| The investigation of the earthquake damage after the Wenchuan earthquake shows that most of the RC frame destruction sites are concentrated in the column end,and the "strong column weak beam" failure mode is less.The appearance of this phenomenon is of course related to the destructive power of strong earthquakes,but on the other hand,it is also related to the imperfect design of the RC frame.It has been shown that,considering the eccentricity of the column after the random characteristics of the frame column bearing capacity seismic reliability in some cases will be lower than the target more reliable indicators,which is also considered difficult to achieve strong column weak beam failure mode One of the reasons,but because of the reliability of the beam to carry out less research,so the existing research on the different parameters of the case of strong column weak beam design reliability changes in the law is not enough.This paper has carried on the corresponding research to this question,completes the main work as follows:(1)Considering the variability of the constitutive critical parameters of the material,such as the ultimate pressure strain,the strength and the strength of the steel,and the possibility of the column cross section under the action of the earthquake,and the calculation model of the beam-column fine resistance based on the static equilibrium equation The Combined with the existing horizontal seismic action,vertical gravity load,concrete and steel constitutive parameters such as the probability model,and considering the random characteristics of the column section eccentricity,Monte Carlo method is used to analyze the RC frame strong column weak beam under different design parameters Design reliability,clear the reliability of the design parameters with the law of change.And then from the design partial safety considerations,by achieving a given target reliability indicators to improve the standard column end moment increase coefficient,so the column bearing capacity design.(2)The two-level and second-level framework models are designed by normative method,and then the pure frame model is calculated and the reliability of the strong column weak beam at each node in the model of the floor within the effective flange is considered.Reliable indicators of the nodes to be improved.Finally,the time-history analysis of Perform-3D is carried out to compare the ratio of the out-of-pocket and the beam-to-column energy consumption of the original model and the improved model to verify the effect of the improved method on the yield mechanism of the strong column weak beam.The results show that Level frame,when the target reliability index is 4.0,for the lower floor can have enough assurance rate in the rare earthquakes under the effect of "strong column weak beam" yield mechanism,but for the upper floor,to improve the effect is not big,It is recommended to increase the minimum allowable rate limit. |
