Reinforced concrete infrastructure, Understanding the past, present and future

钢筋混凝土基础设施，了解过去、现在和未来

• 批准号: EP/J002887/1
• 负责人: Janet Lees
• 金额: $ 5.84万
• 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: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ002887%2F1
• 关键词: Reinforced; concrete; infrastructure; Understanding; past

The construction industry is of critical importance to the UK economy and typically represents between 6-8% of the national GDP. But the large scale of this output comes at an environmental cost. The efficient design and lifetime extension of structures is therefore a social, environmental and economic priority. The focus of this proposal is reinforced concrete where a major complication in delivering efficient, sustainable, low-maintenance solutions is that the performance of these structures reflects numerous factors including the initial design, the in-service conditions, the load history and any interventions during the service life. In service, one of the challenges is that there is an interaction between the concrete and the internal reinforcement and this behaviour is not currently well understood. This problem is exacerbated when considering how shear forces are transferred since questions still remain about how even a basic reinforced concrete structure carries these forces under static load conditions. Indeed, the 2006 collapse of the de la Concorde Overpass in Quebec is a tragic reminder of the impact of the initial design, in-service repairs and bridge management all contributed to the eventual collapse. It is therefore clear, considering the potential environmental and public safety issues, that a fundamental investigation to ascertain the types of structures and loadings which may be susceptible to time dependant changes in load sharing mechanisms that could be detrimental to the structural performance is overdue. The situation becomes even more complex when interventions to increase or re-establish the strength of an existing structure are required. For example, the application of additional external fibre reinforced polymer (FRP) reinforcement has been found to be an effective means to achieve the capacity increases required to keep existing structures in service. FRPs have a high strength to weight ratio and are lighter and more durable than equivalent steel strengthening systems. However, this additional reinforcement changes the load-sharing behaviour of the structure. Furthermore, in many cases, the provision of the additional reinforcement addresses an immediate strengthening need where speed and ease of installation are primary considerations. However while the initial motivation may be for a short-term intervention, it is likely that, due to the disruption and costs associated with demolition and reconstruction, many of these FRP strengthening systems will be in service for a considerable period of time. To date, the longer term in-service performance of strengthened RC structures has not been adequately addressed. Cost-effective approaches for extending the life of existing infrastructure are becoming increasingly important in the current era of financial constraints.This project seeks to address these identified gaps through the establishment of a high-level, enduring, international collaboration between the University of Toronto (U of T), Canada, Queen's University, Canada and the University of Cambridge, UK. The particular strength of this collaboration is that it brings together the necessary expertise to re-evaluate the time- and load-dependent baseline conditions in an existing reinforced concrete structure and to then assess and predict the long-term performance of both unstrengthened and FRP-strengthened structures. This enhanced understanding will inform asset owners and managers and lead to improved design and maintenance strategies.

建筑业对英国经济至关重要，通常占全国GDP的6%-8%。但这种大规模的产出是以环境为代价的。因此，结构的有效设计和寿命延长是社会、环境和经济的优先事项。这项提议的重点是钢筋混凝土，其中提供高效、可持续、低维护解决方案的一个主要复杂因素是，这些结构的性能反映了许多因素，包括初始设计、使用条件、荷载历史和使用寿命期间的任何干预措施。在使用中，其中一个挑战是混凝土和内部钢筋之间存在相互作用，目前对这种行为还没有很好的了解。当考虑剪力如何传递时，这个问题变得更加严重，因为问题仍然存在，即使是基本的钢筋混凝土结构在静载条件下也如何承载这些力。事实上，2006年魁北克协和式立交桥的坍塌是一次悲剧性的提醒，提醒人们最初的设计、使用中的维修和桥梁管理都是最终坍塌的原因。因此，考虑到潜在的环境和公共安全问题，很明显，早就应该进行基本调查，以确定哪些结构类型和荷载可能会受到荷载分担机制随时间变化的影响，从而可能损害结构的性能。当需要干预以增加或重建现有结构的力量时，情况变得更加复杂。例如，应用额外的外部纤维增强聚合物(FRP)加固已被发现是实现保持现有结构使用所需的能力增加的有效手段。FRPS具有很高的强度与重量比，并且比同等的钢加固系统更轻、更耐用。然而，这种额外的加固改变了结构的荷载分担性能。此外，在许多情况下，提供额外的加固解决了直接的加固需要，其中速度和安装的简易性是主要考虑因素。然而，虽然最初的动机可能是短期干预，但由于拆除和重建相关的干扰和成本，许多玻璃钢加固系统将在相当长的一段时间内投入使用。到目前为止，加固钢筋混凝土结构的长期使用性能还没有得到充分的解决。在当前财政紧张的时代，延长现有基础设施寿命的成本效益方法正变得越来越重要。该项目寻求通过在加拿大多伦多大学(U Of T)、加拿大女王大学和英国剑桥大学之间建立高水平、持久的国际合作来解决这些已确定的差距。这种合作的特别优势在于，它汇集了必要的专业知识，以重新评估现有钢筋混凝土结构中依赖时间和荷载的基线条件，然后评估和预测未加固和FRP加固结构的长期性能。这种加深的了解将告知资产所有者和管理人员，并导致改进设计和维护战略。

项目成果

Size effects in unreinforced and lightly reinforced concrete beams failing in flexure

• DOI: 10.1016/j.engfracmech.2021.107987
• 发表时间: 2021-09
• 期刊: Engineering Fracture Mechanics
• 影响因子: 5.4
• 作者: L. Nelson;J. Lees;L. Weekes

Reinforcement lay-out implications for reinforced concrete half-joint structures

钢筋布置对钢筋混凝土半节点结构的影响

• 发表时间: 2016
• 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

Assessment of Reinforced Concrete Half-Joint Structures: Dealing with Deterioration

钢筋混凝土半节点结构的评估：应对恶化

• 发表时间: 2014
• 作者: Desnerck, P

Integrated Fracture-Based Model Formulation for RC Crack Analysis

• DOI: 10.1061/(asce)st.1943-541x.0002058
• 发表时间: 2018-07
• 期刊: Journal of Structural Engineering
• 影响因子: 4.1
• 作者: T. Fayyad;J. Lees