Assembly and Connection of Precast/Prestressed Concrete Members - Validation and Optimization of two Accelerated Construction Methods

预制/预应力混凝土构件的组装和连接 - 两种加速施工方法的验证和优化

• 批准号: 531188-2018
• 负责人: ElSalakawy, Ehab
• 金额: $ 2.04万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=697721
• 关键词: Assembly; Connection; Precast; Prestressed; Concrete

The use of precast/prestressed structural concrete components offers several advantages over their cast-in-place counterparts including ease and speed of construction, achieving more efficient and complex shapes, long spans, high levels of fire resistance, enhanced durability and sustainability. However, it is essential that these individual structural components be assembled and connected to form an integral structure that can resist different types of load combinations during its service life. This research proposal focuses on the assembly and connection of two common types of precast structural elements. The first type is the assembly of adjacent bridge box girders that are butted against each other to form the bridge deck through transverse post-tensioning (TPT). The current practice is to apply the TPT through discrete transverse diaphragms, which does not prevent the cracking and differential deflection between girders, but rather interrupts utility lines and results in additional costs particularly in skewed bridges. The first objective of this research is to investigate the feasibility of providing uniformly distributed TPT through the top flange of box girders and evaluate cracking, deflection and load sharing capacity between girders. The second type of connection to be studied is the one between hollowcore slabs and supporting elements in buildings, which ensures the integrity of the structure. This connection is intended to resist horizontal in-plane loads. The current practice is to use reinforcing steel bars as anchors for such connections. However, no design guidelines are available to predict the capacity of such a connection or its mode of failure. The second objective of the proposed research is to evaluate, characterize and develop models to predict the strength of such connections. Full- and large-scale laboratory testing and analytical investigations will be performed to assess the performance of assembled precast elements to assess specific problems related to their application in bridges and buildings. This will lead to safe and new structures with improved performance, better durability, less construction cost and cutting the maintenance cost for infrastructure owners such as the Ministries of Transportation, Municipalities and Public Works.

使用预制/预应力的结构混凝土组件比现场铸造具有多个优点，包括易于速度和施工速度，实现更高效，更复杂的形状，长跨度，高度的防火性，增强的耐用性和可持续性。但是，必须组装这些个体的结构组件并连接形成一个不可或缺的结构，该结构可以在使用寿命期间抵抗不同类型的负载组合。该研究建议着重于两种常见的预制结构元素的组装和连接。第一种类型是相邻的桥梁盒子的组装，它们相互交战以通过横向后张紧（TPT）形成桥梁甲板。当前的做法是通过离散的横向隔膜应用TPT，这并不能阻止大梁之间的开裂和差异偏转，而是中断了效用线，并导致额外的成本，尤其是在偏斜的桥梁中。这项研究的第一个目的是研究通过盒子梁的顶部法兰提供均匀分布的TPT的可行性，并评估大梁之间的开裂，偏转和负载共享能力。要研究的第二种连接是空心板和建筑物中支撑元素之间的连接，这确保了结构的完整性。该连接旨在抵抗水平的面内载荷。当前的做法是将加固的钢筋作为这种连接的锚点。但是，没有设计指南可以预测这种连接或其故障方式的能力。拟议的研究的第二个目标是评估，表征和开发模型以预测这种连接的强度。将进行全面和大规模的实验室测试和分析调查，以评估组装预制元素的性能，以评估与桥梁和建筑物中其应用有关的特定问题。这将导致安全和新的结构，具有提高的性能，更好的耐用性，更低的建筑成本以及降低基础设施所有者的维护成本，例如交通运输部，市政当局和公共工程。