Experimental and theoretical study of encased-plate composite structural walls

Abstract

Reinforced concrete and steel plate structural walls have been widely used as lateral-load resisting systems in multi-storey buildings. However, they have a number of shortfalls which could be mitigated if a composite construction consisting of steel plates and concrete is used. The encased-plate composite wall studied herein is formed by embedding a steel plate inside a conventionally- reinforced wall.The behaviour of encased-plate composite walls under pure in-plane shear was studied in an experimental study involving a number of small-scale wall units. In-plane shear tests were carried out on both individual components and on composite walls. The results showed that the behaviour of composite wall was different from its individual components due to the interaction between the encased-plate and the concrete. While the stiffness of the composite wall was higher than that of its individual components, no improvement in ultimate load carrying capacity was associated with composite action.The test programme further included seven encased-plate composite structural walls tested under in-plane lateral loads. The only test parameter included in the study was the thickness of the encased-plate. The walls were designed to fail in either shear or flexure, and the results demonstrated the effectiveness of the proposed system in resisting shear stresses. A full-field deformation monitoring system based on particle image velocimetry (PIV) and close range photogrammetry was introduced and used to map the deformation and strain distribution of walls during structural testing.Numerical analysis based on the nonlinear finite element method was carried out within the study. After validation against experimental results, the analysis was applied for a wide range of conventionally-reinforced and encased-plate composite structural walls. Numerical analysis was used to represent the behaviour of encased-plate composite walls within a parametric study that covered a wide variation of parameters that were thought to influence their performance. The finite element model provided better understanding of wall behaviour, and the analysis results showed that walls? aspect ratio, plate thickness, axial loading and central panel?s longitudinal reinforcement were the main parameters affecting the behaviour of encased-plate composite walls.The study also included the development of an analysis method for predicting the shear strength and behaviour of both conventionally-reinforced and encased-plate composite structural walls. The method was based on the softened truss model and utilised a newly proposed cracking angle of diagonal concrete struts. The cracking angle was developed using a regression analysis of the reported shear capacity values of 100 experimental structural walls. The proposed method was then used to predict the shear capacity and deformation behaviour of the new test walls, and the results compared well with the experimental data.In the light of the experimental observations and numerical modelling, it was concluded that the encased-plate composite structural wall system presented an attractive structural option in lateral load resisting wall applications especially when high shear stresses were expected.

Date of Award	2010
Original language	English
Awarding Institution	University of Dundee
Supervisor	Ahmed El-Sheikh (Supervisor)