Browsing by Author "Induprabha, SAD"

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item: Conference-Full-text
Contribution to numerical modelling of concrete- masonry interface In concrete framed structures with masonry infill
(2013-12-01) Induprabha, SAD; Dilrukshi, KGS
Masonry infills have long been used as interior partitions and exterior walls in buildings. They are usually treated as non-structural elements, and their interaction with the bounding frame is often ignored in design. Nevertheless, infill contributes strength to a structure and will interact with the bounding frame when the structure is subjected to strong lateral seismic loads, when the infill is stressed due to movements of an overlying slab or any other case of in-plane or out of plane lateral loading. This interaction may or may not be beneficial to the performance of the structure, however, and it has been a topic of much debate in the last few decades. The interaction of the infill is governed by the relative stiffness and strength characteristics of each individual component and most importantly the interface characteristics that decide the degree of composite action. An interface is a special contact plane on which nonlinear relations between stresses and displacement discontinuities are present. Very often initiation and propagation of cracks along these interfaces are the cause of failure of the relevant structures. Similarly, in the case of concrete framed masonry assemblages, the bond between the masonry and the concrete frame is a weak link, through which failure is possible. Therefore to simulate this behaviour, interface elements with a suitable constitutive model can be utilized. This paper explores finite element models developed to simulate the behaviour of concrete- masonry interface of masonry infill. In this study, brick-concrete couplets were mathematically modelled, using commercially available software ANSYS. The adopted numerical strategy consists of simplifying the concrete-masonry-mortar interface to a zero thick interface, modelling the brick units and the concrete units with three dimensional solid brick elements and modelling the bond using zero thickness interface elements with a cohesive-zone model (CZM) for mixed-mode fracture based on damage mechanics introduced by Alfano and Crisfield(2001).
item: Conference-Full-text
Experimental approach to investigate concrete-masonry interface
(Department of Civil Engineering, University of Moratuwa, Sri Lanka., 2011-12) Premadasa, PKS; Liyanage, SK; Ariyarathna, HDAR; Induprabha, SAD; Dilrukshi, KGS; Ratnayake, N
A masonry infill wall is a common cell in a concrete framed building. More importantly the bond between concrete and masonry has considerable effect to the performance of infill masonry walls and hence to the frame structure itself. Therefore, understanding of the element interaction between concrete and masonry become very important and has become a topic of considerable researchinterest in the past few decades. Many researchers have tried to represent this interaction numerically. However, reliable numerical analysis can be achieved only with the correct mechanical properties which are obtained experimentally. This paper presents the results of a series of experimental studies carried out to determine the tensile and shear behaviour of concrete masonry interface relevant to the Sri Lankan brick masonry. Tests were carried out in accordance with ASTM standards. In this study, the effect of the mortar designation and the joint thickness on the bond was also investigated. From the results, it can be concluded that properties of the bond is significantly affected by the roughness of the brick used and workmanship apart from the mortar designation and joint thickness. Also it can be recommended to use 10 mm mortar joints in construction, since both shear and tensile strength of the joints get reducedwhen the joints become thicker, irrespective of the mortar designation.
item: Conference-Extended-Abstract
Finite element modelling of short span soil-steel bridge structures used in Southern highway in Sri Lanka
(2010) Induprabha, SAD; Rajapaksha, RPGKS; Siriwardana, KDYE; Jayasinghe, MTR; Lewangamage, CS
The corrugated soil Steel Structures, consisting of a combination of shells of corrugated steel plates and surrounded with well compacted backfill soil have been used in Sri Lanka for the first time in Southern Transportation Development Project as underpasses and drainage structures. This has been selected for the lower cost and the lesser construction time. In this study the effect of height of soil cover over the structure, on the stress in the steel shell of Metal Arch Underpass (MAUP) structures is analyzed to determine an optimum range for soil cover and to evaluate the structural safety of the prevailing structures. The commercially available Finite Element Software ANSYS, SAP 200 and PLAXIS 1.5 are used in modelling the structures.