Day 12 civil war PWD-Arches&Cables,fixed beams,plastic analysis

Front

In a three hinged arch, the shear force is usually

Back

maximum at springing

Answer explanation

In a three hinged arch, the shear force is generally maximum at the springing because of higher reaction concentration at supports.

Front

Effect of temperature rise on horizontal reaction of the cable.

Back

Decreases

Answer explanation

When the temperature rises, the cable expands in length. For a suspension or cable-supported system:

• The sag increases due to expansion.

• With a larger sag, the horizontal reaction (thrust at supports) actually decreases

Front

The highest point of the arch is known as

Back

Crown

Answer explanation

The crown is the topmost point of an arch, while rise is the vertical distance between crown and springing line, span is the horizontal distance, and abutment is the end support.

Front

Minimum tension in a light cable of span 'l' and dip 'h' subjected to a U.D.L of 'w' per metre run on the horizontal span is at:

Back

Middle point of cable

Answer explanation

For a uniformly distributed load on a cable, the horizontal component of tension is minimum at the lowest point, i.e., the middle of the cable.

Front

Horizontal thrust for a two hinged semicircular arch of radius R with UDL 'w' over entire span

Back

2wR/3π

Answer explanation

For a two-hinged semicircular arch under uniform load, the horizontal thrust H = 4wR / 3π.

Front

Which among the following is statically determinate: 2-Hinged arch, Hingeless arch, 3-Hinged arch, None of these

Back

3-Hinged arch

Answer explanation

A 3-hinged arch is statically determinate since equilibrium equations alone are sufficient to solve it, unlike 2-hinged or hingeless arches.

Front

The shape factor of an I section is

Back

1.14

Answer explanation

The shape factor of an I-section is approximately 1.14, which is the ratio of plastic moment capacity to yield moment.

Front

Moment of resistance for a plastic hinge is

Back

Plastic moment capacity

Answer explanation

At a plastic hinge, the section rotates freely while sustaining constant maximum moment equal to its plastic moment capacity.

Front

A fixed beam of uniform section is carrying a point load at its midspan. If the moment of inertia of the middle half length is now reduced to half its previous value, what happens to the fixed end moments?

Back

Increase

Answer explanation

Reducing stiffness (I) in the midspan increases flexibility, resulting in larger end moments at the fixed supports. Thus, fixed end moments increase.

Front

When there is no load on the beam, what are the fixed end moments?

Back

Zero

Answer explanation

With no external load applied, the beam has no bending moment. Hence, fixed end moments are zero.