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


Volume 2 Issue 1 March - May 2013

Article

Mechanics of reinforced flyash slopes: a qualitative review

Harvinder Singh*
*Associate Professor, Department of Civil Engineering, Guru Nanak Dev Engineering College, Ludhiana, India.
Singh, H. (2013). Mechanics of reinforced flyash slopes: a qualitative review. i-manager’s Journal on Structural Engineering, 2(1), 1-5. https://doi.org/10.26634/jste.2.1.2263

Abstract

Flyash-a waste by product-is proving a versatile material for the geotechnical use despite its low shearing strength. Past research has demonstrated its potential use in construction of embankments/slopes, filling of low land area etc. It is, now, a well documented fact that use of reinforcing element(s) in flyash slopes and other applications proves beneficial in enhancing its load carrying capacity. In this article, it has been tried to present the mechanics behind this phenomenon and a set of forces working, silently, inside the reinforced flyash/soil mass/slopes that become responsible for strength enhancement of the system. It will help readers to visualise reinforced-flyash system in term of forces and develop simplified analytical expressions governing the behaviour of reinforced slopes.

Research Paper

Reliable Seismic Structural Analysis using Interval Ground Motion

Mehdi Modares* , Adam Venezia**
* Assistant Professor, Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago.
** Former Graduate Student, Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago.
Modares, M., and Venezia, A. (2013). Reliable Seismic Structural Analysis using Interval Ground Motion. i-manager’s Journal on Structural Engineering, 2(1), 6-13. https://doi.org/10.26634/jste.2.1.2264

Abstract

Abstract: Seismic analysis is an essential procedure to design a structure subjected to ground motion. However, throughout conventional seismic analysis, the structure is subjected to a limited number of recorded earthquake excitations. Moreover, the presence of variations and uncertainties in the recorded excitations within a single, and among different earthquakes is not considered in current seismic analysis procedures. One methods of quantifying the impreciseness and uncertainty is the interval or unknown-but-bounded representation. In this work, a new computationally feasible method for seismic structural analysis with interval uncertainty in the response spectrum is developed, which is capable of obtaining the bounds on the structure’s dynamic response. Using this method, first, the response spectra from various recorded earthquakes are combined in order to construct an interval function referred to as an interval response spectrum. Then, the response spectrum analysis is performed using the developed interval response spectrum, and the bounds of the dynamic response of the structure are obtained. This computationally feasible method shows that calculating the bounds on the dynamic response does not require an iterative procedure such as Monte-Carlo simulation. Numerical example problems, which illustrate the developed algorithm, are presented, along with a comparison of solutions obtained by Monte-Carlo simulation.

Research Paper

Experimental and Analytical Comparison of RC Beam Strengthened with GFRP Strip

H.S. Jadhav* , Sachin Matade**
* Associate Professor & Head, Department of Civil Engineering, Rajarambapu Institute of Technology, Maharashtra, India.
** Senior Engineer, K. S. B.Tech., Pune, Maharashtra, India.
Jadhav, H.S., and Matade, S. (2013). Experimental and Analytical Comparison of RC Beam Strengthened with GFRP Strip. i-manager’s Journal on Structural Engineering, 2(1), 14-19. https://doi.org/10.26634/jste.2.1.2265

Abstract

This study presents experimental performance and modes of failure of reinforced concrete (RC) beam strengthened with externally (bottom side) bonded glass fiber reinforced polymer (GFRP) strip. Experimental results compared with presenting finite element modeling of R C beam using ANSYS software. The finite elements model uses a discrete approach to reinforced concrete and three dimensional layered elements to model the fiber reinforced polymer (FRP) composites. The comparison is made for load deflection curve at midspan and mode of failure. The result obtained from finite element analysis was calculated at same location as the experimental test of the beams and accuracy of was compared. The load–deflection curve from finite element analysis is good agreement with the experimental results

Research Paper

Study of Engineering Properties of Recycled Concrete Aggregate Concrete

P K Gupta* , Ritesh Bhatia**
* Deportment of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee, India.
** Structural Engineer, Aurora, Illinois.
Gupta, P.K., and Bhatia, R. (2013). Study of Engineering Properties of Recycled Concrete Aggregate Concrete. i-manager’s Journal on Structural Engineering, 2(1), 20-26. https://doi.org/10.26634/jste.2.1.2266

Abstract

A series of experiments were conducted on two grades of concrete namely M25 and M40 with three nominal replacement ratios of 0%, 25% and 50% using recycled concrete aggregates (RCA). The RCA concrete was obtained using a new mix design in which the residual mortar content of the recycled aggregates was considered as a part of sand in the new concrete. For the six mixes, tests were conducted to determine the engineering properties of the RCA concrete and the results were compared to that of the natural aggregate concrete. A total of 72 specimens were cast and tested. The tests conducted included Slump, Non-destructive testing, Compressive strength, Splitting tensile strength and Elastic modulus. Based on the investigations it was found out that the proposed method gave comparable results to that of the concrete made of natural aggregates. Compressive strength, UPV, Rebound Hammer and Elastic modulus values were established to be more than that of the natural aggregate concrete while Slump and Splitting tensile strength were lesser

Research Paper

Behaviour of Waste Plastic Fibre Reinforced Concrete Produced by Conventional Aggregates and Recycled Aggregates under Alkaline Environment - an Experimental Investigation

Prahallada M.C.* , Prakash K.B.**
* Professor, Department of Civil Engineering, Christ University Faculty of Engineering, Bangalore, Karnataka, India.
** Principal, Government College of Engineering, Haveri, Karnataka, India.
Prahallada, M.C., and Prakash, K.B. (2013). Behaviour of Waste Plastic Fibre Reinforced Concrete Produced by Conventional Aggregates and Recycled Aggregates under Alkaline Environment - an Experimental Investigation. i-manager’s Journal on Structural Engineering, 2(1), 27-31. https://doi.org/10.26634/jste.2.1.2267

Abstract

The addition of fibres into concrete has been found to improve several of its properties like tensile strength, cracking resistance, impact, wear and tear, ductility, fatigue resistance etc. Many types of fibres like steel fibres, carbon fibres, GI fibres, glass fibres, asbestos fibres etc. can be used in fibre reinforced concrete. Waste plastics can also be used as fibres. The disposal of waste plastic is resulting in environmental pollution. Plastic is a non-biodegradable material, and it neither decays nor degenerates in water or in soil. On the other hand it pollutes the water and soil. Plastic if burnt releases many toxic gases, which are very dangerous to health. Such plastics can be used in concrete in the form of fibres to impart some additional desirable qualities to the concrete. This paper presents the results of waste plastic fibre reinforced concrete (WPFRC) produced from recycled aggregates subjected to alkali attack. The different percentages waste plastic fibre used in the experimentation are 0%, 0.5% , 1%, 1.5%, 2%, 2.5% and 3% with an aspect ratio of 50.The results are compared with the waste plastic fibre reinforced concrete (WPFRC) produced from granite aggregates