Axial Compressive Tests and Resistance Design of UHTCC-Encased Rectangular Steel Tubular Bridge Columns

Abstract

Ultrahigh toughness cementitious composite (UHTCC) has attracted particular attention in recent years owing to its exceptional resistance in accommodating large deformations and controlling tensile cracks. These properties are valuable in preventing further deterioration of UHTCC caused by chloride ions and water ingress. Considering these advantageous properties, this study introduces a novel UHTCC-encased steel tubular (UEST) bridge column, designed to achieve both lightweight construction and enhanced durability. To evaluate the axial compressive behavior of the UEST bridge columns, five specimens were designed and fabricated. These specimens included a bare steel tubular column, a laminated UEST column, and composite UEST columns with different types of shear connectors, such as studs and Perfobond Leiste (PBL). Additionally, finite-element (FE) models were established using ABAQUS (version 2021) software and validated against experimental results. Numerous FE examples were analyzed to further investigate the axial resistance of UEST bridge columns with different design parameters including connector type, PBL spacing, stud spacing, steel yield strength, and width-to-thickness ratio of steel tube. Furthermore, several design equations from existing codes were referred to predict the axial resistance of UEST bridge columns, with the most accurate one approaching an average error of 6.8%.