High Performance FRC Energy Absorbing Joints for Precast Concrete Frames (PRESSS)

9307843 Naaman本提案旨在为地震带的预制混凝土结构寻求一种高能量吸收接缝的发展。接缝采用高性能纤维增强水泥基复合材料（HPFRC），如高纤维含量纤维增强混凝土和SIFCON（浆料浸润纤维混凝土）。该节点被设计为梁和柱元件之间的耗能连接器。在接头基体中使用高纤维含量意味着确保高延展性，增加能量吸收，减少剥落，以及在载荷逆转时具有优越的抗剪性。本研究的直接目的是了解控制关节特性及其在单调和循环荷载下的响应的基本机制。设计了实验和分析方案。在实验程序中，提出了两种类型的测试。第一个是为了确定嵌入在HPFRC中的钢筋的粘结剪切应力与滑移特性；二是阐明了加桩加固和不加桩加固复合材料在单调和循环剪切荷载作用下的响应。该分析程序旨在利用两种主要构件材料及其界面的本构特性建立一个模型来预测节点的滞回力矩旋转响应。该研究最终将导致设计出具有最佳延性和吸能性能的节点。＊＊＊

9307843 Naaman This proposal aims at pursuing the development of a high energy absorbing joint for precast concrete structures in seismic zones. The joint is made from high performance fiber reinforced cement based composites (HPFRC) such as high fiber content fiber reinforced concrete and SIFCON (Slurry Infiltrated Fiber Concrete). The joint is designed to act as an energy dissipating connector between the beam and the column elements. The use of high fiber content in the matrix of the joint is meant to insure high ductility, increased energy absorption, reduced spalling, and superior shear resistance during load reversals. The immediate objective of the research is to understand the fundamental mechanisms that control the properties of the joint and its response under monotonic and cyclic loads. An experimental and an analytical programs are planned. In the experimental program, two types of tests are proposed. The first is designed to identify the bond shear stress versus slip characteristics of reinforcing bars embedded in HPFRC; the other is to clarify the response of these composites, under monotonic and cyclic shear loading, with and without dowel reinforcement. The analytical program aims at developing a model to predict the hysteretic moment rotation response of the joint using the constitutive properties of the two main component materials and their interface. This study should eventually lead to designing joints with optimized ductility and energy absorbing properties. ***