Spannglieder mit Kunststoffhüllrohren zur Herstellung von Brücken ohne Betonstahlbewehrung

Tendons with Plastic Ducts for Bridges without Mild Steel Reinforcement Frequently the conventional sealing of concrete bridges does not show a satisfactory serviceability in practice. Imperfect sealing leads to chloride entry into the structure because of bending cracks in the upper side of bridges in the range of negative moments. If a road passes under a bridge, there is the risk of chloride entry caused by salt fog spread on the surface of the bridge. In addition to the restoration liability of the sealing the pavement requires regular repair work. This periodic repair work causes high costs and affects the traffic flow. The method presented in this paper is characterized by omitting corrosion‐sensitive reinforcement and by integrating the pavement in the structure. The aim is to create concrete bridges with improved durability which can be manufactured with comparable costs to conventional concrete bridges. The results of experimental tests on the structural behavior of such structures will be presented.     

环氧沥青混凝土钢桥面铺装裂缝病害修复研究

在桥梁施工工艺中,目前大跨径钢桥基本上采用的是环氧沥青混凝土进行桥面铺装。由于其结构稳固,因此在桥梁中经常使用。本文针对目前在环氧沥青混凝土钢桥面铺装裂缝常见的原因进行了详细的分析,并提出了修复方案,以供相关人员参考。     

Entwicklungen im Stahlverbundbrückenbau – Autobahnbrücken mit einteiligen Verbundquerschnitten

Developments of steel‐composite bridges – motorway bridges with one‐piece composite cross‐sections. On design orders of the German Bundesministerium für Verkehr, Bau‐ und Wohnungswesen (BMVBW) motorway bridges have to be built with two superstructures – one for each carriageway. To get satisfying solutions in design of motorway bridges across valleys too, the authority decided in 1997 that it should be possible to build one‐piece steel‐composite bridges, provided that special suppositions are respected. The acceptance based on the condition, that it is possible to repair the reinforced concrete slap of the one‐piece superstructure as well as separated superstructures. The extensive maintenance of traffic has to be guaranteed all over the repair period. Since 1997 DEGES erected six bridges with one‐piece steel‐composite cross‐sections, three further bridges are under construction. Although the superstructures are designed for the state of the partly replacement of the reinforced concrete slap and therefore they are over dimensioned for the using‐state, these one‐piece superstructures are economic if they have a height of more than 50 m over the bottom of the valley. The following essay describes the one‐piece steel‐composite cross‐sections and gives constructive hints to their components.     

公路改扩建小桥病害植筋处理

目前，公路改扩建的小桥经常会出现混凝土保护层受损等病害，给人们的安全出行埋下了很大的隐患。本文分析了公路改扩建小桥的板体抬高施工工艺，并提出了小桥植筋维修措施，包括定位、钻孔、固化和保护等，以供读者参考。     

Life-cycle evaluation of deteriorated structural performance of neutralised reinforced concrete bridges

For existing reinforced concrete (RC) bridges, the structural performance is highly dependent on the changing properties of concrete and reinforcing steel due to neutralisation-induced corrosion. As neutralisation progresses, the corrosion could become serious enough to deteriorate not only the serviceability, but also the maintainability, of the structural performance. To study the influence of neutralisation on the existing RC bridges, the inspected data and test results collected from 21 bridges in Taiwan were examined to obtain the essential parameters through regression analyses. The regressive parameters related to service time can be employed in evaluating the variation of material and sectional properties in both reinforcements and concrete, and, accordingly, the change of structural performance from time to time could be obtained quantitatively via structural analysis. As a consequence, the performance degradation curve of an existing RC bridge can be predicted and, if necessary, the appropriate timing for repair or retrofit could be suggested. The results obtained could facilitate the minimisation of life-cycle cost for the neutralised RC bridges and enhance the functionality of a bridge management system (BMS).     

提高钢筋混凝土桥梁耐久性的措施研究

钢筋混凝土桥梁的腐蚀与劣化是桥梁运营中的一个不容忽视的问题,对既有桥梁进行病害检测与修复是提高其耐久性的必要措施,文中阐述了桥梁工程中钢筋及混凝土的腐蚀机理,分析了不同的病害原因,并制定了针对性的修补措施,提出对桥梁要进行整体保护。     

An Object-Oriented Diagnostic System for Prestressed Concrete Bridges

Abstract: A prototype knowledge-based diagnostic system for understanding the problems in prestressed concrete bridges is presented. The object-oriented approach is used for the system development. The system is completely interactive, making extensive use of pictures and diagrams along with textual explanation to explain difficult concepts in a multilingual environment. The system compares the new case of damage with the various types of damages that are stored in the knowledge base. It explains to the user the details of design and construction that may lead to this damage and the related repair methods. The system indicates the applicability of textual and pictorial explanations in developing an environment for the diagnosis of problems in prestressed concrete bridges.     

曲线箱梁桥震后病害分析及加固对策

以某预应力混凝土连续弯箱梁桥为研究对象,探讨了该桥在地震后发生主梁、桥墩偏位、支座损坏等病害的原因,并提出了具体的维修加固对策,以期为今后类似桥梁的施工提供理论依据。     

Dynamic analysis of a bridge repaired by CFRP: Experimental and numerical modelling

A significant number of existing reinforced-concrete bridges all over the world require maintenance and repair. Hence, the need for a rapid evaluation procedure for the diagnosis of existing bridges. This paper presents the application of a dynamic analysis methodology for structural evaluation of reinforced-concrete bridges. The methodology is based on the application of ambient vibrations non-destructive testing method and the identification of the structure total response using finite element method. A case study of a three span reinforced concrete bridge in a strong seismic activity area in the north of Algeria is analysed. The ambient vibration testing was carried out on the bridge, before and after its repair by the application of carbon fibre composites. The tests were conducted using an acquisition system made up of four accelerometers with three components placed at specific locations on the bridge. The finite element model gave comparable results to the experimental ambient vibrations tests. The modal parameters of the bridge before and after repair were identified by this in situ testing. The application of composite material to strengthen the structure increases the transverse rigidity of the structure and thus its modal frequency.     

预应力混凝土桥梁的发展与展望

从组成混凝土的材料、张拉技术、施工方法和结构抗震性能的发展状况等方面阐述了预应力混凝土桥梁的发展,并对其进行了展望,提出了提高预应力混凝土工艺水平的建议,从而促进预应力混凝土桥梁的发展.     

预拱度分析

从预拱度定义入手,阐述预拱度在不同混凝土桥上的应用,并对普通钢筋混凝土简支梁、预应力钢筋混凝土简支梁、普通钢筋混凝土连续梁预拱度的计算作了探讨,以期桥梁建成后正好在设计线上与路线相协调.     

Instandsetzung einer “müden” Straßenbrücke mit orthotroper Fahrbahn

Repair of a “tired” road bridge with orthotropic deck. The proneness to fatigue of steel bridges with an orthotropic deck appears in many damages because of the increasing traffic of heavy vehicles. On the example of an aggrieved highway‐bridge the specific weak points and the executed damage analysis will be shown. The gained knowledge leaded to the development of different alternatives of repair and to the presented repair concept. To improve the global characteristics of the structure additional supports will be built, for the local strengthening a reinforced concrete slab will be built as composite structure with the existing steel deck.     

混凝土桥梁裂缝的成因

为了加强对混凝土桥梁裂缝的认识，简述了混凝土桥梁裂缝所造成的危害性，全面分析了混凝土桥梁裂缝的种类和产生的原因，以方便在设计或施工中找到更可行的控制裂缝的方法，达到预防裂缝产生的目的。     

露石混凝土在桥面调平层中的应用

主要介绍了露石混凝土在桥面调平层施工中的几个重要环节,并通过与常规调平层表面处理的工艺进行比较,概括了露石混凝土应用的优点,指出露石混凝土的应用有效防止了桥面铺装在荷载作用下产生的推移等病害,从而提高桥梁的使用寿命.     

影响刚构桥施工阶段稳定性的若干因素探讨

大跨度预应力混凝土连续刚构桥的稳定问题是这类桥梁设计和施工过程中的关键问题之一。本文利用三维空间数值仿真模型,考虑几何非线性、材料非线性以及钢筋混凝土的压碎、开裂、骨料嵌锁效应等多种非线性因素的影响,着重分析了预应力混凝土连续刚构桥悬臂施工阶段的稳定性问题。详细讨论了墩身初始缺陷、墩身断面尺寸、墩身配筋率等若干因素对预应力混凝土刚构桥施工阶段稳定性的影响效应。相关结论可为同类桥梁的设计和施工提供参考。     

钢—混凝土组合桥混凝土徐变收缩分析

本文介绍钢混凝土组合桥梁混凝土徐变、收缩分析的方法,研究内容涉及结合梁桥及钢管混凝土组合拱桥。文末给出了可供参考的结论     

梁桥结构的常见病害及相关检测技术

介绍了河南地区中小跨径混凝土梁桥的常见病害,并对其进行了分类。基于这些常见病害,介绍了混凝土强度、保护层厚度、碳化深度、混凝土渗透性、氯离子含量、钢筋锈蚀等与耐久性相关的检测技术。     

Failure tests on concrete bridges: Have we learnt the lessons?

Full-scale failure tests of bridges are important for improving understanding of bridges’ behaviour and refining assessment methods. However, such experiments are challenging, often expensive, and thus rare. This paper provides a review of failure tests on concrete bridges, focusing on lessons from them. In total, 40 tests to failure of 30 bridges have been identified. These include various types of bridges, with reinforced concrete or prestressed concrete superstructures, composed of slabs, girders and combinations thereof. Generally, the tests indicated that theoretical calculations of the load-carrying capacity based on methods traditionally used for design and assessment provide conservative estimates. It can also be concluded that almost a third of the experiments resulted in unexpected types of failures, mainly shear instead of flexure. In addition, differences between theoretical and tested capacities are often apparently due to inaccurate representation of geometry, boundary conditions and materials.     

重大灾害时公路桥梁加强抢修研究

根据公路桥梁加强抢修的基本原则和指导思想,提出了公路桥梁加强抢修的主要手段,即整修使用、原跨修复、桥上架桥、桥下加强、桥旁架桥,并给出了抢修组织建议,以更好地完成抢修任务。     

混凝土桥梁的优化等耐久性设计

混凝土结构截面耐久性不等,是设计中不合理现象.本文以常遇大气环境下的混凝土桥梁为分析对象,从截面内钢筋脱钝时间相等入手,提出了混凝土桥梁等耐久性设计原则和方法;依据年均投资额的比较,提出了混凝土桥梁耐久性优化设计方法;算例说明:优化等耐久性设计可较大程度地延长桥梁结构耐久寿命,具有较好的经济效益.