部分斜拉桥的索力测试与分析

结合某部分斜拉桥的索力测试过程,对测出的数据进行分析总结,得出的一些有规律的结论:该类型斜拉桥的索力测试采用频率法是可行的;对于长度较短的拉索,必须考虑刚度对索力的影响。     

加筋土桥台筋带最大拉力试验研究

通过室内大比例模型试验,研究自重作用下加筋土桥台的最大筋带拉力的变化规律。加筋土桥台最大筋带拉力作用线的上部是离面板约为墙高0.2倍左右距离的垂直顶面的直线,下部渐渐向面板靠拢,近似为一条以面板顶点为极点的对数螺旋线。最大筋带拉力上部(垂线段)较大,下部渐小。基于试验结果与现场实测结果,提出最大筋带拉力与对应最大筋带拉力作用线距面板的水平距离成正比的计算模型。与其他理论及实验结果的比较表明,该计算模型对最大筋带拉力的预测能有效地反映刚性面板影响,能更准确地预测实际的最大筋带拉力,其预测值与实测结果的误差只有14%,而其他理论预测值与实测结果的误差均大于50%。     

压密注浆在城区护岸加固工程中的应用

该文介绍了压密注浆技术在城区护岸加固工程中的应用。根据主城区河道整治工程实际情况,采用压密注浆法处理部分旧的护岸工程,减少了社会、环境影响,节约了工程造价。     

盾构区间下穿并截除人行天桥部分桥桩的对策

以沈阳地铁2号线工业展览馆站—文体路站区间(以下简称工—文区间)下穿文化路立交桥人行天桥并截除部分桥桩为例,为确保盾构掘进过程中该天桥桥体的安全,通过对桥桩截桩后管片后期承载力、结构变形等特点建立三维数值模型,并进行计算分析后,进一步优化设计方案,同时采取了以下措施:施工前先对人行天桥两端桥墩处采用临时钢托架进行支撑加固;掘进过程中合理优化盾构掘进参数,同时采取同步注浆与二次补强注浆措施,不但避开了立交桥主桥桥桩,同时还避免了采用桩基托换这一高风险、高代价方案。竣工并通车运营后,经过近1年的跟踪监测,桥梁结构稳定,最终变形收敛至稳定值,充分验证了该措施的可行性。     

Learning-based traffic signal control algorithms with neighborhood information sharing: An application for sustainable mobility

This research applies R-Markov Average Reward Technique based reinforcement learning (RL) algorithm, namely RMART, for vehicular signal control problem leveraging information sharing among signal controllers in connected vehicle environment. We implemented the algorithm in a network of 18 signalized intersections and compare the performance of RMART with fixed, adaptive, and variants of the RL schemes. Results show significant improvement in system performance for RMART algorithm with information sharing over both traditional fixed signal timing plans and real time adaptive control schemes. The comparison with reinforcement learning algorithms including Q learning and SARSA indicate that RMART performs better at higher congestion levels. Further, a multi-reward structure is proposed that dynamically adjusts the reward function with varying congestion states at the intersection. Finally, the results from test networks show significant reduction in emissions (CO, CO₂, NO_x, VOC, PM₁₀) when RL algorithms are implemented compared to fixed signal timings and adaptive schemes.     

Artificial intelligence for traffic signal control based solely on video images

Learning-based traffic control algorithms have recently been explored as an alternative to existing traffic control logics. The reinforcement learning (RL) algorithm is being spotlighted in the field of adaptive traffic signal control. However, no report has described the implementation of an RL-based algorithm in an actual intersection. Most previous RL studies adopted conventional traffic parameters, such as delays and queue lengths to represent a traffic state, which cannot be exactly measured on-site in real time. Furthermore, the traffic parameters cannot fully account for the complexity of an actual traffic state. The present study suggests a novel artificial intelligence that uses only video images of an intersection to represent its traffic state rather than using handcrafted features. In simulation experiments using a real intersection, consecutive aerial video frames fully addressed the traffic state of an independent four-legged intersection, and an image-based RL model outperformed both the actual operation of fixed signals and a fully actuated operation.     

洋河大桥桥梁病害处理及加固设计

针对已有桥梁病害及桥梁使用工况改变进行有目的桥梁结构加固设计,有关加固措施及施工经验可为类似桥梁加固提供借鉴。     

软基地段明洞不均匀沉降后的回填安全性及加固措施研究

为分析厦门翔安海底隧道软基地段明洞不均匀沉降后的回填安全性和加固措施,采用荷载-结构模型进行研究。综合研究结论如下:1)填土后明洞差异沉降预测值为80 mm,最小安全系数为2.11,虽然结构安全系数满足要求,但不均匀沉降将导致裂缝、错台及渗水,严重影响隧道使用功能和耐久性;2)提出采用大孔径树根桩加固明洞衬砌两侧拱脚,TSS钢花管注浆加固仰拱中央,灌浆封闭裂缝,分层对称填土的综合处理方案;3)经现场监测验证,预测沉降规律与实测吻合较好,加固措施成效良好,变形得到治理。     

桥梁翼板横向改道通车顶撑加固施工技术探讨

因赣江南大道下穿桥施工,南昌大桥西引桥需改道通车。车辆改道行驶后将改变南昌大桥翼缘板受力模式。为了确保南昌大桥结构安全,必须对南昌大桥翼板进行加固。对此,采用钢桁架进行顶撑加固施工。该文介绍了南昌大桥梁板加固施工技术,可供同行参考。     

碳纤维布在旧桥加固工程中的应用

简要地介绍了人类开发利用建筑材料的历史、碳纤维材料的特点及用途、采用碳纤维布加固试验梁的试验结果及其在桥梁加固工程中的应用。结合两座桥梁工程中的应用实例,验证了碳纤维布的加固效果,总结了应用碳纤维布时的注意事项,可供相关专业人员参考。