Portal Frame The Overall Collapse Analysis And Purlin Bearing Capacity Test Research

The steel portal frame structures are commonly used in China and their size becomes bigger and bigger .Due to the advantages of lightness ,the economy in steel usage, the low cost, the large span, the fast and easy erection and installation and short install construction period etc, portal frame structures almost completely replace other forms. However, as the design and construction of such frame is relatively simple, such frame in the design, construction and supervision, and supervision than other types of architectural structure of the importance attached relatively short, the actual project has exposed a lot of problems.In this paper, the collapse investigation has been carried. The failure mode of the purlin, the tension bar, the portal beam and column, etc. was investigated. The collapse process and reasons inducing the collapse of the structures under the snow load were analyzed and discussed. Some key problems related to the safety and reliability Choose the most common form of the section and layout scheme, the full scale model in the vertical load were taken .The conventional loading capacity tests in the vertical load were taken. the simple C-purlin the full-scale model of the performance of a pilot research and analysis. The stability bearing capacity of purlin was calculated by formulas of two criterion and some design manual, and compare with the test results. The conclusions will improve and simplify the design methods in the future. The theoretical analysis ignored the distortion of the section and worked out the equations of displacement, loading capacity by means of energy method. The equations provide accurate by the results of tests .According to the actual situation, as compared the norms at home and abroad, put forward China's light steel norms deficiencies. Design Method for the future provide the basis for improvements. In order to enhance occasional larger load structure under the overall reliability ,in practical engineering design and construction, these problems must be taken into consideration carefully.