A comparative study on the seismic performance of concrete and steel Diagrid structures

Abstract

In recent years, concrete Diagrids have been more widely used in the current Diagrid building designs, especially with mid-rise buildings. Looking through the entire portfolio of completed Diagrid structures, there are very few Diagrid tall building structures located in the area where seismic forces govern the lateral design. An investigation on the seismic performance of concrete Diagrid structures would give the engineers a better understanding of this unique type of structural system. A comparative research was conducted in this paper on the seismic performance of concrete Diagrid structures comparing to steel Diagrid structures. Two building height scenarios were considered for mid-rise 8-story buildings and high-rise 60-story buildings. Response spectrum analysis was used for two different earthquake locations corresponding to code based seismic design approach using ASCE 7-10. The seismic performances of both types of Diagrid structures were also compared to 8-story moment frame buildings and 60-story outrigger buildings for the two scenarios respectively. With all member sizes set to be fixed across all models, steel Diagrids were found to be performing better than concrete Diagrids in terms of natural period and controlling top drifts while concrete was tested to be better at controlling top accelerations. Comparing to outrigger and moment frame systems, both concrete and steel Diagrid structures were tested to be stiffer and more effective in restraining top drifts but less satisfying in limiting top accelerations.