Earthquake Engineering

Step 1: Recall MMI scale progression.
- Very weak tremor felt only by a few → lowest order.
- Felt indoors but little/no damage → next.
- Felt by many with minor damage (plaster, objects fall) → moderate intensity.
- Severe shaking with structural damage → higher intensity.

Step 2: Arrange given events.
- C → least intensity (felt only by a few).
- A → moderate, noticeable indoors but no damage.
- D → stronger, felt by nearly everyone, minor damage.
- B → highest among given, severe shaking and structural damage.

Step 3: Conclusion.
Correct sequence: C, A, D, B.

Step 1: Understanding earthquake-resistant design.
In earthquake-resistant design, structures are expected to behave in a ductile manner. The failure mechanism should ensure life safety, meaning beams should form plastic hinges rather than columns, so that collapse can be avoided.

Step 2: Strong Column – Weak Beam Concept.
If columns are stronger and beams are weaker, the plastic hinges form in the beams, which can redistribute loads and dissipate energy without sudden failure.

Step 3: Why not other options?
- (A) Weak column – Strong beam: This causes column failure, leading to sudden collapse (undesirable).
- (C) Strong column – Strong beam: Impractical in design, uneconomical.
- (D) Weak column – Weak beam: Dangerous and unsafe.

Step 4: Conclusion.
The correct design philosophy is Strong column – Weak beam.

Step 1: Recall purpose of SHAKE.
SHAKE is a widely used computer program in geotechnical earthquake engineering that performs **1-D ground response analysis** using wave propagation methods.

Step 2: Analysis of options.
- (A) ETAB: Used for structural modeling and design, not specifically 1-D wave propagation.
- (B) SHAKE: Developed for 1-D site response analysis using wave propagation — correct.
- (C) STAAD: General-purpose structural analysis program.
- (D) PLAXIS: A finite element software for soil and rock mechanics, not limited to 1-D wave propagation.

Step 3: Conclusion.
Therefore, the correct answer is (B) SHAKE.

Step 1: Understanding ground motion.
Ground motion depends on properties of seismic waves, site geology, and distance from the source (epicenter).

Step 2: Check each factor.
- Wave types: Different seismic waves (P, S, surface) cause different levels of ground shaking.
- Site conditions: Local soil and rock conditions greatly amplify or reduce shaking.
- Distance from epicenter: Closer sites experience stronger motion.
- Type of structure: This affects how a structure responds to motion, but does not affect the ground motion itself.

Step 3: Conclusion.
The type of structure does not influence the ground motion itself.