Study On The Seismic Strengthening Of The Infilled Frame Structure With Constructional Deficiency

Because of the flexible layout and the good heat insulation performance of theinfilled wall, it was widely used in frame structure to form infilled frame structure.However, the infilled wall was seriously damaged in the previous earthquake, and thefailure mode were multiple, especially the out-of-plane collapse of the wall. Not onlydid this have a negative impact on the overall structure, but also the collapse of thewall block the rescue routes, resulting in serious losses of life and property. So theconnection between the infilled wall and the frame is very important.Relevant specifications have clear provisions for the seismic details of infilledRC frame, however, because the difficult construction and high cost, the constructionenterprises did not carry on the construction according to the specifications. Atpresent, the research of the simulation on seismic performance of the infilled wallis very limited. In this paper, the ANSYS finite element analysis was adopted tosimulate the filled wall that existing constructional deficiency in practical engineering,then, put forward the strengthening measures and simulated the structure before andafter strengthening, made a contrastive analysis of their capacity. The following arethe main work of this paper:(1)To simplify the structure according to the practical construction measures,established the finite element model of the one-story one-span infilled frame and thefive-story infilled frame that existing constructional deficiency in practicalengineering, then the structure models were calculated with the ANSYS softwareaccording to the time-history analysis, study on the displacement and the destructionof the filled wall in small earthquake, medium earthquake and strong earthquakerespectively to test whether the models meet the anti-seismic standard. The resultsshow that: when the infilled wall exist constructional deficiency, the infilled framestructure can not meet the standard of “no collapse in strong earthquake”.(2) The strengthening measures of the infilled wall were put forward, then, inorder to analysis the ultimate capacity and the developments of cracks, the uniformload out-of-plane were applied on the models before and after strengthening. The result show that the out-of-plane capacity of the infilled wall strengthened by plantingsteel bar method is greater than strengthened by steel-bonded method, and theout-of-plane capacity with these two method are both greater than the infilled wallbefore strengthening. Then strengthening improves the ductility greatly of the wall.The out-of-plane ultimate capacity of the infilled wall decreased with the increase ofthe ratio of height to thickness, and increased with the increase of the compressivestrength.(3)The time-history analysis of the models after strengthening was carried on,input earthquake waves along the longitudinal and transverse of the structurerespectively, and then observed the characteristics of development and thedistribution of stress and strain. The result show that the structure after strengtheninghas a good seismic performance, satisfy the standards of seismic.