Vol 3 Issue 2 October 2015-March 2016

Abstract: A dome may be defined as a thin shell generated by the revolution of a regular curve about one of   its axes. The shape of the dome depends up on the type of the curve and direction of the axis of revolution. The roof is curved and used to cover large storey buildings. The shell roof is useful when inside of the building is open and does not contain walls or pillars. Domes are used in variety of structures such as roof of circular areas, circular tanks, exhibition halls, auditoriums etc. Domes may be constructed of masonry, steel, timber and reinforced cement concrete. In this paper we design RCC dome roof structure   by using manual methods which gives detail design of RCC domes. The procedure of designing RCC domes was clearly explained and from the Analysis and design we get the Meridional Reinforcement, hoop Reinforcement of a dome and ring beam Reinforcement.

Keywords: Dome, wind load, live load and dead load, Analysis, diameter of dome.

Title: Reinforced Cement Concrete (RCC) Dome Design

Author: SHAIK TAHASEEN

International Journal of Civil and Structural Engineering Research

ISSN 2348-7607 (Online)

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Abstract: Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. Concrete structures usually show some self-healing capacity, i.e. the ability to heal or seal freshly formed micro-cracks. This property is mainly due to the presence of non-hydrated excess cement particles in the materials matrix, which undergo delayed or secondary hydration upon reaction with water. Scientists have developed a new type of self-healing concrete in which bacteria mediate the production of minerals which rapidly seal freshly formed cracks, a process that concomitantly decreases concrete permeability, and thus better protects embedded steel reinforcement from corrosion. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is negatively charged, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. It was found that use of bacteria improves the stiffness and compressive strength of concrete.

Keywords: Bacterial concrete, Self-Healing Capacity, Crack Formation, Durability, Split Tensile Strength, Stress-Strain curves.

Title: Effect of Bacteria on 28days Split Tensile Strength of Concrete and Its Stress-Strain Curves

Author: SHAIK NASREEN, Dr. T. SURESH BABU

International Journal of Civil and Structural Engineering Research

ISSN 2348-7607 (Online)

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Abstract: IS 456:2000 is the most influential and used code in India which plays a leading role related to concrete and reinforced concrete in many areas such as education, design, production, construction etc. Continuous research focuses on gaps in knowledge and the research findings renovate or alter existing codal provisions or add new provisions to raise the role of concrete industry to a higher level of performance. The general environment to which the concrete will be exposed is classified into five levels of severity, that is mild, moderate, severe, very severe and extreme in increasing degree of severity as per Cl 8.2.2.1 of  IS 456:2000. A test programme was initiated to investigate the validity of the specified clause of code relative to durability. Of the five environmental exposure conditions, the first two exposure conditions namely mild and moderate cases are taken for investigation. The code specifies that if the detailing of reinforcement is as per code, the currently stipulated increased covers would not adversely affect the crack width development and ensures the durability of concrete. The reported test results show that mere adoption of detailing of steel reinforcement as specified in the code, ensuring durability, relative to crack growth is not totally valid.

Keywords: Crack width, concrete cover, durability, RC slabs.

Title: Experimental Study on the Increased Cover Specifications in IS 456:2000 and the Resulting Crack Width Implications in RC Slabs for Mild and Moderate Exposure

Author: Dr. D. Sree Ramachandra Murty, Durga Venkatesh Reddy

International Journal of Civil and Structural Engineering Research

ISSN 2348-7607 (Online)

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Abstract: The traditional method for designing bridge decks in the United States, otherwise known as the Equivalent Strip Method, as presented in the AASHTO LRFD Bridge Design Specifications has been in practice for a considerable amount of time.  More recently the Empirical Deck Design has become more accepted and ultimately codified by being incorporated into the 2012 AASHTO LRFD Bridge Design Specifications; however, there is hesitation by many states in the US to actually implement it due, mainly, to the fact that is thought to produce more cracks when compared to the traditional design method.  An increase in cracking can lead to an increase in the corrosion of reinforcing steel, and, ultimately, a decrease in expected service life.  Epoxy coating is a commonly used corrosion delaying mechanism and has been around for many years.  However, more recently stainless reinforcing steel has been considered due to its incredible corrosion resistance.  It is postulated that, although stainless steel does have a higher initial cost, when used in conjunction with empirical design, stainless steel may be the most cost-beneficial when evaluating the ownership cost for a bridge deck over the course of the expected service life.  This paper describes an investigation of economic viability of using stainless steel in bridge deck design.  Results indicate that there is a high likelihood that implementing stainless steel reinforcement following the empirical bridge deck design approach will produce the lower annual costs over traditional AASHTO bridge deck design with epoxy-coated reinforcement while still resulting in a high quality, serviceable bridge deck.

Keywords: Empirical bridge deck design, stainless steel, epoxy-coated reinforcing, life cycle cost analysis.

Title: Economic Viability of Implementing Empirical Bridge Deck Design with Stainless Reinforcing Steel

Author: Meghan Cronin, Brent M. Phares

International Journal of Civil and Structural Engineering Research

ISSN 2348-7607 (Online)

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Abstract: The design of a highway bridge is critically dependent on standard norms of a particular region or country and criteria like loadings and support conditions. Naturally, the importance of highway bridges in a modern transportation system would imply a set of rigorous design specifications to ensure the safety, quality and overall cost of the project. This paper discusses the parametric study of two different cross-sections of box-girder for same loading conditions to find the most economical cross-section. The design standard of India, IRC was followed in design of Box-girder superstructures subjected to IRC class AA loading. Optimized Cross-sections was found by comparing the different design parameters. As result of this exercise it was found that bending moment and stresses for self-weight and superimposed dead load were different for different cross-section. The cross section with minimum value of bending moment requires less steel to counter the bending stresses. Less reinforcement leads to the most economical cross-section for box girder. The result shows the multi cell box girders are costlier as compare to the single cell box girder, when the loading and support condition were kept same for both the cross-section. Analysis is carried out using the MIDAS Civil Software which is based on finite element method of analysis.

Keywords: Pre-stressed Concrete, Box-girder, IRC loading.

Title: Analysis and Design of Prestressed Concrete Box Girder by Finite Element Method (3 Cells & 1 Cell)

Author: Mayank Chourasia, Dr. Saleem Akhtar

International Journal of Civil and Structural Engineering Research

ISSN 2348-7607 (Online)

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