Author: | Wong, Yau-keung |
Title: | Design development in moment connections between cold-formed steel members |
Degree: | M.Sc. |
Year: | 2000 |
Subject: | Building, Iron and steel Steel, Structural Structural design Hong Kong Polytechnic University -- Dissertations |
Department: | Multi-disciplinary Studies Department of Civil and Structural Engineering |
Pages: | x, 141 leaves : ill. (some col.) ; 30 cm |
Language: | English |
Abstract: | This paper presents findings of an experimental investigation with a number of tests on cold-formed steel column members with bolted moment connections under lateral loads. A total of 8 component tests with different connection configurations were carried out to examine the strength and the stiffness characteristics of the test specimens. Various moment connection configurations with gusset plates of hot rolled steel were proposed to accommodate members in practical orientations. Two types of cold-formed steel, two lipped C sections back to back and a box C section with interconnections, are used as column members. Only the webs of lipped C sections are connected with bolts. From the experimental investigation of cold-formed steel columns with bolted moment connections, the mode of failure was identified as flexural failure of connected members. The maximum moment resistance of the column base connections is to be found 60% and 100% of the moment capacity of the connected double lipped C sections and the connected box C sections respectively among the eight tests. It is demonstrated that moment connections among the cold-formed members were structurally feasible and economical through rational design. It is also found that the pitch distance of the bolt group is preferably specified between 180mm to 240mm. It was because the moment capacity of the members would not be increased significantly even the pitch distance is increased further. It is also not practical to use larger gusset plates for bolted moment connections in cold-formed steel sections. Moreover, four different specimens of the cold-formed steel members were tested under the lateral load using strain gauges to investigate the stress distribution in the connection in order to understand the structural performance of the connected members. It was found that the difference between the moment obtained from the test and that measured from the strain gauges is in a range between 93% to 115% for lipped C sections and 76% to 119% for box sections. The moment resistance of the bolt group may be obtained from the difference of the applied moment at two locations of the connections based on the measured stress distribution obtained from the strain gauge measurement. Based on the finding of the eight numbers of tests on cold-formed steel column bases under a lateral load, a calibration exercise was performed to validate a set of supplementary design rules for bearing resistance of the bolted connections and flexural failure of connected member against the test data. Those supplementary design rules have been proposed in some research works(8,9). In addition, plastic hinge analysis was also demonstrated to be applicable in predicting the lateral load resistance of cold-formed steel portal frames, thus, simplifying the entire design process while utilizing materials at high structural efficiency. |
Rights: | All rights reserved |
Access: | restricted access |
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File | Description | Size | Format | |
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b15320595.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 7.08 MB | Adobe PDF | View/Open |
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