Evaluation of Plastic Rotation Demands for Earthquake Design of Reinforced Concrete Beams

2012 ◽  
Vol 109 (1) ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Plastic Rotation ◽  
Earthquake Design

scholarly journals A Parametrical Analysis for the Rotational Ductility of Reinforced Concrete Beams

2013 ◽  
Vol 7 (1) ◽  
pp. 242-253
Author(s):  
Domenico Raffaele ◽  
Giuseppina Uva ◽  
Francesco Porco ◽  
Andrea Fiore
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Closed Form Solution ◽  
Form Solution ◽  
Reinforced Concrete Beams ◽  
Shear Cracks ◽  
Technical Standards ◽  
Mechanical Reinforcement ◽  
Plastic Rotation

The assessment of the plastic rotation of reinforced concrete beams is an essential aspect to avoid structural brittle collapses. The value actually available can be generally determined as sum of two different components. The first, due to bending, the second for inclined shear cracks. This paper presents a simplified model which provides the flexural plastic rotation of the rectangular beams with a ``closed-form solution''. The approach is substantially dimensionless and includes main influencing factors the cross -section, as mechanical material properties, ductility, geometrical and mechanical reinforcement ratio, confinement effects. In closing, in order to appreciate the reliability of the procedure, a comparison with models proposed by international technical standards is made.

Evaluation of ductility and allowable moment redistribution in reinforced concrete structures

2000 ◽  
Vol 27 (6) ◽  
pp. 1286-1299 ◽  
Author(s):  
Adnan Shakir ◽  
David M Rogowsky
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Bond Slip ◽  
Plastic Rotation ◽  
Moment Redistribution ◽  
Rotation Capacity ◽  
The Moment ◽  
Plastic Rotation Capacity

Designers can use moment redistribution to reduce the design bending moment envelope. Code provisions for moment redistribution are not entirely rational. They neglect the effects of important parameters on permissible moment redistribution and can be very conservative. To establish a realistic limit on permissible moment redistribution, one needs a rational model for predicting the plastic rotation capacity of critical sections (plastic hinges). This paper presents a model for computing the plastic rotation capacity, θp, and permissible moment redistribution, β, in reinforced concrete beams. Important parameters, affecting θp and β, are identified and incorporated in the model. The model is validated against experimental results and shows good agreement. A comparison of the moment redistribution limits is made between the model and CSA A23.3-94. Although the code provides a reasonable estimate of β for unfavourable combinations of parameters, the code can be very conservative when conditions are favourable for moment redistribution. Deeper beams with closely spaced stirrups allow significantly more moment redistribution than that predicted by the code.Key words: moment redistribution, ductility, plastic rotation capacity, bond-slip, shear cracking, reinforced concrete beams, c/d, ultimate concrete strain.

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