A strength superposition method for steel reinforced concrete (SRC) beam-column design

This study presents a new design approach called “Direct Strength Superposition Method (DSSM)” for possible application in the ultimate strength design of SRC beam-columns. The concept of strength superposition is based upon the fact that a SRC member is actually a combination of steel shape and reinforced concrete. In the proposed DSSM, some basic rules of strength superposition are established. With these rules, the strength of a SRC beam-column can be obtained by direct superposition of the strengths of the steel part and the RC part that are calculated according to the current AISC-LRFD specification (1993) and ACI code (1989) , respectively. In this study, the influence of the bond between steel shape and concrete is neglected. To account for the possible error caused by this simplification, a modification is made by reducing the specified compressive strength of the concrete. Finally, a comparison is made among the SRC beamcolumn test results obtained by other researchers and the predictions found by the proposed DSSM, the AISC- LRFD specification (1993) and ACI code (1989). The comparison shows that the proposed DSSM gives satisfactory predictions of the SRC beam-column strengths.