08-12-2012, 05:02 PM
ANALYTICAL INVESTIGATION TO VALIDATE CODAL PROVISION IS 13920 : 1993
ANALYTICAL INVESTIGATION.ppt (Size: 984.5 KB / Downloads: 88)
INTRODUCTION
Beam,column and joints are the integral part of a structure to resist external forces
Beam column joint is an important component of a reinforced concrete moment resisting frame and should be designed and detailed properly, especially when the frame is subjected to earthquake loading.
Failure of beam column joints during earthquake is governed by bond and shear failure mechanism which are brittle in nature.
Design of confinement reinforcement for RC columns
This paper was done by N. Subramanian in Indian concrete journal,2010
Transverse reinforcements in columns in the form of hoops,cross-ties, or spirals play an important role in safeguarding the columns, especially when they are subjected to strong earthquakes or accidental lateral loads.
The current equations for confinement reinforcement in IS 13920 code do not provide consistent level of safety against deformation and damage associated with flexural yielding during earthquakes.
Hence an equation for the design of confinement reinforcement for ductile earthquake resistant rectangular and circular columns is suggested for inclusion in the next revision of the code.
Parameters that affect the performance of confining reinforcement, such as effective confining pressure or ratio of concrete strength to tie strength, axial load level, unconfined cover concrete thickness, longitudinal reinforcement and spacing, and curvature ductility factor.
CONCLUSION
Properly designed and detailed confining transverse reinforcements prevent buckling of longitudinal bars, avoid shear failure and provide sufficient ductility.
The formula provided in IS 13920:1993 code has to be revised as it does not consider all the parameters that affect the behaviour.
Hence an equation has been proposed, which considers all the parameters and found to correlate with the existing experimental results as well as provides sufficient deformation ductility