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Shape optimization of steel reinforced concrete beams
K. S. Babu Narayan,Katta Venkataramana 한국계산역학회 2007 Computers and Concrete, An International Journal Vol.4 No.4
Steel reinforced concrete is perhaps the most versatile and widely used construction material. The versatility is attributed to mouldability of concrete to any conceivable shape. The inherent property of cracking of concrete is the reason for its low tensile strength and hence the design approach of RCC sections in flexure adopts the cracked section theory where in concrete in tension zone is ignored. Means, modes and methods of exploitation of concrete strength by conceiving shapes other than rectangular whereby ineffective concrete in tension zone is reduced and incorporated in compression zone where it is effective needs consideration. Shape optimization of beams is attempted in this analytical investigation employing Sequential Unconstrained Minimization Technique (SUMT). The results clearly show that trapezoidal beams happen to be less costlier than their rectangular counterparts, their usage needs serious reconsideration by the designers.
Flexural bond strength behaviour in OPC concrete of NBS beam for various corrosion levels
Shetty, Akshatha,Venkataramanaa, Katta,Babu Narayan, K.S. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.1
Corrosion is one of the primary reasons why structures have limited durability. The present investigation is carried out to study the behavior of RC (Reinforced Concrete) structural members subjected to corrosion. Experimental investigations were carried out on National Bureau of Standard (NBS), RC beam specimens made of Ordinary Portland Cement (OPC) concrete. Load versus deflection behaviour was studied for different levels of corrosion i.e., 2.5%, 5%, 7.5% and 10%. It is observed that for every percentage increase in corrosion level, there is about 1.6% decrease in load carrying capacity. Also as the amount of corrosion increases there is a reduction in bond stress.
Pushover analysis - result borders due to hinge formation orders
Kulkarni, Supriya R.,Narayan, K.S. Babu Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.2
Performance evaluation of RC frame building by nonlinear static pushover analysis that accounts for elastic and post elastic behavior is becoming very popular as a valid decision making tool in seismic hazard resistant designs. Available literature suggests great amount of interest has shown by researchers in suggesting refinements to geometric and material modelling to bridge the gap between analytical predictions and observed performances. Notwithstanding the attempts gaps still exists. Sequence of plastic hinge formation which has great influence on pushover analysis results is an area less investigated. This paper attempts to highlight the importance of hinge sequence considerations to make analysis results more meaningful. Variation in analysis results due to different hinge sequences have been quantified, compared and bounds on analysis results have been presented.
Strategy for refinement of nodal densities and integration cells in EFG technique
Bhavana S.S. Patel,Babu K.S. Narayan,Katta Venkataramana 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.5
MeshFree methods have become popular owing to the ease with which high stress gradients can be identified and node density distribution can be reformulated to accomplish faster convergence. This paper presents a strategy for nodal density refinement with strain energy as basis in Element-Free Galerkin MeshFree technique. Two popular flat plate problems are considered for the demonstration of the proposed strategies. Issue of integration errors introduced during nodal density refinement have been addressed by suggesting integration cell refinement. High stress effects around two symmetrical semi-circular notches under in-plane axial load have been addressed in the first problem. The second considers crack propagation under mode I and mode II fracture loading by the way of introducing high stress intensity through line crack. The computational efficacy of the adaptive refinement strategies proposed has been highlighted.
Flexural bond strength behaviour in OPC concrete of NBS beam for various corrosion levels
Akshatha Shetty,Katta Venkataramana,K.S. Babu Narayan 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.1
Corrosion is one of the primary reasons why structures have limited durability. The present investigation is carried out to study the behavior of RC (Reinforced Concrete) structural members subjected to corrosion. Experimental investigations were carried out on National Bureau of Standard (NBS), RC beam specimens made of Ordinary Portland Cement (OPC) concrete. Load versus deflection behaviour was studied for different levels of corrosion i.e., 2.5%, 5%, 7.5% and 10%. It is observed that for every percentage increase in corrosion level, there is about 1.6% decrease in load carrying capacity. Also as the amount of corrosion increases there is a reduction in bond stress.