Sub-Paneling of Masonry Walls Using Precast Reinforced Concrete Elements for Earthquake Resistance

Abstract

Some traditional designs of masonry structures have shown acceptable structural performance during past earthquakes. In these structures, a grid of horizontal, vertical, and/or diagonal elements divide a large wall into smaller wall areas and provide confinement to masonry panels. In addition, grid elements provide a definite shearing plane along which masonry blocks can slide adding to deformability and energy-dissipation capacity. Inclined elements significantly add to lateral stiffness and strength depending on whether they can develop a complete truss action for lateral loads. Cyclic tests were conducted on five half-scaled wall specimens with different sub-paneling schemes using RC precast grid elements. Experimental results and finite element studies were used to develop simplified predictive relations for strength and stiffness response based on a confinement factor representing the grid element density. These relations can be used to configure the grid elements for desired performance levels with additional inputs about the global behavior.

In‐plane and out‐of‐plane behavior of confined masonry walls for various toothing and openings details and prediction of their strength and stiffness

“…The Equation (17) proposed in the Chinese code [30] defines a new variable, v em , which represents the shear strength along the stair-stepped damage of the masonry. Rai et al [31] proposed a simple method to estimate the performance parameters of walls subpaneled with RC elements. Rai et al [31] proposed a simple method to estimate the performance parameters of walls subpaneled with RC elements.…”

“…This relationship only takes into account the contribution of tie-columns installed in the middle of the wall. Based on the experimental and numerical analyses, strength and stiffness of the sub-paneled walls were directly correlated with the degree of confinement (Equation (18)) [31]. These sub-paneled walls consist of load bearing infill masonry confined by a framework of connected RC elements.…”

“…Experimental study conducted by Marinilli and Castilla [13] and Rai et al [31] showed that the inclusion of the interior tie-columns can significantly enhance the ductility, peak capacity, and damage distribution of masonry walls. Experimental study conducted by Marinilli and Castilla [13] and Rai et al [31] showed that the inclusion of the interior tie-columns can significantly enhance the ductility, peak capacity, and damage distribution of masonry walls.…”

“…Using the Equation (21) in Table III and damage indices I d , the stiffness of CM wall can be estimated at various damage levels. Rai et al [31] correlated the stiffness at initial cracking with the confinement factor l i,t / p as given by Equation (23), which also considered the role of interior tie-columns. The stiffness K cr is same as effective stiffness K e mentioned earlier.…”

Unprecedented Drought in North East India Compared to Western India

“…The lack of earthquake-resistant features in these masonry structures could also be due to high cost and non-availability of structural timber in the Himalayan region. The use of materials other than timber, such as precast RC and steel members, for confining masonry should be investigated for wider application 22 . Though the out-of-plane failure of walls in unreinforced masonry buildings was more common, the in-plane damage by step-type diagonal cracks in masonry walls extending to the full storey height was also observed, which further reduced the out-of-plane strength of walls and increased the risk of out-of-plane collapse.…”