Assessment of Axial Capacity of RC Stub Column Confined with Unplasticized Polyvinyl Chloride Pipe

Abstract

In recent years, strengthening and enhancement of durability of concrete columns have increased significantly in the medium-rise or high-rise buildings across the globe. Strengthening of a concrete column may lead to the section composite as it uses encasing techniques. In this presentation, instead of post-strengthening of columns, the authors wish to utilize the advantage of composite sectional properties to enhance the durability of the concrete column. In general, steel tubes are extensively used for such purpose in the past decades, as design guidelines are available in the literature and various codes of practice. In the present investigation, reinforced concrete-filled unplasticized polyvinyl chloride pipes are taken up as composite column sections to study its structural behavior, viz. failure pattern, bond strength, confinement, and flexural behavior as it simultaneously improves the response with better confinement along with protecting the same from adverse environmental hazards, as well as to study its effectiveness as low-cost housing. Seventy-two confined (filled) column and 27 unconfined column specimens were tested to investigate the effects of various parameters on the ultimate load-carrying capacity and the load–deformation behavior of the columns. All the specimens are found with localized failure. Concrete column exhibits sudden failure when displacement reached the range of 3.4–6.7 mm. While for the confined reinforced concrete column, it reaches 22.3 mm without sudden failure while retaining its integrity. Detail study shows that ductility of specimens increases with the increase in pipe thickness. Finally utilizing the extensive experimental data and with the help of EUROCODE-4, a mathematical model based on response surface methodology has been proposed for the purpose of predicting the load-carrying capacity of the confined as well as unconfined RC stub columns.