Seismic response of slab-column connections constructed with high-strength concrete

Structures located in low seismic zones require only nominal ductility whereas for structures located in seismic zones significant ductility is required. Ductility of concrete increases as strength increases; the use of high-strength concrete in structures located in moderate to high seismic zones may be advantageous for increasing resistance and energy dissipation, which can be used to enhance ductility and seismic energy. Four interior slab-column connections were tested under simulated earthquake-type loads to investigate the effect of using high-strength concrete in connections. Two slabs were made with high-strength concrete of 75 MPa and two were made with normal strength concrete of 35 MPa. The four specimens were made with high-strength concrete columns. Two slabs were reinforced with a steel reinforcement ratio of 0.5 percent and the other two with 1 percent. As concrete slab strength increases from 35 to 75 MPa, the ductility by displacement and rotation increases by 100 and 125 percent respectively. Also, shear strength, moment capacity, drift percent, and rotation capacity increase by 20, 31, 37, and 50 percent, respectively, when high-strength concrete slabs of 75 MPa are used instead of 35 MPa normal strength concrete.