Dynamic Analysis of Sloped Building Attached With a Mass Damper

Abstract

Sloped building can be defined as a building whose foundation is resting on a sloped ground profile. An area having an altitude more than 600m from mean sea level or an average slope of 30 degrees may be classified as hilly. The shortage of plain ground in hilly areas compels construction of structures on sloping ground such as residential building, hospitals, hotel, colleges and offices resting on hilly area. It comprises about 21% of total land area of India. In general the structures are vulnerable to damage when subjected to strong ground motion on a plain ground but this damage is further enhanced for the case of structures on sloping ground. In order to control the damage, due to the strong motion response, various techniques are available. The Passive Dampers is also one of those system in which the passive damper dissipates the major part of the seismic energy developed in the structure regardless of any external power source. The property of passive damper doesn’t change while the structure vibrates due to seismic action and thereby cannot be altered. In this study In this behaviour of four storied sloped frame having step back configuration is analyzed for sinusoidal ground motion with slope angles ofi20̊ in commercial software by performing a linear time history analysis and experimental study is carried out in a single storey frame structure under excitation of sinusoidal ground motion. The same test is then again conducted with tuned mass damper and the time history of displacement is again observed for the same ground motion. From the above analysis, it has been observed that time history of floor displacement increases when model frequencies get closer to natural frequency. As the slope angle increases, stiffness of the model increases due to decrease in height of short column and that results in increase of earthquake forces on short column