Effect of high-strength concrete columns on the behavior of slab-column connections

Current code provisions for the design of slab-column connections are based on the test results of connections constructed with relatively low compressive strengths not exceeding 40 MPa. Hence, further investigations are needed to develop and evaluate more research data to determine whether the code requirements ave realistic and adequate for high-strength concrete al levels considerably higher than 40 MPa. Results of tests conducted on seven interior slab-column connections (75 to 85 MPa) and normal-strength concrete slabs (30 to 40 MPa) are evaluated for use in the design of slab-column connections. The variables selected for this study are strength of concrete, flexural steel reinforcement ratio, and moment-to-shear ratio. It has been found that the use of high-strength columns increased connection shear strength compared to normal-strength concrete by about 5 percent in the case of no moment and 17 percent in the case of high moment. Not only was shear strength increased bur the connection performance was greatly enhanced by the use of high-strength concrete columns.