Ramesh Babu

Central Power Research Institute | CPRI · Earthquake Engineering and Vibration Research Centre

Though infills are considered as non structural elements, they tend to interact with the frame subjected to lateral loading. Due to the presence of infills there will be increase in the strength of the structure with increase in stiffness of structure resulting in increase in inertia force. The experimental study presented in this thesis mainly foc...

For transmission of electricity from power generation plant to substations, many types of structures are being used. The main function of these structures is to support the power conductors and earth-wire. 4-legged steel lattice tower is one of these structures, which is widely used for this purpose. The main drawback of a 4-legged lattice tower is...

In Nuclear Power plants, snubbers that are expensive, complex and require frequent maintenance have often been used as seismic supports in piping systems. Passive dampers such as Elasto-Plastic Damper (EPD) and Shape Memory Alloy Damper (SMAD) are cheap, simple, cost effective and reliable. They can be used for replacing snubbers in piping systems...

Infill walls provide durable and economical partitions that have relatively excellent thermal and sound insulation with high fire resistance. Monolithic infilled walls are provided within RC structures without being analyzed as a combination of concrete and brick elements, although in reality they act as a single unit during earthquakes. The perfor...

Generally seismic isolation is achieved by supporting the structure on laminated rubber bearings, friction pendulum bearings, roller bearings etc. Very little work has been performed using soil as a base isolation media. Experiments and analytical work has been performed on a structural model with isolated footing and found encouraging results. Det...

Post earthquake studies have clearly shown that the seismic performance of substation is very weak and results in damage causing huge direct and indirect loss to the power utilities. Considerable time is spent to repair, retrofit or replace the damaged substation equipment and to restore power supply. Many substation equipments failed when installe...

This paper discusses the development of a composite cross arm for a power transmission line tower using FRP pultruded profiles. The mechanical performance of the composite cross arm has been evaluated using experimental testing and an analytical solution as well as a finite element simulation. By using the composite cross arm in place of a steel cr...

Post-earthquake surveys have clearly shown that the substation equipment are vulnerable to severe earthquake shaking. Substation equipment like Circuit breakers, lightning arresters, current and voltage transformers have suffered severe damage during earthquakes since these equipment consists of porcelain elements. Hence it is very important that t...

Post earthquake performance of porcelain insulators installed for high voltage substation equipment, in general, revealed their vulnerability to failure, not due to any quality deficiency, but due to failure of their supporting structures. Most of the equipment in standalone state, withstood to tests of induced vibrations conforming to Internationa...

In order to understand the behaviour of RC structures under seismic loads and to validate the models developed, experimental results are needed. Realistic shake table tests are the best possible way to generate information on real-life behavior of structures that can be used to validate the existing or proposed models as well as to evaluate the eff...

As more and more emphasis is laid on nonlinear analysis of RC framed structures subjected to earthquake excitation, the research and development on nonlinear static (pushover) analysis as well as nonlinear dynamic (time history) analysis is in the forefront. For validation of the analytical procedures to develop the lateral load-displacement (pusho...

Recently, there has been increasing interest in using super-elastic shape memory alloys for applications in seismic resistant design. Shape memory alloys (SMAs) have a unique property by which they can recover their original shape after experiencing large strain upto 8 % either by heating (shape memory effect) or removing stress (Pseudo-elastic eff...

The SiCf/SiC ceramic matrix composites find applications in structural, wear resistance and high temperature applications as they are quite superior to their monolithic counter parts due to their improved flaw tolerance, large work of fracture and non-catastrophic failure behaviour. In this investigation, three types of SiCf/SiC composites, i.e., S...

Generally a base isolator shifts the natural period of the building away from that of the predominant period of the most probable earthquakes and provides additional damping to absorb the energy. The present study focuses on the effi cacy of soil, geofi bre reinforced soil and a layer of smooth geosynthetic membrane placed in soil in reducing the s...

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 consider...

The study presented here focuses on the effectiveness of the models adopted for the nonlinear static pushover (NSP) analysis and providing the best model that can predict the nonlinear response of RC buildings with sufficient accuracy with respect to the experimentally obtained results. NSP analysis considers material nonlinearity and is an effecti...

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 a...

Passive energy dissipating devices like elasto-plastic dampers (EPDs) can be used for retrofitting of structures subjected to seismic loads. A model of reinforced concrete structure is tested on shake table with and without EPDs attached in its frames. Using a finite element model of the structure, linear and nonlinear time history analysis is carr...

Comprehensive experimental and numerical studies are carried out on the dynamic characteristics of 3 dimensional (D) reinforced Concrete (RC) frame with Masonry Infill (MI). MI though considered as non-structural element largely effect strength, stiffness and ductility of the framed structure during the application of lateral loads such as wind and...

1. ABSTRACT Passive energy dissipating devices like Elasto-plastic dampers (EPDs) can be used for retrofitting of structures subjected to seismic loads. A model of RCC structure is tested on shake table with and without EPDs attached in its frames. Using a finite element model of the structure, linear and nonlinear time history analysis is carried...

1 ABSTRACT In a nuclear facility radiotoxic materials are being handled in leak tight enclosures called glove boxes. These glove boxes serve as primary confinement for these radiotoxic materials. Hence there is a need to check the structural integrity and leak tightness of the glove boxes when subjected to earthquake loads. For this requirement, ex...