What is the primary purpose of structural analysis in civil engineering?
A To design aesthetic structures
B To estimate the cost of construction
C To select construction materials
D To determine the internal forces and stresses in a structure
Structural analysis is the process of calculating the forces, stresses, and deformations in a structure to ensure it can withstand applied loads safely. It helps engineers understand how a structure will behave under various conditions, ensuring stability and safety.
Which of the following is an example of a point load?
A Uniformly distributed load
B A weight hanging from a rope
C Wind load
D Snow load
A point load is a concentrated force applied at a single point on a structure. A weight hanging from a rope applies a single force at the point of contact, making it a point load. Distributed loads, like wind or snow, are spread over an area.
What does a bending moment diagram represent?
A Distribution of shear forces along a beam
B Deflection of a beam
C Distribution of bending moments along a beam
D Load distribution on a beam
A bending moment diagram shows how the bending moment varies along the length of a beam. It helps engineers identify the points of maximum bending moment, which are critical for designing the beam’s cross-section.
In a simply supported beam, where is the maximum bending moment located under a point load at the center?
A At the center of the beam
B At the supports
C At the quarter points of the beam
D Uniform throughout the beam
In a simply supported beam with a point load at the center, the maximum bending moment occurs at the center because the load is farthest from the supports, creating the greatest moment.
What is the unit of bending moment?
A Newton (N)
B Pascal (Pa)
C Kilogram (kg)
D Newton-meter (Nm)
Bending moment is a measure of the rotational force applied to a structure and is calculated as force multiplied by distance. Hence, its unit is Newton-meter (Nm).
Which of the following is true for a fixed support in a structure?
A It allows rotation and translation
B It allows rotation but prevents translation
C It prevents rotation and translation
D It prevents rotation but allows translation
A fixed support restricts both rotational and translational movement, providing maximum resistance to forces and moments. It is commonly used in beams and frames to ensure stability.
What is the shape of the shear force diagram for a uniformly distributed load on a simply supported beam?
A Parabolic
B Linear
C Rectangular
D Circular
For a uniformly distributed load on a simply supported beam, the shear force diagram is linear. The shear force decreases linearly from one support to the other due to the uniform load distribution.
What is the primary assumption in the elastic theory of structures?
A Materials return to their original shape after load removal
B Materials behave plastically
C Materials undergo permanent deformation
D Materials are rigid
Elastic theory assumes that materials deform under load but return to their original shape once the load is removed. This is based on Hooke’s Law, which states that stress is proportional to strain within the elastic limit.
Which method is used to analyze indeterminate structures?
A Virtual work principle
B Moment distribution method
C Method of joints
D Method of sections
The moment distribution method is a structural analysis technique used to determine the moments in indeterminate structures. It is particularly useful for continuous beams and frames.
What is the primary purpose of influence lines in structural analysis?
A To determine the deflection of a structure
B To calculate the stiffness of a structure
C To analyze the effect of moving loads on a structure
D To design foundations
Influence lines are graphical representations of how a specific force (like shear or moment) at a point in a structure varies as a moving load travels across the structure. They are essential for designing bridges and other structures subjected to moving loads.
Which of the following is a characteristic of a statically determinate structure?
A It can be analyzed using equilibrium equations alone
B It cannot be analyzed using equilibrium equations
C It has more unknowns than equilibrium equations
D It requires advanced methods like the stiffness matrix method
A statically determinate structure has exactly enough equilibrium equations to solve for all unknown forces and moments. No additional compatibility conditions are required.
What is the primary purpose of the stiffness matrix method?
A To calculate deflections in determinate structures
B To determine the load distribution in trusses
C To calculate the buckling load of columns
D To analyze indeterminate structures using matrix algebra
The stiffness matrix method is a powerful tool for analyzing indeterminate structures. It uses matrix algebra to solve for displacements and forces in complex structures.
What is the unit of strain energy in a structure?
A Joule (J)
B Newton (N)
C Pascal (Pa)
D Meter (m)
Strain energy is the energy stored in a structure due to deformation. It is measured in Joules (J), the same unit as work and energy.
Which of the following is true for a pin support?
A It prevents rotation and translation
B It prevents rotation but allows translation
C It allows rotation but prevents translation
D It allows rotation and translation
A pin support allows rotation but prevents translation in any direction. It is commonly used in trusses and bridges to allow for thermal expansion and contraction.
What is the primary cause of buckling in columns?
A Compressive forces
B Tensile forces
C Shear forces
D Torsional forces
Buckling occurs in columns due to compressive forces that exceed the column’s critical load. It leads to sudden lateral deflection and failure, even if the material’s compressive strength is not exceeded.