Reinforced concrete half-joint structures: Structural integrity implications of reinforcement detailing and deterioration

钢筋混凝土半节点结构：钢筋细节和恶化对结构完整性的影响

• 批准号: EP/K016148/1
• 负责人: Janet Lees
• 金额: $ 49.08万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FK016148%2F1
• 关键词: Reinforced; concrete; half; joint; structures

A half joint is a particular type of RC structure. Within the existing UK Highways Agency network alone there are 400+ concrete bridges with half joints. The advantages of this structural form include a level running surface along the bridge deck and the support spans, and precast beams can be easily lifted into place and supported during construction. However, a disadvantage inherent in this type of construction is that there are problems associated with leakage through the joint. This enables moisture to accumulate at the beam seats thereby increasing the propensity for the deterioration of the concrete and reinforcement steel. The situation is adversely compounded by limited access to the bearing seat joint which leads to both inspection and maintenance issues. A further complication is that the detail in the beam seat region represents a potentially sensitive structural detail. Some half-joint structural vulnerabilities may have been present from the outset e.g. in the initial design or construction, some may develop with time e.g. deterioration. Half joint details have come under intense scrutiny since the collapse of a section of the de la Concorde Overpass in Quebec, Canada in 2006. Five people were killed and six others injured. Thus, a key challenge is to understand the lessons to be learned from the Concorde Overpass Collapse, and the inherent vulnerabilities in half joint structures.This project will provide improved analytical tools and experimental evidence for the more accurate assessment of half-joint structures, and will inform the management strategy for half-joint structures throughout the UK. Overly conservative strength assessments can result in unnecessary closures or vehicle weight limits, both of which are costly. Non-conservative strength assessments potentially put public safety at risk. The outcomes of this project are therefore of national, and international importance.The behaviour of reinforced concrete structures in shear is notoriously complex and there is no generally accepted unifying theory. This presents a major difficulty in the analysis of half-joint structures. The current work will explore, compare, extend, and adapt existing theories in the context of half-joint structures. A further goal is to incorporate detailing deficiencies and/or deterioration within the analytical and experimental approaches to thereby enhance the predictive capability for structures in service. The load-sharing implications in non-compliant details and the sensitivity of the structural performance to a deterioration outcome, such as a loss of strength will be investigated. This approach reflects the type of information that would be collated as part of a destructive or non-destructive testing strategy, and provides a general, robust and repeatable framework from which others can benchmark their results. Experiments on small and large scale specimens will be undertaken to provide the essential validation of the expected behavior. Small-scale tests will be used to characterise the bond anchorage behaviour in a representation of a deteriorated system. The large-scale tests will deliver an experimental database of half-joint structures with non-compliant details and determine the influence of strength reductions in the constituent materials. This will provide an important experimental evidence of the behavior of such structures, and highlight the most critical detailing and deterioration combinations. While the project has been inspired by, and will address, the difficult challenges faced by those who build, own and maintain reinforced concrete bridges, the development of the underlying fundamental scientific and engineering understanding will have far greater implications. A fuller understanding of the failure modes and sensitivities associated with complex reinforced concrete details will provide insight into the life-time performance of a wide range of existing infrastructure assets.

半节点是钢筋混凝土结构的一种特殊形式。仅在现有的英国公路局网络中，就有400多座带有半接缝的混凝土桥梁。这种结构形式的优点包括沿着桥面和支撑跨的水平运行表面，并且预制梁可以在施工期间容易地提升到位和支撑。然而，这种类型的结构固有的缺点是存在与通过接头的泄漏相关联的问题。这使得水分积聚在梁座处，从而增加了混凝土和钢筋劣化的倾向。这种情况由于接近轴承座接头的途径有限而变得不利，这导致检查和维护问题。更复杂的是，梁座区域的细节代表了潜在的敏感结构细节。一些半接头结构脆弱性可能从一开始就存在，例如在最初的设计或施工中，一些可能随着时间的推移而发展，例如恶化。自2006年加拿大魁北克德拉协和立交桥的一段倒塌以来，一半的联合细节受到了严格的审查。5人死亡，6人受伤。因此，一个关键的挑战是要了解从协和式立交桥倒塌的教训，和内在的脆弱性，在半连接structures.This项目将提供更好的分析工具和实验证据，半连接结构的更准确的评估，并将告知整个英国的半连接结构的管理策略。过于保守的强度评估可能导致不必要的封闭或车辆重量限制，这两者都是昂贵的。非保守的强度评估可能会危及公共安全。因此，该项目的成果在国内和国际上都具有重要意义。钢筋混凝土结构的抗剪性能是众所周知的复杂，目前还没有普遍接受的统一理论。这是半节点结构分析中的一个主要困难。目前的工作将探讨，比较，扩展和适应现有的理论在半关节结构的背景下。另一个目标是将详细的缺陷和/或恶化纳入分析和实验方法中，从而增强对在役结构的预测能力。将研究不符合要求的细节中的荷载分担影响以及结构性能对恶化结果（如强度损失）的敏感性。这种方法反映了将作为破坏性或非破坏性测试策略的一部分进行整理的信息类型，并提供了一个通用的，强大的和可重复的框架，其他人可以根据该框架对其结果进行基准测试。将进行小型和大型样本的实验，以提供预期行为的基本验证。小规模试验将用于验证退化系统中的粘结锚固性能。大规模测试将提供具有不符合要求细节的半接头结构的实验数据库，并确定组成材料强度降低的影响。这将为此类结构的性能提供重要的实验证据，并突出最关键的细节和劣化组合。虽然该项目受到了建造、拥有和维护钢筋混凝土桥梁的人所面临的困难挑战的启发，并将解决这些挑战，但对基础科学和工程理解的发展将产生更大的影响。更全面地了解与复杂钢筋混凝土细节相关的故障模式和敏感性，将有助于深入了解各种现有基础设施资产的寿命性能。

项目成果

Strut-and-tie models for deteriorated reinforced concrete half-joints

劣化钢筋混凝土半节点的支柱拉杆模型

• DOI: 10.1016/j.engstruct.2018.01.013
• 发表时间: 2018
• 期刊: Engineering Structures
• 影响因子: 5.5
• 作者: Desnerck P

The effect of local reinforcing bar reductions and anchorage zone cracking on the load capacity of RC half-joints

局部钢筋减少和锚固区开裂对钢筋混凝土半节点承载能力的影响

• DOI: 10.1016/j.engstruct.2017.09.021
• 发表时间: 2017
• 期刊: Engineering Structures
• 影响因子: 5.5
• 作者: Desnerck P

Impact of the reinforcement layout on the load capacity of reinforced concrete half-joints

钢筋布置对钢筋混凝土半节点承载能力的影响

• DOI: 10.1016/j.engstruct.2016.08.061
• 发表时间: 2016
• 期刊: Engineering Structures
• 影响因子: 5.5
• 作者: Desnerck P

Inspection of RC half-joint bridges in England: analysis of current practice

英国 RC 半节桥梁的检查：当前实践分析

• DOI: 10.1680/jbren.18.00004
• 发表时间: 2018
• 期刊: Proceedings of the Institution of Civil Engineers - Bridge Engineering
• 作者: Desnerck P

Impact of Material Deterioration on the Strength of Reinforced Concrete Half-Joint Structures

材料劣化对钢筋混凝土半节点结构强度的影响

• DOI: 10.2749/222137815815622753
• 发表时间: 2015
• 作者: Desnerck P