Challenge 8
Challenge 8
- List factors of 4 loads for SLS G-I Combinations as per IRS.
SOLUTION - SLS FACTOR
LOADS SYMBOL G-1
- DEAD LOADS DL 1.0
- PRESTRESSING PR 1.0
- SUPERIMPOSED LOADS SIDL 1.2
- EARTHQUAKE EQ 0
- SHIRNKAGE AND CREEP SC 1.0
2.List factors of 3 loads for ULS G-I Combinations as per IRS.
SOLUTION - ULS FACTOR
LOADS SYMBOL GI
- DEAD LOADS DL 1.25
- SHRINKAGE AND CREEP SC 1
- PRESTRESSING PR 1.15/0.87
- SUPER IMPOSED LOADS SIDL 2
- LIVE LOAD LL 1.75
3.Explain in detail about the reinforcement provided in the RCC cantilever pier cap with drawings.
ANS-
Typically the main tension reinforcements should be provided at the top, to resist the maximum BM occurring at support. They may be curtailed at about half the distance from the support. In addition shear reinforcorcements should be provided at closer spacing near the support to resist shear forces and may be minimum shear reinforcements throughout the beam with hanger bars at the bottom longitudinally.
Very important thing is that the main tension reinforcements should be anchored properly at support or in the adjoining beams.
During construction, the cantilever should be supported and if it is a freehanging cantilever. The supports should not be removed until proper anchoring loads ate applied at support. The releasing of supports should start from the free end.
Main reinforcement is designed for the bending moments in the beams. Since concrete cannot handle tension coming from these bending moments, steel as rebar is provided to resist the tensile stresses.