مرکز منطقه ای اطلاع رساني علوم و فناوري - The effect of anchorage distance with frame on strengthening the infill walled frames

Abstract :

One of the significant problems encountered in our country is that many buildings that have not damaged and have been currently in use do not have desirable safety against the credible earthquake loads. Also, there are other buildings with lateral load resisting system that are supposed to be sensitive to even moderate-intensity earthquake excitations. It has been observed that many buildings inspected aftermath of earthquake are not enough to resist earthquake effects. Due to their high stiffness, shear walls not only carry an important portion of horizontal effects but also limit lateral deformations of load-carrying and non-load-carrying elements of frame systems. Strengthening these systems through filling the spaces of frames with reinforced walls may come out to be an economic solution. If a frame system with filled walls is properly planned, analyzed and constructed, the filled walls can then behave as shear walls increasing the stiffness and strength. Consequently, no other load bearing elements need to be strengthened. This study consists of experimental works of reinforced concrete frames that are deemed as being constructed deficiently at first and strengthened later with mesh reinforcement and plaster on their walls. In this study, three ½ scaled reinforced concrete frames with one-bay, one-story have been produced. The specimens have been obtained by applying mesh reinforcement on infill wall. In one of the specimens, reinforcement has been anchored to the frame and foundation at 30 cm apart, 12 anchors with ∟ shape have been made perpendicular to wall plane. 3 cm thick plaster consistent with national earthquake code has been applied on top surface of mess reinforcement. The plaster has been cured. This specimen has been named as I-FA30-WA12-P1. The other specimens have been constructed such that in the second test, the anchorage distance with frame is 45 cm (I-FA45-WA12-P1), and in the third test specimen, it is 60 cm (I-FA60-WA12-P1). These frames have been tested under reversed cyclic lateral loading. In this study, the effect of anchorage distance with frame on strengthening the infill walled frames has been examined. The changes in load carrying capacity, stiffness and energy absorption properties of tested frames have been sought.