Determination of Partial Safety Factors (γM) for Model Uncertainties for Persian Historical Masonry Materials

Abstract

According to the Eurocode, the partial safety factor (γM) is a coefficient related to the material properties considering the uncertainties in geometry and modeling, which design value for the material properties are determined by dividing the actual value of the material properties by this coefficient. In this paper, determination of γM considering uncertainties for the Persian historical masonry shear wall was studied. To this aim, behavior of different specimens of masonry shear walls (with constant thickness) under in-plane shear loading and constant pre-compression with four different aspect ratios (height to length) and six different boundary constraints (under the effect of lateral walls and ceiling), by considering the uncertainty effect for two parameters of modulus of elasticity and thickness of wall were studied by the nonlinear pushover analyses. The results showed that by increasing the aspect ratio, the lateral shear strength of the walls decreases and γM is increased, whilst by increasing the boundary constraints, shear strength of the walls increases and γM decreases. The more impact of the horizontal component (ceiling) was observed, as compared to the vertical component in one direction, increases the boundary constraints and the lateral load-bearing capacity. It was also observed that the decrease in the initial shear stiffness of the walls was characterized by an increase in the wall aspect ratio, although this parameter changed slightly with changes in boundary constraints. In conclusion, the value of γM for the Persian historical masonry shear wall materials is proposed between 1.1 to 1.8.

Keywords

• masonry shear wall
• persian historical masonry
• uncertainty
• lateral constraints
• nonlinear pushover analysis
• lateral load-bearing capacity
• the partial safety factor (γm)