Management system for expansion joints of road bridges

This paper presents a management system for expansion joints with unique features in the field of road bridge management. The high costs of maintaining equipment, a significant percentage of the conservation budget of the bridges where they are installed, in conjunction with indirect costs and discomfort associated with intervention for their rehabilitation, amply justify the implementation of an autonomous, but integrated, management system, especially for entities responsible for a high number of bridges. The system is based on the classification of types of joints, defects and possible causes, diagnosis methods and maintenance/rehabilitation techniques, inter-correlated by matrices that are duly validated. Based on parameters that define degradation levels, the system also allows the rating of each defect in terms of physical and functional degradation and of detriment to the social envelope of the bridge.     

基于全寿命理念的伸缩缝及支座劣化模型研究

对全寿命理念作了简要介绍,根据桥梁使用状况,通过分析不同维护策略下伸缩缝及支座的性能变化曲线,建立了伸缩缝及支座性能劣化模型,并加以研究,对我国桥梁设计具有一定的参考价值。     

Reduction of traffic-induced vibration of two-girder steel bridge seated on elastomeric bearings

Reinforcing end-cross beam and removing bumps at expansion joints of bridges are proposed to reduce the traffic-induced vibration and to enhance the deck resistance near the expansion joint of a two-girder steel bridge with elastomeric bearings at each support. The reduction effect is investigated by means of a three-dimensional traffic-induced dynamic analysis. This study indicates that traffic-induced acceleration responses as well as dynamic reaction force of the bridge with the elastomeric bearings are greater than those of the bridge with steel pin bearings. It is observed that reinforcing the end-cross beam reduces traffic-induced vibrations regardless of bearing types, and also removing bumps is the most effective in reducing the dynamic reaction force of the bridges. Especially, for the bridge with elastomeric bearings, the maintenance of bumps near expansion joints is very important to improve not only expanding life span of the expansion joint but also the vibration serviceability of bridges.     

Optimum rehabilitation schedule of steel highway bridges

Every bridge component has a different deterioration rate, rehabilitation cost and cost-effective treatment time. The cost-effectiveness of the timings of bridge component rehabilitation is investigated both for individual components and for combinations of components, with the objective of finding optimum bridge life and the most cost-effective rehabilitation schedule. The optimization model makes use of: (1) deterioration curves to predict the condition of bridge components with respect to bridge age; (2) benefit/cost analysis to identify the most cost-effective rehabilitation schedule. The study was conducted using Illinois data for steel bridges covering the period 1976 – 1998. The results show that the most cost-effective timings of rehabilitating individual bridge components are significantly different if the rehabilitations of different components are combined and treated as parts of a system. The results of the analysis indicate that optimum bridge life is 74 years with a best time of combined rehabilitation of both the deck and superstructure in year 44. The study is an attempt to improve current methods of scheduling bridge maintenance, repair and rehabilitation.     

A retrospective evaluation of the performance of liner systems used to rehabilitate municipal gravity sewers

This paper provides new results gathered as part of a 6-year project funded by the U.S. Environmental Protection Agency (USEPA) to document the in-service performance of trenchless pipe rehabilitation techniques. The results from a pilot study focusing on cured-in-place pipe (CIPP) rehabilitation technologies were previously reported and the research program was extended to allow collection of additional CIPP samples and also to extend the study to other rehabilitation technologies (specifically included in this Phase 2 research were fold-and-form, deform–reform, and sliplining technologies). The establishment of a database to house performance evaluation data for rehabilitation technologies used in the water and wastewater sectors is also described. The additional retrospective data for CIPP and other rehabilitation technologies are reported and an overall assessment of CIPP life cycle performance is provided. The examination of CIPP liners with up to 34 years in service and other rehabilitation technologies with up to 19 years of service has shown that all of the rehabilitation technologies are showing little evidence of deterioration in service. The test results for 18 CIPP samples from nine cities across North America indicate that properly designed and installed CIPP liners should meet and likely exceed the typical 50-year expected design life. For the fold-and-form, deform–reform, and sliplining technologies, there are only two to three samples per rehabilitation technology and hence less can be said about overall performance. Nevertheless, all of the samples tested still met the material property requirements at installations after 14–19 years of service. In summary, the results provide an excellent prognosis for the rehabilitation technologies evaluated.     

桥梁伸缩缝病害的预防措施

通过对山西省桥梁伸缩缝装置的普查，分析造成病害的原因主要有设计、施工、养护、自然条件几方面，制定出相应措施，确保了桥梁伸缩缝装置的正常工作，延长桥梁的使用寿命，降低养护成本。     

A probability model for investigating the trend of structural deterioration of wastewater pipelines

Canada’s infrastructure is aging and deteriorating. New legislation requires the municipalities to estimate operating and capital expenditures for running the systems into the future and to develop financial sustainability plans. Wastewater pipelines deterioration is currently not well understood and realistic deterioration models need to be developed.This paper demonstrates how the condition assessment data from trenchless visual inspections of wastewater pipelines can be used to understand the performance of wastewater pipelines. A new ordinal regression model for the deterioration of wastewater pipelines based on cumulative logits is elaborated. The model is presented using the Generalized Linear model formulation and takes into account the interaction effect between the explanatory variables. The new model is demonstrated and validated using the City of Niagara Falls high quality wastewater collection network condition assessment data for reinforced concrete (RC) and vitrified clay (VC) pipes.This new model is found to represent the City of Niagara Falls RC and VC pipes’ deterioration behavior for pipes in service for up to 110 years. RC pipes deterioration is found to be age dependent while VC pipes deterioration is not age dependent. This finding is contrary to other deterioration model studies that indicate that VC deterioration is age dependent. The service life for RC pipes is estimated to be approximately 75 years while VC pipes are found to have an indefinite service life if installed without structural damage.The cumulative logit model can be used to determine wastewater pipelines’ service life, predict future condition states, and estimate networks’ maintenance and rehabilitation expenditures. The latter is critical if realistic wastewater networks’ future maintenance and operation budgets are to be developed for the life of assets and to meet new regulatory reporting requirements. Further research is required to validate this new methodology for other networks and the deterioration modeling of pipe materials other than RC and VC.     

Fatigue life estimates for a slender orthotropic steel deck

Fatigue cracks in several types of welded joints and geometrical details have been reported to occur in a large number of slender orthotropic decks of existing steel bridges in many parts of the world. Some of these cracks are initiated very early, a few years after the bridge is brought into service. That is why it is said that fatigue life estimation for the welded joints of orthotropic decks is not an easy designing task. This is so because the random variation of local stresses is sensitive to many factors, in particular to those involved in the dynamic interaction between the vehicle’s tyres, the pavement and the steel structure.This paper presents and discusses the main causes for the observed cracks and the outcome of the ultimate fatigue life estimates for typical welded and geometrical details of a slender orthotropic deck with trapezoidal cross-section longitudinal ribs. This is the deck of an existing long-span steel bridge, which has been strengthened by adding a reinforced concrete layer fixed with shear studs to the steel deck top plate. This was done to avoid continued and extensive repair work and to enhance the fatigue life expectancy of the steel deck structure. The fatigue life estimation is done with the aid of refined numerical modelling and in situ experimental strain measurements and also by taking into account all the built-in structural alterations, changes in volume of traffic and in vehicles loading which have occurred during this bridge’s 32 years of service life.     

高速公路桥梁伸缩缝维修更换施工技术

伸缩缝装置是桥梁结构的重要构件之一,及时做好桥梁伸缩缝的保养、维修、更换工作并保持伸缩缝的整体完好性,对确保桥梁结构安全,保障行车安全都具有重要意义。本文介绍了伸缩缝更换中旧缝拆除、新缝安装就位和浇筑混凝土等各施工工序的技术要点,指出只有严格控制施工时各工序的质量,才能保证桥梁伸缩缝装置在运营过程中的正常使用和满足耐久...     

Composite (steel-concrete) highway bridge fatigue assessment

Steel and composite highway bridges are currently subjected to dynamic actions with variable magnitudes due to the action of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation in the structures. Depending on the magnitude and intensity, these adverse effects can compromise the structural system response and the reliability which may also lead to a reduction of the expected bridge service life. A composite (steel-concrete) bridge with a 12.50 m roadway width and 0.23 m concrete deck thickness, spanning 40.0 m by 13.5 m was investigated in this work. The computational model, developed for the composite bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations, and was implemented in the ANSYS program. The proposed analysis methodology and the procedures presented in the design codes were initially assessed to evaluate the bridge fatigue response in terms of its structural service life. The stress cycle counting techniques and the cumulative damage rule application had been analyzed through S-N curves, based on an extensive revision of steel and composite bridges’ service life and theoretical fatigue aspects in steel structures. The investigation also considered the recommended procedures used for the steel and composite structures’ main codes. The main conclusions of this paper focused on alerting structural engineers to the possible distortions, associated with the steel and composite bridges’ service life when subjected to vehicles’ dynamic actions.     

桥梁伸缩缝损坏原因及防治

在对洛阳市桥梁进行全面病害普查时,发现桥梁伸缩缝损坏情况严重。文章从设计、施工、养护等方面分析伸缩缝损坏的原因,提出了对各种类型桥梁伸缩缝损坏的防治和处理措施。     

低碳钢对暗缝式伸缩缝变形的分析

为了改善暗缝式改性沥青伸缩缝的使用性能,文章简要介绍了暗缝式桥梁伸缩缝的构造,并通过模拟美佳伸缩缝,用不同厚度的钢板做实验,对伸缩缝装置的弯曲变形进行分析研究.文章的研究成果表明：钢板在不同厚度的情况下,暗缝式改性沥青伸缩缝的弯曲变形有极大的不同,可供桥梁设计及养护工程师参考.     

谈高速公路桥涵养护管理

道路桥涵是高速公路的重要组成部分,其承载能力和通行能力是高速公路安全畅通的关键。尤其像邢临高速公路这种桥涵较多的高速公路,必须加强对桥涵构造物的检査和保养,要保证公路畅通无阻,使其保持完好的技术状态,人为的延长其使用年限。特别是近年来,面临养护人员少、车辆超载严重、道路承载能力有限等诸多现实问题,道路和桥梁养护及维修显得尤为重要。     

简支梁连续板桥的桥面结构设计和内力分析

城市高架桥、立交桥及多跨桥梁的桥面联成一体,可大大改善行车的平顺性,减少车辆的冲击和延长桥梁的使用寿命。简支梁连续板桥只设一个固定支座(橡胶支座),其余均采用四氟乙烯薄板的滑板支座,从而是一种不完全铰的型式。通过大量工程实例、有关设计计算和实地测试,证明采用桥面连接筋符合实际受力状态,伸缩缝设置和桥梁支座的配置,在实际使用中是可行的。     

Condition-based maintenance decision support system for oil and gas pipelines

The 2013 report card of America's infrastructure has scored the condition of oil and gas pipelines as D+ which means that such pipelines are in a relatively poor condition. More than 10,000 failures have been recorded in the US. These failures have resulted in environmental, health and property damages. Therefore, there is a definite need to give more attention to the maintenance of oil and gas pipelines. This paper develops a comprehensive model for the maintenance planning of oil and gas pipelines. The model selects rehabilitation/repair alternatives for oil and gas pipelines based on their condition during their service life. These alternatives are then used to calculate the cash flow throughout the service life of these infrastructures. The model, which uses Monte Carlo simulation and fuzzy approach to address the uncertainties in the estimation of the maintenance operation costs and the economic parameters, calculates the Equivalent Uniform Annual Worth of the identified alternatives. The optimum maintenance programmes consist of the alternatives that have the lowest life cycle cost of oil and gas pipelines. The model is expected to support pipeline operators in the maintenance decision-making process of oil and gas pipelines.     

Development of a bridge maintenance system for prestressed concrete bridges using 3D digital twin model

Abstract

Preventive maintenance is increasingly becoming an essential strategy in the bridge industry owing to its proactive advantage of maintaining the structural sustainability during its entire service life. Several in-use bridges lack an appropriate regular maintenance solution, leading to extra cost during the operation stage. This paper proposes a new generation of the bridge maintenance system by using a digital twin model concept for more reliable decision-making. A detailed solution is proposed in this work to enhance the bridge maintenance process using a parallel solution: a maintenance information management system based on a 3D information model in conjunction with a digital inspection system using image processing. Three-dimensional digital models are required to utilise information from the entire lifecycle of a project, including design and construction, operation, and maintenance, by continuously exchanging and updating data from each stakeholder. For the maintenance of prestressed concrete bridges, the twin models are defined and their uses are presented.     

外环线(西北段)桥梁伸缩缝质量控制

该文介绍上海市外环线(西北段)各种类型桥梁伸缩缝的施工质量控制。分析桥梁结构与伸缩缝的相互关系,找出质量控制点,提出切合实际的工艺流程。立足预控和主动控制;管理上强调依法操作;操作上强化实时监控。全工程共有桥梁单位工程55个,伸缩缝300多道,经检定,合格率100%;经3年运营,伸缩缝始终保持良好,被评为上海市政道路示范工程。     

浅析桥梁伸缩缝的病害及维护措施

文章列举了福州市区桥梁伸缩缝的主要病害,分析了病害的成因,并提出相应的维修方法,及今后在设计、施工、养护方面防治伸缩缝病害的措施。     

Spatial variability of damage and expected maintenance costsfor deteriorating RC structures

The paper develops a technique to predict life-cycle costs, using probabilistic information about the likelihood and extent of corrosion-induced cracking to reinforced concrete (RC) structures. The present paper focuses on the likelihood and extent of severe cracking as the criterion for the timing and cost of maintenance. The life-cycle cost and expected maintenance cost considers multiple repairs and various inspection intervals over the service life of the structural element. A repair cost function is also developed. Two common maintenance strategies are considered: repair and rehabilitation. It was found that for a 2% discount rate the benefits of delaying the timing of repairs outweigh the cost of increased extent of damage, for maintenance of a RC bridge deck.     

Frontier of continuous structural health monitoring system for short & medium span bridges and condition assessment

It is becoming an important social problem to make maintenance and rehabilitation of existing short and medium span(10-20 m) bridges because there are a huge amount of short and medium span bridges in service in the world. The kernel of such bridge management is to develop a method of safety(condition) assessment on items which include remaining life and load carrying capacity. Bridge health monitoring using information technology and sensors is capable of providing more accurate knowledge of bridge performance than traditional strategies. The aim of this paper is to introduce a state-of-the-art on not only a rational bridge health monitoring system incorporating with the information and communication technologies for lifetime management of existing short and medium span bridges but also a continuous data collecting system designed for bridge health monitoring of mainly short and medium span bridges. In this paper, although there are some useful monitoring methods for short and medium span bridges based on the qualitative or quantitative information, mainly two advanced structural health monitoring systems are described to review and analyse the potential of utilizing the long term health monitoring in safety assessment and management issues for short and medium span bridge. The first is a special designed mobile in-situ loading device(vehicle) for short and medium span road bridges to assess the structural safety(performance) and derive optimal strategies for maintenance using reliability based method. The second is a long term health monitoring method by using the public buses as part of a public transit system (called bus monitoring system) to be applied mainly to short and medium span bridges, along with safety indices, namely, “characteristic deflection” which is relatively free from the influence of dynamic disturbances due to such factors as the roughness of the road surface, and a structural anomaly parameter.