大跨径连续梁桥动静载试验研究

依据桥梁设计以及荷载试验的相关规范,结合某特大桥静动载试验工作,介绍某桥的静动载试验理论计算和试验结果,对该桥实际承载能力和结构安全性进行了评价。静动试验结果表明,桥梁的结构强度和刚度满足设计荷载等级的要求,设计合理,施工质量优良。     

亭子口嘉陵江大桥主桥静动载试验研究

介绍了亭子口嘉陵江大桥主桥静动载试验的内容和方法,通过静动载试验了解桥梁结构在试验荷载作用下的实际工作状态,检验桥梁结构的使用承载能力和营运质量是否满足正常使用要求,并通过试验结果与计算结果及规范值的比较分析,对桥梁结构做出总体评价.     

预应力混凝土连续箱梁桥荷载试验

某预应力混凝土连续箱梁桥设计荷载为城—A,为确保该大桥运行时的使用安全,判定其整体质量是否达到设计要求,对该桥梁进行一次静、动载试验,以对桥梁的承载能力和使用性能作一次全面的技术评估,本文介绍了检测内容、加载方案以及静、动载试验评定结果。     

基于荷载试验的钢箱梁悬索桥承载能力研究

通过对某城市千米级大跨度钢箱梁悬索桥进行静动载试验研究,测出桥梁结构在等效设计荷载作用下实际强度和刚度,结果表明,桥梁实际强度、刚度和承载能力满足设计规范要求;同时通过动载试验分析桥梁动力特性和动力响应,为桥梁后期运营和维护提供基础资料。采用的试验方法和试验结果能够为桥梁现状作出科学客观评价,也为今后同类型桥梁结构发展积累经验和数据。     

某高架桥静动载试验与分析

通过一实例介绍某钢筋混凝土连续箱梁桥的静动载试验的具体方法,包括确定控制截面、确定静栽试验的加栽位置、分级加载、测量桥梁在各级试验荷载作用下的应变及位移等。     

某公园人行索桥结构性能研究

以某公园人行索桥为例,介绍了桥梁的主要缺损状况,并通过桥梁静动载试验分析了桥梁结构性能,结果表明,该桥未按桥梁规范要求进行设计和建造,存在结构体系与耐久性问题,虽然静力荷载作用下结构弹性工作状态较好,但其抗扭刚度较小,且竖向振动基频小于3Hz,应进行维修改造。该桥的病害情况及静动载试验方法为同类桥梁的设计、评估、维修加固等提供了一定的参考。     

桥梁检测试验中的挠度测量

本文结合实际桥梁静动载试验,对采用精密水准测量方法测量挠度及应注意的问题进行了探讨。     

大跨径人行天桥静、动载试验检测与评价分析

对长安大学人行天桥进行静、动载试验检测,基于结构损伤识别和承载力评定原理建立了桥梁的有限元数值分析模型,针对该人行天桥的结构特点、结构外观检查结果和使用现状设计了静、动载试验检测方案.对现场静、动载试验数据和数值模拟结果进行了对比,并对该类桥梁结构的承载力与安全性评估、健康检测及损伤诊断过程进行了具体的分析和介绍;对结构性能和使用状态进行了综合评价,并根据其结构损伤和病害特点进一步提出养护方案.结果表明,该桥虽受力状况复杂,但使用状况基本完好.     

响琴峡大桥加固后静动载试验研究

通过对株六复线响琴峡大桥进行全面的检查及静动载试验,得到控制断面的应变、挠度、振幅及加速度等,全方位了解结构在静、动载作用下的工作状态;并结合理论计算结果,综合分析评价该桥的承载能力,确定桥梁结构的安全运营条件,提出运营速度建议。     

浅析桥梁静动载试验检测结果

桥梁静动载试验检测是作为桥梁试通行前的一道必不可少的检验内容,其客观的了解到该待检桥梁的各项质量指标是否达到设计标准要求,对桥梁施工整体质量起到严格把关的作用。本文就通过桥梁的各项静动载试验检测结果,来了解桥梁静动载试验检测内容及参数,以及分析这些桥梁用参数的基数指标,以便对以后的具体工作作出指导性的作用。     

BS5400规范中的荷载及荷载组合

结合对英国规范BS5400中有关荷载规定的理解，就对国内桥梁设计具有重大参考价值的内容，从恒载、二期恒载、活荷载、荷载组合等方面进行了介绍，对于大跨度桥梁横向的动力分析有很好的帮助。     

A hybrid experimental-numerical approach for load rating of reinforced concrete bridges with insufficient structural properties

This article presents a non-destructive approach for load rating of reinforced concrete bridges without structural plans. The approach is found on a hybrid method, which employs vibration and live load testing coupled with numerical simulation and model updating techniques, to converge on estimate of unknown structural parameters. The material properties of bridge and the amount of reinforcing steel for calculating the bending capacity of a bridge are determined through model updating results and nondestructive approaches. The updated model is then employed to determine load effects for calculating load rating factors, and these results are combined with live load test result to arrive at the bridge capacity, and ultimately the load rating. The method is validated by testing a skewed reinforced concrete slab bridge for load rating purposes. The bridge was instrumented with accelerometers and strain gages, and the responses of the bridge under vibration and quasi-static tests were measured. Results demonstrated that the proposed method is capable of determining the bridge capacity and load rating factor with good accuracy, and not only can be used for load rating of concrete bridges without structural information, but also can be useful in condition assessment of existing concrete bridge with available as-built information.     

Proof load testing for bridge assessment and upgrading

Bridge deterioration with time and ever increasing traffic loads raise concerns about reliability of aging bridges. One of the ways to check reliability of aging bridges is proof load testing. A successful proof load test demonstrates immediately that the resistance of a bridge is greater than the proof load. This reduces uncertainty in the bridge resistance and so increases the bridge reliability. The paper considers a reliability-based calibration of intensities of proof loads for aging bridges to verify either an existing or increased load rating taking into account possible bridge deterioration. Intensities of proof loads are calibrated based on a consistent target reliability index. The influence of test risk, dead to live load ratio, and uncertainties associated with dead and live loads and bridge resistance is considered. The results presented in the paper relate to short and medium span bridges.     

基于检测的折算系数法评定桥梁承载力研究

本文针对现有城市桥梁承载力评定方法的不足,提出了根据桥梁综合检测结果、结构固有模态参数测定结果以及使用荷载调查分析结果等数据,确定检算系数、截面折减系数、恶化系数以及活载影响修正系数,并结合桥梁设计和竣工资料,通过结构检算分析,进行荷载效应和抗力效应的比较,从而实现对桥梁承载力评定的方法。该方法综合考虑了结构构件质量现状、荷载状况和整体性能等多因素对桥梁承载能力的影响,使评定结果能够准确反映结构的实际状况,并便于实际应用。     

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。     

后张法预应力混凝土简支梁桥的恒载挠度分析

结合工程实例,使用桥梁专用软件分析了预制简支梁的挠度影响因素,并从理论上建立模型,测试了混凝土养护龄期、预制主梁的存梁期及恒载和活载之比等对板梁变形的影响,为设计施工提供了一些依据。     

整体式弯桥试设计研究

以某实桥为工程背景,进行整体式弯桥的试设计和设计验算。采用MIDAS/Civil2015有限元软件分别建立了原桥和整体式弯桥的3D有限元模型,后者考虑了台-土及桩-土相互作用。对比分析了两者在恒载、活载(汽车荷载)、温度荷载、混凝土收缩以及地震等荷载作用下的受力性能。结果表明:由于梁端固接和台后土压力等影响,恒载、活载、温度及混凝土收缩等荷载作用下,整体式弯桥梁端具有较大的负弯矩; 整体式弯桥在恒载作用下的主梁弯矩值较原桥均匀,而在活载作用下主梁弯矩值与原桥相近; 温度荷载对整体式弯桥的主梁内力影响最大,其次为混凝土收缩效应,在设计中应引起重视; 在恒载、活载作用下,整体式弯桥和原桥的主梁扭矩基本呈反对称分布,且恒载下的主梁边跨扭矩显著小于原桥,而在活载下两者的主梁扭矩相差不大,整体式弯桥表现出较优的抗扭性能; 此外,整体式弯桥的抗震性能明显优于原桥,可有效避免主梁在地震中的侧向偏位和落梁等现象,在高震区使用更具优势。     

基于“零位移法+应力平衡法”确定叠合梁斜拉桥的合理成桥索力

叠合梁斜拉桥的主梁为钢结构,桥面系为混凝土结构。针对叠合梁斜拉桥的特点,结合具体算例,采用平面双层框架模型模拟主梁。首先根据零位移法初定一个成桥索力;然后在此基础上考虑恒载和活载的共同作用,根据应力平衡法确定主梁弯矩的合理恒载可行域;最后根据索力对主梁弯矩的影响矩阵进行调整。这样所得到的索力更加符合斜拉桥的要求。     

Live load model for highway bridges

Load models are developed for highway bridges. The models are based on the available statistical data on dead load, truck loads and dynamic loads. The paper deals mostly with the static live load. The model is derived from truck surveys, weight-in-motion measurements and other observations. Simple span moments, shears and negative moments are calculated for various spans. Extreme 75 year loads are determined by extrapolation. The important parameters also include girder distribution factors and multiple presence (more than one truck on the bridge). Multiple presence is considered in lane and side-by-side with various degrees of correlation between truck weights. The maximum load is calculated by simulations. The developed live model served as a basis for the development of new design provisions in the United States (LRFD AASHTO) and Canada (Ontario Highway Bridge Design Code).     

Methodology for development of live load models for refined analysis of short and medium-span highway bridges

Abstract

The accuracy of bridge system safety evaluations and reliability assessments obtained through refined structural and finite element analyses depends not only on the accuracy of the structural model itself but also on the proper modelling of the maximum traffic loads. While current code-specified live load models were calibrated to properly reflect the safety levels of bridge structures analysed using the simplified methods adopted in bridge design and evaluation manuals, these load models may not lead to accurate results when implemented during refined structural analysis procedures. This paper describes a method to calibrate appropriate live load models that can be used for advanced analyses of bridges. The calibration procedure is demonstrated using actual traffic data collected at a representative weigh-in-motion station in New York State. The proposed calibration methodology is applicable for developing live load models for different bridge service periods, bridge types and design/assessment codes or standards. Live load models obtained using the proposed calibration procedure are readily implementable for deterministic refined analyses of highway bridges to produce similar results to those of complex traffic load simulations. Examples are presented that describe how results of such calibrated live load models would be used in engineering practice.