D45 CHECK YOUR LEVEL

Assertion (A): Still basin is provided after spillway. Reason (R): It prevents scouring downstream.

• Both A and R are true and R is correct explanation
• Both A and R are true but R is not the correct explanation
• A is true but R is false
• A is false but R is true

Answer explanation

Stilling basin reduces energy and prevents erosion—hence, R explains A.

Statement 1: Quick lime is obtained by burning pure limestone. Statement 2: Slaked lime is calcium carbonate.

• Only Statement 1 is correct
• Only Statement 2 is correct
• Both are correct
• Both are incorrect

Answer explanation

Quick lime is CaO; slaked lime is Ca(OH)₂, not CaCO₃. Only S1 is correct.

Which of the following contributes to the reduction of creep in concrete?

• Increase in W/C ratio
• Use of plasticizers
• Higher cement content
• Use of larger aggregate

Answer explanation

Larger aggregates reduce creep by restraining deformation.

A parabolic arch carries a uniformly distributed load. The bending moment at any point in the arch is:

• Zero
• Maximum at crown
• Maximum at springing
• Uniform

Answer explanation

Parabolic arch under UDL has no BM, only axial thrust.

The reduced level of a station is calculated as:

• RL of BM – back sight
• RL of BM + back sight
• RL of previous station – foresight
• RL of previous station + foresight

Answer explanation

RL = BM + BS (in HI method).

In AutoCAD, the 'DIMLINEAR' command is used to:

• Draw arc dimensions
• Place aligned dimensions
• Create linear dimensions
• Draw ordinate dimensions

Answer explanation

DIMLINEAR adds linear horizontal/vertical dimensions.

Which IS code is used for general construction steel design?

• IS 456
• IS 800
• IS 875
• IS 1893

Answer explanation

IS 800 governs general steel design.

A culvert is classified as per IRC if its span is:

• < 6 m
• 6–12 m
• 12–18 m
• > 18 m

Answer explanation

Span < 6 m = culvert, as per IRC classifications.

Critical section for shear in footings is located at a distance of:

• At face of column
• d from face
• d/2 from face
• 2d from face

Answer explanation

IS 456: One 'd' from face of column.

The function of curtain wall in a dam is to:

• Resist uplift
• Prevent seepage under dam
• Protect against waves
• Act as retaining wall

Answer explanation

Curtain walls are used as seepage cut-offs.