ISSN 0970-0137
Current Issue
December 2016 – January 2017 Vol. 43 no. 5


Directions in self consolidating concrete research – mapping using VOS viewer

M. Mymoon, S. Mahendran, R. Lakshmi Poorna and S. Suryakala



In an earlier study the bibliometric analysis of the growth and development of research in the field of self consolidating concrete or self compacting concrete (SCC), based on the scientific literature available from Web of Science during the period from 1997 to 2013 was presented. Self-consolidating concrete (SCC) or self-compacting concrete, as it is sometimes known, arrived as a revolution in the field of concrete technology. During the study period a total of 1579 papers were published in this research area. In Part 2, publications in the period 1997 to 2013 related to SCC were identified in the WoS database and visualization maps were generated using correlation matrices of the most frequently occurring descriptors. Data has been extracted using specialized bibliometric software such as HistciteTM and Bibexcel. VOSviewer software has been used to generate maps. An in-depth analysis has been done to understand the growth metrics of this research area


Effect of Ggbs and Fly ash aggregates on properties of geopolymer concrete

G.Venkata Suresh, P. Pavan Kumar Reddy and J. Karthikeyan



The paper deals with the influence of Ground Granulated Blast Furnace Slag (GGBS) and concentration of sodium hydroxide (NaOH) solution on the physical and mechanical properties of the Geopolymer Concrete (GPC) with fly ash aggregates. The fly ash aggregates were prepared using class C fly ash by adopting pelletization technique without adding any binders. Two types of curing techniques were adopted for aggregates i.e water curing and chemical curing (using NaOH solution). These two types of cured aggregates are called as Water Cured Aggregate (WCA) and Chemical Cured Aggregates (CCA). The tests like compressive strength, water absorption and specific gravity were carried out on the cured aggregates. The strength of CCA was 64.93%, 49.03% more when compared to WCA for 7 and 28 days curing and the water absorption of CCA were 4.0% for 7 days and 4.2% for 28 days. The GPC mixes were cast with CCA and WCA at 0% and 30% replacement of fly ash(class F) by GGBS with different concentrations of NaOH solutions (8M, 10M, 12M). It was observed that the GPC mixes with CCA and WCA at 30% GGBS with 12M NaOH concentration attained maximum compressive strengths of 64.14 MPa and 42.13 MPa cured at room temperature. Among the GPC specimens it is observed that the GPC mixes with CCA had better workability and bonding at the interfacial transition zone.


Experimental investigation on longitudinal shear behaviour of steel concrete composite deck slab

A. Siva, R. Senthil and Saddam M. Ahmed



Composite deck slab is widely used flooring in the construction industry due to its various innate advantages. To improve the shear bond characteristics, the embossments are provided in web or flange of the profiled sheeting. Experimental investigations are needed due to the complex behaviour of the composite deck slabs. In the present study, total six numbers of composite slab specimens with varying shear spans are constructed. The loading is given in two schemes namely shorter and longer shear spans for the specimens cast with concrete M25 grade. During the experimental investigations the composite slab specimens showed different behavioural changes associated with different m-k value. This provides an insight to understand the complex behaviour of composite deck slab. This paper presents points of interest of the exploratory examinations directed on the composite deck section. The assessments of m–k values of embossed profiled sheeting are also proposed.


Finite element analysis of RC beams strengthened with textile reinforced concrete

Smitha Gopinath, Nagesh R. Iyer and Ravindra Gettu



The paper reports the development of a finite element modeling methodology for the response of reinforced concrete beams strengthened with textile reinforced concrete (TRC). Appropriate material models were integrated to simulate the behaviour of the strengthened beam. Asmeared cracking model was used to represent the behavior of TRC. For this, the input data for the tension stiffening model was developed based on tensile characterization test results. The interaction between the various material ingredients was also incorporated in the modeling. Nonlinear finite element analysis was carried out to simulate the response of strengthened beam under flexure, and the results obtained from the analysis are found to be in good agreement with experimental results.


Free vibration and stability analysis of isotropic rectangular plates on elastic foundation based on Levy’s approach using element based differential transformation (EDTM) and (FEM) finite element

S. Rajasekaran



Element based Differential Transform method (EDTM) and Finite Element methods (FEM) are applied to analyze the free vibration and stability of isotropic Levy’s rectangular plates resting on Winkler foundation. Two opposite edges of the plate are assumed to be simply supported and the other two may be of any type of boundary conditions. To develop an analytical approach for buckling and free vibration of stepped and multi-span plates, Levy’ solution that satisfies equilibrium and compatibility conditions at the interfaces is used. In this paper, an exact buckling in-plane loads and natural frequencies are determined for many cases and compared with the published results and using other method such as FEM developed by the author


Modified split disk test for characterization of FRP composites

G. Ramesh, Ravindra Gettu and B.H. Bharatkumar



Fiber reinforced polymers (FRP) are used to wrap reinforced concrete (RC) elements to increase their load carrying capacity and, in such applications, the mode of failure of the retrofitted element is usually governed by the rupture of the FRP when it reaches its ultimate strain. This paper reports the split disk test (as in ASTM D2290) modified to characterize the stress-strain behaviour of FRP using a simple specimen preparation methodology. The results obtained from the modified split-disk tests on glass and carbon-FRP composites are compared with those from uniaxial FRP coupon tests. It is found that the elastic modulus obtained from both the methods are similar but the ultimate strains and the tensile strengths from the split-disk tests are lower. To compare the split disk ultimate strains, FRP confined concrete cylinders of 150 mm in diameter and 300 mm in height were prepared and tested under uniaxial compression, after wrapping with carbon and glass FRP sheets. The average ultimate strains of FRP with split-disk test are lower than the ultimate hoop strains observed in FRP-confined cylindrical specimens. Consequently, strain efficiency factors have been determined for application in design.


Experimental study of steel fiber prestressed concrete beam for shear, bending and torsions

Sudhir P. Patil and Keshav K. Sangler



The low tensile strength and limited ductility, the unavoidable deficiency, of concrete can be overcome by the addition of fibres. In this research, an attempt was made to study the effects of flyash and steel fibers on shear, flexural and torsional strength of high strength prestressed concrete and steel fibre prestressed concrete beam specimens. To study the shear, flexural, pure torsion and combined bending-torsion strength behavior, the total 36 beam specimens of size 140mm x140mm x1500mm were castincluding 12 plain prestressed concrete beam specimens with 20% fly ash replacing to cement by its weight and 24 beam specimens by adding 20% fly ash replacing cement by its weight with1.5% steel fiber by weight of concrete. A primary finding emerging from the experimental program was that the placement of fibers, increased load carrying capacity of high strength fibre reinforced prestressed concrete beam. Steel fibres enhanced ductility, shear, flexural and torsional shear strength. All specimens were tested for single, double point loading, pure torsion, combined bending-torsion after 28 days. Deflections were measured. Experimental, analytical results were compared.


Response evaluation of direct displacement based and force based design method for RC frames

Rutvik K. Sheth and Devesh P. Soni



Seismic design of buildings has traditionally been force-based. It is widely understood now that it is not the force but displacement, which can be directly related to damage. The alternative design approaches are gradually becoming popular in recent times. Design Methodology for Direct Displacement Based Design Method (DDBD) has been presented here in the context of IS code as an alternative to conventional Forced Based Design (FBD). The paper attempts to design moment resisting RC frame using Displacement Based Design method. Regular RC frames of 4, 6, 8, 10, 12 and 15 stories were designed using FBD and DDBD procedure for the parametric study. Evaluation of Response Modification Factor is done using static nonlinear pushover analysis. Also Nonlinear Time History Analysis (NLTHA) was performed for a set of seven ground motions from past Indian Earthquake. Pushover Analysis and NLTHA were carried out using DRAIN-2DX program for performance evaluation of these RC frames. It is observed that design base shear of the frames designed by DDBD is less compared to those designed by FBD. Further, the DDBD designed frames yield higher Response Modification Factor as compared to FBD, implying higher capacity of structure to dissipate energy through inelastic behavior


Numerical studies on reinforced concrete beams subjected to fire load

Aneesha Balaji, Jiji Vijay Pallath, T.M. Madhavan Pillai and Praveen Nagarajan



The current provisions for fire rating of reinforced concrete beam as per Indian Standard code IS 456:2000 is based on tabulated fire rating based on minimum width and cover to reinforcement. The influence of various parameters on the behaviour of reinforced concrete structures subjected to fire is not accounted in the design procedure. This paper presents a three-dimensional nonlinear finite element analysis for evaluating the fire response of reinforced concrete beams using ANSYS. The finite element model accounts for temperature depended thermal properties and a transient time dependent thermal analysis is performed to obtain the temperature distribution in the beam cross-section. The model is validated by comparison with literature on beam tested under fire conditions. The comparison shows that the proposed model is capable of predicting the fire response of reinforced concrete beam with good accuracy. The fire rating of the beam is determined using thermal failure criteria based on critical reinforcement temperature. The tabulated rating provided in IS code is checked by comparing it with the results obtained from numerical analysis. It may be observed that the numerical analysis results are having a lower value than the specified fire rating provided in IS456:2000. Numerical studies are carried out on beam subjected to fire by varying the parameters like type of aggregates, strength of concrete and cover to reinforcement. Through the results of the parametric studies done on beam, it is shown that the parameters have significant influence on fire resistance as per thermal failure criteria. The variation in type of aggregates, increase in strength of concrete and cover to reinforcement increases the fire rating of the beam. It may also note that percentage increase in fire rating decreases with increase in concrete cover. Thus it is improper to excessively increase the cover to reinforcement to improve the fire resistance of beam.



Studies on the development of data compression algorithm for structural health monitoring applications

B. Saranya, B. Arun Sundaram, I. Baskar, A.K. Farvaze Ahmed and S. Parivallal




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