Seismic strengthening of Multi-storey Reinforced Concrete framed Buildings: Seismic strengthening of Multi-storey Reinforced Concrete framed Buildings

Abstract

The field of earthquake engineering  has existence from many years.  Earthquake engineers have made significant contributions to the seismic safety of the several important structures in the country. However, as the recent earthquakes have shown, the performance of normal structures during past earthquakes has been less satisfactory. This is mainly due to the lack of awareness amongst most practicing engineers of the special provisions that need to be followed in earthquake resistant design and thereafter in construction.

Braced frames, besides other structural systems, such as moment resisting frames or shear walls, have been an effective and valuable method to enhance structures against lateral loads. In seismic excitations, inclined elements react as truss web elements that would bear compression or tension stresses. This axial reaction results in less moments and therefore small sizes in beam and column sections with respect to members in similar moment resisting frame . So, in this Paper 2 separate symmetrical  RCC frame buildings one bare frame and another strut frame subjected  to lateral loads are analyzed using software  SAP 2000. Strut systems are employed to study the seismic response of the buildings. The buildings are analyzed for a different load combinations as per IS 1893:2002. The comparison is done between the bare and strut frame on the basis of floor displacements, base shear, hinge formation and  pushover curve.

Seismic performance of the braced building is compared to the unbraced building for evaluating the real strength of the structures and checking  suitable strengthening measures