Facades are popular in modern buildings and are made of different materials such as pre-cast concrete, glass, aluminium, granite or marble and steel. During recent times seismic activity in densely populated areas has resulted in damage and a consequent loss of life. There were many types of building failure, including failure of building facade systems. Facade systems are highly vulnerable and fail more frequently than the buildings themselves with significant devastating effects. During an earthquake building frames suffer large interstorey drifts, causing racking of the building facade systems. The facade systems may not be able to cater for such large deformations and this can result in either functional or total failure at the facade connections or damage by pounding (impact) with adjacent facade panels. Façade failure and collapse can cause serious damage to buildings and injury to people in the vicinity. Moreover, facade represent between 10- 20 % or more of the total building cost depending on the size and importance of the facility and facade material (Facades1980). Considering the cost and safety issues, the importance of a well designed facade system on a building needs to be emphasised. In modern buildings, energy absorbing passive damping devices are very commonly used for energy absorption in order to manage the vibration response of multistorey buildings in an earthquake event. A number of manufactured dampers such as Viscoelastic and viscous, friction and yielding dampers are available. These dampers use a range of materials and designs in order to achieve diverse levels of damping and stiffness. This thesis is an investigation of the seismic behaviour of building facade systems and studies the effects of facade and connection properties on this response. The objectives with energy absorbing connections of the study are to determine and control facade distortions and to establish the required connection properties. Finite Element techniques have been used for modelling and analysis of the building frame, facade and connections. Time history analyses under earthquake loadings were carried out to determine the system response in terms of inter-storey drifts, facade distortions, differential displacement between facades and frames and the axial force in horizontal connections. Connection properties with respect to stiffness and energy absorption capability (or damping) have been modelled and varied to obtain the desired response. Findings illustrate the influence of these connection properties on system response and show that it is possible to control facade distortions to within acceptable limits. They also demonstrate that energy absorbing connections are able to reduce inter-storey drifts and mitigate the detrimental seismic effects on the entire building facade system.

The construction of reinforced concrete buildings with unreinforced infill is common practice even in seismically active country such as Bhutan, which is located in high seismic region of Eastern Himalaya. All buildings constructed prior 1998 were constructed without seismic provisions while those constructed after this period adopted seismic codes of neighbouring country, India. However, the codes have limited information on the design of infilled structures besides having differences in architectural requirements which may compound the structural problems. Although the influence of infill on the reinforced concrete framed structures is known, the present seismic codes do not consider it due to the lack of sufficient information. Time history analyses were performed to study the influence of infill on the performance of concrete framed structures. Important parameters were considered and the results presented in a manner that can be used by practitioners. The results show that the influence of infill on the structural performance is significant. The structural responses such as fundamental period, roof displacement, inter-storey drift ratio, stresses in infill wall and structural member forces of beams and column generally reduce, with incorporation of infill wall. The structures designed and constructed with or without seismic provision perform in a similar manner if the infills of high strength are used.