Analysis and Stepwise Regression of Flexural Load-Capacity of Steel Wire-Reinforced Precast Concrete Sandwich Panels

Abstract

Precast Sandwich Panel (PSP) is a plate element that is lighted, cheaper, and has significantly better thermal insulation compared to conventional concrete plates, which are typically used as wall or slab units. The positive features of PSP make it a probable solution for many constructional issues in Iraq related to low-cost energy-saving housing, temporary camping, and industrial units, which calls for extensive analysis, experimental, and numerical studies to explore the pros and cons of PSPs as low-cost roofing solution. The aim of this study is to evaluate the degree of influence of the geometry, material, and design parameters on the flexural capacity of PSPs and to introduce a pre-design evaluation tool using multi-variable stepwise regressions. Experimental data including 13 input parameters related to the properties of the outer concrete layers, inner insulation core, and shear connectors between them, in addition to cracking and ultimate loads as outputs were analyzed for 50 experimental steel wire-reinforced sandwich plates. Direct correlations showed that none of the studied parameters has a significant sole impact on the flexural strength of the panels, while stepwise regressions showed that most of these parameters are effective. P-values higher than 5% were recorded for some parameters, which were automatically excluded from the regression models, while the T- and F-values revealed different influence degrees for the included parameters. Finally, two multi-variables stepwise regression models were introduced for cracking and ultimate loads with R2 values of 89.3 and 92.6%, respectively, which reflects their high reliability as pre-design simplified analysis tools.