Investigation of a Permanent and/or Emergency Seismic Retrofit Technique for RC Columns and Walls

永久性和应急性抗震加固技术的发展是世界各国地震灾害研究领域的共同课题，也是21世纪世纪的重要课题。在日本，低层或中等高度的钢筋混凝土框架结构中，经常建造各种各样的墙体，如剪力墙、拱肩墙和翼墙。另一方面，众所周知，混凝土的横向约束有助于提高混凝土的强度和延性。针对这一情况，本文提出了利用预应力高强钢筋、钢板和角钢对钢筋混凝土柱或带次墙的钢筋混凝土柱进行抗震加固的方法。由于预张拉，该方法除了传统的抗剪加固和被动约束外，还产生了主动约束。此外，作为一种震损钢筋混凝土柱的应急加固方法，该方法具有一定的工程应用价值 ...更多信息 EMS是合适的，因为抗震改造可以方便和快速地应用，而不需要重型机械作为干式施工方法。主要研究成果如下：1）提出了采用预应力混凝土拉杆和角件施加拉力的方法对钢筋混凝土独立柱进行抗震加固。2）除了钢板或角钢外，预应力混凝土拉杆还施加拉力，直接与柱表面紧密结合，大轴力作用下加固柱的弹塑性性能得到显著改善提出了既能提高柱延性，又能提高柱的强度和延性的配筋方法。4）预应力混凝土拉杆加固独立柱的方法是干法。考虑到这一事实，这种钢筋也可以有效地应用于钢筋混凝土柱的紧急加固和震后立即补救工作。5）纤维模型分析，包括非线性剪力-变形关系，并给出了分析实例。摘要通过试验研究了预应力PC筋加固钢筋混凝土柱的纯弯和粘结性能，并对预应力PC筋的作用进行了验证。少

The development of permanent and/or emergency seismic retrofit technique is a common issue in earthquake hazard field all over the world, and it will be an important topic for the twenty-first century. A large variety of walls, such as, shear walls, spandrel walls and wing walls are often constructed in low-rise or medium height RC frame buildings in Japan. On the other hand, it is well known that transverse confinement of concrete contributes to the enhancement of strength and ductility of concrete. Considering this fact, a seismic retrofit technique of RC columns only or RC columns attached with secondary walls, such as, spandrel or wing walls, by utilizing pre-tensioned high strength steel bars, steel plates and steel angles were proposed in this research. Because of pre-tensioning, the method generates active confinement in addition to conventional shear reinforcement and passive confinement. Furthermore, as an emergency retrofit of the earthquake-damaged RC columns, this method se … More ems to be suitable, because the seismic retrofit can be conveniently and rapidly applied without heavy machinery as a dry construction method. The main research results are summarized as follows :1)By using PC rods and corner pieces through which tensile force was applied, the seismic retrofit of the independent RC column was proposed. This retrofit converts the extreme short column which causes the brittle shear failure into the flexural yielding column which is rich in the ductility.2)In addition to the steel plates or angles, the tensile force applied into PC rod which is directly united firmly around the column surface, the elastoplastic behavior of the retrofitted column under high axial force can be improved drastically.3)The reinforcement which improves not only the ductility but also the both strength and ductility for columns with secondary walls and framed shear walls was proposed.4)The method which reinforces the independent column by applying tensile force into the PC rod, is the dry method. Considering this fact, this reinforcement can also be applied effectively to the emergency retrofit of RC column and remedial work immediately after the earthquake disaster.5)A fiber model analysis including nonlinear shear force-distortion relationship was also tried and analytical examples were presented.6)Axial compression, pure bending and bond behavior of RC columns retrofitted by pre-tensioned PC rods were investigated and the effect of PC rod prestressing was recognized through the loading tests. Less