A Case Study of Seismic Assessment: Five Storey Residential Apartment Building Near Murree


The case study building is located near Murree, a popular hill station and a summer resort for people, especially for the residents of Rawalpindi/Islamabad. The building is a reinforced concrete framed structure with five storeys including the ground floor. Car parking is located at the ground floor while the above floors have residential apartments. The building was constructed after the 2005 Kashmir Earthquake. This building was selected as a case study because it has several seismic vulnerabilities common to mixed-use residential buildings in northern Pakistan. The building was designed for a lower level of seismic forces than those prescribed in the newest edition of the building code – it was designed for Zone 2B, but with the approval of the Building Code of Pakistan (Seismic Provisions-2007), Murree is now in Zone 3. With the new zoning comes more stringent requirements for the structural detailing of the reinforced concrete frame, so the building must now be considered as an ordinary moment frame rather than an intermediate moment frame, meaning the design forces will be higher. The building also has a weak story created by open space at the ground floor, has an L-shaped plan, and has with stiff unreinforced masonry infill walls that were not considered during the structural design of the building.






The case study building was assessed for potential seismic vulnerabilities using the US Federal Emergency Management Agency (FEMA) Pre-standard 310 Tier 1 Checklist modified for Pakistan conditions, as well as the American Society of Civil Engineers (ASCE) Standard 31 Tier 2 and 3 analyses and acceptance and modeling criteria from ASCE 41. Structural analysis showed that the building is anticipated to protect the lives of its occupants in the design earthquake, and was therefore adequately designed to meet the performance expected of residential buildings.

Download
*