Development of High Reliability Steel Structural System Using Structural Joints as Energy Dissipating Elements against Strong Earthquake

提出了一种采用屈曲约束膝撑阻尼器连接的宽法兰梁柱钢结构体系。膝撑式阻尼器由低屈服强度钢制成，通过高强度螺栓与梁、柱连接。这些螺栓阻尼器旨在为结构缝施工工作的稳定质量保证和框架对强震的抗震性提供优势。为了实现这一系统，进行了以下调查。1)给出了膝关节支撑阻尼器的关节单元结构和屈曲抑制方法。根据提出的程序，设计和制作了用于加载试验的全尺寸试验连接。2)对该结构体系的全尺寸梁柱组件进行了加载试验。对节点单元的弹性刚度、结构的屈服极限和破坏极限等基本力学性能进行了试验研究。3)提出了采用膝撑阻尼系统有效抑制梁两端连接柱侧屈曲的方法，并对其有效性进行了实验验证。给出了约束梁屈曲的设计步骤。4)对所提出的结构系统的施工工程问题进行了调查，即车间制造过程，施工现场安装，紧固超高强度螺栓的管理，高效紧固机器的开发。5)给出了膝撑式阻尼系统刚度和强度的计算方法。以某三层建筑的结构设计为例，对其结构性能和造价与普通抗弯矩框架进行了比较。

A steel structural system which consists of wide-flange beams and columns connected by using buckling restrained knee brace dampers are proposed. The knee brace dampers are made of low yield strength steel and connected to beams and columns by high-strength bolts. These bolted dampers are intended to produce advantages on the steady quality assurance related to the construction work of the structural joints and the seismic resistance of the frames against strong earthquakes. In order to actualize this system, following investigations were conducted.1) The configuration of joint elements and the buckling restraining method for knee brace dampers are indicated. According to the proposed procedures, the full-scale experimental connections for loading tests are designed and fabricated.2) Loading tests for full-scale beam-column subassemblies of the proposed structural system are conducted. The fundamental mechanical properties, namely, the elastic stiffness of joint elements, the yield limit and the collapse limit of structures are experimentally inspected.3) The effective restraining method against the lateral buckling of a beam which is connected to the columns at the both ends by the knee brace damper system is suggested and its effectiveness are experimentally confirmed. The design procedures for the buckling restraining of the beam is indicated.4) The issues concerned with construction works for the proposed structural system are investigated, namely, the shop fabricating process, the erection at the construction site, the administration of fastening ultra high-strength bolts, the development of an efficient fastening machine.5) The calculating method of the stiffness and the strength of the knee brace damper systems are indicated. An example of a structural design for a 3 story building is shown and the structural performance and the cost for construction are compared with an ordinary moment resisting frame.