The Research On Design Theory And Application Of New Steel Microwave Towers

New steel microwave tower put forward in this thesis is a tower structure which cross section is triangle and the legs are cold-formed 60° single angles, the rest members all are cold-formed single angles. This tower structure which brings remarkable economic and engineering efficiency is deserved to be applied widely.The stability of cold-formed single angle compression members under different boundary condition and the design theory and method of new steel microwave tower are analyzed theoretically in this paper. The main contents of this paper is divided into the below parts.1. The fundamental principles of nonlinear buckling analysis of cold-formed single angle compression members are discussed in detail. The constitutive relationship, failure criterion, element type and parameters used in ANSYS are expounded also.2. The different boundary restraint conditions of cold-formed single angle compression members in new steel microwave towers are simplified theoretically, and five different calculation models are educed.3. On the basis of considering residual stress, initial eccentricity and crookedness, the ANSYS finite element model using shell element of cold-formed single angle compression members is established, and the nonlinear buckling analysis of cold-formed single angle compression members are proceeded. The accuracy of ANSYS results are confirmed.4. After comparison between the ANSYS calculated results and code results, the conclusion that current codes should be modified is drawn.5. According to aforementioned research conclusions, the simple and practical stability calculation formulas of cold-formed 60° equal-leg and lipped equal-leg single angle axial compression members are advanced, and design method suggestion on the stability of the cold-formed single angle under compression with one-sided bolt connection is made.6. The structural style, structural design, design conformation and foundation design etc are researched, some useful design suggestion is made.7. Comparison between engineering examples, remarkable economic and engineering efficiency of the application of new steel microwave tower is confirmed.