THEORY EXAMINATION (SEM–VIII) 2016-17 EARTHQUAKE RESISTANT DESIGN

SECTION – A

Explain the following (Short Answer Type)

Seismic waves are energy waves produced during earthquakes. The main types include primary waves (P-waves), secondary waves (S-waves), and surface waves, which travel through the earth and cause ground shaking.

The epicenter is the point on the earth’s surface directly above the location where an earthquake originates inside the earth.

Dynamic degrees of freedom refer to the number of independent ways in which a structure can move during vibration, such as translation or rotation.

There are several approaches to develop governing equations of vibrating systems, including Newton’s law method, energy method, and Lagrange’s method.

In structural modeling, assumptions such as linear behavior, small deformations, and uniform material properties are made to simplify analysis.

The time history method analyzes structural response by studying how a structure reacts over time to earthquake forces.

A response spectrum shows the maximum response of a structure to earthquake vibrations at different frequencies.

Typical damage features in masonry buildings include wall cracks and collapse of unsupported walls during earthquakes.

Indian codes require web reinforcement in structures to improve shear strength and ductility during earthquakes.

Machine foundations are structures designed to support heavy machinery and absorb vibrations. Types include block foundations and framed foundations.

Questions (Section A)

What are seismic waves?

Define epicenter.

What is dynamic degree of freedom?

What is response spectrum?

List types of machine foundation.

SECTION – B

Attempt any five (Long Answer Type)

The theory of elastic rebound explains that earthquakes occur when stored energy in rocks is suddenly released after stress accumulation along faults.

Faults and dips are geological features where rock layers move, causing earthquakes due to sudden shifts in the earth’s crust.

An SDOF system is a single-degree-of-freedom structure used to study vibration behavior. Its response depends on mass, damping, and frequency of excitation.

The response of buildings during earthquakes depends on factors such as building height, structural stiffness, material properties, and soil conditions.

Holzer’s numerical technique is used to determine natural vibration periods of multi-degree-of-freedom systems.

Proper reinforcement in beam-column joints increases strength and helps structures resist earthquake forces.

Response spectrum analysis helps engineers design buildings that can withstand different earthquake intensities.

IS code recommendations include proper detailing of beams, reinforcement anchorage, and ductility measures.

Questions (Section B)

Explain the theory of elastic rebound.

What are faults and dips?

What factors affect building response during earthquakes?

What is response spectrum analysis?

Explain reinforcement detailing for earthquake resistance.

SECTION – C

Attempt any two (Detailed Explanation)

Earthquakes are caused by tectonic plate movements, volcanic activity, and sudden release of stress within the earth’s crust.

The equation of motion for a single-degree-of-freedom system describes how displacement changes over time under damping conditions.

Typical damages in reinforced concrete buildings include beam cracks, column failures, and foundation settlement during earthquakes.

Capacity design principles ensure that certain structural elements fail safely while protecting the main structure.

Natural frequencies and mode shapes describe how multi-story buildings vibrate during earthquakes.

Questions (Section C)

What are the causes of earthquakes?

Explain the equation of motion for damped systems.

What is capacity design principle?