泡沫铝桥墩防撞装置的试验研究

通过对不同厚度、不同结构形式的泡沫铝桥墩防撞装置进行的对比模型试验,得出不同防撞装置的耐撞性和对桥墩不同的防护效果,并分析了撞击规律及其原因,以寻求能够对桥墩保护作用具有更明显优势的装置厚度和结构形式;在试验基础上,利用有限元分析软件ANSYS/LS-DYNA对各工况碰撞过程进行了模拟分析,得出了与试验结果相近的结论;相对于承受相同荷载的裸墩,泡沫铝桥墩防撞装置能有效地吸收撞击能量,显著降低荷载对桥墩的作用,因而有良好的防撞效果;研究了二次防撞效果;探讨了装置厚度及结构形式与防撞效果的关系.     

桥梁防船撞装置的数值仿真分析

本文利用非线性有限元分析软件LS-DYNA的显示算法对汕湛高速的某桥进行了船桥碰撞的数值仿真分析,通过对有复合材料防撞装置和无复合材料防撞装置两种工况的对比分析,结果表明在有复合材料防撞装置保护下,桥墩受到的船舶撞击力大幅降低,同时防撞装置吸收了船舶很大一部分的动能,对船桥都起到了很好的保护作用。     

桥梁防撞系统动力特性分析

研究了桥墩防撞系统的动力特性。首先阐述了空间杆系结构有限元分析的基本原理,然后采用大型商业化软件ANSYS建立了桥墩防撞系统的三维有限元模型。在此基础上,简要阐述了结构动力特性分析的基本原理,研究了桥墩防撞系统的动力特性并分析了结构频率和振型的特点。     

如皋长江大桥主桥桥墩防撞设计

以如皋长江大桥为依托,根据相关规范标准,列举了一些传统的桥墩防撞形式,着重对该大桥桥墩防撞设计方案作了研究,并阐述了具体的设计方式,以有效保障桥梁的运营安全。     

带肋夹层板圆形桥墩防撞套箱性能分析

针对钢板-聚氨酯夹层板制作的圆形桥梁防撞装置,采用数值动力计算方法,分析船舶撞击该种防撞套箱不同部位时的防撞性能。结果表明:该种防撞套箱能够很好地避免船舶与墩柱发生直接碰撞,当船舶斜撞程度较大时,套箱可以利用自身的构造优点和材料特点拨开船头,更好地保护桥墩、防撞套箱及船体。     

城市桥梁防撞设计研究

城市桥梁是交通的重要枢纽,也是重要的航道跨越构筑物。在河道中间设置桥墩难免对船舶航道产生影响,导致船桥撞击事故的发生,可能造成船舶损坏沉没、桥梁损毁倒塌,以及重大经济损失和人员伤亡。对常见的桥墩防撞设施的设计方法与策略进行了分析,并对衢州市书院大桥的防撞设计方案进行了探讨研究。     

跨石臼湖航道大桥防撞设施探索

针对跨石臼湖航道大桥的特点,对H200箱型自浮式复合材料防撞设施等6种防撞方案从形式、工作原理、防撞效果、耐腐蚀性、使用年限、后期维护、施工难易、对水环境影响、对船体影响、造价、意见等方面进行了比较分析,综合考虑防撞设施造价和桥墩的自身抗力因素,H200箱型自浮式复合材料防撞设施可在保护桥墩安全的同时,最大限度地保障船舶及船员的安全,符合人性化设计思路防撞设施方案。     

格栅型桥墩防船撞装置模拟分析应用

本文对一种格栅型防撞装置的防撞性能进行了研究。运用有限元软件ANSYS/LSDYNA,对格栅型防撞装置进行三维建模,从钢板厚度、格栅间距、防撞装置厚度三个影响因素分别分析防撞装置的防撞性能。同时,选择防撞性能较优的工况,将防撞装置材料替换成GFRP,分析其碰撞力和吸能水平,并与钢制防撞装置进行对比。研究发现:三个影响因素都会对防撞装置的防撞能力产生影响,其中钢板厚度和格栅间距是主要因素;GFRP防撞装置相比钢制防撞装置有更好的碰撞力折减率,但吸能效果不理想。     

船桥碰撞事故的防御对策

随着交通运输的蓬勃发展,各国船桥碰撞事故频频发生,船桥碰撞问题越来越引起世界各国的广泛关注。防止船桥碰撞事故的措施主要有完善船桥碰撞机理的研究、合理使用桥墩防撞装置、合理选择桥址和增强安全管理手段等方法。最后,针对各种方法提出了几点见解和展望。     

广东某桥船撞数值模拟与防撞设施设计

总结了国内外计算船撞力的公式,并以广东一处桥梁为例,通过经验公式和有限元数值计算得到桥墩防撞的一些设计参数,将数值计算结果与经验公式计算值进行比较,结果表明：数值分析结果小于各经验公式计算值,与欧洲规范较为接近,其中,按中国《公路桥涵设计通用规范：JTG D60—2015》以漂流物来计算船撞力是不可靠的,无法对防撞设施设计提供有力参考。针对大桥的特点,设置浮动式结合固定式钢覆复合材料防撞设施,与传统防撞设施相比,缓冲能力强,能承受更大的撞击力,耐久性更强,可为类似工程设计提供参考以期为类似工程设计提供借鉴与参考。     

车—桥碰撞的数值模拟研究

利用有限元分析软件ANSYS/LS-DYNA,建立了汽车—桥墩碰撞的有限元模型,通过对汽车—桥墩的碰撞过程进行数值模拟分析,得到了碰撞过程中的碰撞力、碰撞能量和桥墩墩顶位移,分析了桥墩受撞破坏的机理,对车—桥碰撞研究具有十分重要的意义。     

近断层地震作用下高速铁路简支梁桥碰撞研究

结合近场地面运动改变结构响应的特点,研究了高速铁路简支梁桥在近场地震作用下的碰撞现象、计算模型以及碰撞力的传播路径,分析了这种梁间碰撞现象对桥墩、梁及支座的影响,指出碰撞现象对固定支座的影响较大。     

车—桥墩碰撞研究方法综述

针对车—桥墩碰撞问题,结合国内外有关研究现状和研究成果,综述了车—桥碰撞问题的研究方法,分别阐述了弹簧模型,刚塑性梁模型及均质地基桩柱模型,并对试验法和数值模拟进行了介绍,提出了研究发展趋势。     

Analysis of girder bridge pier subjected to barge collision considering the superstructure interactions: the case study of a multiple-pier bridge system

This paper aims to numerically evaluate the effects of girder bridge superstructure on the impact responses and load paths transferring the shear force of pier subjected to a moderate-energy barge collision in LS-DYNA. First, two multiple-pier systems of St. George Island Bridge in Florida which have different piers in terms of structural characteristics (such as mass and stiffness), geometry, and the height of impact location are considered as the cases of study. From the numerical barge collision simulations, different impact responses and load transferring paths from the impact location to farther zones are observed. In addition, the sensitivity of impact responses, and the impact load paths transferring shear force to the superstructure mass, stiffness, and damping are studied by developing four different models of pier-superstructure interaction and carrying out a parametric study. It is found that the increase in the value of superstructure parameters has positive effects on the impact forces and the internal stresses in the piers. However, the sensitivity of shear stresses generated at various zones of the pier extremely depends on the impact load paths transferring shear force in different piers with different relative characteristics rather than the superstructure.     

Evaluating effectiveness and optimum design of isolation devices for highway bridges using the fragility function method

Seismic isolation can be used as a practical method to mitigate earthquake hazards for designing new highway bridges or retrofitting existing ones. To realize a reliable and effective seismic isolation design, several important and often interacting factors should be considered, including the ground motion characteristics, structural configurations and properties, mechanical properties of isolation devices and soil-structure interaction etc. This paper adopts the performance-based evaluation approach to investigate the effectiveness and optimum design parameters of isolation devices so as to minimize the overall damaging potential of seismically-isolated bridges. Fragility functions, which define the probability exceeding a performance state at a given set of earthquake intensities, are derived using nonlinear time history analyses of typical highway bridges (conventionally designed or base-isolated) subject to a suite of 250 earthquake motions. The nonlinear models for bridge columns and isolation devices are incorporated and various combinations of isolation parameters, e.g. elastic stiffness, characteristic strength and post-yielding stiffness, representing common types of isolation devices are evaluated. Both Probabilistic Seismic Demand Analysis (PSDA) and Incremental Dynamic Analysis (IDA) methods are used and compared in generating the fragility functions. Damage criteria for both piers and isolation devices are established to relate the component response quantities to global damage states of bridges. The study shows that the mechanical properties of isolation devices have a significant effect on the damage probability of isolated bridges. By evaluating the earthquake intensity required to achieve specified damage states of base-isolated bridges, the optimum combinations of mechanical parameters of isolation devices are identified as a function of structural properties and damage states. The findings can serve as a practical guide for isolation device designs where the uncertainties with ground motions and variability of structural properties are effectively incorporated under the fragility function framework.     

金马大桥投标方案设计

金马大桥系广州至肇庆高速公路上的一座特大桥梁。桥梁工程范围１８００ｍ，桥梁宽度为２６．５０ｍ。桥位处河宽、水深、流急，下部结构工程施工难度较大。本文就该桥的一个设计投标方案，简略地叙述了桥位自然条件和设计技术标准，重点地介绍本设计方案的指导思想、总体布置和结构体系、主桥的设计计算、主墩的防撞设计，以及本方案的主要特点等。     

低配筋大比例尺圆端型桥墩抗震性能的试验研究

本文通过对低配筋大比例尺圆端形桥墩的拟静力试验,研究了其非线性滞回特性,计算了延性比、耗能特性及最大抗力,分析了它们与剪跨比和配箍率之间的关系,得出了低配筋桥墩抗震设计的基本参数。     

尾道大桥在强震作用下的非线性动力反应研究

采用非线性动力时程分析法对日本尾道大桥的抗震性能进行研究.通过建立该桥三维有限元模型,探讨在地震作用下该桥的受力特点,并对其主要结构构件的弹塑性反应进行分析.经分析得出,在地震作用下,尾道大桥的桥面主梁处于弹性状态,桥墩剪切强度不足,需要进行补强加固.     

地震作用下横向碰撞对连续梁桥地震反应的影响

地震作用下,结构的碰撞问题被认为是影响结构地震反应和结构抗震性能的一个重要因素,碰撞是一种非常复杂的非线性问题,其影响因素很多.采用非线性时程地震反应分析方法,探讨了横向地震作用下梁体与抗震挡块间的碰撞对连续梁桥地震反应的影响,结果表明:梁体与抗震挡块间的碰撞不仅产生很大的撞击力.还会导致桥墩的地震需求增大,对结构抗震不利.通过参数分析表明接触单元刚度、初始间隙以及墩高等参数对碰撞效应有很大影响.     

Effects of soil–pile interaction on the response of bridge pier to barge collision using energy distribution method

Abstract

In this paper, the effects of soil–structure interaction (SSI) on the response of a girder bridge pier is evaluated by assessing the energy distributions in the barge–pier collision system. The finite-element models of two example piers of St. George Island Causeway Bridge, which have different structural and geometrical characteristics, are developed in LS-DYNA software to simulate the barge–pier collision scenarios. By comparing the energy distribution results among the barge and pier components, it is obtained that barge bow component has greater value of the internal energy contribution than pier components in the barge collision with more stiff pier. While, in the barge collision with more flexible pier, the pier components including the pier structure, piles and SSI have more internal energy contributions than the barge component. In addition, From the comparison of energy absorbed by the pier structure between the cases with and without SSI, it is found that the effect of the substructure and its relevant SSI on the response of the more flexible pier affected by the produced large deformations and relative displacements of the pier substructure, is more than that of stiff pier which displaces with semi-rigid and global deflections.