Steel Fibre Reinforced High Performance Concrete Beam Under Half Cyclic Loading

Vol.2  No.4

Year: 2014

Issue: Dec-Feb

Title : Steel Fibre Reinforced High Performance Concrete Beam Under Half Cyclic Loading

Author Name : K.Gomathi, S.Elavenil

Synopsis :

Concrete structures are often subjected to various types of static and dynamic forces. Fibre reinforcement improves the behaviour of reinforced concrete beams. Experimental investigations were made to study the response of steel fiber reinforced concrete beams under half cyclic loading. Fourteen beams, of which two were control beams, all having size of 150x225x1800 mm length are prepared using cement concrete grade M 30 and designed as under reinforced beam. Twelve beams are strengthened with the addition of straight steel fibres in different volume fraction of 0.5%, 0.75% and 1% for the aspect ratios of 65 and 80. The observations of ductility, rotational capacity and residual strength are compared with steel fibre reinforced concrete beams through hysteric load-deflection and moment-rotation curves. It was found that the provision of 1 % volume fraction of fibres with aspect ratio 80 has better performance in terms of 18% increase in ductility index, 5.4% increase in rotational capacity and 44% increase in residual strength. Steel fibre reinforced concrete beams have exhibited smaller crack width compared with control beams.

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Comparative Study and Analysis of Multi-Storied Base Isolated Building

Vol.2  No.4

Year: 2014

Issue: Dec-Feb

Title : Comparative Study and Analysis of Multi-Storied Base Isolated Building

Author Name : Shakir Gani, Anand Gharad

Synopsis :

Base isolation technique is one of the most widely implemented seismic protection systems in earthquake prone areas. The term 'base' refers to the foundation of a structure and 'isolation' refers to reduced interaction between the ground and the structure resting over it. Base isolation is a very effective way to counteract the damaging component of seismic forces and is one of the most widely implemented and accepted seismic protection systems. The mechanism of the base isolator increases the natural period of the overall structure, and decreases its acceleration response to earthquake / seismic motion.A multi-storied R.C.C (Reinforced Cement Concrete) building with lead rubber bearing is introduced throughout this study.Validation of SAP2000 for base isolation technique using a mathematical model is carried out. Comparison between base shear values considering fixed base for the static and dynamic analysis is shown. Also the comparison between the base shear values of fixed and isolated base considering dynamic analysis (response spectrum and linear time history) is explored. For response spectrum analysis, the reduction in base shear value for base isolated building is upto 62%, whereas for the same base isolated building and for linear time history analysis, this reduction is upto 85% - 90%.

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An Experimental Study On High Strength Concrete Using Fly Ash And Alccofine

Vol.2  No.4

Year: 2014

Issue: Dec-Feb

Title : An Experimental Study On High Strength Concrete Using Fly Ash And Alccofine

Author Name : Mohammed Qureshi, Dr. Yogendra Tandel, Bhavin Patel

Synopsis :

This paper presents the effects of using Fly Ash (class F) and Alccofine materials on performance of high-strength concrete with M60 grade of IS cube specimen. Fly ash replacement varies from 26% to 18% and Alccofine replacement varies from 4% to 12%. We are using Poly Carboxylate Ether based superplasticizer for achieving workability of concrete. Dosage of superplasticizer is same for all mix proportions. Five types of mix proportions containing Fly Ash and Alccofine with different proportions in addition to ordinary Portland cement were investigated and tested for compressive strength, split tensile strength, flexural strength and loss in weight and compressive strength for durability aspects. The result shows that all the concretes achieve compressive strength higher than 41 MPa that is required for high strength concrete as per ACI 363. It is also observed that the strength gain at 28 to 56 days was higher than 7 to 28 days. Durability characteristics of high strength concrete with admixtures containing class F Fly Ash and Alccofine were conducted by acid resistance and sulphate attack at 28 days. The result shows that fly ash and Alccofine added as a cement replacement in concrete offers good response for durability criteria.

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Optimal Dynamic Allocation Of Servers To Tasks Using Simultaneous Perturbation Stochastic Algorithm

Vol.2  No.4

Year: 2014

Issue: Dec-Feb

Title : Optimal Dynamic Allocation Of Servers To Tasks Using Simultaneous Perturbation Stochastic Algorithm

Author Name : Shalabh Bhatnagar, Shreya Thusoo

Synopsis :

In this paper, an algorithm for simulation based parameter optimisation over discrete sets using the basic Simultaneous Perturbation Stochastic Algorithm (SPSA) has been developed. The objective function to be minimised is itself the long run average of certain objective functions whose noise estimates are obtained via simulation. Arrivals follow a Markov Modulated Poisson Process (MMPP) while the service times are generated exponentially. Application of this algorithm for the Dynamic Allocation of Servers has been studied and its authenticity has been checked for varying parameter values. Certain modifications have been introduced for the specified case for speedy convergence of results and study of the sensitivity of the algorithm with respect to its parameters and step-size. The results have been presented and verified to fall along the expected line.

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Effect Of High Temperature And Cooling Regimes On Residual Properties And Spalling Of HPFRCC

Vol.2  No.4

Year: 2014

Issue: Dec-Feb

Title : Effect Of High Temperature And Cooling Regimes On Residual Properties And Spalling Of HPFRCC

Author Name : Sekar

Synopsis :

The work reported in this paper was carried out to study the effect of high temperature and cooling regimes on residual properties and spalling of High Performance Fibre Reinforced Cement Composites (HPFRCC). The properties studied include residual compressive strength and residual density. A total of 168 numbers of High Performance Concrete (HPC) cubes of size 100 x 100 x 100 mm were cast with and without steel fibres. The cubes were heated to different levels of elevated temperatures using an electric furnace and cooled by two different cooling systems and then finally tested for residual properties at different ages. Test results indicate that, irrespective of cooling regimes, HPC and HPFRCC cubes heated at 250°C had a higher residual strength than unheated cubes at all ages of testing. But, when they were heated at 500 and 750°C, they had a lower residual strength than unheated cubes. Cubes cooled by furnace cooling had a higher residual strength than cubes cooled by water cooling. HPC and HPFRCC cubes exposed up to 750°C had a lower residual density than unheated cubes at all ages of testing. There is a recovery of strength with time when exposed to low elevated temperature than to high elevated temperature. At 750°C, the colour of HPC and HPFRCC cubes became white and cracks were observed in HPC cubes, where as no cracks were formed on HPFRCC cubes. Incorporation of steel fibres into HPC cubes improved its fire resistance.

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Concrete self-healing capability using bacterial action – a comparative study

Vol.2  No.3

Year: 2013

Issue : Sep-Nov

Title : Concrete self-healing capability using bacterial action – a comparative study

Author Name : AKASH BHARDWAJ, PARAMPREET KAUR

Synopsis :

Cracking is a frequent cause of complaints in the concrete industry. Cracking can be the result of one or a combination of factors such as drying shrinkage, thermal contraction, restraint (external or internal) to shortening, sub grade settlement, and applied loads or can also be caused by freezing and thawing of saturated concrete, alkali- aggregate reactivity, sulphate attack, or corrosion of reinforcing steel. So, there is a need for the development of such an inherent biomaterial, which is a self-repairing material and can remediate the cracks and fissures in concrete. Bacterial concrete is one among such a material, which can successfully remediate cracks in concrete. This technique is an ecofriendly desirable as well as a natural method that can be taken into consideration in recent concrete industry era. The Paper discusses the comparative study of concrete self healing capability using different types of bacteria viz Bacillus Sphacricus, B. Cohnii. Hence this is a Biological Remediation of cracks repairment.

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Modeling the building life cycle for energy sustainability under conditions of uncertainty

Vol.2  No.3

Year: 2013

Issue : Sep-Nov

Title : Modeling the building life cycle for energy sustainability under conditions of uncertainty

Author Name : JENNIFER R. DICKS, Richard H. McCuen

Synopsis :

The demand for energy is high and is expected to continue increasing with the growth in both population and technological development. With the increase in energy demand, concerns about environmental issues, such as the depletion of nonrenewable energy sources, environmental pollution, health and safety hazards, and the production of waste, also increase. In order to meet sustainability goals, methods of conserving energy need to be explored and implemented. In this study,a model of the construction-deconstruction life cycle of a building was developed to assess the significance of energy savings when recyclable materials, reusable materials, renewable energy sources, and more efficient systems are incorporated. The model enables both the evaluation of the energy requirements for each process for any building type and the assessment of energy savings from conservation efforts. When compared with the energy requirements of a standard home, the use of reusable materials conserved significantly has more energy than any other scenario. Using of recyclable building materials was another effective method of energy conservation, but the savings were not as great as with reusable materials. The use of energy efficient systems conserved the least energy and the use of renewable energy sources resulted in a savings that was between the use of efficient systems and the use of recyclable materials.

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Entropy based assessment of hydrometric network using probabilistic approach

Vol.2  No.3

Year: 2013

Issue : Sep-Nov

Title : Entropy based assessment of hydrometric network using probabilistic approach

Author Name : N VIVEKANANDAN

Synopsis :

Establishment and maintenance of a hydrometric network in any geographical region is required for planning, design and management of water resources. Setting up and maintaining a hydrometric network is an evolutionary process, wherein a network is established early in the development of the geographical area; and the network reviewed and upgraded periodically to arrive at the optimum network. This paper presents the methodology adopted in assessing the hydrometric network using entropy theory adopting normal and log-normal probability distributions. The technique, involving computation of marginal and conditional entropy values, is applied to the upper Bhima basin up to Ujjani reservoir for illustrative purposes; and results presented. The derived optimum hydrometric network for the basin is evaluated based on WMO guidelines for minimum density of hydrometric network.

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Bullet speed attenuation on different shapes of domes

Vol.2  No.3

Year: 2013

Issue : Sep-Nov

Title : Bullet speed attenuation on different shapes of domes

Author Name : Dr RAM RANJAN SAHU, Pramod Kumar Singh

Synopsis :

A dome resembles the hollow upper half of a sphere and has been used from the ancient times in building structures. It has inherent structural strength when properly built and can span large open spaces without interior supports. These domes can be subjected to missile and bullet attacks and can get damaged. Now a days many types of monolithic domes are being built to intercept missile attack. The damage depends upon the striking mass, its shape and velocity. The heavier the object and the faster it moves, the more damage it will cause. Also the shape of the striking object has an important role in piercing the target. An analytical study was planned on the bullet impact on different shapes of the domes. The speed attenuation was studied and reported. The effect of bullet nose shape and dome boundary conditions are also discussed.

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Seismic resistance of RC structures using base isolation

Vol.2  No.3

Year: 2013

Issue : Sep-Nov

Title : Seismic resistance of RC structures using base isolation

Author Name : C. Jayaguru

Synopsis :

An earthquake is a sudden violent shaking of the ground. Many aseismic construction designs and technologies have been developed over the years in attempts to mitigate the effects of earthquakes on buildings, bridges and potentially vulnerable contents. Seismic Isolation is a relatively recent, and evolving, technology of this kind. Though the concept of base isolation as a means of earthquake protection is more than 100-years old, its application to civil engineering structures is relatively new, and the base isolation research is pursued in India only for the last twenty years. This paper introduces the concept of Natural rubber base-isolators for the seismic (earthquake) resistance of Reinforced Concrete (RC) – framed buildings. The design of base isolators is explained with an objective to bring awareness and confidence in structural engineers in India for use of this technique in seismic areas. In addition, an analytical study is carried out to validate the effectiveness of base isolators in RC structures using SAP2000 NL.

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