Consider the following statements regarding the "Structural Layout" for an RC building 1. Columns should preferably be located at or near the corners of a building and at the intersection of walls. 2. Beams are generally provided under the walls to transfer the partition loads directly to the columns. 3. To ensure lateral stability, the center of mass and center of rigidity of the building should be kept as far apart as possible. Which of the statements given above are correct?
- A1 and 2 onlyCorrect
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3
Solution
Concept
RC Building Structural Layout and Torsion Control
Formula
N/A
Step-by-step solution
1. Evaluate statement 1 and statement 2, noting that placing columns at corners and beams under walls ensures proper load transfer. 2. Evaluate statement 3, noting that the center of mass and center of rigidity should be kept as close as possible to prevent torsion. 3. Conclude that statements 1 and 2 are correct and select Option (a).
Explanation
Placing columns at corners/intersections and putting beams under walls ensures proper load transfer throughout the building. However, keeping the center of mass and center of rigidity far apart causes severe twisting (torsion) during earthquakes, so they should actually be as close together as possible. Therefore, only statements 1 and 2 are correct.
Shortcut
To remember RC Building Structural Layout rules, keep these key points in mind: - Columns & Beams: Place columns at corners/intersections and beams directly under walls for efficient load transfer. - Mass & Rigidity (CM & CR): Keep Center of Mass and Center of Rigidity as CLOSE as possible to minimize eccentricity and prevent severe torsional twisting during earthquakes.
Common mistake
A common mistake is selecting option D (or B/C) by incorrectly assuming that the center of mass and center of rigidity should be kept far apart for stability. In reality, increasing the distance between them creates a large eccentricity, leading to severe torsional effects (twisting) during lateral loads like earthquakes, so they should be located as close to each other as possible.
Correct answer: A) 1 and 2 only