is a primary concern in design to optimize performance and durability.