Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

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Subject: search.filters.subject.Masonry materials

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    Influence of masonry infill on fundamental natural frequency of 2D RC frames
    (2010) Chethan, K.; Ramesh Babu, R.; Venkataramana, K.; Sharma, A.
    Reinforced Concrete (RC) framed structures with Un-Reinforced Masonry (URM) infill panels form a major portion of all the RC framed structures worldwide. The URM panels are considered as non-structural members, which is fairly good assumption under gravity loads, however, it is not the same under lateral forces. Under seismic loads, the stiffness additions due to infill panels modify the dynamic behavior of the structure significantly by altering the frequency of the structure. A research project has been taken up at Earthquake Engineering and Vibration Research Centre (EVRC), Central Power Research Institute (CPRI), Bangalore to investigate the influence of masonry infill on fundamental natural frequency of RC frames. 2D RC frames of one bay and two bay having single storey, double storey and three storeys are cast and tested for bare frame and many combinations of URM infill panels. Tri-axial shake table is used for testing. The details of the numerical analysis and experimentation carried out in the research project are brought out in this paper.
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    Studies on the influence of infill on dynamic characteristics of reinforced concrete frames
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Chethan, K.; Ramesh Babu, R.; Venkataramana, K.; Sharma, A.
    The basic investigation under dynamic loads starts with the estimation of the natural frequencies of the structure or system under consideration. This is an important parameter under dynamic analysis. Hence a detailed study has been carried out on the influence of masonry infill (MI) on fundamental natural frequency of RC frames. MI though considered as non-structural element largely affect the strength, stiffness and ductility of the framed structure during the application of lateral forces such as wind and earthquake loads. Experimental and Numerical studies are carried out on RC frames under different configurations of MI in addition to bare frames. The RC frames are designed and detailed as per the relevant Indian standard codes. A simple numerical method has been formulated to obtain the natural frequencies of RC frames with MI using FE analysis. Tri-axial shake table is used for the determination of natural frequencies experimentally. This is a part of the collaborative project between BARC, Mumbai and CPRI, Bangalore focusing on the Response evaluation of RC frames under dynamic loading. This paper consists of numerical formulation, FE analysis, Shake table tests and comparison of results. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Shear strengthening of unreinforced masonry walls using GFRP (glass fiber reinforcement polymer) bars
    (2012) Zyad, T.; Bajpai, K.K.
    Unreinforced masonry (URM) walls exhibits poor seismic performance under moderate and high seismic demand. The present experimental and analytical study, performed on brick masonry panels strengthened by glass fiber reinforcement polymer (GFRP) bars, was aimed to investigate the effectiveness of alternate shear reinforcement technique to reduce seismic damage. A series of three unreinforced masonry (URM) panels and three strengthened panels were subjected to diagonal compression tests according to ASTM E519. Tests were also carried out to determine compression strength of masonry prism, coefficient of friction and bond strength between masonry and mortar. Different reinforcement configurations were evaluated based on analytical studies, to come up with the most effective design for strengthening. The study pointed out that the reinforcement in the diagonal direction increases the effective bond length of the bars intersecting the diagonal crack, thus making the reinforcement design, more effective and more economical. © 2012 Cafet-Innova Technical Society.
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    Free vibration studies of box type laterite masonry structures
    (2012) Unnikrishnan, S.; Narasimhan, M.C.; Venkataramana, K.
    Box-type laterite masonry structures are widely seen in south-west coastal areas of India. Not many studies are available in the literature on the dynamic response of such structures. Free vibration analysis of box-type laterite masonry structures has been attempted in this study, as a preliminary to a detailed dynamic analysis. Finite element analysis has been conducted to And the natural frequencies and corresponding mode shapes of box-type laterite masonry buildings. Results of detailed parametric studies conducted to find the effect of various parameters like modulus of elasticity of laterite masonry, provision of a lintel band or a roof slab, openings in long walls and aspect ratio on the natural frequencies and their mode shapes of box-type laterite masonry buildings are presented and discussed in this paper.
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    Effect of containment reinforcement on the seismic response of box type laterite masonry structures-an analytical evaluation
    (2013) Unnikrishnan, S.; Narasimhan, M.C.; Venkataramana, K.
    Laterite blocks are used for construction of masonry walls since ages in the South-western coastal areas of India. The south-west coastal areas of India lie in zone III of seismic zonation map of Indian code IS 1893-2002. In spite of the fact that laterite is the most favored masonry material in these regions of India, the structural performance of laterite masonry has not been systematically investigated. Again there are no previous studies addressing, in detail, the seismic performance of laterite masonry buildings. Now that these areas are becoming more and more important from point of view of trade and commerce, there is a need for a detailed research on the seismic response of laterite masonry structures located in these areas. The present paper reports the results of such a study of the seismic response of box-type laterite masonry structures. Time history analysis of these structures under El-Centro acceleration has been performed using commercial finite element software ANSYS. Effect of 'containment reinforcement' on the seismic response of box type laterite masonry structures has been evaluated. © 2013 Techno-Press, Ltd.