Fundamental Research on New Technologies derived from Bond Control of Tendons in pre-stressed Concrete Members

考虑到不久的将来全球的资源和环境，建筑既需要存量，又需要流动。本研究旨在探索适合混凝土结构性能设计的新技术和设计方法，有以下两个目标。(a)开发具有高自定心力和优越耗能的重复使用预制混凝土结构构件。(b)预估预应力筋粘结特性对预应力混凝土结构力学性能的影响。主要结论如下。1)预制混凝土砌块间的可分离缝是一种新发明。通过单剪试验研究了不同装配应力、接头材料强度、接头深度等条件下接头的力学特性。试验结果表明，该节理具有良好的可分性和实用抗剪强度。2)对混凝土砌块组成、无粘结预应力筋拼装的预应力混凝土梁进行了循环往复加载试验。试验结果表明，在梁侧附加低强度钢筋作为阻尼装置，梁能获得较好的消能效果；在梁剧烈挠曲时，柱刺附近的第一块混凝土块仅出现轻微损伤，显示了混凝土块的可重复使用性。3)采用分割单元法对循环反向荷载作用下预应力混凝土梁荷载-变形关系的等效阻尼系数进行了分析研究。根据分析结果，综合考虑梁截面中预应力筋的粘结特性、数量和位置等因素，导出了等效阻尼系数的计算公式，该公式能较好地预测试验结果。

Considering resources and environment in the near future globe, both to be stock and to be flow will be demanded for architectures. This study which aim to investigate new technologies and design methods suitable for performance design of concrete structures, has following two objectives. (a) Development of reuse pre-cast concrete structural members with high self-centering force and superior energy dissipation. (b) Estimations of influence of bond characteristics of prestressing tendons on mechanical properties of prestressed concrete structures. Following main conclusions are obtained.1) A separable joint between pre-cast concrete brocks are developed newly. Mechanical characteristics of the joint with various assembling stress, strength of joint materials, depth of joints and so on were investigated through uni-shear test. The test results show that the joint has very useful separability and practical shear strength.2) Cyclic reversal loading tests on prestressed concrete beams consisted of concrete blocks and assembled by unbond prestressing tendons were carried out. Test results reveal that the beam can get superior energy dissipation by the use of additional low strength reinforcing bars attached on the beam sides as a damper device and shows reusability of concrete blocks owing to only slight damages observed in the first concrete block adjacent to column stab, even though under severe deflection of the beam.3) Analytical studies on equivalent damping factor of load-deformation relations of prestressed concrete beams subjected to cyclic reversal load were conducted using divided element method. From results of the analysis considering factors such as bond characteristics, amount and location of prestressing tendons in the beam sections, an equation to estimate equivalent damping factor which predicts experimental results with practical accuracy are derived.