Seismic assessment of irregularities in steel special moment resisting frame with asymmetric-plan building (case study: Gedung D - Universitas Dharma Andalas)

Abstract

The limitation of land is becoming the issue where the symmetric-plan building could not always be the proper choice. Besides that, the demands of architectural and esthetical construction also quickly increase. Then, there is the possibility where asymmetric-plan building will be the choice, in this case Gedung-D Universitas Dharma Andalas. But, designing asymmetric-plan building is having obstacle where the past studies revealed that the damage under strong ground motion become the major problem. It is because the asymmetric-plan will lead excessive torsion due to the horizontal irregularities or soft-story issue due to vertical irregularities. Then, it certainly affects the stability of structure. This research conducted the seismic assessment of asymmetric-plan 5-story building where Gedung-D Universitas Dharma Andalas, Padang will take place. The assessment is conducted by modeling three dimensional steel special moment resisting frame with seismic design category-D. Equivalent lateral force is applied to obtain early identification and response spectrum analysis is used in the next procedure to fulfill additional requirements. Based on SNI 1726:2019, the building has been categorized as horizontal irregularities where torsional irregularities and re-entrant corner irregularities mostly happened. It indicates that the other additional requirements need to be reconsidered such as increasing the design force about 25%, the amplified accidental torsions, P-? effect. In the other hand, vertical irregularities do not act toward this building. However, there are some inadequate values of inter-story drifts in X-direction toward drift limit. Then, it is concluded that this asymmetric-plan multi-story building needs to be designed in lateral resistance if this will be planned in future and act the good seismic performance.