This comprehensive study investigates the nuanced impact of flanges, height-to-length aspect ratios, wall thickness, and pre-compression levels on Persian historical MASONRY WALLS under uncertainty conditions. Numerical testing of 100 MASONRY wall specimens, varying across five lateral constraints (flanges), four height-to-length ratios, three wall thicknesses, and three pre-compression levels, was conducted. The study also examined the influence of uncertainty on the modulus of elasticity. Results demonstrated a substantial dependency of ultimate shear force (Fu), ultimate drift (δu/H), and effective stiffness (𝐾𝑒ff) on the considered variables. Fu and 𝐾𝑒ff increased with higher lateral constraints, wall thicknesses, and pre-compression levels, decreasing with reduced aspect ratios. Simultaneously, δu/H decreased with higher lateral constraints, wall thicknesses, and pre-compression levels, increasing with reduced aspect ratios. Estimated values for Fu ranged from 292.5 to 1357.4 MPa, δu/H spanned from 1.61 to 3.43, and 𝐾𝑒ff varied from 7.72 to 158.9 kN/mm. Proposed partial coefficients for partial coefficients (γM), displacement capacity (γdu), and effective stiffness (γk) were introduced through models incorporating uncertainty, revealing that increasing lateral constraints and wall thicknesses, and decreasing aspect ratios, led to heightened values for γM and γk and reduced values for γdu. With increasing pre-compression levels, all safety factors increased. The safety factors (γM: 1.18–1.96, γdu: 1.16–1.76, γk: 1.157–1.967) optimize Persian historical MASONRY structures, providing crucial insights for varied conditions were proposed.

This paper presents a method for failure analysis and studying post failure behavior of MASONRY shear wall. MASONRY structures are blocky systems that have great importance in civil engineering. MASONRY structures such as stone and brick WALLS, arches and vaults in tunnel supports and bridges, constitute a great percent of existing structures especially some with historical value all over the world. It is very important that a method can analytically model MASONRY structures and their behavior under vertical and horizontal loads in order to determine their short and long-term stability. MASONRY structures generally consist of intact units (MASONRY blocks, stone, brick, clay units) separated by discontinuities (mortar joints). Laboratory and field observations have showed that these discontinuities have a strong and non-linear effect and dominate the deformation and strength behavior of MASONRY structures. The occurrence and propagation of the brittle cracking and sliding also have a great effect in behavior of MASONRY structures. This modified DDA method can capture the behavior and can handle the problem adequately. For considering the effect of cracking and fracturing in blocks some modifications to the original method have been developed and implemented in the original DDA code. Finally with some simple examples capability of this new method has been demonstrated.

Confined MASONRY buildings are used in rural and urban areas of Iran. They performed almost satisfactory during past moderate earthquakes of Iran. There is not a methodology in Iranian Seismic Code (Standard 2800-3rd edition) to estimate their capacities quantitatively. In line with removing this constraint, an attempt is made to study in-plane behavior of two squared confined MASONRY WALLS with and without opening by using a numerical approach. These WALLS are considered based on Iranian Seismic Code requirements. Finite element 2D models of the WALLS are developed and a pushover analysis is carried out. To model the non-linear behavior of the confined MASONRY WALLS, the following criteria are used: (1) The Rankine-Hill yield criterion with low orthotropic factor to model the MASONRY panel; (2) The Rankine yield criterion to model reinforced concrete bond-beams and tie-columns; (3) The Coulomb friction criterion with tension cutoff mode to model the interface zone between the MASONRY panel and reinforced concrete members. For this purpose, the unknown parameters are determined by testing of MASONRY and concrete samples; and by finite element analysis. Comparing the results show that the initial stiffness, the maximum lateral strength and the ductility factor of WALLS with and without opening are different. Also, the severe compressed zones of the MASONRY panels within the confining elements are found different from what are reported for the MASONRY panels of infilled frames by other researchers. This study shows that a further investigation is needed for estimating capacity of confined MASONRY WALLS with and without opening analytically and experimentally. Also where openings, with medium size are existed, the confining elements should be added around them. These issues can be considered in the next revisions of Iranian Seismic Code.

Based on the seismic design codes to prevent soft-story failure, columns of a soft story must be designed for amplified loads due to the discontinuity of braces or shear WALLS in that story. Because of the MASONRY infill WALLS discontinuity, Soft story failure has been reported in the recent earthquakes. Most national seismic design codes don't consider the effect of MASONRY infill WALLS for the design of the soft story. This paper aims to investigate the soft story failure and then present a simple formula for the design of soft-story in moment resisting frame structures. In this paper, the different arrangements of MASONRY infill WALLS are considered. Structural modeling was carried out based on reliable parameters and some national or international seismic design codes. By using nonlinear static analysis, a simple methodology is proposed and the main result is a simple formula that can be used for the engineering design of concrete moment resistant frames.