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Bandyopadhyay, Srijit
- Natural Base Isolation System for Earthquake Protection
Abstract Views :221 |
PDF Views:89
Authors
Affiliations
1 Department of Civil Engineering, Indian Institute of Technology, Kharagpur 721 302, IN
2 Structural and Seismic Engineering Section, Homi Bhaba National Institute, Mumbai 400 094, IN
1 Department of Civil Engineering, Indian Institute of Technology, Kharagpur 721 302, IN
2 Structural and Seismic Engineering Section, Homi Bhaba National Institute, Mumbai 400 094, IN
Source
Current Science, Vol 107, No 6 (2014), Pagination: 1037-1043Abstract
The performance of a well-designed layer of sand, geo-grid, geo-textiles and composites like layer of sand mixed with shredded tyre (rubber) as low-cost base isolators is studied in shake table tests in the laboratory. The building foundation is modelled by a 200 mm × 200 mm and 40 mm thick, rigid plexi-glass block. The block is placed in the middle of a 1 m × 1 m tank filled with sand. The selected base isolator is placed between the block and the sand foundation. Accelerometers are placed on top of the footing and foundation sand layer. The displacement of the footing is also measured by transducers. The whole set-up is mounted on the shake table and subjected to sinusoidal motion with varying amplitude and frequency. Sand is found to be effective only at very high amplitude (>0.65 g) of motion. Among all the different materials tested, the performance of a composite consisting of sand and 50% shredded rubber tyre placed under the footing is found to be the most promising as a low-cost, effective base isolator.Keywords
Base Isolation, Earthquake Protection, Shake Table Test, Shredded Rubber Tyre.Full Text
- A Comparative Assessment of the Seismic Response of an Earthen Dam Using Analytical Simulation and Empirical Methods
Abstract Views :262 |
PDF Views:80
Authors
Affiliations
1 Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, IN
2 Civil Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur 721 302, IN
1 Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, IN
2 Civil Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur 721 302, IN
Source
Current Science, Vol 113, No 05 (2017), Pagination: 902-910Abstract
This article presents the permanent deformation of an earthen dam located in the vicinity of a safety related structure for Mw = 6.5 design basis earthquake. A non-linear 2D dynamic analysis using a real earthquake motion compatible with the design spectrum was performed to check the earthquake-induced deformations of the dam. Deformations of the dam were also estimated by semi-empirical and empirical methods suc has Seed and Makdisi’s method, Newmark’s double integration method, Jansen’s method and Swaisgood’s method. Results from different methods are compared to obtain a range for the value of permanent deformations of the dam. It is observed that the lateral deformation obtained by Seed and Makdisi’s method is the highest while Jansen’s method predicts the highest crest settlement. The crest settlement of the dam is found to vary between 11.8 mm and 17.8 mm, which is within the safety limits according to IITK-GSDMA guidelines.Keywords
Earthen Dam, Dynamic Analysis, Deformations, Non-Linear Finite Element Analysis.Full Text
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