四川山区处在极其特殊的地理位置,桥梁建设面临巨大挑战,开展桥梁防震的相关研究具有重要意义.文章总结了近年来四川桥梁建设面临的地震引发的直接和间接灾害,归纳总结了四川省内已建桥梁防震主要措施,对山区桥梁建设具有借鉴意义.

在近场地震作用下,为减小桥塔塔身弯矩,悬索桥桥塔创新性地设置波形钢腹板横梁.以大渡河大桥为研究对象,基于横梁拟静力试验数据,建立结构动力数值计算模型并输入不同类型的近场地震动计算结构的地震响应,探究采用波形钢腹板横梁悬索桥的优势和近场效应对结构响应的影响规律.研究表明:采用波形钢腹板横梁的桥塔有自重轻、刚度小的优势,更符合强柱弱梁和强剪弱弯;在高烈度的近场作用下,以波形钢腹板横梁的延性作为抗震策略是合理的.脉冲效应对本桥响应影响较大,因此建议此类型桥梁应重视近场脉冲效应;而上盘效应对本桥的响应小于无近场效应的地震动,故处于上盘的桥梁是更安全的;在横向地震激励下,近场脉冲效应对主塔的位移和弯矩影响较大.

四川山区处在极其特殊的地理位置,桥梁建设面临巨大挑战,开展桥梁防洪的相关研究具有重要意义.总结了近年来四川桥梁建设面临的洪水引发的直接和间接灾害,归纳总结了四川省内已建桥梁防洪主要措施,对山区桥梁建设具有借鉴意义.

预制装配式建筑因其具有节能、环保等优势被广泛应用于建筑工程建设中,但其施工安全问题切实存在,文章对预制装配式建筑施工安全风险进行了详细探究,总结了施工各个阶段存在的危险源,并探究了安全风险防控的具体措施,以便为建筑企业提供参考,能够在预制装配式建筑施工中精准识别危险源,并对安全风险展开有效的防控,实现施工安全.

南宁英华大桥为45 m+410 m+45 m单主缆钢箱梁悬索桥.该桥设置单主缆,主缆采用预制平行高强钢丝索股结构.全桥共布置40对吊索,均采用预制平行钢丝束.主索鞍采用全铸造结构,塔顶设有格栅底座.该桥采用散索套散开主缆,通过结构优化,有效解决了采用传统散索套所带来的索股不稳定及难以架设的技术难题.主缆锚固采用钢拉杆锚固系统,锚固方式为无粘接后锚承压式.主塔为曲面桥塔,采用文物“羊角钮编钟”作为造型元素,下塔柱为预应力混凝土结构,上塔柱为钢结构.主梁采用扁平流线型钢箱梁,全宽37.7 m,中心高3.5 m.锚碇均为重力式锚碇,由于本桥为单主缆结构,因此两岸均只在引桥正下方设1个锚碇.

泸定大渡河兴康特大桥主桥为1100 m单跨钢桁梁悬索桥,针对该桥桥址区地震动参数高的特点,开展结构抗震设计关键技术研究.基于延性抗震设计理念提出耗能型中央扣,将防屈曲钢支撑用作中央扣杆件,防屈曲钢支撑的两端以铰接形式与缆、梁连接,只承受轴向力,不产生弯矩.基于组合设计思想提出波形钢腹板钢—混组合桥塔横梁,利用预应力混凝土顶板和底板抗弯、高强度钢腹板抗剪.对比耗能型中央扣与传统刚性、柔性中央扣对悬索桥抗震性能的影响;对比波形钢腹板钢—混组合桥塔横梁与普通钢筋混凝土、钢桥塔横梁的抗震性能,并对组合桥塔横梁进行缩尺模型试验,结果表明:铰接式耗能型中央扣能显著改善高烈度震区大跨径悬索桥的抗震性能;波形钢腹板钢—混组合桥塔横梁具有良好的综合抗震性能,连接构造安全可靠.

对南宁市英华路—青山路立交工程方案设计中的方案选择、两个主要出入口的交通组织以及凤岭南路隧道口的处理等三处设计要点进行了逐一论述,其"因势设计"的设计理念和采取的设计方法可为今后市政工程类似情况的设计提供一定的借鉴和参考。

介绍了南宁市的城市情况及邕江桥梁的总体情况,结合南宁市罗文大桥的建设条件,提出了四个桥型设计方案,并对四个方案的优缺点进行对比。在城市桥梁桥型方案设计,进行了一些有益的实践和探讨。

A semi-analytical and semi-numerical approach for earthquake induced hydrodynamic force on elastic rectangular hollow bridge pier was developed to study the seismic response of Mangjiedu deep-water bridge located in an area where earthquakes occur quite frequently.Based on linear radiation wave theory,the interior and exterior hydrodynamic forces on pier were got by eigen-function expansion method.This method avoided solving fluid-solid model directly,and was efficient for bridge engineering.The modal analysis,spectrum analysis and transient analysis were introduced respectively and the results showed that the influence of hydrodynamic force can not be neglected for Mangjiedu bridge because the 168 meter high piers could almost all in water.

The results of the investigation on 1 657 bridges damaged in Wenchuan earthquake in Sichuan Province were summarized;and seven types of macro-earthquake damages of highways and bridges were presented.For beam bridges and arch bridge,the main damages were girder displacement,girder falling,pier damage by shear force,pier and girder crushing and cracking,bridge abutment wall and ribbed slab cracking,bridge abutment filler sloughing,arch ring and spandrel cracking,etc..All of the damage reasons of the bridges were analyzed preliminary;and the influential factors for selections of bridge sites and types were also put forward.The countermeasures were presented at last for girder displacement and pier damage.

介绍了"5.12"汶川地震的震源特性及四川公路网的受损状况,根据地震造成的灾区范围确定公路桥梁震害调查范围.在桥梁震害调查基础上归纳总结汶川地震公路桥梁的宏观震害,主要包括地质次生灾害及近场地震的影响,并对梁式桥及拱桥的几种典型震害进行了归纳和初步分析.根据震害,提出了桥位选择、桥型、桥墩形式及墩柱抗震构造细节等相关的抗震对策.

首先介绍了"5.12"汶川地震的震源特性及四川公路网的受损概况,对重灾区国省干线公路1657座桥梁震害调查检测结果加以归纳,总结出公路桥梁的宏观震害,并对梁式桥及拱桥的几种典型震害进行了归纳和初步分析。根据震害,提出了桥位选择、桥型、桥墩形式及墩柱抗震构造细节等相关的抗震对策。

首先介绍了汶川大地震的地震作用特征,进而通过实地调查,对在汶川大地震中遭到严重损坏的百花大桥进行了详细的研究研究了第5联整体倒塌过程以及下部结构和上部结构的主要损坏特征,对震害的成因进行了分析,最后对连续梁桥的震害进行了总结。

This paper introduces the characteristics of the seismic action of Wenchuan Earthquake,makes a detailed study of the Baihua Bridge subjected to the severe damage in the Earthquake through filed investigation,which mainly includes the collapse process of the global structure of the fifth continuous girder unit and the features of the major damage to the substructure and superstructure of the Bridge,analyzes the formation causes of the damage and also summarizes the damage to the continuous girder bridge.

On the basis of investigation of the seismic damage to the simply-supported girder bridges in several violent earthquake events at home and abroad in the recent years,the seismic damage to the bridges is categorized and its causes are analyzed.In comparison of the relevant seismic specifications for bridges both in China and foreign countries,the insufficiencies of the current specifications of China are expounded,the performance of the simply-supported girder bridges used with the seismic mitigation and isolation techniques in the seismic damage is introduced and the proposals for the seismic design of the bridges in seismic regions are made as well.

以在建的南宁大桥为工程背景,采用 Euler-Bernoulli 梁及 Timoshenko 梁两种单元模式,分析了大跨径曲线梁非对称外倾拱桥动力行为特点。分析结果表明,由于两拱肋间无横向联系,拱肋振动模态较多,且频率较低,此外,拱肋横向振动模态通常两阶伴随出现;不同单元模式使拱肋横向振动的频率出现一定的差值。

提出了大跨径曲线梁非对称外倾拱桥的桥型概念,分析这一桥型的力学特点,并结合南宁大桥简要介绍这一桥型的设计要点。

外倾式拱肋的受力必须考虑扭转作用,针对设置足够纵向加劲肋和横隔板的空间正交异性闭口薄壁钢箱拱肋,用不同单元进行对比模拟。通过对悬臂状态和成桥状态在外荷栽作用下位移和应力的对比,采用初等梁单元模拟具有足够的计算精度。组合模型中,在梁和板的连接边界上采用基于平截面假定的位移约束方式能够满足局部构造精细分析的需要。