scholarly journals DEFORMATIONAL ANALYSIS OF PRESTRESSED HIGH‐STRENGTH CONCRETE MEMBERS USING FLEXURAL CONSTITUTIVE MODEL

2005 ◽  
Vol 11 (2) ◽  
pp. 145-151
Author(s):  
Renata Zamblauskaitė ◽  
Gintaris Kaklauskas ◽  
Darius Bačinskas
Keyword(s):  
Constitutive Model ◽  
Prestressed Concrete ◽  
Linear Time ◽  
High Strength ◽  
Concrete Members ◽  
Calculation Technique ◽  
Short And Long Term ◽  
Modulus Method ◽  
Creep And Shrinkage

In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to short‐ and long‐term deformational analysis of flexural partially prestressed concrete members. The effect of tension stiffening and non‐linear time effects of creep and shrinkage are taken into account. Effective modulus method is used for modelling long‐term deformations. The proposed calculation technique is based on the layered approach and use of material stress‐strain relationships. Curvatures prediction results were tested against experimental data of partially prestressed concrete beams reported in literature.

scholarly journals LONG‐TERM DEFORMATION ANALYSIS OF NON‐CRACKED PC MEMBERS USING FLEXURAL CONSTITUTIVE MODEL AND DESIGN METHODS

2006 ◽  
Vol 12 (2) ◽  
pp. 124-133
Author(s):  
Renata Zamblauskaite ◽  
Gintaris Kaklauskas ◽  
Povilas Vainiūnas
Keyword(s):  
Constitutive Model ◽  
Prestressed Concrete ◽  
Linear Time ◽  
Deformation Analysis ◽  
Stress And Strain ◽  
Concrete Members ◽  
Calculation Technique ◽  
Modulus Method ◽  
Creep And Shrinkage

In this paper, an attempt has been made to extend application of the recently proposed Flexural constitutive model to long‐term deformation analysis of prestressed concrete members. The effect of non‐linear time effects of creep and shrinkage are taken into account. Effective modulus method is used for modeling of long‐term deformations. The proposed calculation technique is based on the layered approach and use of material stress and strain relationships. Curvatures and deflections prediction results were tested against experimental data of prestressed concrete beams reported in the literature.

scholarly journals Long-Term Characteristics of Prestressing Force in Post-Tensioned Structures Measured Using Smart Strands

2020 ◽  
Vol 10 (12) ◽  
pp. 4084 ◽  
Author(s):  
Sang-Hyun Kim ◽  
Sung Yong Park ◽  
Se-Jin Jeon
Keyword(s):  
Prestressed Concrete ◽  
Mechanical Strain ◽  
Prestress Losses ◽  
Prestressing Force ◽  
Eurocode 2 ◽  
Study Results ◽  
Girder Bridge ◽  
Creep And Shrinkage ◽  
Term Monitoring

The proper distribution of prestressing force (PF) is the basis for the design of prestressed concrete (PSC) structures. However, the PF distribution obtained by predictive equations of prestress losses has not been sufficiently validated by comparison with measured data due to the poor reliability and durability of conventional sensing technologies. Therefore, the Smart Strand with embedded fiber optic sensors was developed and applied to PSC structures to investigate the long-term characteristics of PF distribution as affected by concrete creep and shrinkage. The data measured in a 20 m-long full-scale specimen and a 60 m-long PSC girder bridge were analyzed by comparing them with the theoretical estimation obtained from several design equations. Although the long-term decreasing trend of the PF distribution was similar in the measurement and theory, the equation of Eurocode 2 for estimating the long-term prestress losses showed better agreement with the measurement than ACI 209R and ACI 423.10R did. This can be attributed to the more refined form of the predictive equation of Eurocode 2 in dealing with the time-dependency of the PF. The study results also confirmed the need to compensate for the temperature variation in the long-term monitoring to derive the actual mechanical strain related to the PF. We expect our developed Smart Strand to be applied practically in PF measurement for the reasonable safety assessment and maintenance of PSC structures by improving several of the existing drawbacks of conventional sensors.

Critical review of CSA A23.3-94 deflection prediction for normal and high strength concrete beams

1998 ◽  
Vol 25 (3) ◽  
pp. 474-489 ◽  
Author(s):  
Alaa G Sherif ◽  
Walter H Dilger
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Bilinear Method ◽  
Short And Long Term ◽  
The Mean ◽  
Effective Moment Of Inertia

The purpose of this paper is to critically review the provisions of CSA A23.3-94 for the deflection calculations of normal and high strength reinforced concrete beams. Comparison is made with the provisions of CEB-FIP MC 90 and EC 2 which is similar to the MC 90. Both short- and long-term deflections are discussed. Tests from the literature are used to assess the calculation methods suggested by the codes. These methods are the effective moment of inertia approach, the mean curvature approach, and the bilinear method. A parametric study is carried out to investigate the effect of the level of loading, shape of bending moment, and reinforcement ratio on the predicted deflections.Key words: code predictions, deflections, long term, reinforced concrete beams, short term.

Losses in partially prestressed concrete

1988 ◽  
Vol 15 (5) ◽  
pp. 890-899
Author(s):  
B. DeV. Batchelor ◽  
Jayanth Srinivasan ◽  
Mark F. Green
Keyword(s):  
Key Words ◽  
Prestressed Concrete ◽  
Effective Modulus ◽  
Highway Bridge ◽  
Design Code ◽  
Bridge Design ◽  
Prestress Losses ◽  
Concrete Members ◽  
Modulus Method

The calculation of prestress losses by the age-adjusted effective modulus method is analyzed and compared with the Ontario highway bridge design code predictions for partially prestressed concrete. Specifically, the effect of nonprestressed reinforcement on prestress losses is studied. The age-adjusted effective modulus method for calculating prestress losses is outlined, and plots of prestress losses versus partial prestressing ratio are presented and analyzed. It is shown that prestress losses decrease with increasing amounts of nonprestressed reinforcement. Also, the Ontario highway bridge design code expressions, which are intended for use with fully prestressed sections, are not suitable for use in the design of partially prestressed concrete members. Key words: concrete (prestress), design, partial prestressing, prestress losses.

scholarly journals Prepared experimental study for durability verification of FRP reinforced concrete members

2021 ◽  
Vol 1209 (1) ◽  
pp. 012055
Author(s):  
S Blaho ◽  
K Gajdošová
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
High Strength ◽  
Bending Test ◽  
Reinforced Concrete Structures ◽  
Reinforced Polymers ◽  
Concrete Members ◽  
Four Point Bending

Abstract Major advantage of fibre reinforced polymers (FRPs) is their high strength and low weight to strength ratio. These are also the main reasons for a choice for this material in the process of design of reinforced concrete structures. Since there is no corrosion of FRP, this reinforcement could be strongly recommended for concrete reinforcement in aggressive environment. Till today there is no sufficient knowledge of long-term behaviour of FRP-reinforced concrete structures. Design codes give low utilization capacity of FRP materials and are not supposed to be correct according to the real behaviour in a few experiments of last decades. Reduction factors limit the mechanical properties in the range from 0.95 for CFRP to 0.5 for GFRP. In the paper there is presented a prepared and today realized long-term experimental study based on four point bending test on simply supported concrete beams reinforced with GFRP reinforcement.

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