Seismic performance and cost-effectiveness of high-rise buildings with increasing concrete strength

The relationship between the seismic performance and economics of high-rise buildings when designed to different material strengths is investigated in this paper. To represent the modern high-rise construction, five 60-story reinforced concrete buildings with varying concrete strengths, ranging from 45 MPa to 110 MPa, are designed and detailed to fine accuracy keeping almost equal periods of vibration. Detailed fiber-based simulation models are developed to assess the relative seismic performance of the reference structures using incremental dynamic analyses and fragility functions. It is concluded that a considerable saving in construction cost and gain in useable area are attained with increasing concrete strength. The safety margins of high-strength concrete in tall structures may exceed those of normal-strength concrete buildings, particularly at high ground motion intensity levels. The recommendations of this systematic study may help designers to arrive at cost-effective designs for high-rise buildings in earthquake-prone regions without jeopardizing safety at different performance levels.