Theoretical Analysis of Natural Vibration Frequency for Unbonded Prestressed Concrete Beams

2012 ◽  
Vol 594-597 ◽  
pp. 882-885 ◽  
Author(s):  
Feng Ge Li ◽  
Rong Li
Keyword(s):  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Flexural Rigidity ◽  
Variable Stiffness ◽  
Natural Vibration Frequency ◽  
Test Results ◽  
Unbonded Tendons ◽  
Proposed Model ◽  
Calculation Results

This papers deals with the study of the influence of prestress force on the natural frequencies for unbonded prestressed concrete beams. A total of 5 unbounded prestressed concrete simply support beams were constructed and tested. The test results show that the prestress force has little effect on the nature frequencies of unbonded prestressed concrete beams. A model of variable stiffness is proposed to calculate the natural frequencies of prestressed concrete beams with unbonded tendons, which assumed that the flexural rigidity of the beam is changing when beams vibrating. The calculate results show that the calculation results by the proposed model agree well with experimental ones.

Finite Element Analysis of Natural Vibration Frequency for Unbounded Prestressed Concrete Beams

2013 ◽  
Vol 351-352 ◽  
pp. 1034-1037
Author(s):  
Feng Ge Li ◽  
Yan Zhao
Keyword(s):  
Finite Element ◽  
Vibration Frequency ◽  
Prestressed Concrete ◽  
Natural Vibration ◽  
Concrete Beams ◽  
Variable Stiffness ◽  
Natural Vibration Frequency ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program

An experimental investigation on the dynamic characteristics of unbounded prestressed concrete simply support beams is presented. A total of 5 unbounded prestressed concrete simply support beams were constructed and tested. The influence of prestressing on natural vibration frequency of concrete beams is studied by applying prestress gradually. A model of variable stiffness is proposed to calculate the natural vibration frequency of unbounded prestressed concrete beams. The finite element program Sap2000 is used to calculate the frequency of unbounded prestressed concrete beams. The results show that the calculating results agree well with experimental ones.

Experiment Study on Dynamic Characteristics of Unbounded Prestressed Concrete Beams

2012 ◽  
Vol 166-169 ◽  
pp. 273-276 ◽  
Author(s):  
Feng Ge Li ◽  
Rong Li
Keyword(s):  
Experimental Investigation ◽  
Dynamic Characteristics ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Test Results ◽  
Experiment Study ◽  
Concrete Crack ◽  
Test Study ◽  
Concrete Damage

An experimental investigation on the dynamic characteristics of unbounded prestressed concrete simply support beams is presented in this study. A total of 3 unbounded prestressed concrete simply support beams were constructed and tested. The main variables considered in the test study were the prestress level, the position of prestressed steel and concrete damage. The test results shows that the natural frequencies and model shape of prestressed concrete beams change with the prestress level and the position of prestressed steel, and that the existence or not of concrete crack have certain effects on the dynamic characteristics of prestressed concrete beams.

Ductility analysis of prestressed concrete beams with unbonded tendons

2008 ◽  
Vol 30 (1) ◽  
pp. 13-21 ◽  
Author(s):  
J.S. Du ◽  
Francis T.K. Au ◽  
Y.K. Cheung ◽  
Albert K.H. Kwan
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Unbonded Tendons

Feasibility Study of Prestress Force Prediction for Concrete Beams Using Second-Order Deflections

2018 ◽  
Vol 18 (10) ◽  
pp. 1850124 ◽  
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Chun-Chung Chen ◽  
Yu-Chi Sung ◽  
Nerio Tullini
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Flexural Rigidity ◽  
Beam Theory ◽  
Concrete Bridges ◽  
Prestress Loss ◽  
Prestressed Concrete Bridges ◽  
Loss Prediction ◽  
Euler Bernoulli Beam ◽  
Post Tensioned

The safety and sustainability of prestressed concrete bridges can be improved with accurate prestress loss prediction. Considerable loss of the prestress force may imply damages hidden in the bridge. In this study, a prestress force identification method was implemented for concrete beams. Based on the Euler–Bernoulli beam theory, the procedure estimates the prestress force by using one or a set of static displacements measured along the member axis. The implementation of this procedure requires information regarding the flexural rigidity of the beam. The deflected shape of a post-tensioned concrete beam, subjected to an additional vertical load, was measured in a short term in several laboratory experiments. The accuracy of the deflection measurements provided favorable prestress force estimates. In particular, the “compression-softening” theory was validated for uncracked post-tensioned concrete beams.

scholarly journals CALCULATING THE CARRYING CAPACITY OF FLEXURAL PRESTRESSED CONCRETE BEAMS WITH NON-METALLIC REINFORCEMENT

2010 ◽  
Vol 2 (6) ◽  
pp. 5-13
Author(s):  
Mantas Atutis
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Elastic Response ◽  
Structural Behaviour ◽  
Moment Capacity ◽  
Calculation Results ◽  
Fibre Reinforced Polymer ◽  
Frp Reinforcement ◽  
Metallic Reinforcement

The article reviews moment resistance design methods of prestressed concrete beams with fibre-reinforced polymer (FRP) reinforcement. FRP tendons exhibit linear elastic response to rupture without yielding and thus failure is expected to be brittle. The structural behaviour of beams prestressed with FRP tendons is different from beams with traditional steel reinforcement. Depending on the reinforcement ratio, the flexural behaviour of the beam can be divided into several groups. The numerical results show that depending on the nature of the element failure, moment resistance calculation results are different by using reviewed methods. It was found, that the use of non-metallic reinforcement in prestressed concrete structures is effective: moment capacity is about 5% higher than that of the beams with conventional steel reinforcement.

Flexural ductility of prestressed concrete beams with unbonded tendons

2009 ◽  
Vol 6 (6) ◽  
pp. 451-472 ◽  
Author(s):  
F.T.K. Au ◽  
K.H.E. Chan ◽  
A.K.H. Kwan ◽  
J.S. Du
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Unbonded Tendons ◽  
Flexural Ductility

scholarly journals A New Formula for Prediction of Crack Widths in Reinforced and Partially Prestressed Concrete Beams

2001 ◽  
Vol 4 (2) ◽  
pp. 101-110 ◽  
Author(s):  
S. H. Chowdhury ◽  
Y. C. Loo
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Published Data ◽  
Test Results ◽  
Average Crack ◽  
Laboratory Investigations ◽  
Width Measurements ◽  
The Comparative Study ◽  
New Formula ◽  
Crack Widths

A new formula for predicting the average crack widths in reinforced and partially prestressed concrete beams has been developed incorporating four governing parameters. The performance of the proposed formula is checked using the authors' test results which includes crack spacing and crack width measurements from 18 reinforced and 12 partially prestressed concrete beams. Also included in the comparison are published data on 76 beams from other laboratory investigations. The comparative study indicates that the predictions are accurate. The performance of the proposed formula is also compared with three major code formulas, viz those recommended in the ACI Building Code, the British Standard and the Eurocode. It is concluded that better correlation with test data is achieved by the proposed formula.

Research on Stress Increase of Unbonded Tendons at Ultimate in Prestressed Concrete Continuous Beams

2012 ◽  
Vol 166-169 ◽  
pp. 1554-1557
Author(s):  
Xiao Dong Wang ◽  
Wen Zhong Zheng ◽  
Ying Wang
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Simulation Analysis ◽  
Analysis Method ◽  
Stress Increase ◽  
Continuous Beams ◽  
Unbonded Tendons ◽  
Index Ratio ◽  
Prestressed Reinforcement ◽  
Rational Evaluation

Rational evaluation for stress increase of unbonded tendon at ultimate is the basis to exactly compute flexural load bearing capacity of unbonded prestressed concrete beams. Moment-curvature nonlinear analysis method is adopted to compile programs for calculating stress increase at ultimate in unbonded prestressed continuous beams. The precision of the method is proved by comparing results of 16 experimental two-span unbonded prestressed continuous beams to the prediction value of stress increase at ultimate. Based on the simulation analysis, law of the influence of some basic factors to stress increase at ultimate in unbonded tendons in continuous beams is obtained, such as non-prestressed reinforcement index, prestressed reinforcement index, ratio of span to depth and loading type. Then formulas for calculating stress increase at ultimate in unbonded tendons in prestressed concrete continuous beams were established.

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