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.

与现浇构件相比，预制/预应力结构混凝土构件的使用具有多种优势，包括施工简便、速度快、实现更高效和复杂的形状、大跨度、高水平的耐火性、增强的耐用性和可持续性。然而，必须将这些单独的结构部件组装和连接以形成整体结构，以在其使用寿命期间抵抗不同类型的载荷组合。该研究计划重点关注两种常见类型的预制结构元件的组装和连接。第一种是相邻桥箱梁通过横向后张法（TPT）相互对接形成桥面的组装方式。目前的做法是通过离散的横向隔板应用 TPT，这并不能防止梁之间的开裂和差异偏转，而是会中断公用设施线路并导致额外的成本，特别是在斜桥中。本研究的第一个目标是研究通过箱梁顶部翼缘提供均匀分布的 TPT 的可行性，并评估梁之间的裂缝、挠度和荷载分配能力。要研究的第二种连接类型是空心板与建筑物支撑元件之间的连接，它确保了结构的完整性。该连接旨在抵抗水平面内负载。目前的做法是使用钢筋作为此类连接的锚固件。然而，没有设计指南可用于预测此类连接的容量或其故障模式。拟议研究的第二个目标是评估、表征和开发模型来预测此类联系的强度。将进行全面和大规模的实验室测试和分析调查，以评估组装预制构件的性能，以评估与其在桥梁和建筑物中应用相关的具体问题。这将带来安全的新型结构，具有更高的性能、更好的耐用性、更低的建筑成本，并降低交通运输部、市政当局和公共工程部等基础设施所有者的维护成本。