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

从资源和环境的角度考虑，在不久的将来，对建筑提出了既要存量又要流动的要求。本研究旨在探索适合混凝土结构性能设计的新技术和新设计方法，主要有以下两个目的。(A)开发高自心向力和高耗能的重复使用预制混凝土结构构件。(B)预应力筋粘结特性对预应力混凝土结构力学性能影响的估算。主要结论如下：1)提出了一种新型的预制混凝土预制块之间的分体式节点。通过单剪试验，研究了不同装配应力、节点材料强度、节点深度等因素对节点力学性能的影响。试验结果表明，该节点具有很好的分离性和实用抗剪强度。2)进行了由混凝土砌块拼装的无粘结预应力混凝土梁的反复荷载试验。试验结果表明，在梁侧附加低强度钢筋作为阻尼器，即使在梁的严重挠度下，也能获得较好的耗能效果，且由于靠近柱刺的第一个混凝土块损伤较小，混凝土块具有较好的重复使用性。3)采用分裂单元法对反复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，考虑粘结特性、梁截面中预应力筋的数量和位置等因素，推导出等效阻尼系数的估算公式，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.