Rapid repair techniques for severely earthquake-damaged circular bridge piers with flexural failure mode

In this study, three rapid repair techniques are proposed to retrofit circular bridge piers that are severely damaged by the flexural failure mode in major earthquakes. The quasi-static tests on three 1：2.5 scaled circular pier specimens are conducted to evaluate the efficiency of the proposed repair techniques. For the purpose of rapid repair, the repair procedure for all the specimens is conducted within four days, and the behavior of the repaired specimens is evaluated and compared with the original ones. A finite element model is developed to predict the cyclic behavior of the repaired specimens and the numerical results are compared with the test data. It is found that all the repaired specimens exhibit similar or larger lateral strength and deformation capacity than the original ones. The initial lateral stiffness of all the repaired specimens is lower than that of the original ones, while they show a higher lateral stiffness at the later stage of the test. No noticeable difference is observed for the energy dissipation capacity between the original and repaired pier specimens. It is suggested that the repair technique using the early-strength concrete jacket confined by carbon fiber reinforced polymer （CFRP） sheets can be an optimal method for the rapid repair of severely earthquake-damaged circular bridge piers with flexural failure mode.

Rapid repair of severely earthquake-damaged bridge piers with flexural-shear failure mode

An experimental study was conducted to investigate the feasibility of a proposed rapid repair technique for severely earthquake-damaged bridge piers with flexural-shear failure mode. Six circular pier specimens were first tested to severe damage in flexural-shear mode and repaired using early-strength concrete with high-fluidity and carbon fiber reinforced polymers （CFRP）. After about four days, the repaired specimens were tested to failure again. The seismic behavior of the repaired specimens was evaluated and compared to the original specimens. Test results indicate that the proposed repair technique is highly effective. Both shear strength and lateral displacement of the repaired piers increased when compared to the original specimens, and the failure mechanism of the piers shifted from flexural-shear failure to ductile flexural failure. Finally, a simple design model based on the Seible formulation for post-earthquake repair design was compared to the experimental results. It is concluded that the design equation for bridge pier strengthening before an earthquake could be applicable to seismic repairs after an earthquake if the shear strength contribution of the spiral bars in the repaired piers is disregarded and 1.5 times more FRP sheets is provided.

基于不确定信息的震后道路抢修时序

基于震后灾情信息的不确定性特点,提出了基于盲信息理论的路径费用表达和处理方法,通过对路径费用的盲数形式进行合理降阶,可获取一定可信度下的路径费用期望,并以此为基础,设计了多起点单讫点的简单路径搜索的分层算法,得到满足应急时限的有效路径。出于提高应急效率和减少伤亡的考虑,提出了通行能力保障系数的概念,用以量化各需求点与出救点的连通性,据此设计震后路径抢修排序算法。算例结果表明,提出的路径抢修排序算法合理,可为应急决策提供有效的支持。

基于改进Dijkstra算法的机场抢修决策模型研究

机场抢修决策模型是实现机场道面快速抢修的核心环节,传统的机场抢修决策模型普遍存在模型假设脱离实际、计算结果在实际中难以应用等缺点。文中将GIS技术应用于机场抢修决策,提出基于限制区域的Dijkstra改进算法的最优路径模型,在此基础上,探讨"单对单"、"多对单"和"多对多"3种模式下机场抢修决策模型的建立方法。

X射线引导下椎间盘激光修复术加速患者快速康复

目的:探讨X射线引导下椎间盘激光修复术加速患者快速康复的效果。方法:采用回顾性方法,2017年1月至2018年12月收治的椎间盘突出症患者临床资料分析,其中46例患者采取中医辨证用药、针灸、郑氏推拿疗法、腰围保护、骨盆牵引、卧床休息等为主的保守治疗方法为对照组,40例激光椎间盘修补术为观察组,围手术期采取快速康复措施。比较两组患者入院时、治疗1周后、治疗2周后的VAS评分、患者满意度、住院天数、并发症发生率。结果:两组患者治疗后症状和功能均明显缓解,椎间盘激光修复组患者满意度较高,无术后感染、血肿、神经损伤等并发症发生。结论:X射线引导下椎间盘激光修复术有助于患者快速康复,安全性高,与传统保守治疗相比,减少恢复时间,让患者更为满意。该方法有效安全,为临床提供新的思路,可以作为参考。

复合胶凝体系道路快速修补材料早期强度试验

为研究不同缓凝剂和水玻璃模数作用下,矿粉取代率、缓凝剂掺量和水胶比对复合胶凝体系道路快速修补材料早期强度的影响,取矿粉对水泥熟料的质量取代率分别为0、20%、40%和60%,氯化钡或硝酸锌两种缓凝剂的掺量分别为1%、1.5%、2%和2.5%,2.8和3.0两种模数的水玻璃掺量为30%,水胶比分别为0.30、0.33、0.36和0.39,测试各组配合比4 h抗折强度,结果表明:(1)试样4 h抗折强度在1.17~2.33 MPa,利用碱激发复合胶凝体系制备道路快速修复新型材料具有可行性,但需要优化配合比以进一步提升其早期强度;(2)选用氯化钡为缓凝剂和2.8模数的水玻璃模时,较优配合比为矿粉取代率20%,缓凝剂掺量1%或2%,水胶比为0.39或0.36;(3)选用硝酸锌为缓凝剂和3.0模数的水玻璃模时,较优配合比为矿粉取代率0或20%,缓凝剂掺量1%,水胶比为0.30。

复合胶凝体系道路快速修补材料的4h抗折强度和抗压强度

为研究矿粉质量取代比和水胶比对复合胶凝体系道路快速修补材料性能的影响,分别取磨细矿粉占胶凝材料(矿粉和特种水泥熟料)总质量的比为0%、20%、25%、30%、35%、40%、45%和50%,水胶比分别为0.15、0.2和0.25,测试各组配合比试件的4 h抗折强度和抗压强度。研究结果表明:(1)水胶比为0.15时,试样4 h抗压强度和抗折强度均随掺加矿粉占总胶凝材料质量比的增加而先增加,后降低;水胶比为0.2和0.25时,试样4 h抗压强度和抗折强度均随掺加矿粉占总胶凝材料质量比的增加而降低,其中水胶比为0.25时的降低幅度较0.2时的更大;(2)试验条件下,矿粉的合理质量比在20~30%,在水胶比为0.15~0.2左右时,相应的4h抗折强度和抗压强度分别在4.0和14.0 MPa左右。研究成果对“碳达峰、碳中和”总目标的实现和工业废料利用都具有科学和现实意义。

玉环电厂超超临界1000MW汽轮机组快冷系统的应用

华能玉环电厂的超超临界1 000 MW汽轮机组故障时,为缩短停机冷却时间,采用快速冷却(快冷)系统。2号机组故障停机时,应用了快冷系统,缩短了10天检修工期。该厂4台机组在停机检修中累计投入快冷系统11次,都取得了较好的效果,节约了大量的检修工期。

Experimental study and field application of calcium sulfoaluminate cement for rapid repair of concrete pavements

The fast-track repair of deteriorated concrete pavement requires materials that can be placed, cured, and opened to the traffic in a short period. Type III cement and Calcium Sulfoaluminate （CSA） cement are the most commonly used fast-setting hydraulic cement （FSHC）. In this study, the properties of Type III and CSA cement concrete, including compressive strength, coefficient of thermal expansion （CTE） and shrinkage were evaluated. The test results indicate that compressive strength of FSHC concrete increased rapidly at the early age. CSA cement concrete had higher early-age and long term strength. The shrinkage of CSA cement concrete was lower than that of Type III cement concrete. Both CSA and Type III cement concrete had similar CTE values. Based on the laboratory results, the CSA cement was selected as the partial-depth rapid repair material for a distressed continuously reinforced concrete pavement. The data collected during and after the repair show that the CSA cement concrete had good short-term and long-term performances and, therefore, was suitable for the rapid repair of concrete pavement.

GPS在高速公路快速抢修中的应用

利用基于GPS的几何定位技术和施工装备,对高速公路进行精确的测量和机械化施工抢修,迅速高效地完成高速公路的快速抢修;分析了工程机械先进技术的发展方向,提出了使用基于3D GPS技术的工程机械是未来高速公路快速抢修的发展目标与方向的观点。

Influencing factors and optimization on mechanical performance of solid waste-derived rapid repair mortar

There is a great demand for high performance rapid repair mortar(RRM)because of the wide use of cement concrete.Solid-waste-based sulfoaluminate cement(WSAC)is very suitable as a green cementitious material for repair materials because of its characteristics of high early-age strength and short setting time.However,the influence and optimization of various factors of WSAC-based RRM,such as water-to-RRM ratio,binder-to-sand ratio and additives,as well as the further solid waste replacement of aggregate,remain to be studied.This paper comprehensively studied the influence of the above factors on the performance of WSAC-based RRM and obtained a green high-performance RRM by optimizing these factors.The experimental results showed that the early and late strength of the obtained RRM is excellent,and the setting time and fluidity are appropriate,which reflected good mechanical properties and construction performance.Ordinary Portland cement(OPC)doping could not improve RRM strength.It was feasible to prepare RRM with gold tailing sand replacing part of the quartz sand.This paper provides data and a theoretical basis for the preparation of high-performance RRM based on solid waste,expanding the high value utilization of solid waste,which is conducive to the development of a low carbon society.

400 V低压配网监测及快速抢修系统

400 V低压配电网的智能化程度与供用电的质量及可靠性密切相关。设计一种可以不停电安装的400 V低压配网监测及快速抢修系统,提高电力抢修部门工作效率。

一种机场混凝土道面快速修补材料用的胶凝体系制备及微观机理分析

为制备一种机场混凝土道面快速修补材料用的胶凝体系,研究了铝酸盐水泥掺量对硅酸盐水泥-铝酸盐水泥二元胶凝体系凝结时间、力学性能的影响;其后,再加入石膏构成硅酸盐水泥-铝酸盐水泥-石膏三元胶凝体系,进一步研究了石膏掺量对三元胶凝体系凝结时间、力学性能的影响,从而初步确定快速修补材料所用的硅酸盐水泥-铝酸盐水泥-石膏三元胶凝体系的配合比。与此同时,运用X射线衍射和环境扫描电子显微镜分析胶凝体系的微观结构、水化产物,揭示了胶凝体系水化进程和水化机理。

基于配网GIS的电力快速抢修综合平台的应用

文章从配电网CIS、调度自动化、抢修车辆监控、呼叫中心、营销MIS这几个电力企业常见的信息化系统的协作应用出发，组建一套基于配电网GIS的电力快速抢修系统。