Seismic Vulnerability of RC Shear Wall Building with a Dome Roof in Moderate Seismic Region of Saudi Arabia

Recent seismic events in low-to-moderate seismicity regions of Saudi Arabia have led to concerns on the vulnerability of RC buildings constructed in Saudi Arabia up to mid-1990’s. These buildings were designed for gravity loads only, and potential for damage during seismic event is high. Buildings with dome at the roof level are an architectural feature in many buildings. Monolithic dome at the roof of the structure stiffens the upper part of structure requiring special consideration in seismic design. This paper presents the assessment of seismic vulnerability, using nonlinear static pushover analysis, of an eight-story building with shear walls and a large dome at the roof level, under a moderate intensity earthquake. The building is located in western region of Saudi Arabia, which is Region 3 as per Saudi Building Code. Pushover analysis is carried out using the software SAP2000 incorporating inelastic material behavior for concrete and steel, for a typical 2D frame in the building with a shear wall. The shear wall is modeled using the shell element and mid-pier approaches. A 3D pushover analysis of the building is also carried out with mid-pier model for shear walls. The presence of heavy mass at the roof results in yielding of hinges in the roof-level columns supporting the dome. The beams connected to the shear wall and the shear walls of the building are deficient under seismic load. Strengthening of beams, columns at the roof level under the dome and shear walls is warranted to meet the seismic demand.