单边拓宽改造在旧拱桥中的研究

针对旧拱桥的缺陷,采取单边拓宽改造工程进行加固处理,借用桥梁博士模型进行了荷载分析,并阐述了改造工程的设计及施工理念,通过对改造后荷载试验结果进行分析研究,证明了该改造方法的优越性。     

议城市桥梁与公路桥梁设计荷载标准

对公路桥梁设计荷载标准与城市桥梁设计荷载标准进行了介绍分析,并对两种桥梁的荷载标准进行了异同点分析,以便根据桥梁设计的实际需求选择正确的荷载标准。     

拓宽及提载对空心板桥旧板受力影响分析

公路拓宽工程在我国随着交通量的增长屡见不鲜,且随着交通荷载的变化,进行拓宽的同时往往要考虑其能否满足新的汽车荷载等级要求并进行适当改造。在我国运营的中小跨径桥梁中,空心板桥数量庞大,空心板桥拓宽连接接缝的连接方式及刚度对荷载的横向分布系数变化影响已有不少研究,而综合考虑横向分布系数变化及汽车荷载变化的影响更具有实用价值。因此,以某高速公路拓宽工程为背景,选取一批有代表性的空心板桥开展拓宽分析,研究不同跨径旧桥拓宽后横向分布系数的变化,并综合考虑汽车荷载等级提高引起的空心板活载内力变化,判断其改造的必要性,为类似工程的拓宽改造提供参考。     

三跨预应力连续梁桥动载试验分析

对现有桥梁在动荷载下的受力参数与理论计算的参数相比,得出了该桥梁的实际使用状态,通过模拟实际桥梁,分析了各种不利荷载作用下桥梁的受力响应,该动荷载试验分析结果为箱形连续梁桥的动荷载控制设计提供了数据支持。     

基于连续箱梁桥错孔拓宽方式拼接内力分析

针对桥梁拓宽新旧桥由于河道限制桥梁需错孔布置的情况,结合观澜分离立交桥的拓宽实际,利用Midas/Civil进行拓宽仿真模拟,分析了错孔桥梁拼宽前后新、旧主梁各关键截面在各荷载工况下的内力,指出错孔桥梁在新旧拼接后旧桥内力增大较多,需采取必要的承载力加固措施,以满足承载力要求。     

溧阳南渡桥改造工程

溧阳南渡桥位于南京至杭州的干线公路上,是1959年底建成的双曲拱桥(净跨为40m),由于当时设计、施工等原因以及两次溧阳地震的影响,致使桥梁病害严重,列为危险桥梁。1980年后,桥址处每昼夜混合交通量已逾6000辆,且大吨位车辆也急剧增多。急需拓宽桥面,提高荷载标准和通行能力。1984年对该桥进行改造。本文主要介绍原桥状况评定、改造工程的设计构思与计算要点、施工概况、荷载试验、经济效益以及新桥的抗震性能分析等等,为软土地基上双曲拱桥的技术改造提供借鉴。     

国内外桥梁拓宽方法及技术分析

随着公路运输的快速发展，大量早期建成投入运营的公路桥梁，服务水平已明显降低，已成为公路运输线上的“瓶颈”。不利于沿线经济的长期可持续发展。对原有公路拓宽改建，提高原有公路桥梁的使用功能，节约工程投资，是旧路改建工程通常采用的有效途径。虽然我国在桥梁加固改造上积累了相当的经验，但是还没有一个系统的桥梁拓宽改建规范，也没有在桥梁拓宽改建方面对于设计资质做出明确的规定，已有的旧桥改造设计大都是根据以往的设计经验所进行的，缺乏规范标准以指导生产实践。因此，旧桥的拓宽改建方法的探索总结具有重要的实际工程意义。     

南马大桥桥面拓宽可行性研究

以南马大桥桥面拓宽工程为例,在充分考虑桥梁外观及桥面拓宽横断面布置方案的基础上,进行了桥梁静载试验,分析了拓宽后桥梁的受力性能,结果表明,拓宽后的桥梁满足使用荷载要求且性能良好。     

旧桥拓宽工程中若干影响因素的分析研究

以预应力混凝土连续箱梁桥拓宽改造工程为例,采用Midas FEA有限元软件建立新旧桥梁模型,分析研究在旧桥拓宽改造工程中收缩、徐变、基础沉降等因素对桥梁结构内力的影响,对类似工程的施工设计有一定的指导意义。     

市政桥梁拼宽加固设计研究

桥梁加固属于市政桥梁维修加固中非常重要的技术举措,重点是将其运用至桥梁拓宽改造和维护桥梁基本功能的实践中.市政桥梁改造阶段,为更好地满足车流量的实际通行需要,应该积极落实好拼宽加固的设计细节,采取科学的方式,妥善维护桥梁整体的稳定程度.本文重点从市政桥梁拼宽加固的基本要求、设计方式和基本方法上加以分析,同时提出合理化建...     

浅析高速公路中小跨径桥梁的加宽设计

对深圳梅观高速公路中的横岭中桥加宽设计作了介绍,包括桥面、上部结构、下部结构等方面的加宽方法,为相关设计积累了宝贵的经验,以期指导类似桥梁加宽设计。     

Monitoring the dynamic characteristics of an urban bridge before,during and after widening

The dynamic characteristics of a multi-span pre-stressed concrete urban bridge before, during and after widening operations have been studied. The widening operations have been carried out by adding two new bridges on the either sides of the old bridge. The decks of the new bridges have been structurally separated from the old one by two longitudinal joints on the either side of the old bridge. The dynamic characteristics have been extracted from operational modal tests in three phases during different stages of the widening operations. The dynamic interaction between the new parts and the old part of the bridge has also been investigated. The results show that after the completion of the widening works, and when the whole bridge was placed in service condition, this interaction affects the natural frequencies of almost all the vibration modes of the bridge. It was also found that the longitudinal joints were unable to effectively isolate the new parts from the old part. Finally, in order to achieve a consistent behaviour in the first bending mode of the new and old bridges, a geometrical index has been introduced. This index includes both the effects of stiffness and mass properties of the bridge deck. In widening projects, where the span lengths, material properties and support conditions of the two bridges are taken the same, adopting equal geometrical indices leads to almost equal values of the natural frequencies and similar mode shapes in the first bending mode. The proposed index can be used in the initial design stage for such projects.     

高速公路桥梁加宽设计

详细分析了山西省太古高速公路一座加宽桥的方案设计,论述了加宽设计需考虑的多项因素,并介绍了上部下部结构均不进行连接、上部下部结构均进行连接以及上部结构连接下部结构不连接三种加宽方案,以供类似桥梁加宽设计时参考。     

郑漯高速改扩建工程桥梁加宽方案设计

结合工程实例,介绍了项目背景、设计标准以及公路一般路段横断面的设置情况,并对桥梁加宽设计方案以及刚构中墩的连接设计方案分别进行了分析比选,以供类似桥梁的加宽设计参考。     

Investigation of Live Load Deflection Limit for Steel Cable Stayed and Suspension Bridges

Long span bridges such as steel cable stayed and suspension bridges are usually more flexible than short to medium span bridges and expected to have large deformations. Deflections due to live load for long span bridges are important since it controls the overall heights of the bridge for securing the clearance under the bridge and serviceability for securing the comfort of passengers or pedestrians. In case of sea-crossing bridges, the clearance of bridges is determined considering the height of the ship master from the surface of the water, the trim of the ship, the psychological free space, the tide height, and live load deflection. In the design of bridges, live load deflection is limited to a certain value to minimize the vibrations. However, there are not much studies that consider the live load deflection and its effects for long span bridges. The purpose of this study is to investigate the suitability of live load deflection limit and its actual effects on serviceability of bridges for steel cable-stayed and suspension bridges. Analytical study is performed to calculate the natural frequencies and deflections by design live load. Results are compared with various design limits and related studies by Barker et al. (2011) and Saadeghvaziri et al. (2012). Two long span bridges are selected for the case study, Yi Sun-Sin grand bridge (suspension bridge, main span length?=?1545 m) and Young-Hung grand bridge (cable stayed bridge, main span length?=?240 m). Long-term measured deflection data by GNSS system are collected from Yi Sun-Sin grand bridge and compared with the theoretical values. Probability of exceedance against various deflection limits are calculated from probability distribution of 10-min maximum deflection. The results of the study on the limitation of live load deflection are expected to be useful reference for the design, the proper planning and deflection review of the long span bridges around the world.     

斜交简支空心板梁桥拼宽静力特性分析

以跨径20m的简支斜交空心板梁桥拼宽为工程背景,运用ANSYS有限元软件建立全桥空间有限元模型,分析了在汽车荷载和新老桥不均匀沉降作用下桥梁的静力特性,比较了20cm、25cm、30cm和35cm四种不同接缝高度对受力特性的影响.分析结果认为:对于20m跨45度斜交空心板梁桥拼宽,新老桥不均匀沉降值应控制在5mm之内,...     

Highway bridge loadings

The paper presents a comparison of the AASHTO design live loadings for bridges with various other loading situations. Comparisons are made with some European design live loads, with native and foreign legal loads, normal permit overloads, and abnormal permit loads. The results of a bridge load rating exercise are presented. Some actual bridge load histograms are given, as well as a comprehensive histogram based on the national loadometer surveys for 1970. Fatigue loadings and damage are discussed in the light of actual and design loadings.

It is concluded that it may be timely to increase the AASHTO HS design loadings. To improve the bridge load rating process, it is suggested that some standard load rating vehicle and test method be employed. Further refinement of the fatigue design provisions for steel bridges do not seem warranted in light of the great variation of actual loadings on bridges.     

Aktuelle Entwicklungen im Straßenbrückenbau

Current developments of road bridges in Germany. In connection with the major tasks after the reunification of Germany for the creation and improvement of the traffic infrastructure in the East German States an exceptionally large number of bridges and other transportation structures have newly been built or have been rehabilitated in connection with the widening of Freeways. The engineers in charge took up this opportunity quickly to initiate new technical developments and to realize innovative solutions. This is true for reinforced and pre‐stressed concrete bridges as well as for steel composite bridges in particular. Many good examples for current bridge design were built especially for the Freeways A71/A73 across the Thuringia Forest and for the A4 around Dresden. At the same time the German national codes were replaced by the modern European Eurocodes so that the state‐of‐the‐art of bridge design in Germany today is compatible with international standards.     

既有铁路钢筋混凝土梁桥动态可靠性评估

介绍了既有桥梁结构的动态可靠性分析方法,提出了桥梁的恒载概率模型、活载概率模型及抗力概率模型,并对可靠度计算方法中的验算点法进行了介绍。以一座既有铁路钢筋混凝土梁桥为工程背景,计算了该桥的活载效应统计参数、恒载效应统计参数及抗力统计参数等,利用验算点法计算了桥梁结构构件的可靠度指标,又采用PNET方法分析了整个桥梁体系的可靠性,最后给出了桥梁的可靠性评估结果。结果显示动态可靠性评估应用于铁路钢筋混凝土梁桥可以得到较好的评估结果。     

跨海重轨桥梁选型及其结构体系研究

以对某跨海重轨桥梁的桥型论证为背景,着眼于重载和海域环境两个特点,从桥梁概念性设计的角度论述了整体式桥梁下部结构、箱梁式桥梁上部结构、桥梁经济跨径、桥梁预应力体系四个方面的内容。然后,经过数值计算,验证了方案体系总体刚度能满足要求。论文最后,为更科学地确定桥梁标高,对跨海桥梁承受波浪荷载进行了初步探讨,同时提出了下一阶段应进行人工岛和港口防波堤对桥位的掩护作用分析的必要性。