Performance Evaluation of High Volume Fly Ash Concrete

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:Performance Evaluation of High Volume Fly Ash Concrete
Author Name:Sri Harsha G. and Binimol Babu 
Synopsis:
The utilization of fly-ash in concrete as partial replacement of cement is gaining immense importance today, mainly on account of the improvement in the long term durability of concrete combined with ecological benefits. Technological improvements in thermal power plant operations and fly-ash collection systems have resulted in improving the consistency of fly-ash. The present study was carried out to determine the effect of high volume fly ash on concrete mechanical properties. Different types of concrete mixes were prepared that consist of 40%, 50%, 60% and 70% of class F fly ash by weight of cement which where compared with plain concrete. The mechanical properties of high volume fly ash concrete are evaluated for 7, 28, and 56 days.

Comparative Study on High Strength Fiber Reinforced Self Curing SCC And Conventional Cured SCC

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:Comparative Study on High Strength Fiber Reinforced Self Curing SCC And Conventional Cured SCC
Author Name:V. Lohitha, R. Krishneswar and B. Narendra Kumar
Synopsis:
Self-Compacting Concrete (SCC) is a high performance concrete that can flow through every corner in the congested reinforcement sections under its own weight without segregation and bleeding. The SCC is developed by increasing the paste volume and using chemical and mineral admixtures. The fresh and hardened characteristics of SCC are affected by the water available for hydration, humidity and temperature. Curing is adopted to ensure the availability of water for the hydration of cement and this can be done in two ways, i.e., Water adding techniques, and Water-retraining techniques. Self-curing concrete is developed by water retaining technique using various methods. Addition of curing compound to SCC results in self-curing self-compacting concrete (SCSCC). In the present study, the self-curing selfcompacting concrete is developed by using polyethylene glycol as the curing compound and by replacing river sand with quartz sand as fine aggregate. The self curing process is initiated by adding polyethylene glycol to the concrete specimens. To increase in tensile strength, the steel fibers of 1.5% of the cement content are added. The paper addresses the effect polyethylene glycol on fresh and the hardened properties of M60 grade SCSCC. The mechanical properties are presented for 7 and 28 days and are compared with the same grade of SCC with various methods of curing.

A Study of Papercrete towards Building Sustainable & Resilient Infrastructure

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:A Study of Papercrete towards Building Sustainable & Resilient Infrastructure
Author Name:Syed Kaiser Bukhari, Maqbool Yousuf and Ayaz Mohmood Dar
Synopsis:
The study is based on the tests carried out on Papercrete to know about its properties. The investigations show that the Papercrete can be used as a very good supplement of wood as it has strengths comparable to wood. Papercrete is an experimental material which replaces an amount of cement with paper in the normal concrete mix. The total weight, cost and CO emissions during its production as compared to the normal concrete are considerably reduced. It has 2 been seen that Papercrete is a lightweight material which is 10 times lighter than the normal concrete with excellent heat and acoustic insulation properties. Weight of 1 mix of Papercrete 60:20:20 was found to be as low as 2600 g in comparison to 26000 g of concrete cube. It has been seen that Papercrete is very workable and can be formed into different shapes such as blocks, panels and sheets with ease. The study has concluded that the dried Papercrete has a rough surface which increases its surface area and provides a very strong bond from one block to the next. There are significant challenges in constructing with Papercrete but also opportunities. Deep knowledge in material properties and long term liability advances in processing and building aspects combined with future material technology can bring Papercrete closer to standardization. This work is based on conducting different experimental tests on various ratios of Papercrete in order to determine its behavior as a building material. The possibilities of its uses in construction have also been determined from the study of these properties.

Effect of pH and Curing Time Behaviour on Strength Properties of Expansive Soils

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:Effect of pH and Curing Time Behaviour on Strength Properties of Expansive Soils
Author Name:B. Bhavana and Suresh Kommu 
Synopsis:
Avoiding of unsuitable site conditions is not practically possible due to rapid urbanization, so there is a need for soil stabilization. Now-a-days environment is getting polluted by disposal of waste into water bodies without adequate treatment due to which chemical behaviour of water may vary which causes changes in pH of water. This study deals with stabilization of expansive soils using ordinary Portland cement and Portland slag cement separately with different proportions (3%, 5%, 7.5% and 10%) under varying pH conditions (pH=5, pH=7, and pH=9) using UCS and CBR tests. The main objective of this study was to find out the effect of acidic and alkaline nature of curing water on strength characteristics of two different stabilized soils with respect to curing periods (7,14, and 28 days). The test results clearly have shown a significant improvement in strength characteristics of stabilized soils with respect to curing ages.

Effect of Tank Height on the Seismic Performance of Intze Type Water Retaining Structures

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:Effect of Tank Height on the Seismic Performance of Intze Type Water Retaining Structures
Author Name:G. Anuja and A. Mallika 
Synopsis:

Water is the lifeline of humankind. During the earthquakes their safety and functionality is of major concern. Elevated water tanks consist of huge water mass stored in a tank at the top and is supported by a slender staging system, which is of critical significance contributing towards the failure of the tank during earthquakes. Due to the dynamics of fluid structure interaction, the seismic behavior of elevated water tanks is a complex phenomenon to understand.

In the present study, the seismic performance of intze type of elevated water tanks with various heights of the cylindrical portion for same storage capacity are considered. Seismic analysis is performed considering the elevated water tank as a two degree of freedom system. Different water levels in the tank are studied and the responses such as time periods, sloshing wave heights, base shear and overturning moments are investigated, compared and presented.

Comparative Study of PSC Box Girder Bridge Design Using IRC 112-2011 and IRC 18-2000

Vol. 5  Issue 2
Year:2016
Issue:Jun-Aug
Title:Comparative Study of PSC Box Girder Bridge Design Using IRC 112-2011 and IRC 18-2000
Author Name:Shreedhar R. and Shreyansh Patil
Synopsis:
A bridge is a structure built to span physical obstacles such as a waterbody, valley or road to have accessibility for people and vehicles. The design and construction of road bridges require an extensive and thorough knowledge of the science and technology involved with adequate experience of bridge engineering. In India, till now Pre-stressed concrete road bridges are designed and constructed according to Indian road congress guidelines as per IRC: 18-2000 code in which working stress method is adopted. Recently, Indian road congress has introduced another code IRC- 112: 2011 for the design of pre-stress bridges using limit state method. The study of bridge design using the limit state method is discussed to enlighten the recently introduced IRC-112: 2011. The present study has been performed to know the difference in design using IRC-112:2011 and IRC-18:2000 and attempt is made to study undefined parameters of IRC: 112-2011 such as span to depth (L/D) ratio. The present study is based on the design of PSC Box girder by working stress method using IRC- 18-2000 and limit state method using IRC- 112: 2011 code specifications. It is observed that for Box girder, L/D ratios are 33 and 26 respectively for limit state method and working stress method. In Box girder, bridge quantity of concrete can be saved in limit state method. The present study may help in limit state method of Box Girder Bride design for defining L/D ratio.

Advanced Retrofitting Techniques For Reinforced Concrete Structures: A State-Of-The-Art Review

Vol. 5  Issue 1
Year:2016
Issue:Mar-May 
Title:Advanced Retrofitting Techniques For Reinforced Concrete Structures: A State-Of-The-Art Review
Author Name:Soumya Gorai and P.R. Maiti 
Synopsis:
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.

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

Vol. 5  Issue 1
Year:2016
Issue:Mar-May 
Title:Effect of Mineral Admixtures (Micro Silica And GGBS) on Compressive Strength of Ternary Blended Concrete
Author Name:S. Vijaya Bhaskar Reddy and P. Srinivasa Rao 
Synopsis:
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.

Retrofitting Of RCC Beam Using Jacketing Method

Vol. 5  Issue 1
Year:2016
Issue:Mar-May 
Title:Retrofitting Of RCC Beam Using Jacketing Method
Author Name:Anurag Chaturvedi and R.D. Patel
Synopsis:
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.

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

Vol. 5  Issue 1
Year:2016
Issue:Mar-May 
Title:A Study on Flexural Behavior of Two-Way Bending on GPC Slab under Simply Supported Edge Conditions.
Author Name:K. Nehemiya, Rambabu, T. Chandra Sekhar Rao and N.V. Ramana Rao
Synopsis:
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.

Stress-Strain Behavior Of M100 Grade High Strength Hybrid Fibre Self Compacting Concrete Using Quartz Materials

Vol. 5  Issue 1
Year:2016
Issue:Mar-May 
Title:Stress-Strain Behavior Of M100 Grade High Strength Hybrid Fibre Self Compacting Concrete Using Quartz Materials
Author Name:B. Narendra Kumar and Kolli Ramujee 
Synopsis:
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.

A Survey On Post Seismic Damage Detection Approach Based On Piezoelectric Sensor

Vol. 4  Issue 4
Year:2016
Issue:Dec-Feb
Title:A Survey On Post Seismic Damage Detection Approach Based On Piezoelectric Sensor
Author Name:yogita kushwaha, R.D. PATEL
Synopsis:
The concept of Structural Health Monitoring of concrete structures under the seismic load condition has recently made the more attention in the research community of earthquake and structural engineering. Due to destruction of expensive structures, this research makes the attraction of researchers who are doing their research work in the field of damage detection based on the piezoelectric smart sensor. In this review work, the way of post seismic damage detection of structure using the smart aggregate a piezoelectric – based device which have embedded in the reinforced concrete structure and the way to monitor their damage after the effect of an earthquake. During this presented review, a study work has conducted to describe the methodology that has employed to detect the postseismic damage of concrete structure and the methodology of electro-mechanical impedance sensor that has been used for the health monitoring of the structure. The PZT which was embedded in the structure during the construction and the variation in the impedance of the sensor before and after the seismic attacks were extracted as the damage sensitive features are utilized to detect the area of damage. This technique is very important in non –destructive testing and have also tried to attract the attention of the reader. After analyzing the damage of the structure through the attack of an earthquake, the required repair and serviceability can be provided to structure to sustain the structural failure.

Study On The Behaviour Of Cold Formed Steel (CFS) Rack Columns

Vol. 4  Issue 4
Year:2016
Issue:Dec-Feb
Title:Study On The Behaviour Of Cold Formed Steel (CFS) Rack Columns
Author Name:M. Venkatesan
Synopsis:
This paper presents the detailed investigation of experimental and numerical studies on the buckling behaviour of coldformed steel rack columns under axial compression. Compression tests were conducted on four short cold formed rack columns with both end hinged condition. The experimental investigation was focused on the strength and behaviour of cold formed steel rack columns. For each specimen, a shell finite element Eigen buckling and non-linear buckling analysis were conducted using finite element software ANSYS. The finite element analysis included relevant geometric imperfections. It is demonstrated that, the finite element model closely predicts the experimental ultimate loads and the behaviour of the cold-formed rack columns. Comparisons of experimental and numerical results are done. Conclusions and scope for future work is presented based on the results.

Development Of Modified Jute Reinforced Concrete: An Overview

Vol. 4  Issue 4
Year:2016
Issue:Dec-Feb
Title:Development Of Modified Jute Reinforced Concrete: An Overview
Author Name:Syed Kaiser Bukhari, Ayaz Mohmood Dar and Maqbool Yousuf 
Synopsis:
The study is purely based on the tests carried out on jute mortar to observe the various changes and to know about its different properties. A result of 36 specimens (27cubes and 9 beams) with varying chemical modified ratios has been included in the experiment. A total 27 cube samples of 150mm x 150mm x 150mm size and 9 beams of 100mm x 100mm x 500mm were prepared to experiment. The result of specimens has been brought out in which compressive strength and flexural strength for each are evaluated for 7 and 28 days. The results were then compared with the conventional mortar specimens for each chemically modified jute at the respective ages. Results found shows that, the compressive strength increases by 48%, flexural strength increases by 55% and water absorption of chemically modified jute decreases by 50-60%. The investigation shows that, the chemically modified jute reinforced mortar is a very durable material and has higher strength than ordinary mortar and that too at very low cost when compared to new technological innovative materials.

Influence Of Earthquake Incidence Angle On Seismic Response Of Irregular RC Buildings

Vol. 4  Issue 4
Year:2016
Issue:Dec-Feb
Title:Influence Of Earthquake Incidence Angle On Seismic Response Of Irregular RC Buildings
Author Name:M. Sri Kanya, B.D.V. Chandra Mohan Rao
Synopsis:
Multistorey RC framed buildings, irregular in plan, often exhibit unfavorable seismic behaviour. In this study, the influence of the earthquake incidence angle on the seismic response of irregular RC framed buildings is examined. Three multistory RC buildings, One regular in plan and Two plan irregular buildings (C-shape, L-shape) are investigated for critical seismic incidence angle. For a good comparison, all the three buildings having the same floor plan area are modeled. The Linear Time History Analysis (LTHA) has been carried out for these three buildings by considering the twelve different earthquake directions and rotating the direction by 15o for each analysis, ranging from 0o to 180o. All these three buildings are modeled using ETABS Software and are subjected to Northridge earthquake accelerogram. It is observed from the study that, the seismic behavior of these three buildings is considerably influenced by the seismic incidence angle. The various parameters observed in this study are axial forces in columns, storey drift, storey shear and maximum storey displacement. The results reveal that the direction of earthquake incidence angle considerably influences the response of multistorey RC buildings

Buckling Analysis Of Plates With Holes Of Various Shapes

Vol. 4  Issue 4
Year:2016
Issue:Dec-Feb
Title:Buckling Analysis Of Plates With Holes Of Various Shapes
Author Name:T. Priyanka and B.D.V. Chandra Mohan Rao 
Synopsis:
In many structural components such as beams, columns or plates, failure develops not only from excessive stresses but also from buckling. The buckling behavior of plates subjected to in-plane loads is an important aspect in the preliminary design of any structural component. The knowledge of critical buckling loads, mode shapes is vital for reliable structural design. There is a necessity for providing the holes of various shapes in the plates for various purposes. In this paper, the buckling behavior of rectangular plates with holes of various shapes is investigated. The finite element modeling and buckling analysis of the plates has been carried out using ANSYS 14.5. Plates with three varieties of shapes of holes i.e., Triangular, Square and Rhombus have been studied. The plates are investigated for different positions of the holes (i.e. Center, Top) and for various a/b ratios ranging from 2 to 12 at an increment of 2 and for various b/t ratios ranging from 20 to 100 at an increment of 20. Finally, buckling loads of the plates with holes is compared wrt. shape of the hole, location of the hole and some useful conclusions are drawn.

Black Spot Identification And Audit Analysis For Heterogeneous Traffic Conditions In Hyderabad City – A Case Study

Vol. 4  Issue 3
Year:2015
Issue:Sep-Nov
Title:Black Spot Identification And Audit Analysis For Heterogeneous Traffic Conditions In Hyderabad City – A Case Study
Author Name:T. Sri Lakshmi Sowmya, A. Ramesh, B.N.M. Rao and M. Kumar
Synopsis:
Accident black-spot is the place where road traffic accidents have historically been concentrated. In these locations, accidents are not a random event but are common due to varying factors like road environment, traffic factors, and vehicle conditions. In metropolitan cities like Hyderabad in India, road traffic is heterogeneous and vehicular movement is highly influenced by surrounding vehicular traffic which is resulting in frequent accidents. In order to overcome the increasing number of road accidents, the present study helps to analyze the black-spot locations in the city where the major road accidents take place. Accident data for the past three years (2012-2014) in Hyderabad city was collected from police records in terms of time, date of occurrence, details of accidents such as fatal, injury, and property damage, and type of vehicles involved. This data is analyzed using accident frequency method and accident severity method for identification of black-spot locations. These identified black-spot locations are ranked in terms of severity of occurrence and analyzed to bring out the accident contributing factors for each location. Audit studies were conducted at black-spot locations for achieving improvement measures for reduction in cause of road accidents. A black-spot model was also developed using multiple linear regression analysis. Narrow roads, steep curves, improper illumination, improper traffic signals, and lack of speed sign boards were observed as a few major causes for road accidents at highly ranked black- spot locations. From the study, it was also observed that rash driving, and signal jump play a vital role for increasing accident rates in the city.

Push Over Analysis Of Plan Irregular Reinforced Concrete Buildings With And Without A Lead Rubber Base Isolator

Vol. 4  Issue 3
Year:2015
Issue:Sep-Nov
Title:Push Over Analysis Of Plan Irregular Reinforced Concrete Buildings With And Without A Lead Rubber Base Isolator
Author Name:M. Rakesh and B. Narendra Kumar
Synopsis:
Earthquakes are one of the natural disasters that occur due to the sudden violent movement of earth's surface which releases energy and has high destructive power which can cause significant loss of life. On the other hand, earthquakes cause severe damage to property, especially to man-made structures and it provides architects and engineers with a number of important design criteria foreign to the normal design process. As many researchers studied and reviewed that seismic isolation is the best solution for the earthquake resistant of the structures and its application is the most constructive technique to protect structures against destruction from the earthquake strike and has gained growing majority during past decades. This is because base isolated confines the effects of the earthquake strike, a workable base largely separating the structure from the ground motion, and the structural counter accelerations are usually less as compared to the ground acceleration. The aim of the present study is to know the effect of the Lead rubber bearing base isolator on the seismic behaviour of plan irregular RC buildings i.e., (L Shaped, T Shaped and U Shaped) with different building heights. Static Pushover Analysis has been carried out using SAP2000 version 17 to know the seismic behaviour of buildings with and without Base Isolator.

Investigation On Shear Lag Phenomenon In RCC Framed Tube Structures

Vol. 4  Issue 3
Year:2015
Issue:Sep-Nov
Title:Investigation On Shear Lag Phenomenon In RCC Framed Tube Structures
Author Name:Gyani Jail Singh, Sasankasekhar Mandal and Rajesh Kumar 
Synopsis:
In the present study, a 40 storey RCC framed tube building has been examined. The shear lag phenomenon is analysed in the framed tube structures, by various methods and are reported. The detailed investigation of the phenomenon in the tubular buildings is lacking. As the height of the buildings increases, the lateral load (wind load) becomes governing factor for design. Positive and negative shear lag occur in the bottom and top portion of the building, respectively. As the height increases, axial force in column is immediately adjacent to the corner column increase and with further increase in height, it shifts towards central column. Some column of compression flange may also develop tension right from the support depending upon height of the structure. Columns in upper storeys are critical columns for the designer as they may develop tension. The quantitative estimate will help in the design to fix preliminary section dimensions of different structural members.

Optimization Of Rectangular Box Girder Bridges Subjected To IRC Loading With Volume Minimization

Vol. 4  Issue 3
Year:2015
Issue:Sep-Nov
Title:Optimization Of Rectangular Box Girder Bridges Subjected To IRC Loading With Volume Minimization
Author Name:B. Satyanarayana and A. Mallika 
Synopsis:
In any structural design, safety and economy of the structures are the main objectives therefore, it is necessary to obtain the optimum geometric shape of the structure so that it can carry the imposed load safely and economically. In the present paper, analysis and optimization of the rectangular box girder bridges subjected to IRC loading are presented. The shape optimization of the box girder bridge with volume minimization as the objective are subjected to a constraint on Von-Mises stresses. Numerical examples of single and twin cell box girder sections are considered for analysis and optimization. Ansys 13.0 is used for analysis and optimization. For the single cell box girder bridge, the volume of the structure was reduced by 40 percent and 54 percent volume reduction was obtained for the twin cell box girder.

A Study On Structural Behavior Of Reinforced Cement Concrete Slabs Of High Strength Hybrid Fiber Reinforced Self Compacting Concrete

Vol. 4  Issue 3
Year:2015
Issue:Sep-Nov
Title:A Study On Structural Behavior Of Reinforced Cement Concrete Slabs Of High Strength Hybrid Fiber Reinforced Self Compacting Concrete
Author Name:B. Narendra Kumar, P. Srinivasa Rao and G. Deepa 
Synopsis:
An experimental program is carried out to evaluate the contribution of hybrid fibers on the structural behavior of high strength hybrid fiber reinforced self compacting concrete slabs. A total of six slabs is cast and tested. The slab dimension is 1200mm x 1200mm and the thickness is 100mm. The slabs are cast with the addition of hybrid fibers (steel and glass fibers) varying from 0% to 1.5% of weight of powder content. The slabs are tested under loading frame to obtain the load and deflection characteristics, first crack load, and the ultimate load. The Reinforced Cement Concrete slabs are designed as per IS: 456 (2000). Addition of hybrid fibers enhanced the first crack load and post cracking behavior. A marginal improvement in the ultimate load carrying capacity is observed. It is observed that, the load carrying capacity of reinforced cement concrete slabs with hybrid fibers (1.0 % steel fibers + 0.75 % glass fiber) showed an improved load carrying capacity compared to all other slabs.

Investigation On Pozzolanic Effect Of Mineral Admixtures In Roller Compacted Concrete Pavement

Vol. 4  Issue 2
Year:2015
Issue:Jun-Aug
Title:Investigation On Pozzolanic Effect Of Mineral Admixtures In Roller Compacted Concrete Pavement
Author Name:S. Krishna Rao, P. Sravana and T. Chandrasekhara Rao
Synopsis:
In the present paper the pozzolanic effect of two different mineral admixtures( Fly ash and Ground granulated Blast Furnace slag) in Roller compacted concrete (RCC) was studied quantitatively with various strength indices namely specific strength ratio(R), index of specific strength(K) and contribution rate of pozzolanic effect to strength(P). Cement was partially replaced with mineral admixtures by 10%, 20%, 30%, 40%, 50% and 60% by weight respectively for Fly ash (FA) and Ground granulated Blast Furnace slag (GGBS). Besides the strength properties, these indices showed that early curing age, specific strength of Fly ash Roller Compacted Concrete (FRCC) decreases with increase in FA content, whereas the specific strength of GGBS Roller Compacted Concrete (GRCC) increases with increase in GGBS content. After 90 days of Curing, the contribution of mineral admixture effect on Flexural Strength of FRCC and GRCC are 50% and 63 % respectively.

Mechanical Properties Of Concrete Reinforced With Steel-Polypropylene Hybrid Fibers

Vol. 4  Issue 2
Year:2015
Issue:Jun-Aug
Title:Mechanical Properties Of Concrete Reinforced With Steel-Polypropylene Hybrid Fibers
Author Name:Pragana. N. Javali and S. Elavenil 
Synopsis:
This study presents strength properties of concrete reinforced with steel-polypropylene hybrid concrete and compared it with steel fiber reinforced concrete and polypropylene concrete. Hybrid Fiber Reinforced Concrete (HFRC) is formed from a combination of different types of fibers, which differ in material properties, remain bonded together when added in concrete and retain their identities and properties. The combining of fibers, often called hybridization, is investigated for a M40 grade concrete. The fibers used polypropylene and steel (crimped) fibres with different fiber proportions of steel and polypropylene. Compressive test and split tensile strength were performed and finally the result was extensively analyzed to associate with above fiber combinations. Based on experimental studies, the paper identifies fiber combinations that demonstrate maximum compressive and split tensile strength of concrete.

Effect Of Symmetrical Floor Plan Shapes With Re-Entrant Corners On Seismic Behavior Of RC Buildings

Vol. 4  Issue 2
Year:2015
Issue:Jun-Aug
Title:Effect Of Symmetrical Floor Plan Shapes With Re-Entrant Corners On Seismic Behavior Of RC Buildings
Author Name:P. Sanketh and B. D. V Chandra Mohan Rao
Synopsis:
The Seismic behavior of buildings critically depends on its overall shape, size, and configuration. Buildings with re-entrant corners in plan are considered to be irregular by many seismic design codes. The seismic behavior of RC buildings with symmetrical floor plan shapes having re-entrant corners (H shape, + shape) is investigated in this paper. Various types of building plan configurations with increasing amount of irregularity (A/L ratio) as per IS 1893 code are modelled and analyzed using ETABS 2015 software. A regular plan building is also modelled as a bench mark problem to compare all irregular models. Response spectrum analysis has been carried out for all these models located in seismic zone V of India. Various dynamic parameters such as Story displacement, Story drift and Base shear are compared and some useful conclusions are drawn.

High Strength Self Compacting Concrete Beams Under Flexure.

Vol. 4  Issue 2
Year:2015
Issue:Jun-Aug
Title:High Strength Self Compacting Concrete Beams Under Flexure.
Author Name:S. Sesha Phani, T. Seshadri Sekhar and P. Srinivasa Rao
Synopsis:
To build high rise building by reducing column sizes and increase available space, to build the super structure of long span bridges and to the durability of bridge decks, a high strength is needed. High strength concrete was used in South Wacker in Chicago of 80 Mpa, Baynunah Tower in Abu Dhabi of 80 Mpa and Frankfurt Trianon in Germany of 125 Mpa. If high strength concrete is self-compacting, the production of densely reinforced building element from high strength concrete with high homogeneity would be an easy work. In the present experimental investigation, attempts are made to study the comparative study of flexural behaviour of High Strength hybrid fibre reinforced self compacting concrete beams of M 100 grade with addition of varying percentages of crimped steel fibers 0, 0.5,1.0, 1.5% and Glass fibers 0%, 0.03%. The studies indicated that the addition of glass fibre and steel fibers in certain proportions in High Strength hybrid fibre reinforced self compacting concrete beams had contributed towards development of high performance and high strength concrete which is the need of the hour.

Strength And Ductility Of Steel Fibre Reinforced High Performance Concrete (SFRHPC) Flexural Members

Vol. 4  Issue 2
Year:2015
Issue:Jun-Aug
Title:Strength And Ductility Of Steel Fibre Reinforced High Performance Concrete (SFRHPC) Flexural Members
Author Name:T. Sekar
Synopsis:
This paper presents results of an experimental investigation carried out to study strength and ductility of conventionally reinforced high performance concrete flexural members (i.e. beams) additionally reinforced with steel fibres. Totally ten beams of 150 x 200 x 2200 mm size were cast with and without steel fibres, and tested under two point flexural loading. For casting beams, a high performance concrete (HPC) of M60 grade, and short discrete steel fibres of 0.5 mm diameter were used. The main variables considered in this study are: three different aspect ratios of steel fibres viz. 50, 75 and 100, and in each aspect ratio, three different volume fractions of fibres viz. 0.50%, 0.75% and 1.0%. Test results indicate that addition of steel fibres to conventionally reinforced HPC beam improves strength, ductility and other engineering properties markedly, and the improvement achieved is more when fibre length or fibre content is more. However, the rate of improvement reduces with increase in fibre content. Besides, incorporation of steel fibres improves cracking behaviour of beam by increasing first crack load, and also by forming large number of fine cracks. Furthermore, introduction of steel fibres improves dimensional stability and overall integrity of beam by effective 'fibre bridging action' across cracks. Empirical equations are also proposed to predict strength and ductility of SFRHPC composite beam in terms of 'fibre reinforcing index'.

Effect Of Relative Stiffness Of Beam And Column On The Shear Lag Phenomenon In Tubular Buildings

Vol. 4  Issue 1
Year:2015
Issue:Mar-May
Title:Effect Of Relative Stiffness Of Beam And Column On The Shear Lag Phenomenon In Tubular Buildings
Author Name:G. J. Singh, S. Mandal and R. Kumar
Synopsis:
Relative stiffness of beam and column plays an important role in design and analysis of any building. This paper presents the effect of varying stiffness in terms of cross section and moment of area of beam and column, and on shear lag phenomenon. Variation of axial force in the column is affected by the variation of stiffness of beam as well as column. It has been observed that the beam stiffness has more significant impact on the variation of the axial force and base bending moment of the tubular buildings. This impact of the beam stiffness may be understood in the terms of additional bending moment which is generated in the flange panel of the tubular buildings. Effect of increasing column stiffness has increased base bending moment in both flange and web columns due to increased rigidity of the building.