analysis with excellent accuracy The numerical results obtained using the Updated Lagrangian and the Co-rotational elastic beam elements are used to select the framework in which the 3-D plastic-zone element is formulated, and to justify some of the approximations that are introduced to the fomulation. It is demonstrated through numerical examples that quite excessive plastic-zone beam elements have been used by previous researchers, greatly exacerbating the inefficiency of plastic-zone analysis. In general, only 3 elements are required to accurately model a storey column, and 4 or 5 elements are sufficient for a base column with a rigid support. A series of advanced analyses and second-order elastic analyses/designs are carried out on two steel space frames composed of circular hollow sections. Various shortcomings of th latter procedure are illustrated and explained. The rotation capacity required of circular hollow sections is also investigated in the case study. The theoretical weight savings that can be achieved through the use of advanced analysis to design the steel space frames are computed for different conditions. The issue concerning the appropriate capacity factor to be used in advanced analysis is also discussed A simple yet effective branch-switching algorithm for tracing the secondary equilibrium path of elastic framed structures is presented in an appendix. Another appendix contains a concise review on the behavior and strength of semi-rigid steel frames. Words and Expressions νt.放弃,停止 tion n.感觉 controversy n.争论,论战 inconsistencies n.不一致,矛盾,不相容 spatial ad.空间的,立体的 年到头的,不断的 tead.共轭的 Irrespective城.不顾的,不考虑的,与……,无关的 commutativity n,可交换性 preceding ad.前面的,以前的 Langrangian n.ad拉格朗日算符,拉氏算符 tangent n.切线 d.切线的 Wagner effect Wagner效应 cubic ad.立方的,正面体的 fyv.ⅵ.证明合理,正确 approximation n.近似,接近 excessive ad过度的,非常的,极大的 g 加重,激怒,恶化
空间刚架 shortcoming 缺点,不足 6.2 The Behavior of Thin-walled Concrete Filled Steel Tubes Thick-walled concrete filled steel tubes have been under extensive experimental investigation for many years due to the inherent advantages of this type of member. Recently due to economic considerations, thin-walled steel tubes, often in conjunction with high strength concrete, have become popular(multi-story building construction, bridge piers and foundations). However there is very little available research which has been conducted on the behavior of this type of member. In this thesis an extensive experimental investigation into the behavior of thin-walled steel tubes filled with medium to very high strength concrete is presented The response of the unfilled steel tube has been experimentally investigated. the axial load was applied concentrically and for some specimens at small eccentricities. The restraint provided by an internal medium was experimentally modeled for axially loaded tubes. The complete material properties of the thin- walled steel tubes were measured. This included residual stresses and geometric imperfections. Confinement of medium to very high strength concrete by thin-walled circular steel tubes has been experimentally investigated. Three different axial compression tests were conducted which inchuded: concentrically loading the steel and concrete simultaneously; concentrically loading only the concrete(steel unbounded and only used as confinement ); and eccentrically loading the steel and concrete simultaneously at eccentricities of D/20 and D/10, where d is the extemal diameter of the steel tube The results from the experimental investigations have been compared to estimates from several design methods. After modification, these design methods can be used to conservatively estimate the strength of thin-walled steel tubes filled with medium to very high strength concrete under the examined loading conditions Words and Expressions inherent ad.国有的,本来的,内在的 mult- storey多层 pIer h.桥墩 unfilled ad.空的,未填满的 eccentricity 偏心距,离心率 straint n押制,制约,约束 residual ad.剩余的,残余的 imperfection n.缺陷 confinement n密封,限制,约束
unbonded adi无束缚的,自由的 simultaneously ad同时,一起 estimate 估计,预算 modification n.修正,改变,处理 6.3 Effects of Differential Settlement on Storage Tank shells In this thesis, attempts have been made to highlight the influence of the differential(uneven) settlement on the shell of closed and open-top steel storage tanks, with special attention given to understanding of the physical response of the practical cylinders, which have non-uniform shell thickness. Settlement is imposed as a vertical translation at the base, generally but not exclusively in the form of harmonic curves. Both theoretical and experimental investigations are carried out to fulfil this aim In theoretical approach, inextensional theory, membrane theory and semi-membrane theory ave been applied for linear analysis of the shell. a simple expression has been developed for maximum meridional stress resultant at the bottom of the shell of closed-top tanks,verses maximum settlement. Finite Element Analysis(FEA), regarded as the most accurate solution, was sed to gain insight into the behavior of more realistic cases, to assess the accuracy and limitations of the more limited solutions, and to carry out parametric studies at different levels of taper, aspect ratios and slenderness. Sensitivity of closed-top cylinders to circumferential restraints at the top was figured out and then assessed in the numerical study. The finite element analysis has also been carried out on the refined mesh models both in linear buckling and nonlinear approaches. In a linear buckling parametric study the buckling of cylindrical panels, as a part of whole cylinder, have been investigated leading to developing an expression for critical stresses and critical ttlements of cylinders under edge de formation. In limited geometries, the nonlinear and post-buckling behavior of tanks under harmonic settlements have been studied with attention given to the effect of imperfection and internal pressures on the shell behavior The experimental program has been conducted on seven precisely machined steel specimens of 600 mm diameter with uniform and stepped wall shells by using a test rig completely designed by researcher. Both open and closed top models were tested under low imposed settlement in a linear approach and large settlement in the non-linear and post-buckling study. Particular attention has been given in the measurement of circumferential stresses developed in the girder of open top models and meridional stresses at the base of closed-top models. The buckling mode of shear form have been experienced in the uniform shells and at the top of stepped shells Words and Expression differential (uneven) settlement不均匀沉降,差异沉降,沉降差
highlight n.重点 vt.着重强调,成为注意的中心 open-top断口式的 v.v施加,利用 inextensional ad.非伸编的 n.薄膜 meridional d.最高的,子午线的 insight n.洞察,深入了解 斜度 circumferential ad.圆周,周长 refined ad.严密的,精确的 网格,筛格 n.底板,翼片 imperfection n.缺陷 桁架 girder steel工字钢,钢梁 6.4 Behavior of Purlin Sheeting Systems Roof and wall systems often consist of cold-formed steel channel or Z-section pu TrAIns crew.fastened to high tensile profiled steel sheeting. The objective of this thesis is to investigate the behavior of these roof and wall systems. For this purpose, both theoretical and experimental studies have been performed A non linear elastic purlin analysis, developed for the specific purpose of determining the lateral deflections of, and stresses in, the unconnected flanges of simply-supported and c purlins screw fastened to sheeting and subject to wind uplift loading, is described. The analysis incorporates a purlin design model, which models the distortional behavior of screw-fastened purlins under wind uplift loading. The purlin design model includes the torsional restraint provided by the sheeting to the purlin. By including the distortional and local (flange-web)buckling failure stresses in the non-linear analysis, purlin failure loads and failure modes can be predicted Two experimental investigations are presented. In the first investigation, purlin-sheeting connection tests were performed in an effort to quantify the magnitude of the torsional restraint provided by sheeting to a screw-fastened purlin. In particular, the effect of the location of the screw-fastener on the magnitude of the restraint was examined In the second investigation, a seri of full-scale vacuum rig tests simulating wind uplift loading on simply-supported screw-fastened channel and Z-section purlins was described. The purpose of the tests was to obtain accurate non-linear response data for unbridged (unbraced) purlins, and for purlins with intermediate bridging
The failure loads, failure modes, lateral deflections and stresses of the screw-fastened purlins in the vacuum rig tests are compared with those predicted by the non-linear analysis. In addition, the failure loads and failure modes of both simply-supported and continuous screw-fastened purlins determined from vacuum rig tests conducted earlier are compared with those predicted by the non-linear analysis. The accuracy of the non linear analysis in predicting purlin failure loads and failure modes is examined From the failure loads predicted by the non-linear analysis for the simply-supported and continuous screw-fastened purlins subject to wind uplift loading, R-factors have been calculated. The calculated R-factors are compared with the R-factors in the proposed Australian/New Zealand design standard The potential of using the non- linear analysis to determine R-factors in order to minimize testing is discussed, including calibration of the design model for limit states design Words and Expressions purlin(e)n.檩条 螺栓 fasten v.ⅵ.固定,连结 vv.做成型材 n.凸缘 lift v.n.提高,升起 distortional n.变形的 ify 确定 rIg n.设备,装备 unbridged 减.无支撑的 使……最小 calibration 校准,检查 6.5 The Behavior of Bolted Moment End Plate Connections in Rectangular Hollow Sections Subjected to Flexure The main objective of this thesis is to investigate the behavior of bolted moment end plate connections joining square(SHS) and rectangular(RHS) hollow sections subjected to pure flexural loading. The studies carried out into this type of connection include experimental, theoretical and numerical and design aspects An extensive test program into the behavior of two types of bolted end plate connections was carried out. The experimental tests were performed on beam splice connections located at the midspan of a beam subjected to four point bending. The four-point bending arrangement ensured that the connection was subjected to flexural loading only