scholarly journals A Model for the Analysis of Ultimate Capacity of RC and PC Corroded Beams

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Antonino Recupero ◽  
Nino Spinella ◽  
Francesco Tondolo
Keyword(s):  
Prestressed Concrete ◽  
Mechanical Response ◽  
Concrete Beams ◽  
Bending Moment ◽  
Experimental Tests ◽  
Collapse Mechanism ◽  
Steel Rebar ◽  
Axial Forces ◽  
Residual Capacity ◽  
Corrosion Of Steel

Corrosion of steel in reinforced and prestressed concrete beams is very common for structures and infrastructures. It can drastically reduce the resisting section of rebar, modify the mechanical response of the steel rebar, and also determine cracking of the surrounding concrete because of the volume expansion effect of rust. Moreover, it heavily influences the bond between steel rebar and concrete. Few experimental tests are available in the literature, where the structural behavior of reinforced and prestressed concrete beams, in presence of corrosion of longitudinal and transversal reinforcement, is analyzed. A reduction of the bearing performance is observed with an increasing level of rebar corrosion. Indeed, a changing collapse mechanism is evidenced through the tests and may be addressed to the not obvious consequences of corrosion. In this paper, a physical model based on a consistent equilibrium and ultimate strength theory is employed in order to explain the residual capacity of corroded beams. The model is based on limit analysis, and it is able to take into account the interaction between shear, bending moment, and axial forces.

scholarly journals Ultimate flexural strength of prestressed concrete beams: validation and model error evaluation

2018 ◽  
Vol 11 (2) ◽  
pp. 307-330
Author(s):  
M. W. MOURA ◽  
M. V. REAL ◽  
D. D. LORIGGIO
Keyword(s):  
Cross Section ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Experimental Tests ◽  
Error Evaluation ◽  
Moment Capacity ◽  
Percentage Difference ◽  
The Cross ◽  
Concrete Elements

Abstract In this work a computational model is presented to evaluate the ultimate bending moment capacity of the cross section of reinforced and prestressed concrete beams. The computational routines follow the requirements of NBR 6118: 2014. This model is validated by comparing the results obtained with forty-one experimental tests found in the international bibliography. It is shown that the model is very simple, fast and reaches results very close to the experimental ones, with percentage difference of the order of 5%. This tool proved to be a great ally in the structural analysis of reinforced and prestressed concrete elements, besides it is a simplified alternative to obtain the cross section ultimate bending moment.

scholarly journals Non Destructive Behavior of Corroded Reinforced Geopolymer Concrete Beams

2019 ◽  
Vol 9 (2) ◽  
pp. 5411-5414
Keyword(s):  
Polymer Material ◽  
Concrete Beams ◽  
Experimental Tests ◽  
Steel Bar ◽  
Long Time ◽  
Reinforcement Bar ◽  
Object Of Study ◽  
Corrosion Of Steel ◽  
Non Destructive ◽  
Natural Corrosion

Corrosion of steel reinforcement bar embedded in geo-polymer material has been an object of study to confirm its technical viability. The available alkalinity of geo-polymer material initially was suspected to be harmful for alkali-silica reaction, but then it was found to be beneficial to maintain passivity of the steel bar in concrete. Many researchers carried out studies on the influence of corrosion on bond, generally developed on the basis of experimental tests in specimens subjected to artificial corrosion. The current density applied to accelerate the corrosion influences the bond strength. Since, natural corrosion develops in a very long time, an artificial corrosion has been provided

Beams prestressed with unbonded tendons at ultimate

1996 ◽  
Vol 23 (6) ◽  
pp. 1220-1230 ◽  
Author(s):  
Marco Andrea Pisani ◽  
Emilio Nicoli
Keyword(s):  
Numerical Analysis ◽  
Key Words ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Experimental Tests ◽  
Safety Factors ◽  
Unbonded Tendons ◽  
External Tendons ◽  
Simplified Method ◽  
Good Agreement

This paper presents a numerical investigation on beams and slabs prestressed with either unbonded internal or external tendons. Twenty-three experimental tests (beams and slabs prestressed with unbonded internal tendons) were numerically simulated to verify the reliability of the numerical algorithm adopted. The good agreement established enables us to study the behaviour of these beams in depth and to compare it with the behaviour of similar beams prestressed with external tendons. The numerical analyses were then repeated after including the safety factors related to the materials. The outputs were then compared with the results adopted by making use of the simplified method suggested by Eurocode E.C.2 Part 1-5, to check the size of the error involved in the adoption of the latter. Key words: numerical analysis, unbonded internal tendons, external tendons, European Prestandard, prestressed concrete, beams, post-tensioned.

Bending Moment–Shear Force Interaction Domains for Prestressed Concrete Beams

2005 ◽  
Vol 131 (9) ◽  
pp. 1413-1421 ◽  
Author(s):  
Antonino Recupero ◽  
Antonino D’Aveni ◽  
Aurelio Ghersi
Keyword(s):  
Prestressed Concrete ◽  
Shear Force ◽  
Concrete Beams ◽  
Bending Moment ◽  
Force Interaction ◽  
Interaction Domains

scholarly journals Vibrations of cracked reinforced and prestressed concrete beams

2008 ◽  
Vol 6 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Zsolt Huszár
Keyword(s):  
Cross Sections ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Bending Rigidity ◽  
Elastic Range ◽  
Non Linear ◽  
Linear Vibrations ◽  
Prestressed Beams

The dynamic behaviour of bent reinforced concrete beams in elastic range is significantly influenced by cracks caused by former loads. Considering this fact a more accurate calculation of the eigenfrequencies of the beams is available. Experiments have shown that the features of vibration differ from the results obtained by the well-known linear model, if cracked zones exist. The cause of this phenomenon is that the bending rigidity of the cross-sections in the cracked range depends on the sign of the actual bending moment. Therefore the vibration shows non-linear characteristics in the elastic range as well. The dynamic behavior of bent prestressed concrete beams is similar. The dynamic characteristics of prestressed beams besides cracks is influenced also by the intensity and eccentricity of the axial force. For a detailed investigation of the problem, experiments and non-linear analysis were performed. On the basis of these the virtual eigenfrequencies of the non-linear vibrations were determined.

Experimental tests on corroded prestressed concrete beams subjected to transverse load

2019 ◽  
Vol 20 (6) ◽  
pp. 2220-2229 ◽  
Author(s):  
Antonino Recupero ◽  
Nino Spinella
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Experimental Tests ◽  
Transverse Load

Prestressed high-strength concrete beams under torsion and bending

1999 ◽  
Vol 26 (2) ◽  
pp. 197-207
Author(s):  
Samir A Ashour ◽  
Sabry A Shihata ◽  
Ali A Akhtaruzaman ◽  
Faisal F Wafa
Keyword(s):  
Prestressed Concrete ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
High Strength ◽  
Torsional Stiffness ◽  
Test Results ◽  
Torsional Strength ◽  
Interaction Diagram ◽  
Strength Concrete

Test results of 16 rectangular prestressed high-strength concrete beams subjected to the combined action of torsion and bending are presented. The major variables were the ratio of torsion to the bending moment (T/M) and the prestressing level. The beams were subjected to two levels of prestressing, corresponding to 0.05fc' and 0.10fc', where fc' is the compressive strength of concrete (about 90 MPa). Test results showed that the torque-twist relations for the test beams were approximately linear up to cracking and thereafter became nonlinear. Increasing the T/M ratio and the prestressing level increases both torsional stiffness and strength. Several theoretical methods available in the literature developed for normal-strength concrete were used to predict the torsional strength of the tested high-strength concrete beams. Interaction equations were used along with some other methods to predict the torsional capacity in the presence of a bending moment. Good agreement was observed between the experimental and theoretical results.Key words: beams (supports), bending, cracking, failure, high-strength concrete, interaction diagram, prestressed concrete, stiffness, torsion, torsional strength.

scholarly journals Softened Truss Model for Reinforced Concrete Beams under Torsion Combined with Axial Force

2020 ◽  
Vol 1 (1) ◽  
pp. 79-96 ◽  
Author(s):  
Luís Bernardo ◽  
Cátia Taborda
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Solution Procedure ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Axial Forces ◽  
Truss Model ◽  
Theoretical Predictions ◽  
Good Agreement

The Generalized Softened Variable Angle Truss Model (GSVATM) allows one to compute the global behavior of reinforced concrete (RC) beams under torsion, including the pre- and post-cracking stage. In a previous study, such a model was successfully extended to cover prestressed concrete beams under torsion with longitudinal and uniform prestress. In order to continue to extend the theoretical model for other loading cases, in this article, the GSVATM is extended to cover RC beams under torsion combined with external and centered axial forces. The changes in GSVATM are presented, as well as the modified calculation solution procedure. Some theoretical predictions from the extended GSVATM are compared with numerical results from the non-linear finite element method (FEM), where good agreement is observed for the studied trends.

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