Behaviour of composite beam-column flush end-plate connections subjected to low-probability, high-consequence loading

This paper aims to investigate the performance of beam-column flush end-plate connections when using blind bolts. The paper studies the strength on medium rise buildings in regions of medium to high seismicity. This paper presents the result of both experiments and finite element analysis on composite beam-column flush end-plate connections subjected to low-probability, high-consequence loading. The earthquake actions were determined using the earthquake code, AS1170.4, Standard Australia (2004) [44]. Considerable savings were apparent when moving from a pinned connection to a semi-rigid connection. Not only in terms of weight savings, but more importantly the ability to reduce the floor-to-floor heights, which can considerably reduce the cost of services and facades and subsequently mass and inertia of the structure. This can also result in more lettable floor space due to reduced column sizes and the possibility of adding another floor for the same total height compared with the pinned connection. The experimental studies and finite element analysis enables improvement to the design of the connections to be used in engineering practice.     

卧式多级离心泵的检查与维修

介绍了多台高压卧式多级离心泵不同程度的转轴抱死现象,重点分析了故障引发的可能原因,通过反复调试,逐项排除各种因素,最终发现驱动端轴承支架径向固定方式不合理,后经改进处理和试运行,证明此种处理方式适当,其他同型号的泵也依次处理,消除了设备隐患,确保了机组安全、稳定运行。     

风电塔筒基础的设计研究

风电塔筒与基础连接一般采用地脚螺栓,因个别螺栓拧紧时断裂,处理较困难,有的工程改为埋入式基础.即在基础内埋置一段钢筒,与上部塔筒采用高强螺栓法兰盘连接,螺栓即使拧断,也可轻易更换.但这种基础受力较差,国内外均有整体拔出时出现倒塌事故的案例,且造价也较高.对风电塔筒基础设计进行研究,采用合理的地脚螺栓连接形式,可避免预埋...     

重庆朝天门长江大桥主桥钢梁安装设计

重庆朝天门长江大桥主桥采用(190+552+190)m中承式连续钢桁系杆拱桥结构,为双层桥面布置的公轨两用大桥,也是世界上跨度最大的拱桥.主梁边跨采用临时墩辅助的伸臂法架设,中跨采用扣索塔架辅助伸臂安装,先合龙主拱,再合龙系杆.主桁杆件的设计与安装步骤及控制工况息息相关,需要确定各个施工工况下扣索及临时系索的索力、保证...     

轨枕螺栓扳手冲击机构的设计计算

介绍了一种用于铁路轨枕螺栓装卸工作的电动冲击扳手,对其冲击结构及工作原理做了详细的阐述,给出了行星减速器传动比的求解公式以及在冲击过程中主压力弹簧和冲击块的动力学计算模型,并进行了计算。为其他电动冲击扳手的设计提供了一种简便而合理的动力学计算方法。     

连铸工程钢包回转台安装

主要介绍了连铸工程钢包回转台的安装方法,结合以往工程实际,从设备吊装方案的选择、主要安装工序和施工方法、施工注意事项等方面进行了阐述,旨在为以后类似工程中高效完成钢包回转台安装给予借鉴。     

加固用钢结构栓焊并用连接承载性能研究

栓焊并用连接节点在钢结构加固工程中具有很好的应用前景,但螺栓连接与焊接连接的刚度和延性的差异,使得栓焊并用连接受力性能复杂,其承载能力并不是螺栓连接与焊接的简单叠加。进行了高强度螺栓摩擦型连接与侧端部角焊缝并用连接试件承载性能的试验研究,得到了摩擦型高强度螺栓连接与角焊缝焊接的并用连接试件的承载力与螺栓和焊缝承载力的关系,分析了栓焊并用连接节点的承载性能。结果表明,高强度螺栓摩擦型连接与侧焊缝焊接连接在一定的强度范围内可以很好地共同工作。根据试验结果提出了栓焊并用连接节点的设计建议。     

转角塔斜柱斜面式基础施工控制方法

介绍了地脚螺栓不带火曲斜柱斜面式基础施工中转角塔坑底根开,基础顶根开,基础预偏的计算以及施工中对根开、坡度、高差的全过程控制,结果表明：该方法能够高效控制塔脚板与塔腿主材中心线的重合,并能够在施工过程中精密控制技术尺寸。     

A numerical model of fully grouted bolts considering the tri-linear shear bond–slip model

A numerical model of fully grouted bolts is proposed in this study by implementing the tri-linear bond–slip relationship of bolts into the numerical framework presented by Hyett et al. (1996). The bond–slip relationship of bolt–rock interface is simplified and represented by the tri-linear model. The proposed numerical model is characterized by (1) its ability in modeling decoupling mechanism of bolt–rock interface, i.e. the degradation of the interfacial shear bond stress along bolts; (2) its easy implementation in a numerical code. The proposed numerical model is verified with the pullout tests, and good agreements with the experimental results can be observed in terms of axial stress distributions in the bolt, shear stress distributions along the bolt and load–displacement relationship. The proposed model also gives a reasonable prediction on the behavior of bolts installed in the field.     

WJ-7型扣件在列车冲击下动力仿真分析

为了分析WJ-7型扣件弹条在列车高速运行下所引起的铁轨对弹条的冲击影响,采用Midas FEA有限元软件建立详细的扣件系统有限元模型,基于车辆-轨道耦合动力学理论,分析WJ-7型扣件弹条在安装过程中的受力及列车冲击荷载作用下的受力特性,对比分析静力与冲击力下的应力大小与位置和不同冲击力下的应力位置与大小。弹条在1、2和3k N冲击力作用下,弹条的最大应力发生在与铁垫板接触的部位,最大应力为1853MPa。10k N的扣压力下的静力分析,弹条的最大应力同样发生在与铁垫板接触的部位,最大应力为1765MPa。随着列车的反复通过,弹条容易在这区域萌生裂纹最终裂纹扩展导致弹条发生疲劳断裂。数值分析结果与现场多处弹条断裂破坏位置吻合,分析结果可为以后弹条的设计,优化,安全提供参考依据。