基于支持向量机的混凝土泵车支腿故障诊断方法

针对混凝土泵车支腿频繁发生开裂的问题,提出了一种基于支持向量机的故障诊断方法。混凝土泵车在施工过程中,施工状态的不同,直接影响到支腿的承载情况。对支腿故障进行分析,找出支腿最易出现开裂的关键位置,研究出了影响支腿关键位置承载的主特征量,搭建关键位置受力的支持向量机预测模型。运用MATLAB编写支持向量机预测程序,对模型进行训练和验证,通过输出的应力曲线图对支腿故障进行预测。实例验证了支持向量机对支腿关键位置应力预测的可行性。该方法相对于BP神经网络在小样本上更加精确,并为泵车工况参数的选择提供了理论支持。     

深圳大百汇主塔楼结构设计与分析

深圳大百汇主塔楼高度为375m,超高层主塔楼是集办公、酒店、公寓和商业为一体的综合体,结构体系采用带伸臂桁架与腰桁架的钢管混凝土柱-钢梁框架-核心筒混合结构体系。塔楼建筑立面呈纺锤形,外框柱沿曲线布置而形成一系列的斜柱。介绍了主塔楼结构方案的确定方法及结构设计重点,描述了曲线布置的斜柱体系对抗侧刚度的提高效应、伸臂桁架的选取及优化、斜柱引起钢梁水平轴力的计算方法,基于性能抗震思想对结构及构件进行大震性能评估。结果表明塔楼整体刚度与构件满足抗风与抗震的性能要求。     

Distribution of strong earthquake input energy in tall buildings equipped with damped outriggers

The seismic design of optimal damped outrigger structures relies on the assumption that most of the input energy will be absorbed by the dampers, whilst the rest of the structure remains elastic. When subjected to strong earthquakes, nevertheless, the building structure may exhibit plastic hinges before the dampers begin to work. In order to determine to which extent the use of viscously damped outriggers would avoid damage, both the host structure's hysteretic behaviour and the dampers' performance need to be evaluated in parallel. This article provides a parametric study on the factors that influence the distribution of seismic energy in tall buildings equipped with damped outriggers: First, the influence of outrigger's location, damping coefficients, and rigidity ratios core‐to‐outrigger and core‐to‐column in the seismic performance of a 60‐story building with conventional and with damped outriggers is studied. In parallel, nonlinear behaviour of the outrigger with and without viscous dampers is examined under small, moderate, strong, and severe long‐period earthquakes to assess the hysteretic energy distribution through the core and outriggers. The results show that, as the ground motion becomes stronger, viscous dampers effectively reduce the potential of damage in the structure if compared to conventional outriggers. However, the use of dampers cannot entirely prevent damage under critical excitations.     

液压传动在汽车起重机设备中应用及故障排除

液压传动是机械设备自动化装置中的重要组成环,本文通过对液压起重设备工作原理的详细剖析,详述了起重机设备中的回转、起吊、变幅及起升等机构的工作原理,并对液压起吊设备在工作过程中出现的常见故障进行详细分析,并给出各种故障诊断的排除方法,最后总结其各分油路的结构特点,为改进和设计新的液压系统油路提供借鉴和参考。     

普利中心结构设计和分析

普利中心主塔楼为总高度300 m的超限高层,采用钢管混凝土柱框架+型钢混凝土核心筒+环带桁架+等效伸臂的混合结构体系。介绍该工程地基基础的设计、结构体系的特点、抗震性能化设计原则和方法、整体弹性计算结果以及罕遇地震作用下的动力弹塑性分析结果。着重阐述设计中的一些关键问题,包括核心筒的剪力墙、外围钢管混凝土钢框架、仅设置环带桁架的加强层、全楼层角部全刚接钢框梁形成的等效伸臂等。     

沈阳市府恒隆广场伸臂桁架C型槽超厚板焊接质量控制技术

沈阳市府恒隆广场项目整体采用型钢混凝土框架-核心筒结构体系,造型独特,整个塔楼在L23—L25、L41—L43、L59—L61设置加强层,整个加强层由伸臂桁架与腰桁架组成,介绍其加强层伸臂桁架C型槽超厚板焊接方法,该方法有效改善厚板焊接施工质量控制难、焊接质量难以保证等问题。     

Analysis of a high‐rise steel structure with viscous damped outriggers

Damped outriggers for tall buildings draw increasingly attentions to engineers. With a shaking table test, two models of a high‐rise steel column‐tube structure are established, one with outriggers fixed to the core and hinged at the columns, whereas the other's cantilevering outriggers are connected to columns by viscous dampers. According to their dynamic properties, five earthquake waves are selected from the Ground Motion Database of Pacific Earthquake Engineering Research Center (PEER), and two artificial waves are generated by software SIMQKE_GR. Under various peak ground accelerations (PGAs), nonlinear time‐history analysis is applied to compare structural elastic seismic responses, including accelerations, inter‐story drifts, base shear force, damper's response and additional damping ratios. It is concluded that under minor earthquakes, accelerations, inter‐story drifts and base shear force of structure with damped outriggers are larger than or nearly equal to those of the one with fixed outriggers, and the viscous dampers hardly work. But as PGA increases, the contrary situation happens, and the effect of viscous dampers is enhanced as well. The additional damping ratio reaches around 4% under mega earthquakes. Copyright © 2013 John Wiley & Sons, Ltd.     

香港超高层钢结构工程施工技术

介绍香港环球贸易广场钢结构施工技术,包括塔吊布置、主体钢结构施工、大楼周边安全防护、垂直运输设施等的施工技术。     

上海外滩中信城Ⅰ期塔楼结构优化设计

本文对上海外滩中信城Ⅰ期塔楼的结构设计方案进行了优化。通过调整核心简墙体厚度、柱位布置,将钢骨混凝土柱改为钢管混凝土柱,调整伸臂桁架加强层等措施,获得了很好的效果。减轻结构自重的同时,也减小了地震作用,结构刚度变化更为和顺,延性提高,还增加了使用空间。与原设计相比,节约混凝土约1．27万m^2、钢材825t,减少桩75根,增加有效使用面积约1800m^2,带来的经济效益约合人民币5000万元。     

Improved analytic method for outrigger structures considering floor stiffness

Current analytical models for outrigger structures in super high-rise buildings tend to oversimplify by not considering the stiffness of individual floors. This paper introduces a more refined calculation model, based on the substructure method, which takes floor stiffness into account. To verify our proposed approach, we derived a mathematical algorithm and developed a finite element model using ANSYS. When compared to traditional methods that only account for outrigger stiffness, our model, which incorporates both outrigger and floor stiffness, provides improved accuracy in calculating vertex displacement. It also suggests an upward shift in the optimal position for the outrigger and bolsters the overall building's lateral stiffness. To further our analysis, we introduced an equivalent stiffness calculation formula, using the Bayesian parameter estimation method. When applied to dynamic analysis, this formula aligns closely with the results from the finite element simulations. Furthermore, the suggested algorithm for determining the best position for the outrigger is consistent with theoretical calculations. By considering the contribution of regular floors to the overall structure, we found that the fitted equivalent core tube stiffness offers a reliable reflection of structural stiffness. Lastly, when this equivalent stiffness was applied to a dynamic analysis based on Rayleigh's energy method, there was a noticeable reduction in computational effort. This yields not only more efficient calculations but also precise results, rendering it particularly valuable during the initial design phases of high-rise buildings.