# Flexural Performance of Removable Deck Slabs with Fixing Device Details
## 1 Introduction  
The growing demand for high-rise buildings has resulted in the widespread use of steel and composite structures that combine steel and reinforced concrete. Such structures offer reduced cross sections, light member weight, and long spans, making them suitable for large buildings. As the size of buildings increases, the use of deck plates is also on the rise, as they help improve economic feasibility and shorten construction periods [1; 2; 3]. Unlike the conventional reinforced concrete (RC) structure, deck plates are manufactured by truss girder integration and serve as concrete formwork and load-bearing elements during construction, eliminating the need for temporary construction, such as supports [4; 5; 6]. However, despite their numerous benefits, several challenges remain to be addressed, such as the need to ensure the safety of the developed product during construction and use. A conventional deck plate design consists of a truss girder with one upper reinforcing bar and two lower reinforcing bars connected by a lattice, with the truss girder and spacer contact welded to fix the position of the spacer. A spacer is used to separate the upper truss girder and the lower floor plate from each other, and a support member is used to support the truss girder. Deflection evaluation was performed according to the details of the truss girder to ensure safety during the construction of the conventional deck plate. The deflection of the deck plate varied depending on the lattice bar and deck height [7]. However, the fixing details of the lower floor and truss girder were not addressed, and this design presents a risk of corrosion due to the integration of the deck plate and trussgirder, with the bottom plate made primarily of galvanized steel. Moreover, if there is a leak in the hardened concrete floor plate, it is difficult to locate and repair the damage or replace the deck plate. These issues prompted the development of alternative deck plate designs. Several studies [8; 9; 10] have been conducted to address the issue of the inability to replace the lower plate of the truss girder integrated deck plate. A promising solution is a separable deck plate between the truss and the deck plate. This allows for the removal of the steel plate and plywood from the mold assembling the deck plate, eliminating the disadvantage of integrated deck plates. Research and development efforts are ongoing to optimize the performance of detachable deck plates and ensure their practical application in the construction industry. Removable deck plates have attracted attention as a potential solution to the disadvantages of integrated truss girder deck plates. However, concerns have been raised regarding the concentrated stress at the junction between the bottom plate and the truss during construction load application, which may lead to collapse or deformation due to excessive deflection. Excessive coupling of the truss girder and the steel plate may also result in the deformation of the tensile reinforcing bar before concrete placement or weak coupling to the spacer or nut for demolding. As a result, research has focused on improving the structural safety of removable deck plates. [PERSON] et al. [8] conducted a load test on a reusable deck to demonstrate structural safety during construction. However, their study did not consider the impact of the fixing device connecting the truss wire and the galvanized steel sheet on safety during construction, highlighting the need for further research on optimizing the fixing device. A previous study [9] evaluated the safety of deck plates in which the lattice reinforcing bar and the steel deck were integrated during construction without the use of a fixing device. The experiment involved loading at four locations to simulate a uniformly distributed load. The results confirmed that the lattice reinforcing bar in the support section received a compressive force, resulting in buckling. However, the load in this study was only applied to the upper rebar.