# Study on Shear Performance of Web-Embedded Composite Shear Connector
## 1 Introduction  
The stud [1; 2; 3; 4] and perfobond rib shear connector (PBL) [5] are two types of traditional shear connectors. The PBL shear connector is rigid, whereas the stud shear connector is flexible [6]. The stud shear connector has the characteristics of convenient construction, low cost, and consistent shear resistance in all directions [7; 8; 9; 10]. The PBL shear connector has higher shear resistance and shear stiffness, as well as having the advantages of excellent fatigue resistance and simple construction [11; 12; 13; 14; 15; 16]. The web-embedded connector is a type of shear connector that effectively combines the stud shear connector and the PBL shear connector.  
Web-embedded connectors originate from puzzle (PZ)-shaped composite dowel shear connectors, the removal of traditional shear connectors in case of the low utilisation of the upper flange, and the cutting of steel plates into various shapes to connect with concrete. Germany first used PZ shear connectors without a flange plate to build the Perkinger Vaiduct [17], following which different types of web-embedded connectors began to appear. The yield strength of the steel rebar also changes when the fabrication process changes, which also affects the shear properties of the shear connector. When the Tempcore process is used, the yield and ultimate tensile strengths of the rebar increase [18; 19].  
[PERSON] [20; 21] proposed a new composite beam with an embedded web, wherein the upper flange plate was removed from the structure to form a steel plate shear connector with a slot at the upper end of the web plate. The Pennsylvania Department of Transportation developed a highway bridge comprising T-shaped steel beams and penetrating rebars embedded in concrete slabs. [PERSON] [22] developed a full-scale bridge model and studied its flexural performance; the results showed that the design and manufacturing method satisfied the AASHTO limit state standard [23]. [PERSON] [24] constructed nine external U-shaped steel-concrete composite beams with an embedded web (WUSCB) and investigated the effects of the shear span ratio, concrete wing width, joint spacing and inclination angle, bottom longitudinal bar diameter, stud and stirrup setting, and U-shaped steel web height-to-thickness ratio on its shear performance.  
However, the research on web-embedded connectors is insufficient, and there is no universal consensus. When considering different internal geometries, there remains considerable research space for web-embedded connectors.  
Therefore, this study proposed an economical and reasonable connection web-embedded composite shear connector (WECSC) that saves construction time and improves the efficiency of WECSCs, which are directly used in web hole T-shaped steel (Figure 1). The WECSC comprises four parts: concrete, embedded steel web, penetrating rebar, and studs. In order to study the shear properties of the WECSC, seven push-out specimens of six types with different internal structures were designed and made in this paper, and push-out tests were carried out on them, focusing on the analysis of the failure forms, load-slip curves, and load-strain curves of the tests. The specimen was simulated by ABAQUS (2022) finite element software, and an expanded parameter analysis was carried out on the basis of the test. Through experiments and finite element analysis, the failure form and force transfer mechanism of the composite shear key with embedded web are discussed, and the proportion of different shear members in the ultimate bearing capacity of the composite shear key with embedded web is expected to be obtained. In addition, considering the existing calculation equation and combining it with the test data of this study, an equation for calculating the ultimate shear bearing capacity (USBC) was proposed and verified through tests and finite element simulations. The flowchart of this paper is shown in Figure 2.  
Figure 1: Structural map of WECSC.