Evaluation of Shear Design Procedures for Reinforced Concrete Members under Axial Compression

The failure of the Sleipner offshore platform, which involved a total economic loss of nearly one billion dollars, has indicated that serious deficiencies exist in the current procedures for the design of reinforced concrete wall elements subjected to combined shear and axial compression. The current ACI Building Code requirements for shear design of members subject to axial compression and shear are based on only a few tests of reinforced concrete members subjected to high levels of axial compression. This paper compares the results of twenty-four reinforced concrete elements subjected to varying levels of axial compression with the current design requirements of the ACI 318-99 and the AASHTO-LRFD specifications. The results demonstrate that the detailed procedure recommended by ACI 318-99 for shear design of members subjected to high levels of axial compression can lead to unconservative designs. The simple method specified by the ACI code was able to predict the experimental results conservatively, and with more consistency than the detailed method. The AASHTOLRFD procedure was able to predict the strength, as well as the mode of failure, consistently.