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Probabilistic Format for Seismic Risk Analysis
of RC Buildings in the Indian Context
--C M Ravi Kumar, K S Babu Narayan, D Venkat Reddy and K Venkataramana
As more and more emphasis is being laid on nonlinear analysis of Reinforced Concrete (RC)-framed structures subjected to earthquake excitation, the research and development on both nonlinear static (pushover) analysis as well as nonlinear dynamic (time history) analysis are in the forefront. Due to prohibitive computational time and efforts required to perform a complete nonlinear dynamic analysis, researchers and designers all over the world are showing keen interest in nonlinear static pushover analysis. The paper presents the overview of seismic provisions in Indian seismic codes published by the Bureau of Indian Standards with regard to seismic analysis and design. Since the country lies in earthquake-prone area and many of the past earthquakes have high number of casualties due to collapse of buildings and dwellings, an attempt has been made to present the complete details of methodology in a probabilistic manner to assess the seismic risk of RC buildings based on pushover analysis due to nonexistence/availability of code practices in the Indian context. Thus, the format may be used as a guideline for seismic risk analysis. © 2013 IUP. All Rights Reserved.
Response of Two-Way Asymmetric
Multistorey Buildings Under Biaxial Excitation
--K Kumar Nishant and Rajul K Gajjar
With the reduction of available space, the structures are developing vertically rather than horizontally and increase in height of structures tends to attract more seismic forces. IS:1893 (2002) stated that seismic analysis should be performed on structural model which is excited with forces in two orthogonal directions separately. But an actual earthquake will have its effect in both the directions simultaneously. Limited research has been carried out on the effect of such biaxial excitation on multistorey building having biaxial eccentricity. The paper deals with the comparison of the nonlinear behavior of G+5, G+10 and G+15 storey buildings with biaxial eccentricity during biaxial excitation by time-history analysis. The angle of incidence of earthquake forces is varying between 0 and 360o. The building having regular plan with eccentricity along each of x and y directions, has been studied. Time-history analysis has been carried out using SAP2000 after validating a preliminary model with the experimental results available in the reference literature. © 2013 IUP. All Rights Reserved.
Strength of Concrete Based on Pozzolanic
Material Incorporated with Steel Fibers
--A Sofi and A Sasidharan
The paper presents a comprehensive study on the properties of concrete containing Fly Ash (FA) and steel fibers. FA is a residual material of energy production using coal, which has been found to have numerous advantages for use in the concrete industry. Some of the advantages include improved workability, reduced permeability, increased ultimate strength, reduced bleeding and reduced heat of hydration. The use of FA in concrete is found to affect strength characteristics adversely. Fiber Reinforced Concrete (FRC) is concrete containing fibrous material which increases its structural integrity. The addition of fibers to concrete considerably improves its structural characteristics such as static flexural strength, impact strength, tensile strength, ductility and flexural toughness. For long-term strength, toughness and high stress resistance, Steel Fiber Reinforced Concrete (SFRC) is increasingly being used in structures such as flooring, housing, precast, tunnelling, heavy duty pavement and mining. Generally, aspect ratios of steel fibers used in concrete mix are varied between 50 and 100. In this paper, properties studied include compressive strength, flexural tensile strength, splitting tensile strength of hardened concrete. FA content used was 0%, 30% and 50% in mass basis and fiber volume fraction was 0%, 0.5%, 0.75% and 1% in volume basis. The laboratory results showed that the steel fiber addition either into portland cement concrete or FA concrete improves the tensile strength properties. The performed experiments showed that the behavior of FA concrete is similar to that of Portland cement concrete when FA is added. © 2013 IUP. All Rights Reserved.
Time and Cost Comparison of Construction
of RCC, Steel and Composite Structure Building
--B L Rajput, Mohammed Ali Hussain, Nadar Nissar Shaikh and Jeet Vadodaria
At present, India requires construction of many houses at right prices because of huge housing shortage. With the use of conventional or traditional materials and technology, it is not possible to complete the construction of buildings with rapid pace. Therefore, the industry must use some alternative materials and technology for fast-track building construction. The paper presents a comparative study on time and cost of building made up of three different structural systems like Reinforced Cement Concrete (RCC), steel and composite structures. Taking the same plan, floor area, floor-to-floor height and loading conditions, the building was designed considering three structural systems, and the structural element cost was calculated for all the three structures. Microsoft Project (2003) (MSP) was used for time scheduling, and the optimum time required for building construction with the three structural systems was calculated. In comparison with RCC structure, steel structure saves 18.66% and composite structure saves 32.02% in construction time, thereby providing savings in net cost. The cost of construction of composite steel structure is 41.28% higher when compared to RCC structure and cost of steel structure is 38.19% higher when compared to RCC structure. © 2013 IUP. All Rights Reserved.
Research Note
A General Analysis of Equipment Cost
and Management in Flyover Project
--P Valli, C Antony Jeyasehar and J Saravanan
In modern days, constructions are fully mechanized which increase the cost of equipment up to 30%. Proper planning, selection, procurement, installation, operation, maintenance and replacement of equipment play an important role in equipment management for the successful completion of the project. With the growing use of machinery, it has become necessary for construction engineers to be thoroughly familiar with the construction application and upkeep of the wide range of the modern equipment (Cox, 1971). © 2013 IUP. All Rights Reserved.
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