METHOD FOR RESTORING FORCE CHARACTERISTIC OF RC FRAME CONSISTED WITH SHEAR WALLS AND SLAB

Abstract

 The behavior of RC frame consisted with shear walls and slab is influenced by slab, when earthquake happens. So, the behavior characteristic of slab was studied. On this study, the evaluation of effective region of slab is very important. At first, this evaluation method was developed. Secondly, with this method, the calculating method of restoring force characteristic of slab was developed.

 

 By experiment and FEM analysis results, the following knowledge was obtained.

 1. The region of slab main bars yielding was very wide. It was almost slab width.

 2. The right angles bars of slab with main bars were yielding.

 3. The elastic stiffness of slab was not changed, if the slab width changed.

 

 Assumptions of the proposed method are the following.

 1. The elastic effective region of slab at critical section is determined by the flexural stiffness of slab length direction and the torsional stiffness of slab width direction at shear wall side. The upper limit of this region is half of inside measurement length of slab.

 2. The effective region of slab at flexural yielding is equal to the elastic region without the upper limit.

 3. The yielding of slab right angles bars with main bars is considered.

 4. In calculation method of restoring force characteristic of slab, the flexural cracking and the flexural yielding are considered.

 

 It was found that the calculation results by the proposed method for the elastic stiffness, the flexural yielding moment and the restoring force characteristic of frame consisted with slab and shear wall corresponded well with experiment and FEM analysis results.