Comparative Studies of the Confined Effect of Shear Masonry Walls Made of Autoclaved Aerated Concrete Masonry Units

Radosław Jasiński; Tomasz Gąsiorowski

doi:10.3390/ma16175885

Comparative Studies of the Confined Effect of Shear Masonry Walls Made of Autoclaved Aerated Concrete Masonry Units

Materials (Basel). 2023 Aug 28;16(17):5885. doi: 10.3390/ma16175885.

Authors

Radosław Jasiński¹, Tomasz Gąsiorowski^{2

3}

Affiliations

¹ Department of Building Structures and Laboratory of Civil Engineering Faculty, Faculty of Civil Engineering, Silesian University of Technology, Akademicka 5, 44-100 Gliwice, Poland.
² Department of Building Structures, Faculty of Civil Engineering, Silesian University of Technology, Akademicka 5, 44-100 Gliwice, Poland.
³ Expertise Office TMG Sp. z o.o., Św. Stanisława 14/Ip, 32-540 Trzebinia, Poland.

Abstract

Confined walls are popular in areas exposed to seismic action. The advantage of such structures is increased load-bearing capacity, ductility, and energy dissipation. Confined masonry walls are also used to restrain the intensity of cracking and improve load-bearing capacity in areas exposed to seismic action. This paper describes the research on 18 confined walls and presents a comparison with research on unconfined walls (referenced models). The confined models were classified into three series: HOS-C-AAC-without openings and with confining elements around the perimeter; HAS-C1-AAC with a centrally positioned opening and circumferential confinement; and HAS-C2-AAC with a centrally positioned window opening and additional confinement along the vertical edges of the opening. The area of the window opening was 1.5 m². All walls were made of autoclaved aerated concrete (AAC) masonry units of the nominal density class of 600. The walls were tested under initial compressive stresses σ_c = 0.1; 0.75; and 1.0 N/mm². The reference models without confinement (six models of the series HOS-AAC without openings and the series HAS-AAC with openings) were prepared from the same masonry units, had almost the same outer dimensions, and were tested under the same initial compressive stresses σ_c. The analysis was performed for the morphology of cracks, stress values at the moment of cracking and failure, stiffness, and angles of shear strain. The morphology of cracks was found to depend on initial compressive stresses and the presence of an opening. A significant increase in compressive stress leading to cracks and failure stresses was observed with increasing values of initial compressive stresses. As the wall behavior was clearly non-linear, the bilinear relationship described by energy dissipation E, stiffness at the moment of cracking K_cr, and maximum displacement u_u was proposed to be included in the engineering description of the relationship between horizontal load and displacement of confined walls. Confinement along the vertical edges of the opening having an area of 1.5 m² (acc. to EN 1996-1-1) increased the maximum forces P_max by ca. 45% and marginally affected the ductility of the wall when compared to the elements with circumferential confinement.

Keywords: autoclaved aerated concrete AAC; confined masonry; masonry structures; shear walls.

Grants and funding

The research was financed from the own funds of the Department of Building Structures and Laboratory of Civil Engineering Faculty Silesian University of Technology. Experimental tests of walls made of autoclaved aerated concrete, financed by the Solbet Company.