7review[钢结构基本原理复习].pptVIP

(1) High strength of steel, light weight of structure（钢材强度高，结构质量轻） (2) Isotropic material, high reliability（材质均匀，可靠度高） (3) Convenient fabrication, quick erection（制作方便，施工快速） (4) Good leakproofness（密闭性好） (5) Heat-resistant but not refractory（耐热不耐火） (6) Be corroded easily , maintained costly（易腐蚀，维修费用大） a. The ultimate limit states: The basic combination of load effects shall be considered and, if necessary, the accidental combination of load effects shall also be considered. b. The serviceability limit state: The load standard combination of steel structure design is only considered. (1) 疲劳破坏的特征： —— 脆性破坏 (2) 影响因素： 构件和连接的构造类型 循环次数 循环应力比 应力幅 残余应力 (1) 普通受剪螺栓： 从受力直至破坏经历四个阶段，由于它允许接触面滑动，以螺杆剪断或孔壁受压破坏的极限状态作为设计准则 (2) 普通受拉螺栓：以螺栓被拉断作为承载力极限状态 (3) 高强度螺栓： 高强度螺栓在拧紧时，螺杆中产生了很大的预拉力，而被连接板件间则产生很大的预压力。连接受力后，由于接触面上产生的摩擦力，能在相当大的荷载情况下阻止板件间的相对滑移。当外力超过了板间摩擦力后，板件间即产生相对滑动。高强度螺栓摩擦型连接是以板件间出现滑动为抗剪承载力极限状态；而承压型是允许板件产生相对滑移后螺栓受力，最后以螺栓被剪断或挤压破坏为抗剪承载力极限状态。 Effect of residual stress in member (焊接残余应力) Initial out-of-straightness (初弯矩) Accidental non-concentric loading (初偏心) Different End Conditions (端部约束不同) * * 钢结构基本原理复习 Design Principles of Steel Structure Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Design Principles of Steel Structure 1 Summarize Key 1: What are the features of steel structure? Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. The structural limit state Key 2: The Design Method of Steel Structure Design Principles of Steel Structure 1 Summarize Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (1) Higher fy and fu（有较高的fy 和 fu） (2) Good Plasticity and impact toughness（有良好的塑性和冲击韧性） (3) Good machinability（有良好的加工性能） (4) Good adaptability to working circumstance（对环境良好的适应能力） Design Principles of Steel Structure 2 steel material Key 1: The requirements of steel structure