大体积承台温度控制

文章以百色市竹洲大桥大体积承台施工为例,从主墩承台施工工艺流程、混凝土配合比设计及生产浇注工艺、温控设计及现场温控技术等方面介绍了大桥主墩承台大体积混凝土温度控制技术。     

某特大桥承台混凝土施工温度及质量控制分析

文章以某特大桥为工程背景,从掺加粉煤灰改变混凝土配合比、控制混凝土入模温度、调整冷却管布置、加强保温保湿养护等方面,介绍了冬季大体积承台施工温度及质量控制措施,并对承台温度进行监测分析,结果表明该主墩承台混凝土内部最高温度控制在规范允许范围内,各项监控指标基本满足要求,浇筑后未发现裂缝,温控效果良好,为大桥承台安全顺利建成提供了技术保障。     

巴巴奥约河大桥主墩承台水化热分析

文章采用有限元结构软件对巴巴奥约河大桥主墩承台的水化热进程进行分析,并介绍了大体积混凝土温度和应力的电算方法,对主墩承台温度分布变化规律进行了探讨,为承台大体积混凝土施工提供参考。     

洪屋涡特大桥主墩承台施工

洪屋涡特大桥主墩承台采用单薄壁钢套箱围堰的方法。介绍1号主墩承台套箱设计、拼装下放及拆除的施工技术。     

大体积混凝土施工技术与质量控制——以乌江特大桥主墩承台施工为例

大体积混凝土施工质量直接决定着桥梁主墩承台的稳定性与外观质量。鉴于此,结合乌江特大桥主墩承台施工实例,对大体积混凝土施工技术要点与质量控制对策展开探讨,期望为桥梁大体积混凝土施工提供参考。     

陶乐黄河特大桥主墩双壁钢围堰设计与施工

陶乐黄河公路特大桥位于宁夏回族自治区北部,主墩承台施工受到局部冲刷、深水位和冰凌期的影响,施工工期紧、难度大.因此,主墩承台采用双壁钢围堰进行设计施工.     

大体积承台混凝土施工

文章以新寨河特大桥主墩承台施工为例,介绍了大体积混凝土施工的质量控制要点、施工工艺及质量保障措施,并重点讲述了大体积混凝土在施工中,如何预防因温度应力而引起混凝土开裂的温度监测措施。     

江东大桥第二合同PM26墩承台双壁钢套箱围堰施工

杭州市江东大桥第二合同PM26自锚墩为浅水低桩大体积混凝土承台基础,位于钱塘江主河槽.采用无底双壁套箱围堰施工承台,速度快,质量优,效益好.     

平潭海峡大桥主桥承台钢套箱设计与施工工艺研究

依托平潭海峡大桥主桥承台施工工程,结合所处海域水文特点,介绍了主墩、交界墩钢套箱设计的结构、工况,并阐述了钢套箱安装方法,封底砼握裹力,承台浇筑次数选择等施工工艺,为承台钢套箱设计与施工提供可参考的经验。     

岩溶地区桥梁桩基施工及质量控制探讨

以地质条件较为复杂的某桥梁桩基工程为依托,提出了其10#主墩承台桩基础优化施工方案,并基于此方案进行了桩基础施工过程及质量控制的分析,分析表明,岩溶注浆和溶腔回填混凝土是本桥梁桩基施工质量控制的关键环节。10#主墩承台桩基础施工结束后低应变反射波法检测结果表明,本桥梁桩基施工质量良好,岩溶基础加固效果显著,且本工程施工方案优化及施工技术应用对类似工程有借鉴参考价值。     

橡胶沥青性能影响因素的试验研究

文章依托隆百高速公路橡胶沥青混凝土复合式路面工程,对基质沥青的种类、橡胶粉的掺量以及基质沥青与橡胶粉的加工温度、反应时间等橡胶沥青性能的主要影响因素进行了试验研究。结果表明：基质沥青与橡胶粉的配伍性是影响橡胶沥青储存稳定性及相关技术性能最重要的因素。     

基于物联网技术的换热站自动控制系统

采用物联网技术、传感器技术、自动控制技术,下位机采用PLCS7—200系列及触摸屏,上位机采用组态软件,设计了一套无人值守换热站自动控制系统,实时检测换热站现场运行参数,调节阀门的开度,控制循环泵定温定频运行以及补水泵自动补水。同时,通过物联网技术,实时将换热站监测数据、报警数据、阀门开度等信息传输至因特网,实现数据的远程监控与调节,并能够根据设备运行情况,随时设置运行参数,实现换热站的自动控制。     

内河航标遥控遥测管理初探

文章结合航标遥控遥测技术在贵梧Ⅱ级航道工建设中的应用实践,分析了航标遥控遥测应用管理遇到的主要问题,并提出建立有效的运行管理制度、加强人才的培养和引进、做好系统软硬件的维护管理、加强实时监控的技术管理和深化应用管理等充分发挥航标遥控遥测技术效能的有效措施。     

低液限粉土路基压实工艺的探讨

通过对低液限粉土施工工艺控制过程的实践,总结了低液限粉土的工程特性,提出了低液限粉土作为路基填料施工技术的主要控制要点。     

输油管道仿真技术研究

输油管道仿真是一项综合利用油气储运、流体力学、计算机、网络技术、控制工程等多学科知识的前沿技术。该技术的成熟与发展,对实现管道的经济运行、智能管理有着重要的意义。结合数学模型及模型求解方法,系统阐述了管道仿真技术的基本理论。通过分析仿真技术在管道检漏及顺序输送两方面的应用现状,指出相应的不足之处,并就该技术的进一步发展提出了几点建议。     

Isolated intersection control for various levels of vehicle technology: Conventional,connected, and automated vehicles

Connected vehicle technology can be beneficial for traffic operations at intersections. The information provided by cars equipped with this technology can be used to design a more efficient signal control strategy. Moreover, it can be possible to control the trajectory of automated vehicles with a centralized controller. This paper builds on a previous signal control algorithm developed for connected vehicles in a simple, single intersection. It improves the previous work by (1) integrating three different stages of technology development; (2) developing a heuristics to switch the signal controls depending on the stage of technology; (3) increasing the computational efficiency with a branch and bound solution method; (4) incorporating trajectory design for automated vehicles; (5) using a Kalman filter to reduce the impact of measurement errors on the final solution. Three categories of vehicles are considered in this paper to represent different stages of this technology: conventional vehicles, connected but non-automated vehicles (connected vehicles), and automated vehicles. The proposed algorithm finds the optimal departure sequence to minimize the total delay based on position information. Within each departure sequence, the algorithm finds the optimal trajectory of automated vehicles that reduces total delay. The optimal departure sequence and trajectories are obtained by a branch and bound method, which shows the potential of generalizing this algorithm to a complex intersection.Simulations are conducted for different total flows, demand ratios and penetration rates of each technology stage (i.e. proportion of each category of vehicles). This algorithm is compared to an actuated signal control algorithm to evaluate its performance. The simulation results show an evident decrease in the total number of stops and delay when using the connected vehicle algorithm for the tested scenarios with information level of as low as 50%. Robustness of this algorithm to different input parameters and measurement noises are also evaluated. Results show that the algorithm is more sensitive to the arrival pattern in high flow scenarios. Results also show that the algorithm works well with the measurement noises. Finally, the results are used to develop a heuristic to switch between the different control algorithms, according to the total demand and penetration rate of each technology.     

桥梁吊杆断裂原因及预警技术研究

文章结合桥梁吊杆频繁骤断事故,分析了吊杆断裂的主要原因,并针对当前吊杆安全控制技术措施存在的问题,介绍了吊杆安全预警技术及应用效益。     

连续梁桥支座更换关键技术研究

文章针对目前常用的梁桥支座更换方法存在的问题,提出了一种适合连续桥梁支座更换的新思路,并通过仿真实验分析,验证了该方法的可行性。同时,文章提出了与该方法相适应的三种施工工艺,并对支座更换过程中施工控制的关键技术进行了探讨。     

Multi-agent model predictive control of signaling split in urban traffic networks

The operation of large dynamic systems such as urban traffic networks remains a challenge in control engineering to a great extent due to their sheer size, intrinsic complexity, and nonlinear behavior. Recently, control engineers have looked for unconventional means for modeling and control of complex dynamic systems, in particular the technology of multi-agent systems whose appeal stems from their composite nature, flexibility, and scalability. This paper contributes to this evolving technology by proposing a framework for multi-agent control of linear dynamic systems, which decomposes a centralized model predictive control problem into a network of coupled, but small sub-problems that are solved by the distributed agents. Theoretical results ensure convergence of the distributed iterations to a globally optimal solution. The framework is applied to the signaling split control of traffic networks. Experiments conducted with simulation software indicate that the multi-agent framework attains performance comparable to conventional control. The main advantages of the multi-agent framework are its graceful extension and localized reconfiguration, which require adjustments only in the control strategies of the agents in the vicinity.