Seismic behavior of RC framed shear wall buildings as per IS 1893 and IBC provisions

Jayalekshmi, B.R.,Chinmayi, H.K. Techno-Press 2015 Geomechanics & engineering Vol.9 No.1

Usually the analyses of structures are carried out by assuming the base of structures to be fixed. However, the soil beneath foundation alters the earthquake loading and varies the response of structure. Hence, it is not realistic to analyze structures by considering it to be fixed. The importance of soil-structure interaction was realized from the past failures of massive structures by neglecting the effect of soil in seismic analysis. The analysis of massive structures requires soil flexibility to be considered to avoid failure and ensure safety. Present study, considers the seismic behavior of multi-storey reinforced concrete narrow and wide buildings of various heights with and without shear wall supported on raft foundation incorporating the effect of soil flexibility. Analysis of the three dimensional models of six different shear wall positions founded on four different soils has been carried out using finite element software LS DYNA. The study investigates the differences in spectral acceleration coefficient (Sa/g), base shear and storey shear obtained following the seismic provisions of Indian standard code IS: 1893 (2002) (IS) and International building code IBC: 2012 (IBC). The base shear values obtained as per IBC provisions are higher than IS values.

Seismic response analysis of reinforced concrete frames including soil flexibility

Jayalekshmi, B.R.,Poojary, V.G. Deepthi,Venkataramana, Katta,Shivashankar, R. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.1

The seismic response of RC space frame structures with isolated footing resting on a shallow soil stratum on rock is presented in this paper. Homogeneous soil stratum of different stiffness in the very soft to stiff range is considered. Soil, footing and super structure are considered to be the parts of an integral system. A finite element model of the integrated system is developed and subjected to scaled acceleration time histories recorded during two different real earthquakes. Dynamic analysis is performed using mode superposition method of transient analysis. A parametric study is conducted to investigate the effect of flexibility of soil in the dynamic behaviour of low-rise building frames. The time histories and Fourier spectra of roof displacement, base shear and structural response quantities of the space frame on compliant base are presented and compared with the fixed base condition. Results indicate that the incorporation of soil flexibility is required for the realistic estimate of structural seismic response especially for single storey structures resting on very soft soil.

Seismic response analysis of reinforced concrete frames including soil flexibility

B.R. Jayalekshmi,V.G. Deepthi Poojary,Katta Venkataramana,R. Shivashankar 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.1

The seismic response of RC space frame structures with isolated footing resting on a shallow soil stratum on rock is presented in this paper. Homogeneous soil stratum of different stiffness in the very soft to stiff range is considered. Soil, footing and super structure are considered to be the parts of an integral system. A finite element model of the integrated system is developed and subjected to scaled acceleration time histories recorded during two different real earthquakes. Dynamic analysis is performed using mode superposition method of transient analysis. A parametric study is conducted to investigate the effect of flexibility of soil in the dynamic behaviour of low- rise building frames. The time histories and Fourier spectra of roof displacement, base shear and structural response quantities of the space frame on compliant base are presented and compared with the fixed base condition. Results indicate that the incorporation of soil flexibility is required for the realistic estimate of structural seismic response especially for single storey structures resting on very soft soil.

Seismic analysis of shear wall buildings incorporating site specific ground response

B.R. Jayalekshmi,H.K. Chinmayi 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.3

During earthquake, the motion of ground is affected significantly by source characteristics, source-to-site path properties and local site conditions. Due to the influence of local soil conditions different places experience distinctive amplitude of surface ground motion. Ground response analysis of a specific site utilizing the borehole information at different locations is done in present study. The ground motion with the highest peak ground acceleration for this site obtained from the ground response analysis is used in finite element soil-structure interaction analysis of multi-storey shear wall buildings with various positions of shear walls. The variation in seismic response of buildings and advantageous position of shear wall are determined. The study reveals that providing shear wall at the core of buildings at the specific site is advantageous among all shear wall configurations considered.

Menthol to Induce Non-shivering Thermogenesis via TRPM8/PKA Signaling for Treatment of Obesity

Sanders Owen Davis,Rajagopal Jayalekshmi Archa,Rajagopal Lekshmy 대한비만학회 2021 The Korean journal of obesity Vol.30 No.1

Increasing basal energy expenditure via uncoupling protein 1 (UCP1)-dependent non-shivering thermogenesis is an attractive therapeutic strategy for treatment of obesity. Transient receptor potential melastatin 8 (TRPM8) channel activation by cold and cold mimetics induces UCP1 transcription and prevents obesity in animals, but the clinical relevance of this relationship remains incompletely understood. A review of TRPM8 channel agonism for treatment of obesity focusing on menthol was undertaken. Adipocyte TRPM8 activation results in Ca2+ influx and protein kinase A (PKA) activation, which induces mitochondrial elongation, mitochondrial localization to lipid droplets, lipolysis, β-oxidation, and UCP1 expression. Ca2+-induced mitochondrial reactive oxygen species activate UCP1. In animals, TRPM8 agonism increases basal metabolic rate, non-shivering thermogenesis, oxygen consumption, exercise endurance, and fatty acid oxidation and decreases abdominal fat percentage. Menthol prevents high-fat diet-induced obesity, glucose intolerance, insulin resistance, and liver triacylglycerol accumulation. Hypothalamic TRPM8 activation releases glucagon, which activates PKA and promotes catabolism. TRPM8 polymorphisms are associated with obesity. In humans, oral menthol and other TRPM8 agonists have little effect. However, topical menthol appears to increase core body temperature and metabolic rate. A randomized clinical control trial of topical menthol in obese patients is warranted.

Antioxidant Properties, Anti-inflammatory Effects, and Bioactive Constituents of the Indian Medicinal Rice Njavara Yellow Compared with Staple Varieties

Rathnam Parvathy,Smitha Mohanlal,Chithra Pushpan,Antony Helen,Ananthasankaran Jayalekshmy 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.5

Polar and non-polar extracts of Njavara yellowrice (NYr) and bran (NYb) were investigated for antioxidantactivity, chemical indices, anti-inflammatory effects, andbioactive compounds, of which the results were comparedbetween the 2 staple varieties Uma and Jaya. Methanolextracts of NYb showed significantly (p<0.05) higherantioxidant activity than other varieties with the IC50 valuesof 97 μg/mL (DPPH•) and 48 μg/mL (ABTS•+). NYbshowed a higher anti-inflammatory effect and higherchemical indices (6.36 mg, phenolic content; 1.44 mg,flavonoid content; 3.06 mg, proanthocyanidin content; and15.5 mg, phytate content per gram of dry weight of bran)than NYr and staple varieties. The content of bioactivecompounds, oryzanols (659 μg/mL) and tricin (24.58 mg/100 g bran), were higher in NYb than in other varieties. Evaluation of biological activities and quantification ofbioactive compounds of Njavara yellow are first pursuedherein to corroborate Njavara Ayurveda medicinal use.