Enhancement of lateral in-plane capacity of partially grouted concrete masonry shear walls

Abstract

The goal of the research presented herein is to investigate a new approach to the reinforcement of partially grouted walls, double side-by-side reinforced cells, in order to enhance the seismic performance of such walls. Specifically, the results from the destructive tests of three cantilever full-scale square masonry shear walls are presented. The control wall was constructed using the conventional single cell reinforcement (SR) approach, with the remaining two walls constructed using double cell reinforcement with bond beams (DR), and with the addition of bed-joint reinforcement (DR-JR), respectively. To permit direct comparison, the total amount of reinforcement in the SR and DR walls was held constant. The experimental investigation indicated that the DR reinforcement approach resulted in significantly improved lateral in-plane response compared to the conventional SR approach.Specifically, the DR wall exhibited a 34% increase in shear capacity and 47% increase in displacement ductility. To investigate the effect of grouting on the response of proposed reinforcement details a numerical modeling technique was developed based on the infilled-frame concept and calibrated with the experimental behavior of considered walls. It is evident from the results of numerical modeling that response of walls is in a good agreement with the behavior observed in the experiments. Numerical model showed that the behavior of grouted and ungrouted parts of PG walls are similar to a frame and an infilled, respectively. Grouting double side-by-side cells enhances the frame action of grouted masonry parts and also provides a better confinement for the infilled masonry. As a result of the strengthened frame the performance of wall DR was improved significantly compared to wall SR.

Shear strength expression for partially grouted masonry walls

“…A parametric study was conducted considering different spacing of horizontal and vertical reinforced cells, axial compressive loads, masonry compressive strength, and area of steel. Finally, the proposed expression was verified with experimental results of tested walls by authors [18][19][20] in addition to 42 full-scale PG wall tests available in the literature [10,15,[21][22][23][24][25][26][27][28]].…”

“…shows a comparison between the experimental and numerical results regarding crack pattern and load displacement relationship for the singly grouted wall specimen (please refer to[18] for more details). Before forming cracks at the edges of the wall, stepped-wise cracks initialized at the center of the hollow panels due to the shear action.…”

Damage detection of concrete masonry structures by enhancing deformation measurement using DIC

“…Linear Variable Differential Transformer (LVDT, Schaevitz DC-SE 4000) and strain-gage based displacement transducers (TML, CDP-25) were used to record wall deformations and displacements by using OPTIM data acquisition system, in addition to three load cells to record the applied horizontal and vertical loads. More detail can be found in [19]. DIC images were recorded using an ARAMIS 3D 5-megapixel camera system.…”

Failure analysis and damage detection of partially grouted masonry walls by enhancing deformation measurement using DIC

“…2c. Both the vertical and horizontal grouted cells of the wall contained one D19 bar (19 mm diameter) placed at every 1.8 m. The horizontal and vertical reinforcement ratio of the wall was 0.08% and 0.11%, respectively (see [6,7,8] for more detail).…”

“…Masonry bearing wall buildings remain one of the relatively less studied structural systems particularly in the case of partially grouted reinforced masonry walls, a common building system in the eastern United States [1][2][3][4][5][6][7][8][9][10]. PG walls are essentially reinforced masonry in which only the reinforced cells are grouted while all cells are grouted in fully grouted (FG) walls.…”