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Seismic Evaluation of Masonry Buildings
with Flexible Diaphragm:
A Performance-Based Approach
-- Amit Sharma, Sonu Malviya, Rakesh Khare and Amit Melani
The present work investigates the seismic evaluation of Unreinforced Masonry (URM) building when subjected to seismic (lateral) loading. The Federal emergency management agency published a performance-based design code FEMA-356 (2000). In the present work, performance analysis procedures proposed by FEMA-356 (2000) are applied to a typical URM shear wall building and the results are compared with that of a modified analysis proposed by the researchers. These procedures are also performed for a set of seismic zones suggested by IS:1893(2002).
© 2016 IUP. All Rights Reserved.
An Investigation on Shell Wall of RC Natural Draft Cooling Tower Subjected to Transverse Shear Due to Wind Load
-- Sailesh Adhikari and Amiya K Samanta
The effect of the wind load is predominant on the tall and large structures like cooling tower. The study on the deformation of the critical sections of the shell element in the large structures like cooling tower has been skipped on most of the previous research. This paper presents the ovalization pattern of the cooling tower shell in different mode shapes when subjected to axisymmetric wind loading. This paper studies two different models of cooling towers: the 1st model is located in Andal West Bengal, India which is fully hyperbolic in shape, and the 2nd model is the modification of the 1st cooling tower which has the cylindrical portion above the throat level of the 1st cooling tower. Simulation of the cooling tower has been done using the finite element software ABAQUS, the wind load that has been described in the relevant Indian Standard Code has been expressed in terms of Fourier series using the advanced options available in the software. The cross-section distortion of the cooling tower shell in the nonlinear range of the elasticity in different mode shapes has been studied. A comparison of the two types of cooling tower models in terms of stress, displacement and strain is made in this study.
© 2016 IUP. All Rights Reserved.
Accelerated Testing of Recycled Aggregate Concrete: Establishing Correlation Equations for Flexural Strength Prediction
-- Manjunath M and Prakash K B
In this paper, the effect of accelerated curing on the strength properties of concrete produced by replacing natural coarse aggregates with recycled aggregates is presented, thereby establishing a correlation for flexural strength between accelerated-curing and 28-day normal curing of concrete made with recycled coarse aggregate. The investigation is performed on concrete of grade M20. The different percentage replacement of natural coarse aggregates with recycled aggregates considered are 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%. A reliable correlation between accelerated curing and 28-day curing for flexural strength in the form of linear equation serves as an invaluable decision-making tool for any quality assurance program for concrete produced with recycled aggregate.
© 2016 IUP. All Rights Reserved.
Physicochemical Characteristics of Foundry Sand and Its Treatment for Reutilization
in Foundry
-- Devika G and Praveen A Ghorpade
Preliminary studies were conducted on different types of sands, namely, fresh sand, facing sand and backing sand. The analytical investigations such as surface morphology obtained from Scanning Electron Microscope (SEM) and XRD patterns revealed that there is no significant change in the crystal structure of different types of sands mentioned above. It was important to investigate the changes taking place on the sand surface in the presence of sodium silicate which was added as a binder. Further, research was carried out to investigate the effect of this binder on silica sand at different temperatures. Batch experiments were carried out to clear the surface of the sand grain using different chemicals such as water, glucose, hydrochloric acid (HCl) and ammonium sulphate ((NH4)2SO4) with different concentrations. Thus, treated sand was checked for core hardness and compressive strength by making suitable sand molds. To understand the changes taking place on the surface of sand after treatment, Fourier Transform Infrared Spectroscopy (FTIR) was used. The change in the functional groups of facing sand and treated sand was analyzed. The sand treated with 0.5M Hydrochloric Acid (HCl), which showed best results in terms of compressive strength, was selected for FTIR analyses. The FTIR spectra of treated sand with 0.5M HCl showed the absence of the O–H stretch, which is an indication of the presence of free hydroxyl groups at the band 3640-3200.
© 2016 IUP. All Rights Reserved.
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