Dr Md Akhtar Hossain

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.

In previous research by the authors, the semi-interlocking masonry (SIM) was investigated as infill panels for framed structures and its favourable seismic performance was established through laboratory tests. Confined semi-interlocking masonry (CSIM) is a new application of SIM that aims to enhance earthquake performance of confined masonry buildings. Numerical simulations are performed to estimate the structural capacity of CSIM buildings. Micro and macro-modelling strategies are two major approaches for numerical simulation of masonry buildings. This paper proposes a macro-model for CSIM buildings by using a resettable semi-active damper model to simulate the behaviour of the SIM panel. The hysteretic performance of CSIM walls using the proposed macro-model was compared with the load-displacement pushover curve resulting from the FEA micro-modelling approach. The acceptable match between the responses of CSIM walls obtained from the micro and the macro-model confirmed the capability of the proposed model to capture the capacity of CSIM walls.

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.

The semi-interlocking masonry (SIM) system has developed in Masonry Research Group at the University of Newcastle, Australia. The SIM panels dissipate energy through the sliding friction on bed joints of SIM units during earthquake excitation. To model the SIM panel's behaviour numerically some key parameters need to evaluate experimentally. This study investigates the elastic modulus of SIM prism and thrust force for horizontal and vertical arching during out-of-plane deflection. Three types of bricks were used in tests: topological SIM, mechanical SIM, and without interlocking bricks. In addition, the prisms of topological SIM bricks comprising three and five bricks have been used to find out the mechanical properties of units. This paper presents the results of 18 arching tests: six tests with topological interlocking, six tests with mechanically interlocking units, six tests with ordinary bricks, and 11 prisms of topological SIM bricks for compressive and modulus of elasticity test.