Assessment of Existing Reinforced Concrete Structures

现有钢筋混凝土结构的评估

• 批准号: RGPIN-2017-06031
• 负责人: MartinPerez, Beatriz
• 金额: $ 2.04万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=636471
• 关键词: Assessment; Existing; Reinforced; Concrete; Structures

The main degradation mechanism that affects reinforced concrete (RC) highway infrastructure in Canada is chloride-induced corrosion of reinforcing steel. This damage is often compounded by the action of freezing/thawing cycles characteristic of a Canadian winter. Existing Canadian standards for design of RC structures focus mainly on the structural performance, without an explicit attempt to evaluate the effect of deterioration mechanisms over long periods of time. Although a durability limit state is mentioned in the Canadian concrete design standard, it is merely a prescriptive specification on concrete mix design, minimum concrete cover thickness, and quality control in the placement and curing of concrete at the job site. In effect, the treatment of load carrying capacity and durability has been separated, not only in the codes but also in the profession of structural engineering. To assure the safe in-service performance and minimise the risk of failure of RC infrastructure, it is imperative that testing and analytical/numerical tools are developed to assess the consequences of this deterioration on the serviceability and ultimate capacity of RC infrastructure. The primary goal of this research is to assess the impact of reinforcement corrosion and frost damage on the serviceability and strength of RC infrastructure. Three aspects of this problem are to be investigated: (i) the use of concrete electrical resistivity measurements as a quality control and predictor of durability, (ii) the impact of deterioration mechanisms on the structural behaviour of RC structural members, and (iii) the impact of earthquake load on deteriorated RC bridges. This is intended to be done through both experimental tests and numerical simulations using the finite element method. The experimental program has as its aim to develop testing methodologies of the use of electrical resistivity in combination with existing tests for reinforcement corrosion and frost damage detection and evaluation. The numerical component of the research aims at integrating material deterioration models with current methods of structural analysis in order to simulate the behaviour of RC infrastructure under both in-service and ultimate conditions. The significance of this research is the improved understanding of the effects of deterioration on serviceability and residual strength of RC structures, and the direct application of this knowledge to the effective management of Canada's aging and deteriorating infrastructure through the implementation of assessment guidelines of existing affected structures.

影响加拿大钢筋混凝土(RC)公路基础设施的主要退化机制是氯离子引起的钢筋腐蚀。这种损害往往因加拿大冬季特有的冰冻/解冻循环而加剧。加拿大现行的钢筋混凝土结构设计标准主要集中在结构性能上，没有明确的尝试评估长期劣化机制的影响。虽然加拿大混凝土设计标准中提到了耐久性极限状态，但它只是关于混凝土配合比设计、最小混凝土保护层厚度以及工地混凝土浇筑和养护中的质量控制的规范性规范。实际上，不仅在规范中，在结构工程专业中，承载能力和耐久性的处理也是分开的。为了确保RC基础设施在使用中的安全性能，并将故障风险降至最低，必须开发测试和分析/数值工具，以评估这种恶化对RC基础设施的适用性和最终容量的影响。本研究的主要目的是评估钢筋锈蚀和冻害对钢筋混凝土基础设施的使用性能和强度的影响。这个问题的三个方面将被调查：(I)使用混凝土电阻率测量作为耐久性的质量控制和预测指标；(Ii)劣化机制对RC结构构件结构性能的影响；以及(Iii)地震荷载对劣化RC桥梁的影响。这将通过实验测试和使用有限元方法的数值模拟来完成。该实验方案的目的是开发使用电阻率的测试方法，并结合现有的钢筋腐蚀和冻害检测和评估测试。这项研究的数值部分旨在将材料劣化模型与现有的结构分析方法相结合，以模拟钢筋混凝土基础设施在使用中和最终条件下的行为。这项研究的意义在于更好地了解劣化对RC结构的使用性能和剩余强度的影响，并通过实施现有受影响结构的评估指南，将这些知识直接应用于加拿大老化和劣化的基础设施的有效管理。