The Compilation of Nonlinear Analysis Program for Externally Prestressed Concrete Beams

2014 ◽  
Vol 919-921 ◽  
pp. 1334-1339
Author(s):  
Hui Ju Cai ◽  
Jian Min Zhou ◽  
Ying Gao
Keyword(s):  
Nonlinear Analysis ◽  
Prestressed Concrete ◽  
Static Load ◽  
Concrete Beams ◽  
Geometrical Nonlinearity ◽  
Analysis Program ◽  
Existing Building ◽  
External Prestressing ◽  
External Tendons ◽  
Prestressed Beams

In order to popularize the application of external prestressing technique in existing building green retrofits,this paper presents the compilation of nonlinear analysis program for externally prestressed beams based on both the geometrical nonlinearity type and the material nonlinearity type. Combined the static-load-experiment with 12 concrete beams prestressed with external tendons, the calculative results showed that this program matched relatively well with the experimental results.

Monitoring of External Prestressing Tendons Construction Process of Jiamusi Highway Prestressed Concrete Bridge during Strengthening in China

2010 ◽  
Vol 163-167 ◽  
pp. 2873-2879
Author(s):  
Ali Fadhil Naser ◽  
Zong Lin Wang
Keyword(s):  
Prestressed Concrete ◽  
Concrete Bridge ◽  
Construction Process ◽  
Box Girder ◽  
External Prestressing ◽  
Maximum Value ◽  
External Tendons ◽  
Monitoring Process ◽  
Left And Right ◽  
Prestressed Concrete Bridge

Jiamusi highway prestressed concrete bridge is located in the Jiamusi City within Heilongjiang province in the east north of China. The strengthening and repairing of the bridge structure can be provided an effective and economic solution in appropriate situation. The objective of this study are to monitor the construction process of external prestressing tendons for strengthening of Jiamusi highway prestressed concrete bridge. Monitoring process includes measurement of external prestressing tendons natural frequency, monitoring of tensile forces values of external prestressing tendons, monitoring of development of anchor beams cracks, and monitoring of anchor beam deformation. The results of monitoring process show that the box girder No. 11 has the largest values of proportional coefficient (K) and the maximum value is 327.8. Box girder No. 8 has the largest values of frequency, the maximum value is 3.499. Five levels of tension are used in the application of tensile force in the tension process of external prestressing tendons. These levels are level 1=248.2kN, level 2=496.4kN, level 3=744.6kN, level 4=992.8kN, and level 5=1241kN. The measured tendons elongation values of left box girder No.8 are more than the theoretical values. For left and right box girder No. 9, side external tendons of left box No. 10, and left and right box girder No. 11, the measured values are less than theoretical values of elongation. After tension process, there are no new cracks in the top, web, and bottom of anchor beam and a small number of cracks developed slightly. These cracks are found around ducts of external tendons. The length of cracks rang from 0.03m to 0.5m and width rang from 0.05 mm and 0.25mm. The longitudinal deformation of the interface and top of anchor beam is very small, ranging from 0.001mm to0.115mm, which averaged 0.026mm. The overall state of anchor beams and box girders during strengthening is good.

Experiment of Flexural Behavior of Prestressed Concrete Beams with External Tendons according to Tendon Area and Tendon Force

2009 ◽  
Vol 21 (4) ◽  
pp. 513-521 ◽  
Author(s):  
Sung-Won Yoo ◽  
In-Hwan Yang ◽  
Jeong-In Suh
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Flexural Behavior ◽  
External Tendons ◽  
Tendon Force

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.

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.

Shear Behavior of CFRP Prestressed Concrete Beams without Stirrups

2011 ◽  
Vol 266 ◽  
pp. 126-129 ◽  
Author(s):  
Zuo Hu Wang ◽  
Xiu Li Du ◽  
Jing Bo Liu
Keyword(s):  
Prestressed Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Shear Span ◽  
Compression Failure ◽  
Concrete Members ◽  
Prestressed Beams

Five beams were tested up to failure to study the shear behavior of concrete beams prestressed with fiber reinforced polymer (FRP). Different factors were taken into consideration: the type of prestressing tendons and the shear span ratio. The shear failure modes and the influence of different factors on shear behavior were investigated in details. The test results showed that FRP prestressed beams without stirrups had two shear failure modes: diagonal compression failure and shear compression failure; the shear span ratio was the most important factor to determine the failure mode and shear capacity of the prestressed beams. The shear capacity of concrete members prestressed with FRP tendons was lower than that of concrete beams prestressed with steel cables.

Design Approach for Flexural Capacity of Prestressed Concrete Beams with External Tendons

2018 ◽  
Vol 144 (12) ◽  
pp. 04018215 ◽  
Author(s):  
Fei Peng ◽  
Weichen Xue ◽  
Yuan Tan
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Design Approach ◽  
Flexural Capacity ◽  
External Tendons

Experimental Study on Fatigue Behavior of Prestressed Concrete Beams with Manufactured Sand

2012 ◽  
Vol 517 ◽  
pp. 595-600
Author(s):  
Qian Qian Li ◽  
Li Xin Liu ◽  
Sheng Dong He
Keyword(s):  
Cyclic Loading ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Limit State ◽  
Flexural Behavior ◽  
Natural Sand ◽  
Manufactured Sand ◽  
Allowable Range ◽  
Prestressed Beams

This paper presents the test results of 2 prestressed concrete beams with manufactured sand under cyclic loading, the concrete is made of manufactured sand to replace natural sand with different replacement rates of 50% and 100%. The stress of re-bars and prestressed strands and the strain of manufactured sand concrete are discussed, the rigidity and cracking of the prestressed beams under cyclic loading are analyzed, and the flexural behavior of the beams after 2.5 million times cyclic loading are also discussed and analyzed. The results show that the fatigue behavior of the prestressed concrete beams with manufactured sand to replace the natural sand under cyclic loading is satisfied, the flexural bearing capacity of the prestressed beams after 2.5 million times cyclic loading is still sufficient. The results also show that the crack width and the mid-span deflection of the prestressed beams are in the allowable range at the serviceability limit state. This may be regarded as a reference for the applications of manufactured sand in the prestressed concrete structure .

scholarly journals Experimental and Theoretical Investigation of Bending in Concrete Beams Strengthened with External Prestressing CFRP Tendons

2016 ◽  
Vol 10 (1) ◽  
pp. 492-510
Author(s):  
Yu Tianlai ◽  
Tian Shuai ◽  
Zhao Yunpeng ◽  
Zhang Liyuan
Keyword(s):  
Prestressed Concrete ◽  
Design Theory ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Flexural Properties ◽  
Bending Angle ◽  
Prestressing Steel ◽  
Strength Grade ◽  
External Prestressing

The flexural properties of concrete beams strengthened by external prestressing carbon fibre-reinforced plastic (CFRP) tendons are studied through static loading tests. The loading processes, failure modes, right-sectional strain features, and ductility of the strengthened concrete beams are analysed, permitting comparisons of the influences of the bending angle of the external CFRP tendons, the strength grade of the concrete, the reinforcement ratio of the internal non-prestressing steel, and the loading strengthening level of the external prestressing CFRP tendons on the flexural properties of the beams. Test results show that the external prestressing CFRP tendons can improve the anti-cracking properties, stiffness, and flexural properties of concrete beams. The bending angle of the external CFRP tendons should not exceed 10°, while the reinforcement ratio and loading strength have obvious effects on the flexural properties of the beams they reinforce; conversely, the strength grade of the concrete has relatively little influence on the flexural properties. Based on the results, a bending bearing capacity formula for concrete beams strengthened with external prestressing CFRP tendons is determined according to the design theory of externally prestressed concrete structures; this formula provides the accuracy required for construction and therefore it can be used as a reference for practical engineering.

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.

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