Finite Element Analysis for Seismic Behavior of Bolted Beam-Column Connections in CFT Structures
Date Issued
2007
Date
2007
Author(s)
Huang, Guo-Luen
DOI
en-US
Abstract
From researches, the deformation capacity of the conventional beam-column connections is seriously inadequate. The brittle failure usually occurs at the welding zone. The design of bolted beam-column connections is that welding is carried out at the shop and bolting at the site, thus the guality of the welding can be assured. Moreover, wing plates are welded at beam ends in bolted beam-column connections to make sure that plastic hinges are away from the welding zone. Researches proved that the bolted beam-column connections have excellent seismic resistance satisfying seismic design codes of Taiwan and the US as long as the width-to-thickness of columns, end-plate thickness and wing-plate width suffice for the corresponding limits. In this dissertation, the finite element program ABAQUS is adopted to analyze the influences of wing plates, end plates and stiffeners between flanges to bolted connections, and the seismic hehavior of bolted beam-column connections. Through the convergence analyses collocating the analysis procedure “Riks”, the numerical load-displacement envelope curves are close to the experimental envelope curves. From numerical results, it is proved that the plastic hinge is away from the welding zone as long as the wing-plate width and length are allowable from caculating the design formulas; the brittle fracture of the end plates can be prevent as long as the end-plate thickness is allowable from caculating the design formulas and the upstanding ribs are used; the occurrence of the plastic hinges can be delayed as long as the stiffeners are welded between flanges. For uni-directional bolted connections of rectangular CFT structures, numerical results prove that the design of width-to-thckness ratio of the steel tube can change the main energy-dissipation component. The energy is dissipated by beams when the width-to-thckness ratio is smaller. The energy is dissipated by the panel zone when the width-to-thckness ratio of the steel tube is larger. The energy can be dissipated by the panel zone and the beam at the same time when the width-to-thckness ratio of the steel tube is critical. For bidirectional bolted connections of rectangular CFT structures, numerical results prove that the strength and stiffness of the panel zone can be improved by the pre-stresses of the bidirectional bolts, thus the main energy-dissipation component is the beam. For circular CFT structures, numerical results prove the feasibility of the bolted beam-column connections. Overall, the bolted beam-column connection is certainly a kind of excellent seismic resistant connection.
Subjects
有限元素分析
耐震行為
翼翅擴板
彎撬現象
螺栓式接頭
finite element
seismic behavior
wing plate
prying action
bolted connection
Type
thesis
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