Comparison of Prestressed Concrete Beams and conventionally Reinforced Concrete Beams Under Impulsive Loading

10.14359/7992 ◽  
1961 ◽  
Vol 58 (10) ◽  
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Impulsive Loading ◽  
Reinforced Concrete Beams

FLEXURAL DUCTILITY OF STRUCTURAL CONCRETE MEMBERS SUBJECTED TO LIMITED CYCLES OF REPEATED LOADING

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Nazar Oukaili ◽  
Mohammed Khattab
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Constant Load ◽  
Reinforced Concrete Beams ◽  
Repeated Loading ◽  
Structural Concrete ◽  
Concrete Members ◽  
Flexural Ductility ◽  
High Level

For structural concrete members that may expose to serious earthquake, overload or accident impact, the design of ductility must be given the same importance as the flexural strength. The aim of this investigation is to study the change in ductility of structural concrete flexural members during their exposure to limited cycles of repeated loading. Twenty full-scale beam specimens have been fabricated in to two identical groups; each group consisted of ten specimens. The first group was tested under monotonic static loading to failure and regarded as control beams, while the specimens of the second group were subjected to ten cycles of repeated loading with constant load interval, which ranged between 40% and 60% of ultimate load. Specimens in each group were categorized as follows: two traditional reinforced concrete specimens with different intensity of tension reinforcement; three partially prestressed specimens with bonded strands; three partially prestressed specimens with unbonded strands; and two fully prestressed concrete specimens. The main variable, which was considered for all specimens was the partial prestressing ratio (PPR). It was observed that, the ductility of reinforced concrete beams was insignificantly increased during subjecting to limited repeated loading. For fully prestressed and partially prestressed concrete beams with high level of PPR, the ductility was significantly enhanced, while, it was decreased for specimens with small level of PPR.

scholarly journals On the Effectiveness of Vibration-Based Monitoring for Integrity Management of Prestressed Structures

2021 ◽  
Vol 6 (12) ◽  
pp. 171
Author(s):  
Marco Andrea Pisani ◽  
Maria Pina Limongelli ◽  
Pier Francesco Giordano ◽  
Mattia Palermo
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Decision Makers ◽  
Reinforced Concrete Beams ◽  
Structural Element ◽  
Integrity Management ◽  
Large Research ◽  
Prestressed Beams ◽  
Prestressed Structures

In this paper, the effectiveness of vibration-based tests for the detection of damages for prestressed concrete beams is investigated. Despite large research efforts, discrepant and sometimes contradicting conclusions have been drawn regarding the efficacy and reliability of vibration-based monitoring for prestressed structures. Herein, a contribution to this discussion is provided by tackling the problem from a different perspective. Specifically, the question that this paper intends to answer is: “Do vibration-based tests support decision-makers in integrity management operations for prestressed elements?” The discussion is carried out by comparing the performance of prestressed and ordinary reinforced concrete beams with similar capacities. Both analytical and numerical case studies are considered. Results show that, for prestressed beams, in contrast to reinforced concrete beams, modal parameters can provide information regarding damage only when the structure is close to its ultimate conditions. This makes this information hardly useful for integrity management purposes and the effectiveness of vibration-based tests questionable for this type of structural element.

The Behavior of Reinforced and Pre-Stressed Concrete Beams under Elevated Temperature

2020 ◽  
Vol 47 ◽  
pp. 15-30
Author(s):  
Amr H. Badawy ◽  
Ahmed Hassan ◽  
Hala El-Kady ◽  
L.M. Abd-El Hafez
Keyword(s):  
Reinforced Concrete ◽  
Elevated Temperature ◽  
Prestressed Concrete ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Second Phase ◽  
Prestressed Beam

The behavior of unbounded post tension and reinforced concrete beams under elevated temperature was presented. The experimental work was consisted of two major phases. In the first phase, the objective was studying the mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams respectively were studied. In the second phase, the residual mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams under elevated 400oC, for 120 minutes durations. The failure mechanisms, ultimate load capacity, and deflection at critical sections were monitored. The numerical prediction of the flexural behavior of the tested specimens is presented in this paper. This includes a comparison between the numerical and experimental test results according to ANSYS models. The results indicate that the prestressed beam with steel addition and reinforced concrete beams had higher resistance to beams under elevated 400oC than that of prestressed concrete beam in terms of ultimate capacity. It is also shown that the reinforced concrete beams have higher resistance to beams under elevated temperature than that of prestressed beam, prestressed beam with steel addition.

Shear Capacity Research on Transversely Reinforced Concrete Beams

2015 ◽  
Vol 744-746 ◽  
pp. 283-287
Author(s):  
Can Liu
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Great Influence ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Force Level ◽  
Prestressed Concrete Beam ◽  
Prestressing Force

Inner transverse prestressed bars were used to enhance the shear capacity of concrete beams in this paper, which can be used in transformer beams to reduce the sectional size. Two transversely prestressed one ordinary concrete beams were tested and calculated by finite element method, and the following conclusions can be drawn: (a)The shear capacity of transversely prestressed concrete beam increase rapidly with the increase of the prestressing force level, which means that prestressing force level has a great influence on the shear capacity of transversely prestressed concrete beam. (b) The transverse prestressing bars can efficiently enhance the anti-crack performance of the reinforced concrete beams.

Finite Element Analysis of Reinforced Concrete Beams with Transversely Prestressed Bars

2011 ◽  
Vol 368-373 ◽  
pp. 108-113
Author(s):  
Can Liu ◽  
Bo Wu ◽  
Kai Yan Xu
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Shear Crack ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Failure Loads

This paper presents a method that using inner transverse prestressing bars to enhance the shear capacity of concrete beams, which can be used in new transformer beams to decrease the sectional dimensions. Four transversely prestressed concrete beams and one ordinary reinforced concrete beam were tested. The nonlinear finite element method was applied to analyze them, and the following conclusions can be drawn: (a) The transverse prestressing bars can efficiently increase the shear capacity and failure load of the reinforced concrete beam, the improvement effect is more obvious when exerting the prestressing force on them properly. (b) On the whole, the simulated load-deflection relationships and failure loads of the five specimens agree well with the corresponding tested load-deflection relationships and failure loads. It indicated that the FE models used in this paper predict the structural behavior of the transversely prestressed concrete beams satisfactorily. (c) From the contour of first principal stress, it can be seen that the transverse prestressing bars can efficiently enhance the shear crack resistance of the reinforced concrete beams, if the area of transversely prestressing bars is almost same, the transverse bars with smaller diameter and smaller spacing will be better. It agrees well with the test results.

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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