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

使用预制/预应力结构混凝土构件与现浇构件相比具有多项优势，包括施工方便和快速，实现更高效和复杂的形状，长跨度，高水平的耐火性，增强的耐久性和可持续性。然而，这些单独的结构部件必须组装和连接，以形成一个整体结构，在其使用寿命期间可以抵抗不同类型的载荷组合。本研究计划的重点是两种常见类型的预制结构元件的组装和连接。第一种是将相邻的桥梁箱梁对接，通过横向后张法（TPT）组装成桥面。目前的做法是通过离散的横隔板应用TPT，这不能防止主梁之间的开裂和差异偏转，而是中断公用事业线路并导致额外的成本，特别是在斜交桥梁中。本研究的第一个目的是调查通过箱形梁的上翼缘提供均匀分布的TPT的可行性，并评估梁之间的开裂、挠度和荷载分担能力。第二种连接方式是空心板与建筑物中支撑构件之间的连接方式，它保证了结构的完整性。该连接旨在抵抗水平平面内载荷。目前的做法是使用钢筋作为这种连接的锚。然而，没有设计指南可用于预测这种连接的能力或其故障模式。拟议研究的第二个目标是评估、描述和开发模型，以预测这种联系的强度。将进行全面和大规模的实验室测试和分析调查，以评估组装的预制构件的性能，从而评估与其在桥梁和建筑物中的应用相关的具体问题。这将导致安全和新的结构，具有更好的性能，更好的耐久性，更低的建筑成本，并减少基础设施所有者的维护成本，如交通部，市政部和公共工程部。

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.