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Earthquakes and Structures
  Volume 7, Number 5, December 2014, pages 893-908
DOI: http://dx.doi.org/10.12989/eas.2014.7.5.893
 


Lateral stiffness of reinforced concrete flat plates with steps under seismic loads
Sanghee Kim, Thomas H.-K. Kang, Jae-Yo Kim and Hong-Gun Park

 
Abstract
    The purpose of this study is to propose a modification factor to reflect the lateral 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 analyses. The corner at the step is weak and flexible, and the associated rotational stiffness degradation at the corner of the step is identified through analyses of 6 types of models using a nonlinear finite element program. Then a systematic analysis of stiffness changes is performed using a linear finite element procedure along with rotational springs. The lateral 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 by the other. Such a method is verified by a comparative analysis. Finally, a complex modification factor can be applied to the existing effective slab width.
 
Key Words
    lateral stiffness; slab with step; flat plate, modification factor; effective slab width method
 
Address
Sanghee Kim, Thomas H.-K. Kang and Hong-Gun Park: Department of Architecture and Architectural Engineering, Seoul National University, Seoul 151-744, Korea

Jae-Yo Kim: Department of Architectural Engineering, KwangWoon University, Seoul 139-701, Korea
 

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