| Frame scaffolding with steel tubes has been used widely for its particular advantages such as standardized installation, easily assemble and disassemble, high bearing capacity, safe and reliable application, etc. However, some enterprises develop new product independently or imitate new types overseas for their economic benefits. These new products have usually not been studied scientifically and proved, their safety is difficult to guarantee, that brings about potential safety hazards in construction, which goes against the application and popularization of frame scaffolding with steel tubes.According to the structural characteristics of frame scaffolding with steel tubes, experimental study and theoretical analysis are carried out in this dissertation to study the behavior of frame scaffolding with steel tubes.In experimental research, the experimental method of the three bays-six floors full scale scaffold was adopted. In theoretical analysis, the stability of scaffold is studied as that of semi-rigid steel frames, and finite element analysis software ANSYS 10.0 was adopted to carry out numerical simulation. The main contents of this dissertation are as follows:1. The stability bearing capacity, the failure mode and the influence of crossed-brace, connecting tubes and scaffold boards to the scaffolding structural mechanical behavior have been analyzed by experimental results such as experimental phenomenon, load-stress curve and load-displacement curve.2. The stability of the scaffoldings has been analyzed as that of semi-rigid steel frames by applying the stability theoretic of steel frames, combined with the structural characteristics of frame scaffolding with steel tubes, introducing semi-rigid joints.3. Finite element analysis software ANSYS 10.0 has been adopted to carry out numerical simulation of the scaffoldings used in experiments, including conducting eigenvalue buckling analysis to predict the upper limits of buckling loads and find out bucking shape; and conducting nonlinear analysis considering initial defects of components and geometric nonlinearity of structure. Moreover, the results obtained by theoretical analysis have been compared with the experimental results to verify mutually.4.The influence factors of the stability bearing capacity of frame scaffolding with steel tubes have been analyzed, including analyzing changing laws of the bearing capacity when different joint stiffness are used, influence of the installation of horizontal reinforcing tubes, bottom horizontal tubes, connecting tubes and crossed braces to the stability of scaffolding.5. Based on the results of experimental study and theoretical analysis, calculation formulas of scaffoldings'stability presented in《Safety and technical code for frame scaffoldings with steel tubes in construction》JGJ 128-2000 have been modified and a improved practical calculation formula has been proposed. |
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