scholarly journals Indirect Determination of Residual Prestressing Force in Post-Tensioned Concrete Beam

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1338
Author(s):  
Jakub Kraľovanec ◽  
Martin Moravčík ◽  
Petra Bujňáková ◽  
Jozef Jošt
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Load Test ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Significant Deterioration ◽  
Indirect Determination ◽  
Prestressing Force ◽  
Post Tensioned

A diagnostic survey on the precast prestressed bridge Nižná confirmed significant deterioration due to environmental distress. Evidently, decisive failures of the structure have a similar character as in the previous precast prestressed bridge in Podbiel in the northern part of Slovakia. These failures result from the unsuitable concept of the first generation of precast prestressed concrete beams, which was used in the former Czechoslovakia in the second half of the 20th century. Subsequently, experimental verification using the proof-load test was also executed. This bridge was built in 1956, so at the time of testing, it was 60 years old. The paper presents the indirect determination of prestressing level in one precast post-tensioned concrete beam using the saw-cut method. Experimental measurement was executed during the bridge demolition. Subsequently, a 2D numerical model in ATENA 2D Software, with the assumption of nonlinear material behavior for verification of experimental results, was performed. Finally, the residual prestressing force was evaluated and compared with the expected state of prestressing according to Eurocodes after 60 years of service.

Experimental Studies on Bearing Capacity of Post-Tensioned Unbonded Prestressed Concrete Hollowed Floors

2011 ◽  
Vol 368-373 ◽  
pp. 159-163 ◽  
Author(s):  
Xiao Hua Yang ◽  
Chao Yang Zhou ◽  
Xue Jun He ◽  
Zhi Qing Yang
Keyword(s):  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Plastic Hinge ◽  
Experimental Studies ◽  
Load Test ◽  
Test Results ◽  
Three Stages ◽  
Hinge Model ◽  
Good Agreement ◽  
Post Tensioned

A 1/4 scales four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the ultimate load test on the second-storey floor. By measuring the floor deflection, stresses of steel bars and cracks of floors, the bearing capacity of floor is explored. The bearing capacity tests of floor are divided into three stages: elastic stage, crack growth stage and destruction stage. Based on the test results and crack developments in floor, a improved plastic hinge model is carried out to predict the ultimate loads. The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.

Application of a Unified Constitutive Theory to the Nonproportional Multiaxial Strain Deformation of 1045 Steel

1992 ◽  
Vol 114 (2) ◽  
pp. 147-155 ◽  
Author(s):  
J. A. Sherwood ◽  
E. M. Fay
Keyword(s):  
Inelastic Strain ◽  
Material Model ◽  
Flow Equation ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Unified Theory ◽  
Strain Plasticity ◽  
Dependent Strain ◽  
1045 Steel

An automated procedure for the determination of the material constants in a constitutive equation which is used to model the multiaxial nonlinear material behavior of isotropic materials is discussed. The material model used in this research is a unified theory where the time-dependent strain (creep) and time-independent strain (plasticity) are treated as one (unified) inelastic strain. The flow equation considers the inelastic rate of strain and it is assumed that inelastic strain is present at all levels of stress. Application of the model to proportional and nonproportional biaxial loadings is presented.

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.

An Experimental Study on Effectiveness of Reinforcing Methods on L-Shaped Prestressed Concrete Beam-Column Joints

2008 ◽  
Vol 400-402 ◽  
pp. 887-892
Author(s):  
Wei Yue ◽  
Minehiro Nishiyama
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Experimental Results ◽  
Longitudinal Reinforcement ◽  
Reinforcing Bars ◽  
Positive Direction ◽  
Prestressed Concrete Beam ◽  
Prestressing Force ◽  
Loading Tests ◽  
Cyclic Loading Tests

This paper presents experimental results of cyclic loading tests carried out on three L-shaped prestressed concrete beam-column corner joints. Three types of reinforcing methods to enhance the anchorage performance of beam and column longitudinal reinforcing bars were studied based on the experimental results such as the load-displacement relation curves, deformation capacity, prestressing force variation, and strain measurements of the beam and column reinforcing bars. The test specimens were KPCL1 with the column longitudinal reinforcement with 180-degree hooks at their ends, KPCL2 with the column longitudinal reinforcement bent in a U-shape, and KPCL3 with U-shaped column longitudinal reinforcement and additional transverse reinforcement on the beam longitudinal reinforcement. It can be concluded that the anchorage performance was somehow enhanced by the three reinforcing methods in the positive direction of loading (closing direction), while in the negative direction of loading (opening direction) there was no remarkable improvement.

scholarly journals Research of post-tensioned concrete composite spans with Π-beams of road viaduct

2018 ◽  
Vol 174 ◽  
pp. 03015
Author(s):  
Arkadiusz Mordak ◽  
Zbigniew Mańko
Keyword(s):  
Prestressed Concrete ◽  
Load Capacity ◽  
Static Field ◽  
Load Test ◽  
Static Loads ◽  
Heavy Trucks ◽  
Actual Load ◽  
Analysis Of Results ◽  
Deck Slab ◽  
Post Tensioned

The paper is presented the results of research conducted on the posttensioned prestressed concrete spans made with precast Π-beams of part of seventh spans Eugeniusz Kwiatkowski road viaduct located in Gdynia (between supports no. 97-104) under static field load test. Heavy trucks were used as static loads. Superstructure (main beams), deck slab, and fixed and moving bearings, and also supports (abutment and piers) in both roadways of trestle were tested. Specification and range of conducted research are presented with analysis of results from the tests and calculation, which allowed to the estimate span structures behavior and their actual load-capacity before allow them to normal service on B-class of loads.

Determining the Remaining Prestress Force in a Prestressed Concrete Crosstie

2017 ◽  
Author(s):  
James D. Scott ◽  
Aaron A. Robertson ◽  
Robert J. Peterman ◽  
B. Terry Beck ◽  
Kyle A. Riding ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Crack Opening ◽  
Systematic Evaluation ◽  
Load Testing ◽  
Opening Displacement ◽  
Cross Sectional ◽  
Prestressing Force ◽  
Bending Resistance

The research presented herein focuses on determining the amount of internal prestressing force and bending resistance that is necessary to provide a durable long-term concrete railroad tie. In order to accomplish this, the researchers conducted a systematic evaluation of existing concrete ties that successfully withstood over 25 years of service in track. An experimental method for determining the remaining prestress force in these existing prestressed concrete railroad ties is currently under development. The ties are first loaded in the upside-down orientation, with supports located at the rail seats, and two point loads applied at the center of the tie. A loading rate of 1,000 lb/min was used to initiate flexural cracking in the center of the tie. Once cracking was observed, the ties underwent 200 cycles of loading to reduce the friction between the prestressing tendons and the concrete. When the cycling was completed, the existing crack was instrumented with an extensometer to measure the Crack Opening Displacement (COD). The ties were loaded once more at 1,000 lb/min to develop a Load vs. COD relation. A systematic method of determining the load required to reopen the crack from the Load vs. COD relation is being developed using ties cast at a manufacturing plant that were instrumented with internal vibrating-wire strain gages. Using the load required to reopen the crack, along with the known cross-sectional properties at the center of the tie, the remaining prestress force is calculated through equilibrium of forces. This method allows for the determination of the remaining prestress force in a member with known section properties to be obtained through load testing.

scholarly journals Ductility of prestressed concrete members

1971 ◽  
Vol 4 (1) ◽  
pp. 145-170 ◽  
Author(s):  
R. W. G. Blakeley ◽  
R. Park
Keyword(s):  
Prestressed Concrete ◽  
High Intensity ◽  
Concrete Beam ◽  
Analytical Determination ◽  
Prestressing Steel ◽  
Concrete Members ◽  
Load Factors ◽  
The Moment ◽  
Reinforcement Distribution

An analytical determination of the moment-curvature relationships of prestressed concrete members under high intensity monotonic loading is presented, and compared with experimental results. The effects on ductility of such variables as transverse reinforcement, distribution of the prestressing steel within the section, steel area ratio, and axial load are described. A comparison is made of the ductility available in comparable prestressed and reinforced concrete members. The results of tests on prestressed concrete beam-column assemblies under high intensity cyclic loading are referred to and conclusions are drawn on the seismic resistance of prestressed concrete members. Load factors for seismic design are discussed.

Parametric Study on Reinforced Concrete Beams with Transversely Prestressed Bars

2011 ◽  
Vol 105-107 ◽  
pp. 912-917
Author(s):  
Can Liu ◽  
Bo Wu ◽  
Kai Yan Xu
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Parametric Study ◽  
Concrete Beam ◽  
Steel Plate ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Force Level ◽  
Prestressed Concrete Beam ◽  
Prestressing Force

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, parametric study was carried out to analyze the behavior of transversely prestressed concrete beam, and the following conclusions can be drawn: (a) With the increase of the prestressing force level, the shear capacity of transversely prestressed concrete beam increase rapidly, which means that prestressing force level has a significant effect to the shear capacity of transversely prestressed concrete beam. (b) If the area of transversely prestressing bars is almost same, the transverse bars with smaller diameter and smaller spacing can enhance shear capacity of transversely prestressed concrete beam more efficiently. (c) If steel plate of 100 mm×350 mm×16 mm being changed to steel padding of 100mm×100mm×16 mm the shear capacity of transversely prestressed concrete beam will decrease little. It means in the actual engineering the steel plate can be changed to steel padding, and then the amount of steel will be reduced.

scholarly journals Kustīgās slodzes dinamiskās iedarbes uz autoceļu tiltiem eksperimentāla izpēte un novērtējums

2021 ◽  
Author(s):  
Ilze Paeglīte
Keyword(s):  
Dynamic Load ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Dynamic Performance ◽  
Reinforced Concrete Beam ◽  
Load Test ◽  
Traffic Load ◽  
Dynamic Amplification Factor ◽  
Index Method ◽  
Dynamic Index

Using data obtained from the dynamic load testing of bridges a method was developed to evaluate level of the dynamic performance without performing a dynamic load test. In this method a dynamic index of the bridge is calculated. Dynamic index allows to evaluate the dynamic performance level of existing and new structures taking into account such bridge parameters as span length / height ratio, natural frequency, vibration damping coefficient, relative deflection and international roughness index IRI. Dynamic index method can be used by bridge owners and maintainers to determine the dynamic potential of a particular bridge. The maximum allowable values of the dynamic amplification factor for standard prestressed concrete beam bridges were determined. These values were calculated for maximum allowed traffic load in Latvia. The obtained results can be used for the safety assessment of existing and reconstructed reinforced concrete beam bridges.

Sign in / Sign up

Export Citation Format

Share Document