## 1 Introduction  
Innovative off-site constructions utilizing prefabricated bridge elements (PBEs) are continuously being developed. Although prefabricated systems have been utilized for many different types of bridge members, prefabricated bridge deck elements have emerged as one of the more popular applications. To accelerate construction, prefabricated bridge deck elements have been utilized since the 1970s [1]. The initial deployment was primarily utilized in deck replacement projects when rapid project delivery was required, to reduce interference with local traffic in densely populated areas. Prefabricated bridge deck elements have since been studied extensively in both field inspection studies, and laboratory investigations [2; 3]. The connection material is the first feature influencing the performance of prefabricated bridge deck elements. To be used in field-cast connections, many commercially available grouts have been tested. Previous studies on grout materials have mainly focused on dimensional stability, bond strength to precast concrete, durability, constructability aspects, and new properties [4; 5]. The next feature is the surface preparation of prefabricated bridge deck elements at the connection location. Digital images were utilized by [PERSON] et al. [6] to evaluate the surface roughness level in precast concrete with as-cast, sandblasted, and wire-brushed surface preparations. It was found that as the surface roughness level of precast concrete increased, the bond between cast-in-place and precast concrete improved remarkably. [PERSON] [7] reported a similar result. Finally, the performance of prefabricated bridge deck elements is greatly affected by the connection details between elements. With the increasingly efficient development of the above influencing factors, full-depth deck panel systems became the best choice. The full-depth deck panel system with stud connector clusters embedded in shear pockets is a typical system. However, there are many matters to resolve when utilizing stud connector clusters such as the shear connection [8; 9], consisting of deck uplift, nonuniform shear stress distribution, and local bearing failure of grout in the shear pockets. The use of continuous void connections is an expected resolution, instead of point connections. [PERSON] [10] suggested composite girders with prefabricated deck panels connected to precast concrete girders through the injection channels. Experiments were also conducted to investigate the bending behavior of this prefabricated girder and the connection performance. The good results from these experiments indicate that this is a potential connection type for prefabricated bridge elements. Therefore, prefabricated composite girders, with the steel girders and deck panels connected by injecting mechanical grout into a continuous channel above the steel girders to achieve composite action between the steel girders and deck panels, were proposed by [PERSON] et al. [11], as shown in Figure 1. Such connection of prefabricated composite girders is typically made by means of shear connectors placed within a partial depth block-out in the deck panels. This type of block-out solved concerns about durability compared to a full depth block-out, since the full depth block-out has exposed joints around the perimeter of the block-out after the grout is placed. The top deck reinforcement can be placed over the block-out, which simplifies the layout of reinforcement in the deck panel. In addition, the continuous connection will allow more closely-spaced shear connectors, and uniform shear stress distribution. Greater haunch height can be advantageous for the flow of grout under the deck panels and adjustment during precast deck module installation and connection. Because of such outstanding advantages, this type of connection needs more research attention to accelerate its applicability. In this study, a design of the railway bridge prototype using prefabricated composite girders was conducted.