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Optimum design of reinforced concrete sections in flexure and shortcomings of prescriptive method of design
https://orcid.org/http://orcid.org/0000-0003-1028-1208
Reinforced concrete is a marriage between two conflicting materials, concrete which is highly brittle and steel which is highly ductile. Ductile failure is always desirable than brittle failure as it can result in reduction in loss of life and property. For ensuring ductile failure in reinforced concrete sections the total strain at failure should be high and, in this context, ductility plays a very vital role. However, for achieving higher levels of ductility higher plastic rotations are necessary to occur which might be difficult for reinforced concrete sections to mobilize especially for deeper sections. Beams with nominal bending moment and provided with minimum tension reinforcement need to undergo a significant amount of plastic rotation to accommodate the yielding of steel which might result in partial or total collapse of the section. In the present paper, an attempt has been made to assess and quantify the ductility and plastic rotations of the two extreme types of sections permitted in LSM, balanced and maximum under-reinforced sections for different combinations of concrete and steel grades. Calculations for ductility and plastic rotations of a typical doubly reinforced section have also been presented. Determination of ductility and plastic rotations of under-reinforced sections are quite simple but evaluation of these parameters for balanced sections are not that common and have been derived in the present paper using fundamental principles. The codes do not furnish any information regarding the desirable values of ductility and plastic rotations of reinforced concrete beams. An attempt has also been made to compare some important features of prescriptive method of design and performance-based design and their implication in design of structures. The values of ductility and plastic rotations may give useful information to the designers regarding optimum design of sections in flexure. In the present paper, a relationship has been proposed for calculation of the minimum reinforcement in beams which will result in optimum plastic rotations that will not result in significant damage of the sections.
Optimum design of reinforced concrete sections in flexure and shortcomings of prescriptive method of design
https://orcid.org/http://orcid.org/0000-0003-1028-1208
Reinforced concrete is a marriage between two conflicting materials, concrete which is highly brittle and steel which is highly ductile. Ductile failure is always desirable than brittle failure as it can result in reduction in loss of life and property. For ensuring ductile failure in reinforced concrete sections the total strain at failure should be high and, in this context, ductility plays a very vital role. However, for achieving higher levels of ductility higher plastic rotations are necessary to occur which might be difficult for reinforced concrete sections to mobilize especially for deeper sections. Beams with nominal bending moment and provided with minimum tension reinforcement need to undergo a significant amount of plastic rotation to accommodate the yielding of steel which might result in partial or total collapse of the section. In the present paper, an attempt has been made to assess and quantify the ductility and plastic rotations of the two extreme types of sections permitted in LSM, balanced and maximum under-reinforced sections for different combinations of concrete and steel grades. Calculations for ductility and plastic rotations of a typical doubly reinforced section have also been presented. Determination of ductility and plastic rotations of under-reinforced sections are quite simple but evaluation of these parameters for balanced sections are not that common and have been derived in the present paper using fundamental principles. The codes do not furnish any information regarding the desirable values of ductility and plastic rotations of reinforced concrete beams. An attempt has also been made to compare some important features of prescriptive method of design and performance-based design and their implication in design of structures. The values of ductility and plastic rotations may give useful information to the designers regarding optimum design of sections in flexure. In the present paper, a relationship has been proposed for calculation of the minimum reinforcement in beams which will result in optimum plastic rotations that will not result in significant damage of the sections.
Optimum design of reinforced concrete sections in flexure and shortcomings of prescriptive method of design
https://orcid.org/http://orcid.org/0000-0003-1028-1208
Reinforced concrete is a marriage between two conflicting materials, concrete which is highly brittle and steel which is highly ductile. Ductile failure is always desirable than brittle failure as it can result in reduction in loss of life and property. For ensuring ductile failure in reinforced concrete sections the total strain at failure should be high and, in this context, ductility plays a very vital role. However, for achieving higher levels of ductility higher plastic rotations are necessary to occur which might be difficult for reinforced concrete sections to mobilize especially for deeper sections. Beams with nominal bending moment and provided with minimum tension reinforcement need to undergo a significant amount of plastic rotation to accommodate the yielding of steel which might result in partial or total collapse of the section. In the present paper, an attempt has been made to assess and quantify the ductility and plastic rotations of the two extreme types of sections permitted in LSM, balanced and maximum under-reinforced sections for different combinations of concrete and steel grades. Calculations for ductility and plastic rotations of a typical doubly reinforced section have also been presented. Determination of ductility and plastic rotations of under-reinforced sections are quite simple but evaluation of these parameters for balanced sections are not that common and have been derived in the present paper using fundamental principles. The codes do not furnish any information regarding the desirable values of ductility and plastic rotations of reinforced concrete beams. An attempt has also been made to compare some important features of prescriptive method of design and performance-based design and their implication in design of structures. The values of ductility and plastic rotations may give useful information to the designers regarding optimum design of sections in flexure. In the present paper, a relationship has been proposed for calculation of the minimum reinforcement in beams which will result in optimum plastic rotations that will not result in significant damage of the sections.
Optimum design of reinforced concrete sections in flexure and shortcomings of prescriptive method of design
Asian J Civ Eng
Jha, Bijoy Kumar (author) / Bhanja, Santanu (author)
Asian Journal of Civil Engineering ; 22 ; 769-787
2021-06-01
19 pages
Article (Journal)
Electronic Resource
English
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