Stiffness Modification Factor for Reinforced Concrete Flat Plates with Steps

The purpose of this study is to propose a modification factor to reflect the stiffness modification when a step is located in flat plates. Reinforced concrete slabs with steps have different structural characteristics that are demonstrated by a series of structural experiment and nonlinear analysis. The corner at the step is weak and flexible, and thus the associated rotational stiffness at the corner of the step is identified through analysis of 6 type models using a nonlinear finite element program. Then a systematic analysis on stiffness changes is performed using a linear finite element procedure along with rotational springs. The stiffness of reinforced concrete flat plates with steps is mainly affected by the step length, location, thickness and height. Therefore, a single modification factor for each of these variables is obtained, while other variables are constrained. When multiple variables are considered, each single modification factor is multiplied each other. Such a method is verified by a comparative analysis. Finally, a complex modification factor can be applied to the existing effective beam width.

단차가 있는 철근콘크리트 무량판의 강성보정계수에 대한 연구