These days, the Composite Slabs with Deep Deck plate was commonly used in domestic construction site, and, the application of the Slim Floor system was increased from the Enlargement and High-rise Building. But, Slim Floor system using the Deep Deck was shown safety problem caused by the deflection and local buckling in construction phase when used to more than 6m. Therefore, for solving the problem, the installation of the shores is essential. This study is realize the long span slab without shores from control the deflection through applied the pre-tensioning elements in CAP deck. In addition, by applying the pre-tensioning member as the tensile member of the CAP Deck slab, the pre-tensioning member for the shores tries to be used as the structural member. Accordingly, to determine the flexural performance of the CAP Deck slab through the pre-tensioning force in tensile member, and, the composite effect of the CAP Deck slab by the experiments.

Deep Deck plate is suitable to long span structures because it has larger flexural rigidity than other shape deck plate. but Deflection is critically proportional to span length than other factors. and large deflection makes works anxiety and possibility of structural problems high after casting concrete. to overcome these problems, Preload is introduced to control the deflection of deep deck plate that ha s long span. So in this study, residual strength of preloaded deep deck plate is evaluated by FEM analysis method. for this study 4 analysis models is used and have each preload. Target preload for analysis models is when deck plate cambered to 30mm. 0.0, 0.8, 1.0, 1.2, times of target preload are applied to each analysis models. In result of analysis, Preload influence residual strength of deck plate. And much preload degrade strength of deck plate.

Deep-Deck usually used in long span structure for its larger section properties. but Deep-Deck has difficulties when the span is over 9m because of deflection. Deflection makes workers anxiety and Structural problems. So, Preload is used to the Deep Deck To control the the deflection of the deep deck which has 9m over. In this study, The Preloaded deep deck which has 9m was evaluated by Experments. Result of experiments, preloade and camber have proportional relation