A critical review of IS 13920:2016
  Ashok K. Jain
  IS 13920:1993 has been revised and 2016 edition has been released recently after nearly 25 years. It was under revision for nearly a decade. It is a very widely used Code and all buildings in seismic zones III, IV and V have to conform to this Code. This paper critically reviews this Code. It also provides background matter for confinement reinforcement in circular and rectangular RC columns based on ACI 318 Code that has been adopted in IS 13920 with some modifications. It was noted that (i) there are a few serious typographical errors; (ii) it requires nonlinear analysis to adopt flat slab construction as well as irregular buildings; and (iii) there are a few places where drafting needs improvement. It is strange that this code relies heavily on nonlinear static and dynamic analysis in certain cases. Even IS 1893-part 1-2016 does not specify how to carry out linear time history analysis in view of certain obvious difficulties. Therefore, to jump directly onto nonlinear static or dynamic analysis is scary. It can lead to unnecessary confusion and litigation. Further, this code ignores the shear capacity of concrete for designing shear reinforcement in beams based on ACI 318-2011. However, there were two important conditions in the ACI that have been dropped in IS 13920 without any justification making the latter even more conservative. The ACI 318-2014 clarifies that the shear resistance of concrete is significant and needs to be considered. This is missing in the Indian version. The rules for confinement in circular and rectangular columns are based on ACI-318. The rules for circular columns have been revised in accordance with the revisions in the ACI but not for rectangular columns. The current reinforcement requirements for rectangular columns in IS 13920 are nearly three times of those in the ACI-318. There are many such changes that have been made in the original specifications borrowed from other sources without any solid experimental or theoretical calculations. They are based purely on arbitrary reasons. Finally, it is concluded that the Code is becoming more conservative and rigid while leaving little scope for innovation.