Experimental Investigation of Masonry Infilled R/C Frames

Abstract

Although it is well documented that infills significantly affect the dynamic characteristics and the seismic response of the bare basic structural system, codes are reluctant to encourage consideration of infills as main structural elements, mainly due to structural uncertainties and computational complexities. Part of the uncertainties are due to the very many parameters affecting the behavior of the system, such as infill materials, reinforcing of infills, connection to the surrounding frame, geometry, relative stiffness and strength, local construction techniques etc. In the present paper three successive experimental programs, conducted at the R/C and Masonry Structures Laboratory of the Aristotle University, are described, commented and discussed. All of them refer to single-storey one-bay 1:3 scale R/C moment resisting frames. The first program consisted of 18 specimens, 2 bare and 16 unreinforced masonry (URM) infilled. The second program was an extension and a supplement of the previous one. It consisted of 20 more specimens, 6 bare and 14 URM infilled. The third program was directed towards the investigation of quick and low cost strengthening methods of R/C frames damaged by earthquakes, using several infill techniques. For this purpose 10 of the damaged specimens of the first program were repaired and strengthened.

Full-scale experimental study on masonry infilled RC moment-resisting frames under cyclic loads

“…The failure mechanism depends very much on the strengths of the frame and the infill wall. According to the experimental study conducted by Mehrabi et al [4], Zovkic et al [5] and Stylianidis [7], for the RC frame infilled with high strength blocks, such as hollow and solid concrete blocks, hollow and solid clay brick blocks, the cracks propagated diagonally along the mortar joints. The ''stair-shaped'' crack pattern finally formed due to the high strength infill block and low strength mortar joint.…”

“…Misir et al [6] performed an experimental research work on RC frames with standard and locked bricks and found that locked brick infills have improved out-of-plane stability compared with the standard bricks. Stylianidis [7] introduced three successive experimental programs conducted on RC frames infilled with perforated clay brick block masonry and found that the contribution of the infills to the strength, stiffness and energy dissipation capacity depends on the strength of the infill wall in relation to that of the frame. Pujol and Fick [8] conducted a test on a full-scale three-story reinforced-concrete structure with and without infill walls made out of solid clay bricks, and found that the infill walls were effective in increasing base shear strength (by approximately 100%) and lateral stiffness (by approximately 500%).…”

Seismic Performance of a New Type of Fabricated Tie-Column

“…Many experiments have been conducted and proved that the presence of infill walls significantly increases the strength, stiffness and seismic energy dissipation capacity of buildings [1][2][3][4]. Besides, experience from actual earthquakes suggests that properly constructed infill walls might inhibit the collapse of inadequately designed or insufficiently detailed structural systems [5,6].…”

Mathematical micromodeling of infilled frames: State of the art

“…From the available published experimental [134,31,189,70,87,[92][93][94]138,139,17,158,103,140,95,100,175,132,71] and numerical [135,128,80,86,11,16,186,67,164,64,69,60,161] [110,17,18,42,37,68,172,76,144,176,24,96] data, it can be observed that masonry infill walls (referred to also as infill walls in this paper) can have a significant effect on the structural performance of RC frames under seismic actions. This can result in a localized or global increase of strength and stiffness depending on the extent and the position of the infill walls within the frame.…”