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


Volume 9 Issue 4 December - February 2021

Research Paper

A Step By Step Procedure to Perform Hygroscopic Analysis of Laminated Composite Plate using Six Node Linear Strain Triangular Elements using Fortran Coding

K. N. V. Chandrasekhar* , Ch. Madhusudhana Chary **
*-** Department of Civil Engineering, CVR College of Engineering, Hyderabad, Telangana, India.
Chandrasekhar, K. N. V., and Chary, C. M. (2021). A Step By Step Procedure to Perform Hygroscopic Analysis of Laminated Composite Plate using Six Node Linear Strain Triangular Elements using Fortran Coding. i-manager's Journal on Structural Engineering, 9(4), 1-14. https://doi.org/10.26634/jste.9.4.17558

Abstract

The applications of composite materials in civil engineering cannot be under-emphasized due to their high strength to weight ratio. The laminates are exposed to moisture variations and are often the predominant reason for failure of composite structures. Moisture distributed throughout the volume of the structure may induce residual stresses and extensional strains. Cutouts are often made to lighten the structure for ventilation and accessibility for inspection to other parts of the structure. When the laminates with cutouts are subjected to changes in moisture content the deformations and stress concentrations are observed which may result in the laminate to detach from the structure. The present study is focused on the bending characteristics of plates and shells laminates having different lamina and different boundary conditions subjected to change in moisture content. The formulation is done using six node second order linear strain triangular elements. A standard SSSS plate problem is analysed and the results are validated.

Research Paper

Flexural-Torsional Stability Design of Hotrolled Nonslender Unequal Leg Angles Subjected to Axial Compression

J. V. Sai Babu * , K. S. Vivek **
*-** Department of Civil Engineering, Vasireddy Venkatadri Institute of Technology, Guntur, Andhra Pradesh, India.
Babu, J. V. S., and Vivek, K. S. (2021). Flexural-Torsional Stability Design of Hotrolled Nonslender Unequal Leg Angles Subjected to Axial Compression. i-manager's Journal on Structural Engineering, 9(4), 15-30. https://doi.org/10.26634/jste.9.4.17678

Abstract

Unequal leg angles may be provided in transmission line towers or trusses and hence are subjected to axial compression either in direct or reversal stress states. In axial compression, steel Unequal leg angles are prone to flexural-torsional instability. European and American codes of practices include design provisions to check for flexural-torsional buckling of angle sections under axial compression but the Indian code of practice recommends flexural stability design only. In this simple study, initially a linear buckling analysis of non-slender unequal leg single angles specified is carried out to find the primary mode of buckling. It is observed that flexural-torsional buckling is the primary mode for all the sections considered in the study. Later, the design compressive strengths corresponding to flexural buckling (FB) are presented. Based on the available literature, a simple modification is suggested to determine the design compressive strengths corresponding to the governing flexural-torsional buckling (FTB) mode. It is observed that the design strength due to flexural-torsional buckling, Pd, FTB is always lesser than the design strength due to flexural buckling. The difference is more pronounced in case of sections of intermediate non-dimensional slenderness ratio and greater d/b ratio. Design curves for the considered cases are also provided. A simple equation is proposed in terms of plate slenderness ratio (d/t), (b+d)/t, leg width ratio (d/b) and non-dimensional flexural slenderness ratio (FB). From the study, it is concluded that there is a need for incorporation of a clause exclusively on flexural-torsional stability design of non-slender unequal leg angles subjected to axial compression in future.

Research Paper

A Study on Hinged Column in RC Frame Made with SCC

Hemanth Kumar P. R.* , Vageesh H. P.**, H. Eramma ***, Reena K.****
*-** Department of Civil Engineering, Rashtreeya Vidyalaya College of Engineering, Bengaluru, India.
***-**** Department of Studies in Civil Engineering, UBDT College of Engineering, Davanagere, India.
Kumar, P. R. H., Vageesh, H. P., Eramma, H., and Reena, K. (2021). A Study on Hinged Column in RC Frame Made with SCC. i-manager's Journal on Structural Engineering, 9(4), 31-39. https://doi.org/10.26634/jste.9.4.17733

Abstract

The study investigated on strengthening of columns using composite wrapping technique with a combination of jute fiber and glass fiber. The use of glass fiber adds to the lightness and non-corrosive properties and the natural fiber jute adds on to its biodegradable nature. The study concentrated on the confinement of self-compacting concrete columns with composite wrapping technique. A study on both m-sand and slag sand were carried out to study the structural behaviour of columns. Analytical studies were carried out using ANSYS workbench software and modeling has been done using CATIA software. Four columns were modeled out of which two columns with m-sand and another two columns with slag sand both with wrap and unwrapped conditions were carried out. Analytical results were then compared with the experimental results obtained from previous studies. The results indicated that SCC columns with m-sand showed better load carrying characteristics than columns with slag sand. The wrapped columns exhibited less strain when compared to that of unwrapped columns both in SCC control mix and SCC replaced mix.

Research Paper

Strengthening of Self Compacting Concrete Columns Partially Wrapped with Layers of Jute Fiber

Shashi Kumar * , Vageesh H. P. **
* Department of Structural Engineering, R. V. College of Engineering, Bengaluru, India.
** Department of Civil Engineering at R. V. College of Engineering, Bengaluru, India.
Kumar, S., and Vageesh, H. P. (2021). Strengthening of Self Compacting Concrete Columns Partially Wrapped with Layers of Jute Fiber. i-manager's Journal on Structural Engineering, 9(4), 40-49. https://doi.org/10.26634/jste.9.4.17821

Abstract

Self compacting concrete is also referred as super workable concrete as well as highly flowable concrete which are widely used as innovative material in the fast growing construction industry because of its hardened and fresh state properties. In recent days availability of river sand is less and also focus is more on sustainability development and hence there arose a situation for developing an alternative material by using the industrial waste. In this research work, complete replacement of natural sand by processed slag sand and the properties of SCC determined by using Nan-su method of mix design with incorporating EFNARC guidelines. At present days, the favorite material for the column strengthening is fiber reinforced polymer (FRP). The construction industry requires the sustainable development along with increase in strength. Therefore, column is wrapped by using natural jute fiber by varying number of wrapping layers and the structural behaviour of columns are assessed. A three-dimensional finite element (FE) model has been developed to simulate the behaviour of rectangular SCC columns wrapped with jute fiber. The developed FE model is validated by comparing the loaddisplacement responses which verifies the model to use in future. The FEA results are obtained in terms of axial load vs. axial displacement, axial load-axial strain. The numerical analysis developed by ANSYS displayed a very close simulation and deflection is compared with test results at the same load.

Research Paper

Experimental Investigation on Bending Properties of Composite Short Fibres as a Concrete Disperse Reinforcement

Y. Rama Krishna*
Riga Technical University, Riga, Latvia.
Krishna, Y. R. (2021). Experimental Investigation on Bending Properties of Composite Short Fibres as a Concrete Disperse Reinforcement. i-manager's Journal on Structural Engineering, 9(4), 50-58. https://doi.org/10.26634/jste.9.4.17859

Abstract

This research's objective is to investigate the suitability of minibar fiber grid as reinforcement in concrete composite and its ductile and fracture behaviour. The focus of this research is to investigate the effect in flexural behaviour of replacement of the normal steel reinforcement with high tensile strength of minibar fiber. Minibars mixed in concrete lead to a network of randomly placed fibres throughout the concrete. As the load is applied to the concrete, the minibars act as crack control and distribute the load throughout the concrete increasing the average residual strength of the concrete. In this experiment we will replace some portion of cement with minibars and find the load bearing capacity of the minibar reinforced concrete blocks.