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.

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

Nonlinear numerical analysis of prestressed concrete beams and slabs

2020 ◽  
Vol 223 ◽  
pp. 111187
Author(s):  
Amilton Rodrigues da Silva ◽  
João Paulo de Souza Rosa
Keyword(s):  
Numerical Analysis ◽  
Prestressed Concrete ◽  
Concrete Beams

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

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.

The Effect of the Carbon Epoxy Plate’s Size under Low Velocity Impact

2008 ◽  
Vol 587-588 ◽  
pp. 951-955
Author(s):  
Ana M. Amaro ◽  
Paulo N.B. Reis ◽  
Marcelo F.S.F. de Moura
Keyword(s):  
Numerical Analysis ◽  
Testing Machine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Low Velocity Impact ◽  
Rectangular Plates ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Energies ◽  
Good Agreement

The aim of present work is to study the influence of the plate’s size on low velocity impact on carbon-fibre-reinforced epoxy laminates. Experimental tests were performed on [04,904]s laminates, using a drop weight-testing machine. Circular, square and rectangular plates were tested under low velocity impacts using a hemispherical impactor with 20 mm diameter and 3 J impact energies. The impacted plates were inspected by X-radiography. Numerical simulations were also performed considering interface finite elements compatible with three-dimensional solid elements, which allows to model delamination onset and growth between layers. The results showed that the plate’s size has influence on the delaminated area. Good agreement between experimental and numerical analysis for shape, orientation and size of the delaminations was obtained.

Large-scale fatigue tests on prestressed concrete beams

2021 ◽  
Author(s):  
Dennis Birkner ◽  
Steffen Marx
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Prestressed Concrete ◽  
Large Scale ◽  
Concrete Beams ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Beam Specimen ◽  
The Cross ◽  
Number Of Cycles

<p>For a better estimation of the fatigue lifetime of real structures, tests on large-scale beam specimens are more suitable than on common cylindrical specimens, since effects like local stiffness changes and stress redistributions can be reproduced more realistically. This article presents an experimental setup for large-scale concrete beams subjected to fatigue loading. Additionally, the fatigue tests are simulated with a numerical model. The results of the numerical analysis show a successively increasing damage propagating from the edge into the inner part of the cross-section in the mid span with increasing number of cycles. This results in stress redistributions which extend the lifetime of the structure. The evaluation of the experimental investigation on the first beam specimen shows a larger stiffness degradation at the upper edge than in the centre of the cross-section as well as increasing strains at this location. This matches the expected effects from the numerical analysis.</p>

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