- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
Steel plated composite concrete (SC) walls, which consist of a poured concrete core between two studded steel plates, have been utilized in many applications in lieu of conventional reinforced concrete (RC) walls. For this type of wall, the steel reinforcing plates serve as formwork, which allows for modularization of the design and correspondingly accelerated construction. Recently, both overseas and domestic nuclear power plant (NPP) projects have incorporated SC walls into their designs. When installed in nuclear plant facilities, such walls may be required to resist the effects of extreme loadings such as tornado missile and aircraft impact. The analysis of the structural response of conventional RC walls to such extreme loadings is well understood and is amenable to a simplified and well known inelastic singledegree-of-freedom (SDOF) approach which treats the wall as an effective mass with an easily defined inelastic spring. The purpose of this investigation is to study the SC wall load deformation behavior or resistance function, under missile impact, for input to an SDOF model. Based on pseudo-static nonlinear finite element analyses, the SC wall load deformation behavior under a central concentrated load is investigated for some typical wall panel configurations. System parameters are varied to assess their effects on the resistance function.
The simplified single-degree-of-freedom (SDOF) evaluation methodology for the global inelastic response of conventional reinforced concrete (RC) panel structures for their response to impact loads is well known and is described in Biggs (1964), ASCE Manual of Practice No. 58 (1980) and UFC 3-340-02 (2008). Such response, which is characterized by the development of a collapse mechanism and by deformation of the plate through rotation of the plastic hinges is distinctly different from the localized perforation, penetration, or scabbing response. For RC plate structures, equations to estimate this local response have long been available, and more recently, local relations for the impact resistance of steel-plated composite concrete (SC) walls and slabs have been developed (Tsubota et al., 1993; Mizuno et al., 2005; Bruhl et al., 2013).
CONCLUSIONS AND RECOMMENDATIONS
The load-deformation behavior of impulsively loaded SC panels has been investigated using pseudo-static nonlinear finite element studies. These solutions demonstrate, for a properly designed panel, a structural response sequence defined by localized failure of the concrete, yielding of the bottom plate, tie bar rupture and load displacement strain hardening of the system until the bottom steel plate ruptures. The resistance function exhibits a near-linear displacement hardening effect over the entire plastic range, until rupture. Due to tension stresses which develop in the plates to resist shear, and the increase in shear force resultant with decreasing interface footprint dimension, the load deformation curve is dependent on footprint size.