Improving the Basic Parameters of the Direct Design Method Based On the Displacement in Zipper and CBF Braced Frames

The direct displacement-based design method introduced and expanded by Priestley et al. is one of the functional methods that has the ability to replace the force-based design method. Estimation of hysteresis damping and displacement of yielding are among the key parameters of this method, the error in their estimation leads to the overall error in the estimation of base shear. In this study, 10 bending steel frames with vestibular braces and short and medium zippers have been investigated and evaluated for tremors. With a wide range of analyses, including non-linear dynamic analyses of time history based on natural accelerometers, as well as wear analysis based on different patterns, yielding displacement, damping, effective cycle time, secant cycle time and base shear of the steel bending frames with the above-mentioned hip brace and zipper are analysed. And the relationships presented in the DBD regulations have been verified. Finally, by proposing relationships for damping and displacement of yielding, in relation to improving the performance of the direct design method based on displacement in steel bending frames, it has been done as follows. Given that increasing damping, it underestimates the forces applied to the structure. It seems that Priestley's formula is presented with a higher reliability factor and results in the design of harder and heavier structures, in terms of the amount of steel consumption. The amount of damping is not very sensitive to the changes in the number of openings and in the worst case, the damping has a difference of 3% with the increase in the number of openings.