桥面铺装病害及结构力学分析

桥面铺装体系可以保护桥面板,扩散汽车荷载,是重要的桥梁使用结构。桥面铺装病害主要有坑槽、车辙、滑移和水损坏其中滑移和水损坏与粘结层有着非常重要的关系,只有优化的结构设计加上优质的材料才能保证桥面铺装的正常使用。本文针对桥面铺装病害及结构力学进行分析。     

浅谈公路桥梁桥面常见病害、成因及处理方法

探讨了公路桥梁桥面常见的病害成因,对桥面板渗水、桥面铺装病害、伸缩缝损坏等常见病害进行了分析,同时提出了处理和防治措施。     

复合浇筑式沥青钢桥面铺装层力学计算

钢桥面铺装的病害在大跨径桥梁上仍然很常见,钢桥面铺装已经成为制约大跨径桥梁发展的一个难题。本文采用有限元法对复合浇筑式沥青铺装层进行受力分析,将正交异性钢桥面板、铺装层作为整体,建立有限元模型,研究铺装层在行车荷载作用下的应力、应变规律。     

斜拉桥钢桥面环氧沥青铺装应力分析

桥面铺装在追随桥面板变形的同时承受荷载的直接冲击作用,为明确桥面铺装材料的性能要求及设计目标,首先要对桥面铺装层结构进行力学分析。汽车荷载通过桥面铺装传递到桥面板上,桥面铺装起着传递和分散汽车荷载的作用,因此必须将桥面铺装与桥面板结合在一起进行分析,确定桥面板与铺装层共同受力状态及相互影响效应。     

桥面铺装层裂缝的机理原因和预防措施

桥面铺装层直接承受行车荷载、梁体变形和环境因素的作用,其变形和应力特征与主梁及桥面板结构型式密切相关,一方面可分散荷载并参与桥面板的受力,另一方面起到联结各主梁共同受力的作用,因此,它既是桥面保护层又是桥面结构的共同受力层,应具有足够的强度和良好的整体性,并要有足够的抗裂、抗冲击、耐磨性能。本文分析了桥面铺装层裂缝产生的机理和桥面铺装病害原因,提出桥面铺装层修补及防治的方法,供大家参考。     

桥面铺装病害检测与加固

以某高速公路桥梁桥面铺装出现的病害情况为依据,论述桥面铺装病害的检测方法并分析病害产生原因,提出维修加固设计方案及施工工艺和方法。     

浅谈桥面铺装层裂缝原因及预控措施

目前,在我国公路桥梁建设中,由于桥面的铺装层破坏造成的裂缝、松散和坑槽等病害比较常见。这些病害大都是因为桥面的铺装层损坏引起的,桥面病害的产生不仅与桥面的排水有关,还与桥面的铺装质量有关。本文首先对桥面的铺装层裂缝产生的原因进行分析,再指出影响裂缝的因素,最后对桥面的铺装层裂缝修补措施进行探讨,希望能减少桥面铺装层损坏的问题,给相关人员一定的指导帮助。     

桥梁桥面铺装层的维修技术研究

本文以《桥梁桥面铺装层的维修技术研究》为题,首先对桥梁桥面铺装层存在的主要问题及原因进行了分析,然后提出了加强桥梁桥面铺装层病害的预防,强化维修的相应策略,旨在与同行朋友一起进行业务交流,将桥梁桥面铺装层病害的发生降到最低,不断提升铺装层的维修技术,以便更好地为我国桥梁建设服务。     

桥面混凝土铺装工艺技术探讨

桥面混凝土铺装是桥梁施工中比较重要的一道工序,桥面铺装的主要作用是保护桥面板防止车轮或者履带直接磨耗桥面,防止主梁受到雨水的侵蚀,并借以将车轮的集中荷载进行分散,水泥混凝土、沥青混凝土是我们经常使用的桥面铺装材料。本文结合自己多年从事桥梁工程的经验,对桥面混凝土铺装的施工工艺技术进行探讨。     

钢桥面铺装损伤病害的调查及分析

钢桥面铺装病害产生的原因包括外部因素和铺装自身因素,外部因素主要是铺装温度、交通荷载、桥面板刚度;铺装内部自身因素主要包括混合料的胶结料性能、混合料级配类型、混合料配合比、施工控制质量等因素。本文针对我国典型的钢桥面铺装:双层SMA、浇注式、环氧沥青铺装进行病害调查,分析引起病害的原因,为制定病害处治方案提供依据。     

Visual Inspection of Highway Bridges

The Federal Highway Administration recently conducted an investigation to assess the reliability of visual inspection of highway bridges as implemented by state departments of transportation. The study focused on routine and in-depth inspection, the two most prevalent forms of visual inspection of bridges. Because visual inspection is a highly subjective nondestructive evaluation technique, the results of these bridge inspections can be highly variable and are dependent on many factors. This study included the completion of 10 bridge inspection tasks by 49 practicing state bridge inspectors. With regard to routine inspections, this study showed that condition ratings are assigned with significant variability. Specifically, approximately 68% of condition ratings are within 1 rating point of the average. The results of the in-depth superstructure inspections indicated that these inspections are not likely to detect and identify the specific types of defects for which this inspection procedure is sometimes prescribed. Specifically, widespread defects such as those normally noted during a routine inspection are likely to be noted; however, local deficiencies, such as crack indications, are unlikely to be detected. The results of the deck delamination survey indicate that the accuracy of this type of inspection is relatively poor, with few inspection teams providing results that could be considered to accurately portray the condition of the deck.     

Remote nondestructive evaluation technique using infrared thermography for fatigue cracks in steel bridges

Long‐standing infrastructure is subject to structural deterioration. In this respect, steel bridges suffer fatigue cracks, which necessitate immediate inspection, structural integrity evaluation or repair. However, the inaccessibility of such structures makes inspection time consuming and labour intensive. Therefore, there is an urgent need for developing high‐performance nondestructive evaluation (NDE) methods to assist in effective maintenance of such structures. Recently, use of infrared cameras in nondestructive testing has been attracting increasing interest, as they provide highly efficient remote and wide area measurements. This paper first reviews the current situation of nondestructive inspection techniques used for fatigue crack detection in steel bridges, and then presents remote NDE techniques using infrared thermography developed by the author for fatigue crack detection and structural integrity assessments. Furthermore, results of applying fatigue crack evaluation to a steel bridge using the newly developed NDE techniques are presented.     

Load Testing of an FRP Bridge Deck on a Truss Bridge

New York State has constructed a fiber reinforced polymer (FRP) bridge deck as an experimental project. The goal of the project was to improve the load rating of a 50-yr old truss bridge located in Wellsburg, New York. The FRP deck weighs approximately 80-percent less than the deteriorated concrete bridge deck it replaced. Reducing the dead load increased the allowable live load capacity of the bridge without significant repair work to the existing superstructure, thus lengthening its service life. Load testing was conducted after installation of the FRP deck to study the conservativeness of the design, ascertain the assumptions made on composite action between the deck and the superstructure, and examine the effectiveness of joints in load transfer. This report describes the testing and discusses the results. The results indicate that the design was conservative. The design assumed no composite action between the deck and the superstructure, and the experimental data confirms that assumption. The study also shows that the joints are only partially-effective in load transfer between panels. Peak strains under the test loads were only a very small fraction of the ultimate strength of the FRP deck.     

Materials design for sustainability through life cycle modeling of engineered cementitious composites

Evaluating and enhancing construction material sustainability requires a life cycle perspective of the structures in which they are used, since material properties and durability can have a profound effect on overall infrastructure performance. A framework is proposed to evaluate and enhance the design of “greener” materials that integrates material design, structural design, and life cycle modeling of the built system. This framework is applied to engineered cementitious composite materials, a family of high performance fiber-reinforced composites used as link slabs in a concrete bridge deck. Modeling results show incorporating waste materials, such as fly ash, should be pursued only if the material retains adequate durability for the structural application where it is used. Additionally, traffic congestion resulting from bridge deck construction and rehabilitation events dominates environmental and economic life cycle results, consuming the most energy, producing the largest amount of pollutants, and generating the greatest life cycle costs.     

Probabilistic modeling of chloride-induced corrosion in concrete structures using first- and second-order reliability methods

Concrete structures are subjected to chloride-induced corrosion that can lead to shortened service life. Reliable predictions of life cycle performance of concrete structures are critical to the optimization of their life cycle design and maintenance to minimize their life cycle costs. This paper presents two simplified semi-analytical probabilistic models based on the first- and second-order reliability methods to model the uncertainty of the key parameters including surface chloride concentration, chloride threshold, cover depth and diffusion coefficient, which govern the chloride ingress into concrete and corrosion of reinforcing steel. A case study of a reinforced concrete highway bridge deck is used to illustrate the capability and efficiency of these simplified probabilistic models in modeling the uncertainty and predicting the time-dependent probability of corrosion. The models enable to quantify the impact of the different governing parameters on probability of corrosion and service life, which can be used to develop cost-effective management strategies.     

Review of magnetic methods for nondestructive evaluation (Part 2)

This paper gives a guideline to the literature of magnetic methods for nondestructive evaluation of materials for flaws and defects. This is a sequel to an earlier paper which described magnetic methods for nondestructive evaluation of stress, plastic deformation and microstructure. The present paper discusses magnetic particle inspection, magnetic flux leakage, leakage field calculations and eddy current inspection, including the remote field electromagnetic inspection method. An extensive survey of recent publications in the field is given.     

正交异性钢桥面疲劳开裂研究

正交异性钢桥面板的钢结构桥梁在车辆荷载作用下易出现疲劳开裂,为了解决这一问题,该文采用在正交异性钢桥面板上设置薄层RPC(Reactive-Powder-Concrete)超高性能混凝土层,将钢桥面转变成组合桥面,从而提高了桥面刚度,能有效改善结构受力状态,且不会增加桥梁上恒载重量。通过对某大桥的计算分析表明:采用组合桥面后,车辆荷载作用下的钢桥面应力大幅度下降。钢桥面疲劳敏感点处的拉应力降幅达到71.32%~72.39%,大幅度的提高了钢桥面的抗疲劳寿命;薄层RPC面板的高强度和高韧性,完全能满足组合桥面的最大拉应力10.08MPa的强度要求,成为钢桥面上的永久结构层,可以大幅度降低钢桥面板的开裂风险。     

Berührungslose Prüfung von Kunststoffen mittels photothermischer Wärmewellenanalyse

Remote Testing of Polymers with Photothermal Analysis of Thermal Waves After an introduction to thermal waves a comparison is made of photoacoustic detection methods (gas cell, piezoceramic) and photothermal detection arrangements (front surface and rear surface methods). Previously only photoacoustic methods have been applied to polymer related problems, while the advantages of photothermal measurements – remote and nondestructive evaluation – have been demonstrated on metals. The experimental part of this paper presents first steps to apply photothermal analysis of thermal waves to some problems of polymers: thickness measurement of thin layers; on-surface and subsurface defects; delamination of bonding and coating curing reactions; glass fibre content; orientation of fibres and molecules; aging processes. The present results indicate that the method can be used for nondestructive remote quality assurance of thin layers and foils. Further development is required to apply the method to nondestructive testing of thick walled components.     

Static and fatigue investigation of second generation steel-free bridge decks

This paper outlines the static and fatigue behavior of two different cast-in-place second generation steel-free bridge decks. Although cast monolithically, the first bridge deck was divided into three segments. The first segment was reinforced according to conventional design with steel reinforcement. The other two segments were both steel-free designs with internal crack control grids, one comprised of CFRP, and the other with GFRP. The hybrid CFRP/GFRP and steel strap design is called the second generation of the steel-free concrete bridge deck. The hybrid system reduces the development of longitudinal crack width and eliminates corrosion in the deck. All three segments were tested under a 25 ton and 60 ton cyclic load to investigate fatigue behavior. The second bridge deck is comprised of an internal panel and two cantilevers and incorporates a complete civionics system [Klowak C, Mufti A. Implementation of civionics in a second generation steel-free bridge deck. In: Proceedings of the 33rd annual general conference of the Canadian Society for Civil Engineering. Toronto, Ont., June 2–4, 2005]. The static test outlined in this paper is useful in the development of fatigue theory derived from the fatigue testing of the first bridge deck.     

Rehabilitation and field testing of an FRP bridge deck on a truss bridge

A light-weight FRP deck was used, on an experimental basis, to replace a heavy deteriorated concrete deck improving the load rating of a 60-year old truss bridge located in Wellsburg, New York. This was the first such application in New York State. Load testing was conducted after installation of the FRP deck to study its behavior. Results indicated the conservative nature of the deck design, and no composite action between the deck and the superstructure. The study also shows that the joints are only partially effective in load transfer between panels.