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


Volume 5 Issue 1 March - May 2016

Research Paper

Stress-Strain Behavior of M100 Grade High StrengthHybrid Fibre Self Compacting Concrete using Quartz Materials

B. Narendra Kumar* , Kolli Ramujee**
*-** Professor, Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, India.
Kumar, B.N., and Ramujee, Kolli (2016). Stress-Strain Behavior of M100 Grade High Strength Hybrid Fibre Self Compacting Concrete using Quartz Materials. i-manager’s Journal on Structural Engineering, 5(1), 1-10. https://doi.org/10.26634/jste.5.1.6051

Abstract

In the present study, High Strength Hybrid Fibre Self-Compacting Concrete (HSHFSCC) is developed from High Strength Self-Compacting Concrete (HSSCC) using hybrid fibres by varying the proportion of steel and glass fibres with total fibre content to 1.5% of power content based on its rheological and hardened properties of concrete. This research mainly aims at utilizing the best attributes of earlier models and proposes a new stress-strain model that can well represent the stress-strain behaviour of HSSCC and HSHFSCC. Analytical stress-strain models are proposed to predict the stress-strain behaviour of HSSCC and HFHSSCC based on the results of experimental investigations. The proposed empirical equations can be used as stress block in analysing the flexural behaviour of HSSCC and HFHSSCC.

Research Paper

A Study on Flexural Behavior of Two-Way Bending on GPC Slab under Simply Supported Edge Conditions

K. Nehemiya* , Rambabu**, T. Chandra Sekhar Rao***, N.V. Ramana Rao****
* Assistant Professor, Department of Civil Engineering, D.M.S S.V.H College of Engineering, Andhra Pradesh, India.
** Associate Professor, Department of Civil Engineering, D.M.S S.V.H College of Engineering, Andhra Pradesh, India.
*** Professor, Department of Civil Engineering, Bapatla Engineering College, Andhra Pradesh, India.
**** Professor, Department of Civil Engineering, JNTUH, Telangana, India.
Nehemiya, K., Rambabu, Rao, T.C.S., and Rao, N.V.R. (2016). A Study on Flexural Behavior of Two-Way Bending on GPC Slab under Simply Supported Edge Conditions. i-manager’s Journal on Structural Engineering, 5(1), 11-19. https://doi.org/10.26634/jste.5.1.6052

Abstract

This paper presents the investigation of flexural behaviour of a two way bending on Geo Polymer Concrete slab with simply supported edge conditions. The size of the slab panel adopted is 1m x 1m x 0.05 m. By using yield line theory, the moment of resistance and yield line patterns are predicted and the corresponding theoretical deflections is also computed. Reinforcement details of these slabs are calculated using the ultimate load method as per IS: 456-1978 code provisions. The materials used for the preparation of GPC are regular conventional aggregate materials, flyash, NaOH of 8 Molarity solution using a mix proportion 1:1.74:3.097 and the ratio of alkaline liquid to flyash is 0.45. The mechanical properties like compressive strength, split tensile strength and flexural strengths of GPC are determined. The slab elements are tested with UDL under bending of the loading frame of capacity 1000 kN. The compressive strength of GPC is 28.1 MPa after 28 days of ambient curing. A 6 mm diameter bar with 120 mm spacing of Fe250 grade steel is used as the main reinforcement for casting of slabs. After testing, the test results of experimental bending moments, deflections and crack patterns on tension side are compared to the theoretical values which are computed from Yield line theory.

Research Paper

Retrofitting of RCC Beam using Jacketing Method

Anurag Chaturvedi* , R.D. Patel**
* PG Scholar, Department of Civil Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, India.
** Associate Professor, Department of Civil Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, India.
Chaturvedi, A., and Patel, R.D. (2016). Retrofitting of RCC Beam using Jacketing Method. i-manager’s Journal on Structural Engineering, 5(1), 20-25. https://doi.org/10.26634/jste.5.1.6053

Abstract

This study deals with the experimental investigation for enhancing the flexural capacity of RC beams using epoxy resins (adhesive). Retrofitting method used is concrete jacketing. Three concrete beam specimens with dimensions of 150 mm height, 1800 mm length and 100 mm width were casted in the laboratory. As per the design of the beam, 10j and 8j bars are being provided in tension and compression zones respectively. All beams were geometrically sound (kept constant). Beams were weak in flexure and were strengthened utilizing concrete jacketing method. All the beams were simply supported at both ends with 1675 mm effective span, 125 mm bearings, loaded under more real loading conditions, i.e. center loading and tested till failure by the effect of gradually increasing super imposed load. The deflection of beams is measured. Load deflection curve of control RC1, RC2 and RC3 beam when compared to load deflection curve of retrofitted RC1, RC2 and RC3 beam shows that the retrofitted RC beam shows satisfactory results as compared to the control beam i.e. control beam fails on a maximum load of 30.66 KN while retrofitted RC beam fails on a maximum load of 23 KN. Load deflection characteristics of RC beam and Retrofitted RC beam show retrofitted beams attain about 75% strength of control beam.

Research Paper

Effect of Mineral Admixtures (Micro Silica And GGBS) onCompressive Strength of Ternary Blended Concrete

S. Vijaya Bhaskar Reddy* , P.Srinivasa Rao**
* Professor and Head, Department of Civil Engineering, CMR Technical Campus, Hyderabad, T.S. India.
** Professor and Principal, Department of Civil Engineering, J.N.T.U. College of Engineering, Hyderabad, T.S. India.
Reddy, S.V.B., and Rao, P.S. (2016). Effect of Mineral Admixtures (Micro Silica And GGBS) on Compressive Strength of Ternary Blended Concrete. i-manager’s Journal on Structural Engineering, 5(1), 26-35. https://doi.org/10.26634/jste.5.1.6054

Abstract

Among the many known Supplementary Cementitious Materials (SCMs), the useful ones for concrete are flyash blast furnace slag, silica fume, metakaolin and rice husk ash. Their use with cement has led to the development of binary and ternary blended cement concrete depending on whether cement replacement is carried out with a single SCM or a combination of two SCMs. Cement production lead to consuming significant amounts of natural resources, that has brought pressure to reduce cement consumption by the use of supplementary cementing materials. The aim of the present study is to evaluate the compressive strength performance of ternary concrete containing Industrial by-products like, Micro Silica and GGBFS as a partial replacement of the OPC. Compressive Strength of Ternary Blended Concrete at the age of 7, 28, 60, 90 days for various combinations of Micro Silica and GGBS mixes were investigated. Micro Silica of 0%, 5%, and 10% and 15% along with GGBFS was replaced by 20%, 30% 40% and 50% respectively. All the mixes were studied at water cement ratio of 0.35.

Review Paper

Advanced Retrofitting Techniques for ReinforcedConcrete Structures: a State-of-the-Art Review

Soumya Gorai* , P.R. Maiti**
* Research Scholar, Department of Civil Engineering, Indian Institute of Technology, Kharagpur, India.
** Associate Professor, Department of Civil Engineering, Indian Institute of Technology (BHU), Varanasi, India.
Gorai, S., and Maiti, P.R.(2016). Advanced Retrofitting Techniques for Reinforced Concrete Structures: a State-of-the-Art Review. i-manager’s Journal on Structural Engineering, 5(1), 36-48. https://doi.org/10.26634/jste.5.1.6055

Abstract

Any technology or material has its limitations and to meet the new requirements, new technologies have been invented and used over the ages. A large number of reinforced concrete structures located at seismic prone areas are not capable of withstanding earthquakes according to the current coal provisions. Furthermore the seismic behaviour of the existing buildings are affected due to design deficiency, construction deficiency, additional loads, additional performance demand, etc. Recent earthquakes have clearly demonstrated an urgent need to upgrade and strengthen these seismically deficient structures. The retrofitting is one of the best options to make an existing inadequate building safe against future probable earthquake or other environmental forces. Retrofitting reduces the vulnerability of damage of an existing structure during a near future seismic activity. It aims to strengthen a structure to satisfy the requirements of the current codes for seismic design. A significant amount of research work has been carried out in recent years to develop various strengthening and rehabilitation techniques to improve the seismic performance of structures. This paper aims to present an overview on different innovative and cost effective techniques of retrofitting for strengthening the damaged structures.