Study On Vibration Performance Of Floor System Supported By Cold-formed Steel Joist In Low-rise Residential Structures

This paper mainly presents detailed results on the vibration performance of floor system supported by cold-formed steel joist in low-rise residential structures by finite element analysis and theoretical calculation based on consulting a grate deal of documents.To begin with, the tests on the evaluation of the vibration performance of residential floor system supported by cold-formed steel joist conducted at the Virginia Polytechnic Institute and State University and at the University of Waterloo were introduced in this paper, including the material characteristic, trial devices, test method, test parameters and the test data, and then the frequency and deflection of the test models, predicted by the ATC design method and the CWC design method were compared with the actual test results. The compared results show that the critical parameters which contribute to reduction of the uncomfortable vibrations is the span length, blocking patterns, ceiling, screw pattern and gluing the sub-floor, and that the CWC design method is better in prediction.For the more, finite element analysis is used to simulate each test floor system both under static and dynamic load in this paper in order to predict the vibration performance and identify the critical parameters. Members are modeled as shell elements and the screws connecting of the sheathings to the frame are modeled through coupling methods. The results of finite element analysis indicate that the span length, blocking patterns, ceiling, screw pattern and gluing the sub-floor could add the stiffness of this floor system, and the others such as support edges, joist-end conditions, blocking type and number of strapping rows are inconspicuous. The finite element analysis results are close to that of tests.At last, the floor system was assimilated to an orthotropic plate according to its mechanics characteristics. Then we developed a serials of practical formula for predicting the frequency and deflection of floor system supported by cold-formed steel C-sections on the basis of current research and theory about orthotropic plate.