Story Lateral Stiffness And Stability Analysis Of Tilted Column Frame

Through the research of the formation of the frame, it is found that the tilted frame is more stable than the ordinary one because the tilted column increased its lateral stiffness and thus its displacement and librations are decreased. The tilted frame functioned as the arc so the load is more evenly distributed through the frame members. The horizontal part of the norm force in column could help resist the outside lateral loads. As a result, the limitation of the frame span is enlarged. This kind of the frame is used more and more widely in the industry and civil architectures.The general model of the single-story tilted frame is built on the basis of the mechanical displacement method. The equilibrium equation, the expression of the critical load and the lateral stiffness of the individual story are obtained. The thought of negative stiffhess is explained and utilized to get the critical load. The second-order coefficient is fitted through the comparison of the result of FEA analysis. It is known that the norm load in the beams influence their bend stiffness, so the stiffness ratio of beam and column is decreased to consider this effect. The simplified formula is got and the result is compared with that of the FEA tools- ANSYS. The outcome is satisfied and the formula could be used or referenced in the practical design. The different distribute load patterns are considered and simulated in the ANSYS, and the adverse influence of the main moment to the overall stability of the frame is summarized.The way to judge the stability of multi-story tilted frame is presented also, by considering the mutual impact of the individual story. As for the three-story frame, the beams provide the restriction when the column lost their stability. So the overall sustention ability of the beam could be distributed to the border columns. The overall critical load of the three-story frame could be extracted by solving the equation with two variables.As for the general multi-story frame, the calculating unit of each story is extracted between the point on column where the moment equals zero, the lateral stiffhess of this section is obtained and also the effective length of the specific story. The result of this method is compared with that of ANSYS and the outcome shows the satisfied coincidence between the two and thus the method is practical for real design and reference.Finally, The different methods and suggestions from the National regulation of several different countries are expatiated. The principal of the one-order and second-order analysis is summarized with the stress on the advanced plastic hinge analysis method. The elastic-plastic analysis is carried out with the help of ANSYS, and through the out plotted load-displacement curves, it is found that the early-stage stiffness of tilted frame is obviously higher than the ordinal frame.