i-manager's Journal on Structural Engineering (JSTE)


Volume 3 Issue 2 June - August 2014

Research Paper

Experimental Study on the Properties of Chemical Commixtured Concrete

M. Adil Dar* , Madan Chandra Maurya**, Saqib Fayaz***
*,*** Research Scholar, Department of Structural Engineering, Kurukshetra University, Haryana, India.
** Assistant Professor, Civil Engineering, ShriRamswaroop Memorial University, Lucknow, U.P, India.
Dar, A., Maurya, M.C., and Fayaz, S. (2014). Experimental Study on the Properties of Chemical Commixtured Concrete.i-manager’s Journal on Structural Engineering, 3(2), 1-10. https://doi.org/10.26634/jste.3.2.3015

Abstract

Concrete is the most widely used construction material. It is the second largest consumed material in the world after water. It is used in different ways in the construction industry. It can take any shape it is placed in. This makes concrete a versatile construction material. However during cold weather, if the water in the fresh concrete is allowed to freeze, the concrete will be damaged to such an extent that it is unfit for use. Even if the temperature does not drop below zero, the concrete will not gain strength as quickly as it would during the warmer months. Hence for cold weather concreting we must use an accelerator admixture to speed up the hardening of concrete. An experimental program was undertaken to determine the effect of accelerator admixture on the strength of concrete casted below zero degrees Celsius. Tests on both fresh and hardened concrete were carried out to determine their respective strengths. Different specimens with varying percentage of accelerator admixture and sizes were casted and tested after 7 days and 28 days

Research Paper

Effects of Strength of Confining Material on Strength and Deformation of Stone Column

S.P. Singh* , Chamling**
* Professor, Department of Civil Engineering, National Institute of Technology, Rourkela, Odisha, India.
** Student, Department of Civil Engineering, National Institute of Technology, Rourkela, Odisha, India.
Singh and Chamling (2014). Effects of Strength of Confining Material on Strength and Deformation of Stone Column. i-manager’s Journal on Structural Engineering, 3(2), 11-14. https://doi.org/10.26634/jste.3.2.3016

Abstract

Among the various ground improvement techniques, stone columns (SCs) are widely used for supporting flexible and light weight structures. Stone column derives its load carrying capacity from the confinement offered by the surrounding soil. Stone column fails due to bulging and its load carrying capacity can be increased by preventing lateral bulging. A detailed finite-element analysis on the behaviour of single stone column of 50 mm diameter is studied by varying parameters like loading area and shear strength of soft clay surrounding it. Finite-element analyses have been performed using 15-noded triangular elements with the software package PLAXIS. The effects of loading area and strength of confinement material on bulging response have been investigated in this study. The results indicated that the diameter of bulging decreased with increase in the loading area up to 3 times the diameter of the column, beyond which no substantial change in bulging diameter is noticed. Further, an increase in the strength of surrounding material results in a decrease in bulging shape and the position of the maximum bulging is shifted downwards.

Research Paper

Design of a Flexible Bridge Across the Railway Platform

Prasanthi* , Kishore Kumar**
* Professor, Mechanical Engineering Department, JNTUA College of Engineering, Ananthapuramu, Andhra Pradesh, India.
** Research Scholar, Mechanical Engineering Department, JNTUA College of Engineering, Ananthapuramu, Andhra Pradesh, India.
Prasanthi and Kumar, K. (2014). Design of a Flexible Bridge Across the Railway Platform. i-manager’s Journal on Structural Engineering, 3(2), 15-20. https://doi.org/10.26634/jste.3.2.3017

Abstract

The problem to transfer handicapped or old people is as old as the transportation system itself. Earlier and even now, they are transferred by many methods like Foot-over bridges and escalators. But all these methods are time consuming and slow. These methods are good in general use, but on platforms these cannot be used, as these methods will complicate the transportation and will disrupt the free movement of the people on platforms. So, here our aim is to design a system or device which will be able to transfer the handicapped people from one platform to another, within the given constraints and should also comply with the societies’ exiting conditions. In order to reduce these difficulties, the concept of flexible bridge across the railway platform is proposed. The main aim of the present work is to provide the flexible bridge for the railway platforms in order to overcome these difficulties in the usage of foot-over bridges in railway stations. In this project, it is proposed to design a flexible bridge between the platforms across the railway track which works by the functioning of sensors, micro-controller and DC motor.

Research Paper

Studies on the Leachate Characteristics of Compacted Fly Ash Bed Treated with Lime Column

S.P. Singh* , S. Sangita**
*Professor, Department of Civil Engineering, National Institute of Technology, Rourkela, Odisha, India
** Student, Department of Civil Engineering, National Institute of Technology, Rourkela, Odisha, India.
Singh, S.P., and Sangita, S. (2014). Studies on the Leachate Characteristics of Compacted Fly Ash Bed Treated with Lime Column. i-manager’s Journal on Structural Engineering, 3(2), 21-28. https://doi.org/10.26634/jste.3.2.3018

Abstract

This paper delineates the effect of lime column on the leachate characteristics of compacted fly ash bed. In the present experimental investigation, large scale laboratory model of compacted fly ash bed was prepared by adopting maximum dry density and optimum moisture content condition and a lime column was installed at the center in order to facilitate in-situ stabilization of fly ash. The samples were collected from different radial distances as well as depths after 7, 30, 90 and 180 days of curing periods and subjected to different tests such as pH, leachate analysis and hydraulic conductivity. From the test results, it was observed that lime column treatment is an effective means of reducing the permeability and concentration of metals in the leachate emanating from compacted fly ash bed.

Case Study

Case Studies on Failure of Retaining Walls

Prasad* , Jagadeesh**, Yadunandan***
* Professor, Deportment of Civil Engineering, Sri Jayachamarajendra College of Engineering, Mysore, India.
** Professor, Department of Construction Technology and Management, Jayachamarajendra College of Engineering, Mysore, India.
Prasad, Jagadeesh and Yadunandan (2014). Case Studies on Failure of Retaining Walls. i-manager’s Journal on Structural Engineering, 3(2), 29-34. https://doi.org/10.26634/jste.3.2.3019

Abstract

Retaining walls are important geotechnical structures used to retain earth at two different elevations on either side of the wall. With the explosion of population in urban areas and lack of available space, retaining walls will be an automatic choice especially in hilly terrain. There have been reports of retaining wall failure either under extraordinary loading conditions or due to poor design and construction. This paper attempts to highlight the effects of poor design and construction quality on the performance of existing retaining walls. Two case studies are discussed for the purpose. The first one is the failure of retaining wall at JSS residential school in Ooty. Possible slope failure due to lack of drainage and loss of vegetation in addition to possible wrong assessment of earth pressure on retaining wall resulted in its failure. The second one is the failure of retaining wall at Police Station in Chamarajanagara due to poor construction and lack of drainage to backfill soil. The purpose of this paper is to introduce the actual failure studies of geotechnical structures with reasons for such failure.