SEISMIC VULNERABILITY OF INFILL WALL IN RC BUILDING

Abstract

Nepal observes frequent earthquakes, as it lies in an earthquake prone zone, among which the Gorkha Earthquake (25th April 2015) is one of the Disastrous. So, building shall be more realistic when designed. Nowadays, Reinforced concrete building is more popular as it has its monolithic nature and the seismic performance is quite good. Usually, Reinforced concrete building is designed as bare frame for simplicity and its infill wall is neglected. But in practical, infill walls also acts as a compression member when building is subjected the lateral force. So, with the logic of building response during earthquake is different from the designer’s assumptions and the undesired results may obtained. That’s why the fatalities and the economical losses occurs not only from the assumed structural members such as beams and columns but also from the infill walls can lead to huge losses so the infill walls shall also be considered while designing the building with equal importance as a structural member. This study implies the seismic vulnerability of infill wall in reinforced concrete buildings utilizing non-linear dynamic analysis (TH) of masonry infill building models. Federal Emergency management Agency (FEMA) and Indian standard (IS) code is used to analyze building models. Building models are analyzed using computer structure program. The research quantifies the damage in infill wall due seismic load on different level storey of building. Mode of failure develops in infill wall using non-linear Dynamic analysis (TH).Synthetic Earthquake is scaled with different peak ground acceleration (pga) that varies from 0.05pga to 1pga of commercial building for 5 Storey ,10 Storey,15 Storey and 3 Storey,6 Storey and 9 Storey of Residential Building. Damage state is recognized by plastic hinge formation in the building which is in the state from Immediate Occupancy (IO), Life safety (LS), Collapse Presentation (CP).Maximum inter storey drift ratio is observed in different building at different pga to know seismic vulnerability of infill wall. Infill wall is represented by equivalent strut, in which equivalent strut width is given by Pauley’s and Priestley’s equation; w=0.25d, where d is diagonal length of infill panel. The equation gives average equivalent strut width from all authors. Seismic Vulnerability of the infill wall is determined by the Fragility Curve. Fragility curve is obtained from maximum inter storey drift ratio (%) vs. probability of failure, which easily describes seismic vulnerability of infill wall of buildings.