Current Science

Durgesh C. Rai ¹, Sudhir K. Jain ², C. V. R. Murty ³, Dipanshu Bansal ⁴

Affiliations
1 Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016, IN
2 Indian Institute of Technology Gandhinagar, Ahmedabad 382 424, IN
3 Indian Institute of Technology Jodhpur, Jodhpur 342 011, IN
4 Department of Civil Engineering, State University of New York at Buffalo, US

Abstract

The earthquake simulation on full-scale civil engineering structures in a pseudo-dynamic testing facility provides an affordable and practical means to understand the seismic behaviour of structures as it provides accurate information about their real time response of inelastic behaviour up to failure. One such pseudo dynamic testing facility is nearing completion at IIT Kanpur, which has 15 m × 10 m L-shaped and 10.5 m high reaction wall and 1.2 m thick top slab of the box girder for the strong floor. The anchor points are located in the wall and floor in a square grid of 0.6 m with each point has load capacity of 1.7 MN in tension and 1.0 MN in shear. The 2 m thick posttensioned wall using Freyssinet 12K15 cable system in a novel configuration can resist an overturning moment of 12.7 MNm per metre of the wall. The capacity of the reaction assembly depends upon number of loads applied, combination of loads and interaction between different components of the reaction assembly structure. A methodology based on 'influence coefficients' was developed to estimate the worst load combination for describing load rating of the reaction structure. Finite element analyses in ABAQUS environment were conducted to compute the influence coefficients matrix whose elements can be added linearly to find out the maximum loading effect on the reaction structure which can be used to determine the limiting load for a particular case of load application.

Keywords

Pseudo-Dynamic Testing Facility, Reaction Wall, Seismic Behaviour, Load Rating.

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R. Pradeep Kumar ¹, D. Srinagesh ², T. Seshunarayana ², R. K. Chadha ², Narender Bodige ³, G. Suresh ², D. Hima Chandan ¹, C. V. R. Murty ⁴

Affiliations
1 Earthquake Engineering Research Centre, International Institute of Information Technology, Hyderabad 500 032, IN
2 CSIR-National Geophysical Research Institute, Hyderabad 500 007, IN
3 Department of Civil Engineering, Anurag Group of Institutions, Hyderabad 501 301, IN
4 Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600 036, IN

Abstract

A ground-structure vibration response study was carried out at the Ramappa Temple near Warangal, Telangana, India, shaken by underground blasting undertaken at the neighbouring Devadula Lift Irrigation Project to build water tunnels. The intensities of vibrations were examined – subsurface and ground vibrations were measured using velocity meters, and shaking at the temple using accelerometers. The study concluded that high-frequency vibrations of the ground were filtered by the soft natural clay bed underneath, and vibrations at the temple structure were small and well below the levels that can cause damage to it. Here we present the scientific findings of the vibrations recorded during the blasts and their implications.

Keywords

Heritage Structure, Structural Response, Tunnel Blasting, Vibrations, Vulnerability Assessment.

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