庙嘴三江桥变截面箱梁挂篮设计与施工技术

庙嘴三江桥采用主跨210 m中央索面高低塔斜拉桥。文章介绍了中央索面变截面匝道箱梁牵索挂篮施工方案,通过引入液压同步技术,实现了牵索挂篮多点同步行走,解决了挂篮重心不对称的问题。实践证明,本项目牵索挂篮成功完成塔身处变截面匝道箱梁浇筑施工,大大提高了施工效率和经济效益,对类似的工程具有参考和推广价值。     

桥梁施工中悬臂挂篮技术的应用

文中结合大型混凝土桥梁工程的悬臂挂篮施工模式进行阐述,重点对施工工艺流程中的加载试验方法、挂篮行走步骤、合拢段施工模式以及挠度控制等方面进行技术分析,对类似桥梁工程的施工有着比较好的理论价值与实践意义.     

挂篮施工方法在天津港桥梁工程中的应用

根据天津港南疆港区复线公路桥工程的挂篮施工实践,简要介绍挂篮的主体构成、移动形式、拼装过程及挂篮施工程序,并就施工过程中挂篮的加载试验控制、移动控制、悬臂施工线型控制的内容和方法以及施工线型控制质量标准等做详细说明。     

不对称连续刚构桥稳定性分析

依托在建项目对不对称刚构桥采用悬臂施工过程中的整体稳定性进行分析,在成桥过程中的屈曲变形,经过分析在施工过程中悬臂越长结构受力越大。文章中模拟依托工程中的2号墩,结构右侧最后阶段挂篮失效,造成右侧挂篮和湿重混凝土掉落,在这种不对称状态下,2号墩结构为最不利受力状态,也是影响屈曲变形最不利的情况。     

公路大跨径预应力连续梁桥挂篮施工控制

以乌海黄河特大桥工程为实例,介绍了挂篮施工的流程,涉及设计、拼装、预压、行走及线形控制等方面内容,并针对合龙段施工工艺及质量控制进行分析,旨在提升公路桥梁工程建设水平。     

桥梁施工挂篮智能化控制系统研究

前支点挂篮主要依靠液压系统来完成挂篮的提升、下放、前移等工作,传统液压系统为油泵配合千斤顶单点操作,无法达到多点同步操作,施工投入人员多,自动化智能化集成化程度低。针对传统液压挂篮系统的不足,在乌江大桥主梁施工过程中,研发了国内外首创的前支点挂篮自动化液压控制系统,用以提高作业效率和减少劳动力投入。该系统将工业自动化控制技术引入到挂篮施工中,取得了良好的时间和经济效益,对进一步推动桥梁智能化设备的技术进步具有重要意义。     

挂篮施工在大型桥梁工程的应用及设计要点分析

挂篮施工技术应用于大型桥梁工程中,可在很大程度上提升工程的整体质量和性能,加快大型桥梁工程的施工进度。本文以某大桥主桥桥墩施工过程中采用的挂篮施工设计为例,详细说明挂篮施工在大型桥梁工程中的设计方法及计算要点。     

生米大桥T构挂篮施工工艺

以南昌生米大桥T构箱梁为例,介绍了挂篮设计的原则和方法,详细介绍了挂篮的组成和安装方法,以及挂篮移动操作过程、钢吊杆安装工艺以及悬臂浇注过程.提出了挂篮悬臂施工要注意的安全事项.     

连续梁悬臂施工抗倾覆控制关键技术

本文以S332新建皖河大桥主桥内侧主跨90m连续梁为例,从结构设计稳定性验算、墩顶临时固结技术、不平衡荷载控制技术、挂篮施工过程防坠落技术等方面进行大跨径连续梁挂篮悬臂施工过程T构防倾覆控制技术介绍,通过一系列有效的控制措施,确保了结构体系的安全稳定。为以为其它类似项目的施工方案选择、施工过程控制提供经验。     

悬臂挂篮技术在桥梁施工中的应用探索

在桥梁施工高空作业工程中,会应用到悬臂挂篮技术。先进的悬臂挂篮技术可以保证桥梁施工的工程质量,并且还保障桥梁施工运用悬臂挂篮技术时施工人员的人身安全。基于此,本文旨在对于悬臂挂篮技术在桥梁施工中的应用进行简要的探索研究,以期能够为桥梁施工领域内的施工实践人员提供一些参考。     

Research on the pipeline walking caused by cyclic increasing soil friction for free deep-sea submarine pipelines laid on even seabed

Pipelines are important to offshore oil and gas development, but suffers from the pipeline walking phenomenon due to cyclic temperature variations—where large axial walking distances threaten the safety of pipeline systems. Current research indicates that pipeline walking is triggered by steel catenary riser (SCR) tension, seabed slopes, or thermal transients. This paper proposes a new driving mechanism for the pipeline walking phenomenon, involving cyclic hardening soil strength. The finite element analysis method was adopted to analyse the soil friction difference induced walking phenomenon, and the influence of key parameters on the gain in soil friction on walking distance was studied. Pipeline walking distances under different drainage conditions in the heating and cooling processes were also calculated, and the impact of the degree of drainage in the heating process was determined. To better understand the new pipeline walking mechanism, theoretical analysis of the walking behaviour under different cyclic soil friction conditions was carried out. Analytical solutions for estimating the pipeline walking distance were also provided, based on the simplified theoretical analysis.     

QLY25B型轮胎式起重机行走减速箱（QLY25A-21C）的改造

日照港西港区件杂货码头QLY25B型轮胎式起重机经过数年使用,近年行走机构故障频发,尤其是行走减速箱部分齿轮磨损严重,必须进行改造。阐述了起重机行走减速箱工作原理,分析了故障原因,提出了改进措施。改造后的行走减速箱使用良好,行走机构故障率明显下降。     

Efficient methods to mitigate SCR-induced walking of short subsea flowlines

Steel catenary riser is a long-established option for subsea projects in deep-water regions. Sustained pulling force of steel catenary risers on subsea flowlines in combination with cyclic thermal load throughout the system lifetime may lead to progressive global axial displacement of subsea pipelines which has been termed as ‘walking’. One of the challenges in the deep-water industry is long-term walking of subsea flowlines in a cumulative manner. Common practice methods for walking mitigation are quite expensive operations. State-of-the-art mitigation strategies are proposed in the paper by means of modifying pipe pieces before the installation operation. Bowed pipe pieces and miter joints are two recommended approaches for walking mitigation. The presented mitigation strategies are relatively cost-effective solutions for the pipe-walking challenge and they are able to considerably cease the potential cyclic walking. Comprehensive FE analyses in ABAQUS software are performed to evaluate the proposed deformed pipelines response subject to two loading conditions. Through-life integrity of the suggested pre-deformed pipeline is assessed in terms of effective axial force, local buckles and excessive axial strains. A comparison of the presented method with conventional techniques shows the effectiveness of the proposed configuration. The proposed methods can significantly reduce effective axial force throughout the subsea pipeline by means of artificially introduced deformations. The cumulative walking of the presented method is practically zero. In addition, the influence of combined triggering mechanisms to the walking phenomenon is assessed when the pipeline is located on a sloping seabed and it is subject to non-uniform thermal loads. A parametric study is performed to improve confidence in design and provide a reasonably practical technique with an optimal shape.     

长江上游卵石输移运动规律研究及数值模拟*

基于长江上游东溪口卵石滩段的物理模型,开展了典型系列年卵石输移特征的试验。根据不同水动力条件下卵石输移的实测数据,从动力机理出发确定砾石输移速度。以此为基础,改进了二维数值模型,并将其应用于东溪口河段卵石输移过程模拟。将计算的卵石输沙分布及泥沙冲淤过程与实测值进行对比,卵石走沙轨迹与河道内走沙基本吻合,模拟泥沙冲淤变化与该河段实测分布一致。说明改进后的平面二维卵石推移质运动模型能较为真实地反映河道内卵石输移特性,可为解决长江上游卵石河段泥沙问题与航道整治工程提供理论与数据支撑。     

Motor Driving Leg Design for Bionic Crab-like Robot

The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, which has been used in the robot design. A three closed loop motor control system structure for joint driver is also given, as well as the multi-joint driving system for walking robot leg.     

用于海底ROV在强流干扰下的一种自适应防走滑装置（英文）

This paper proposed a new concept of an adaptable multi-legged skid design for retro-fitting to a remotely-operated vehicle(ROV) during high tidal current underwater pipeline inspection. The sole reliance on propeller-driven propulsion for ROV is replaced with a proposed low cost biomimetic solution in the form of an attachable hexapod walking skid. The advantage of this adaptable walking skid is the high stability in positioning and endurances to strong current on the seabed environment. The computer simulation flow studies using Solidworks Flow Simulation shown that the skid attachment in different compensation postures caused at least four times increase in overall drag, and negative lift forces on the seabed ROV to achieve a better maneuvering and station keeping under the high current condition(from 0.5 m/s to 5.0 m/s). A graphical user interface is designed to interact with the user during robot-in-the-loop testing and kinematics simulation in the pool.     

An adaptable walking-skid for seabed ROV under strong current disturbance

This paper proposed a new concept of an adaptable multi-legged skid design for retro-fitting to a remotely-operated vehicle （ROV） during high tidal current underwater pipeline inspection. The sole reliance on propeller-driven propulsion for ROV is replaced with a proposed low cost biomimetic solution in the form of an attachable hexapod walking skid. The advantage of this adaptable walking skid is the high stability in positioning and endurances to strong current on the seabed environment. The computer simulation flow studies using Solidworks Flow Simulation shown that the skid attachment in different compensation postures caused at least four times increase in overall drag, and negative lift forces on the seabed ROV to achieve a better maneuvering and station keeping under the high current condition （from 0.5 m/s to 5.0 m/s）. A graphical user interface is designed to interact with the user during robot-in-the-loop testing and kinematics simulation in the pool.     

基于PLC的自动化流水线上的自动小车控制系统

采用AB公司MicroLogix1000系列1761-L16BWA型可编程控制器,开发出流水线上自动小车控制系统,取代了以前以单片机为核心的控制系统,克服了人机对话难,修改工艺参数麻烦,维修不便等问题.该系统控制一台行走电机的行走或停止、两台卷扬电机的上升或下降来完成整个工艺过程,同时还利用RS232通讯接口实现了程序监控和工艺参数修改等操作.系统实际运行后性能稳定,效果良好,满足了自动化流水线的工艺要求.     

小型双足步行机器人机械机构设计

本文设计了一种适用于小型双足步行机器人的机械机构。该小型双足步行机器人由单电机驱动,为了使其能够实现稳定静态步行,设计了一种齿轮传动机构和步行机构。然后在Pro/E中完成总体装配并进行运动仿真,结果表明能够实现期望的运动轨迹。     

基于Kane动力学和通路矩阵的水下自重构机器人建模

文章推导出基于通路矩阵和Kane方法的水下自重构机器人的运动学和动力学方程。引入图论的知识解决水下自重构机器人的统一构形描述问题,提出采用通路矩阵描述水下自重构机器人的不同构形,结合Kane方法,建立了水下自重构机器人的运动学和动力学模型。以水下自重构机器人的典型构形(水下四足行走构形)为例,验证了该方法的有效性和可用性。