A Study on the Effectiveness of Bracing Systems in Soft Storey Steel Buildings

A soft storey or a weak storey is one in which the lateral stiffness is less than 70 percent of that in the storey above or it can be less than 80 percent of the average lateral stiffness of the three stories above. For the reduction of lateral deflection of a structure, a bracing system is provided. In seismic design of structure and in high rise structure, the provision of bracing system has become more effective. So this paper aims to find out the effect of bracing on soft storey of steel building. In this paper, G+9 steel frames are modeled with different type of bracing pattern and different combination of soft story using software STAAD Pro. Effect of these different bracings on soft storey is studied for different parameter like column displacement, maximum deflection, storey drift, maximum bending moment, maximum axial force and maximum shear force. From the observed result best type of bracing will be selected.