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Study On The Mechanical Propertoes Of Concrete-Filled Steel Tube Column And Steel-beam Fabricated Joints

Posted on:2012-06-13Degree:MasterType:Thesis
Country:ChinaCandidate:J F ZhaoFull Text:PDF
GTID:2132330332983914Subject:Structural engineering
Abstract/Summary:PDF Full Text Request
Concrete-filled steel tube structure with high bearing capacity, plasticity and toughness, convenient construction, fireproof performance and good economic efficiency etc., is a structure with good developing prospects. Because of concrete filled steel tube with prominent superior performance and economic benefits, along with the development of the high-rise building, the application of concrete-filled steel tubular structure is becoming more and more popular. But node is a difficult problem in application of the concrete-filled steel tube structure and restricts the extension and application of the structure with electro-optical properties in engineering. The design of concrete-filled steel tube column-beam joints is one of the key links which are applications in practical engineering of concrete-filled steel tube structure, so we should focus on researching. Although the study of nodes is quite widespread both at home and abroad, there are still much insufficient, dynamic performance of node is the key of not only designing but also construction, The concrete in steel tube is necessary to casting first for top-down construction method, and concrete brings a lot of inconvenience to construction of nodes which need through concrete-filled steel tube structure and also destruct the concrete-filled steel tube that already bear load, unfavorable to structure, so this paper puts forward a new kind of concrete-filled steel tube node form that facilitating construction, and proceeds the low weeks reciprocating cycle load on the node, later proceeding theoretical analysis on the test result, and studying in-depth on the hysteretic behavior of the node and the influence law of some parameters on node properties. The specific jobs as follows:First,I made six concrete-filled steel tube cross outside reinforcement ring fabricated node which is one to three reduced models, and carry on the low cycle reciprocating cycle load test. I introduce damage phenomenon of each node in detail, and get bearing capacity, rigidity degeneration, energy dissipation and ductility feature of new concrete-filled steel tube node in the low cycle reciprocating load through test analysis. The bearing capacity is slightly lower than the theoretical design value, intensity and stiffness degradation is not apparent in the loading process, ductility and energy dissipation index both conform to code for seismic design of building regulations,it explain this node achieved the seismic design requirements.Secondly, according to reinforcing rings reinforcement plate size, reinforcement ring board form, axial compression ratio, node area reinforcement or not four parameters which are set when designing node specimens,I analyze the influence law about various factors on the bearing capacity and stiffness degradation, ductility performance, dissipation characteristics and load-bearing performances and failure mechanism of nodes.Finally, I study strain stress distribution rule and power transmission mechanism of the node reinforcement ring board, beam, steel tube wall of the node using the theory analysis, analyze the node rigid qualitative estimate based on the deflection analysis, reference related design codes, calculate the bearing capacity of such node.Test and theoretical analysis results show that the load-displacement hysteresis curve of the node of different ring plate size, node area reinforcement form and axial compression ratio are relatively full in early times, without apparent knead shrinkage phenomenon, has sufficient bearing capacity and better ductility and energy dissipation capacity, the degradation of stiffness and strength is not obvious, but at later period because of stress concentration at steel girder flanges and reinforcement ring board place, which enables bearing capacity of nodes declined sharply, lead to the failure of the load, explain such node has excellent seismic energy dissipation capacity, but there are some problems at steel and ring plate joint place. Concrete-filled steel tube beam-column reinforcement ring fabricated nodes are the same as ordinary reinforcement ring nodes and can be regarded as rigid connection, will be able to realize the seismic design concept of "strong column and weak beam" and plastic hinge formed in the ring and beam intersection place, its construction accord with the requirement of architectural design, can be used in design of seismic zone, and the construction is more concise and reasonable, it will have a better applicability certainly, it is of high popularization value.
Keywords/Search Tags:concrete-filled steel tube, Beam-column joints, Hysteresis curve, Seismic performance, Stress distribution, Stiffness
PDF Full Text Request
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