Dr Md Akhtar Hossain

This paper presents an experimental program in which 16 full-scale clay brick unreinforced masonry walls were constructed and tested under in-plane cyclic shear loading. These walls have been divided into four sets of nominally identical specimens constructed with the same masonry units from the same mortar composition by the same mason and cured for a consistent period of time. The repeatability of these tests allows for the variability of the peak in-plane shear capacities of these wall configurations to be investigated. Furthermore, these tests were supplemented with material characterization tests, examining the tensile, shear, compressive, and elastic properties of the masonry utilized in this study. In addition, assessments of the accuracy of the current Australian standard for masonry design, as well as that of other expressions found in the literature, have been made. The findings of this analysis indicate that the Australian standard maintains significant limitations in its ability to correctly determine the shear capacity and failure mechanism of masonry shear walls. This error is reduced, but not wholly mitigated through the application of the deterministic equations present in the other design guides.

Purpose: The study focused on improving stiffness and premature failure, the weaknesses of the other retrofitting techniques and the retrofitted beam. A detailed study regarding the section properties and effective length of the angles was also carried out in this study. Design/methodology/approach: In this article, a comprehensive study was carried out using a finite element method to investigate the behavior and performance of steel angles as a retrofitting technique subjected to flexure. A model was developed in ABAQUS and validated with the available experimental works. The model was then applied to examine the beams retrofitted with the steel angles. Findings: From the investigation, the strengthening technique successfully enhanced the flexural capacity and stiffness of the beam. The stiffness of the retrofitted beam achieved more than 2.5 times of the controlled beam. The thickness and flange width of the angles improved both the load capacity and stiffness whereas, web width, having same flange width, improved the stiffness only. This study also illustrates that a premature failure can be minimized by maintaining L/S (length to span) ratio between 0.7 and 1.0 along with the welding to provide the connections between the angles and stirrups. Practical implications: The developed model and the findings can be used for designing the retrofitting technique for the damaged as well as beams to be increased their capacity. Originality/value: The research focused on the implication of a new technique of retrofitting, steel angles to improve the stiffness of beam, which is one of the major drawbacks of traditional techniques. Moreover, the research aimed to improve premature failure by bonding the retrofitting materials with the stirrups of the mother beam through welding.

Semi interlocking masonry (SIM) is an innovative masonry building system which is being developed in the Centre for Infrastructure Performance and Reliability at The University of Newcastle, Australia. It utilizes a special method of interlocking of mortar-less engineered masonry panels made of semi-interlocking masonry (SIM) units which possess significant energy dissipation capacity due to friction on sliding bed joints between units of the panel during a seismic event. This special method of interlocking SIM bricks allows relative sliding of unit courses in-plane of a wall and prevents out-of-plane relative movement of units. Because all bed joints in a SIM panel are sliding joints, SIM panels can withstand large in-plane displacements without damage. To test SIM panels, a special steel frame with pin connections at each corner was designed and built. The arrangement with pin connections allows application of in-plane shear distortion to the panel of up to 120¿mm. The study presented herein focused on the experimental investigation of displacement capacities of three different types of panels (panel with open gap between the steel frame and top of the panel, panel with foam in the gap, panel with grout in the gap) with two types of SIM units. The paper expands significantly from the previously published conference paper and examines the behavior of SIM panels subject to 100¿mm (5% storey drift) cyclic in-plane lateral displacement on six SIM panels. The horizontal and vertical movement of SIM units were recorded using Digital Image Correlation (DIC) every 10¿s over approximately 8¿h of testing. This study reveals that the DIC displacement outputs show good agreement with displacements measured using traditional instrumentation, even at large displacements (up to 100¿mm). The structural performance of the SIM panels is also analyzed and potential joint opening widths are quantified under large displacement by plotting the outputs from DIC results.