Experimental and Theoretical Study of Thin-covered Composite Dowels considering Multiple Load Conditions

TL;DR

This study investigates the behavior of thin-covered composite dowels under various load conditions, introducing a new failure mode and developing models for their capacity and design in engineering applications.

Contribution

It presents a novel experimental setup, identifies a new failure mode, and develops theoretical models for the capacity and design of thin-covered composite dowels.

Findings

Discovery of Restricted Cone Failure mode.

Parametric analysis of key factors affecting capacity.

Development of capacity and design models.

Abstract

With the widespread application of composite structures in the fields of building and bridge constructions, thin-covered composite dowels are increasingly adopted in various engineering scenarios. This paper presents a design methodology for thin-covered composite dowels, supported by both experimental and theoretical investigations. In the experiment, a novel test rig and specimens are designed to facilitate tensile-shear coupling loading. The study identifies a new failure mode: Restricted Cone Failure (RCF) in thin-covered composite dowels under tensile-shear coupling load, which distinct from conventional composite dowels. This RCF mode is attributed to the thin thickness of the side concrete cover, which restricts the development of the failure cone in the thickness direction. Additionally, a parametric analysis is conducted to evaluate the effects of key factors--such as steel dowel thickness, effective embedment depth, and the tensile strength of steel fiber reinforced concrete--on the bearing capacity and ductility of thin-covered composite dowels. Based on the theoretical findings, comprehensive tensile, shear, and tensile-shear coupling capacity models along with an engineering design model are developed to aid in the practical application of thin-covered composite dowels.