The Structural Strength and Behavior of Steel Framing Floor Using Cold-Formed I-Shaped Joists

• Main Authors: Chu-Yun Wen, 文楚雲
• Other Authors: Chi-Ling Pan
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/by6375

碩士 === 朝陽科技大學 === 營建工程系 === 105 === This research is focused on the structural strength and behavior of the integrated I-shaped joist sheathed with OSB, both experimental and analytical studies were conducted in this study. In addition, the steel framing floor assembled with wall studs was investigated in accordance with the real connecting condition. The OSB boards of both smaller size and regular size were also utilized in the test specimens to study the differences of structural strength. All specimens were assembled with blocking sections to prevent the joists from lateral buckling. The finite element analytical software, ABAQUS, was adopted to establish structural model, material properties, restrain conditions, loading types, boundary conditions, and mesh formulation. The analytical results were used to compare to the tested results including load-displacement relationship, failure mode, and structural stiffness. The AISI prediction based on the concept of transformed section was also used for comparison purpose. It was observed from test results that the ultimate strengths of the specimens sheathed with OSB or installed web stiffeners were much higher than those of the specimens without sheathing or installing web stiffeners. The phenomenon of stress concentration was found between the boards in the specimens sheathed with smaller size of OSB, therefore, the strength of specimen sheathed with smaller size of OSB was lower than the specimen sheathed with regular size of OSB. The stress of transformed section calculated based on the AISI specification has a good agreement with the stress detected from the strain gages mounted on the flange of test specimen. It seems that transformed-section method can be adopted in the computation of the structural strength of floor specimen. By observing the structural behavior of finite element analysis, the model can be used to simulate the failure mode of specimen, and predict the stiffness of steel framing floor system in the elastic range. However, the discrepancies of ultimate strength and displacement were found between the analytical model and test specimen. It is probably due to the initial imperfection in the flange and web of joist during the time of assembly or transportation.