Ductility and Ultimate Capacity of Concrete-Filled Lattice Rectangular Steel Tube Columns

A kind of concrete-filled lattice rectangular steel tube(CFLRST)column was put forward.The numerical simulation was modeled to analyze the mechanical characteristic of CFLRST column.By comparing the load-deformation curves from the test results,the rationality and reliability of the finite element model has been confirmed,moreover,the change of the section stiffness and stress in the forcing process and the ultimate bearing capacity of the column were analyzed.Based on the model,the comparison of ultimate bearing capacity and ductility between CFLRST column and reinforced concrete(RC)column were also analyzed.The results of the finite element analysis show that the loading process of CFLRST column consists of elastic stage,yield stage and failure stage.The failure modes are mainly strength failure and failure of elastoplastic instability.CFLRST column has higher bearing capacities in comparison with reinforced concrete columns with the same steel ratio.In addition,the stiffness degeneration of CFLRST column is slower than RC column and CFLRST column has good ductility.

Seismic Behavior of Diaphragm-Through Connections of Concrete-Filled Square Steel Tubular Columns and H-Shaped Steel Beams

Based on the introductions of a type of diaphragm-through connection between concrete-filled square steel tubular columns (CFSSTCs) and H-shaped steel beams,a finite element model of the connection is developed and used to investigate the seismic behavior of the connection.The results of the finite element model are validated by a set of cyclic loading tests.The cyclic loading tests and the finite element analyses indicate that the failure mode of the suggested connections is plastic hinge at the beam with inelastic rotation angle exceeding 0.04 rad.The suggested connections have sufficient strength,plastic deformation and energy dissipation capacity to be used in composite moment frames as beam-to-column rigid connections.

Influence of Axial Load Ratio on Shear Behavior of Through-Diaphragm Connections of Concrete-Filled Square Steel Tubular Columns

Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular columns. The analysis reveals that smaller axial load ratio can improve the shear bearing capacity and ductility while larger axial load ratio will decrease the shear behavior of the through-diaphragm connections. The parametric studies indicate that the axial load ratio should be limited to less than 0.4 and its influence should be considered in the analysis and design of such connections.

Low cyclic fatigue performance of concrete-filled steel tube columns

Eight concrete-filled steel tubular(CFT) columns were tested subjected to cyclic loading under constant axial load. Experimental parameters included axial compression ratio, loading sequences, and strength of concrete and steel. The seismic performance of CFT columns and failure modes were analyzed. The test results show that different axial load ratios and loading sequences have effects on the load carrying capacity, ductility and energy dissipation capacity of CFT columns, as well as the failure modes of the CFT columns. The failure pattern can be categorized into two types: local buckling failure of steel tube in compression zone, and low cycle fatigue tearing rupture failure of steel tube. The seismic behavior was evaluated through the energy index obtained from each cycle.

往复荷载作用下钢管混凝土格构式柱地震损伤模型及试验研究

为了解巨型组合结构体系中钢管混凝土格构式柱的地震损伤情况,通过对4根四肢钢管混凝土格构柱低周往复荷载试验,得出了四肢钢管混凝土格构柱在低周往复荷载下的破坏形态和构件损伤特征。在试验分析基础上,对经典的Park-Ang损伤模型进行了修正,提出了适用于四肢钢管混凝土格构柱的损伤指数和耗能因子计算公式;并根据试验现象和各阶段特征,选取了经典的Park-Ang损伤模型、基于能量的损伤模型和改进的Park-Ang模型进行对比研究。结果表明:改进的Park-Ang模型能较好的判断四肢钢管混凝土格构柱的损伤程度,且通过损伤值可将构件损伤划分为是否可修、不可修但未破坏和不可修且将破坏三个阶段,并以损伤值0.4作为划分试件是否可修的界限。

某重型钢结构厂房设计

本工程为带有多层行车的重型钢结构厂房,竖向构件采用钢管混凝土格构柱+H型钢柱,屋面采用变截面钢梁。本文主要介绍该工程的结构设计思路、构造要求、计算依据和结果,文中还对钢管混凝土格构柱的设计做了较深入的阐述并对其经济性提出了一些看法。

高强度花岗岩地层中支护结构施工技术优化与应用

在超厚硬岩地质条件下,采用冲击桩机成槽、成孔时,经常会出现桩锤破岩能力低、锤齿磨耗严重等问题。以东莞市城市快速轨道交通线网控制中心综合体工程基坑工程为例,分析了在超厚硬岩地质条件下的施工难点,并提出相应对策,即通过选用高强度合金钢锤齿、对超厚硬岩进行控制爆破以及格构柱立柱桩采用“大桩变小桩、角钢改钢管”等综合施工技术,解决了成槽、成孔效率低,施工成本高的难题。该技术可为同类地质条件下支护结构施工提供借鉴。

某重型钢结构厂房结构设计

对设有300t吊车的重型钢结构厂房进行方案比选,采用12m柱网钢管混凝土格构柱,并对处于受力关键部位的肩梁、基础设计进行说明。

双肢大钢管格构柱支撑架稳定性研究

梁柱式支架在桥梁建设中使用广泛,双肢大钢管格构柱支撑架纵横向连接系普遍采用焊接固定连接方式,存在工效低、安全风险大、气割方式拆除时易造成钢构件损伤浪费等缺点,而放弃这种焊接固定方式,选用便于快速安装拆卸的销栓铰接方式,就需要研究分析对双肢大钢管格构柱支撑架承载能力的影响。该文基于有限元分析,建立不同几何参数条件下的双肢大钢管格构柱模型,通过对比在竖向荷载作用下纵横向连接系采取不同端部约束条件,对模型进行屈曲分析,从理论上研究纵横向连接系采用铰接与固接对双肢大钢管格构柱支撑架稳定性的影响。不同的模型计算结果表明,纵横向连接系铰接边界条件与梁端固定边界条件相比,其结果具有相似的变化规律,整体稳定性能仅略有降低,为选用销栓铰接方式并确保整个支架体系施工安全提供了理论依据。该文提出的能快速安装拆卸的销栓铰接设计方案,可为装配式施工的实际工程运用提供参考。

杭州国际博览中心结构初步设计

杭州国际博览中心长约432m,宽约264m,规模大、功能多,结构体系较复杂。工程主体部分采用钢管混凝土柱与大跨钢桁架组成的框架结构,屋顶花园钢结构采用曲面钢网壳和单层球壳,附属办公楼采用现浇混凝土框架-剪力墙结构。介绍了初步设计中的一些关键性问题及相应的技术措施,包括荷载取值、结构分析与选型、超限情况及抗震性能化设计、结构超长论证分析等,该工程目前已经通过超限审查。

佛山西站单层网壳雨棚结构设计关键技术

佛山西站无站台柱雨棚采用连续10拱单层圆柱面网壳结构形式,雨棚柱支承边界条件复杂,雨棚结构纵向、横向多处跨缝。对该单层网壳雨棚结构设计的几个关键问题进行了探讨,包括单层网壳整体稳定性分析,空间受力复杂的柱头铸钢节点分析,复合受力圆钢管相贯节点计算,雨棚柱柱脚节点设计,站房结构、桥梁结构及站台雨棚整体模型分析以及无站台柱雨棚抗连续性倒塌分析。分析结果表明,该单层网壳结构连接节点构造合理、受力可靠,具有较高的整体稳定承载能力和抗连续性倒塌能力。