Durability of ultra-high performance concrete as joint-fill material for precast bridge desk panels

北美的大多数桥梁在使用寿命即将结束时变得过时和结构缺陷。加拿大许多老化的桥梁将需要在本世纪进行重大修复。目前估计，加拿大国家桥梁基础设施资金赤字每年超过200亿美元。额外的间接费用，如在施工期间关闭主要运输路线所产生的费用，将对国家经济产生严重后果，必须加以解决。为了降低与桥梁基础设施的修复或更换相关的成本，人们强烈希望最大限度地减少施工时间以及对周围环境和所涉及的交通网络的影响。这导致了加速桥梁建设（ABC）实践的发展，该实践使用现场安装的模块化预制桥梁组件，而不是传统的现浇（CIP）混凝土桥面。无论项目是建造新的结构，还是修复现有的受损结构，实施预制桥面板系统都可以大大加快项目进度。拟议的研究项目旨在解决ABC的一个方面，开发的长期性能数据的超高性能混凝土（UHPC）连接预制预应力混凝土面板（PPCP）桥梁系统受到疲劳荷载和温度变化。将对具有UHPC接头和剪切凹穴的板段的比例模型进行测试，并研究接头在负弯曲中的行为。本项目将确定使用UHPC时，透明袋的合适尺寸和形状。将对马尼托巴莫里斯桥上的一个移动安装中的桥路的数据进行分析，并对结构的有限元模型进行验证，并将其用于预测算法，以确定桥梁的疲劳寿命。开发这种方法将是对当前桥梁设计和维护实践的重大贡献。

The majority of bridges in North America are becoming obsolete and structurally deficient as they are nearing the end of their service life. Many aging bridges in Canada will need major rehabilitation in this century. Current estimates place the national bridge infrastructure funding deficit in Canada at more than $20 billion per year. Additional indirect costs such as those incurred due to closures of major transportation routes during construction will have severe consequences on the nation's economy and will have to be addressed. To reduce the costs associated with rehabilitation or replacement of bridge infrastructure, there has been a strong desire to minimize construction time and the impact on the surrounding environment and transportation network involved. This has led to a push for the development of Accelerated Bridge Construction (ABC) practices, which use modular precast bridge components that are installed on-site, rather than conventional cast-in-place (CIP) concrete bridge decks. Whether the project is the construction of a new structure, or the rehabilitation of an existing deteriorated structure, implementing precast bridge deck panel systems can greatly accelerate the project schedule. The proposed research project aims to address one aspect of ABC by developing long-term performance data of ultra high performance concrete (UHPC) jointed precast prestressed concrete panel (PPCP) bridge systems subjected to fatigue loads and temperature variations. A scaled model of the panel segments with UHPC joints and shear pockets will be tested and the behaviour of the joints in negative bending will be investigated. This project will determine suitable size and shape of sheer pockets when using UHPC. Data from a bridge-way in motion installation on Morris Bridge in Manitoba will be analyzed and a finite element model of the structure will be verified and used to predict algorithms to determine the fatigue life of bridges. Developing such an approach will be a significant contribution to current bridge design and maintenance practices.