THE INFLUENCES OF THE SLAB DISCONTINUITIES ON THE INTERNAL FORCES, AT FRAME TYPE REINFORCED CONCRETE STRUCTURES

Abstract

To resist earthquake forces in a confidential manner is one of the fundamental requirements of the structural system design of buildings. The main principles of Earthquake-resistant design of buildings have the symetric plan and regular configuration of the structural system. Regular buildings are easier in application, for designing, dimensioning of structural elements and much more economic for consruction cost. Also, the results of the structural system analysis of regular buildings represent the behaviour of the real structure. For these reasons, regular buildings are prefered for the best building design and analysis. Vertical and horizontal discontinuities in building structures, instant stiffness changes and variation of mass distribution are negative states, display good seismic behaviour. The buildings having irregularities in plan and in elevation are accepted as non-regular buildings. In practise, non-regular buildings are not economic in construction cast, lead to stress concentrations hazardous to the structure and causing erroneous application. If the basic methods of structural analysis for regular buildings are applied to non-regular buildings the effects of irregularities must be considered. Analysis of the regular frame type structural systems according to The Turkish earthquake code is performed on a lineer elastic model assuming different cavity ratios of the floor slab by using SAP2000 Structural Analysis Programme applying simplified modal response spectrum analysis methods. Numerical results of the internal forces of the elements of the structural system are obtained and compared for two different casses in one case the floor diaphragms are sufficiently rigid in their plane, in the other case unsuffiently rigid in their plane.