Nonlinear and time-dependent analysis of continuous unbonded prestressed concrete beams

Lou, Tiejiong; Lopes, Sérgio M.R.; Lopes, Adelino V.

doi:10.1016/j.compstruc.2012.12.014

Cited by 44 publications

(31 citation statements)

References 17 publications

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“…A numerical model was recently developed to predict the geometric and material nonlinear response and the time‐dependent service‐load behavior of continuous beams prestressed by unbonded tendons . The analysis reproduced the experimental results of continuous beam specimens with favorable agreement.…”

Section: Introductionmentioning

confidence: 81%

Experimental investigation of continuous two-layer reinforced concrete beams

Iskhakov

Ribakov

Holschemacher

2017

Structural Concrete

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Funding informationAlexander von Humboldt Foundation.Models and full-scale statically determinate two-layer beams (TLBs) made of steel-fiber high-strength concrete (SFHSC) in the compression zone and normalstrength concrete (NSC) in the tensile zone have been tested by the authors. The present study is a further stage of these investigations, focused on testing a continuous, two-span TLB with optimal steel/fiber ratio as in the previous stages. This is the first experimental investigation of continuous TLBs (CTLBs). The study is aimed at testing the CTLB behavior under positive and negative bending moments in the span and above the middle support. An additional issue that is studied in the course of this work is the influence of bending moment redistribution on the behavior of a CTLB. As in the previous research stages, interaction of the concrete layers in a CTLB was studied to demonstrate the efficiency of such beams for real structures. No cracks between the SFHSC and NSC layers were observed up to the ultimate limit state of the tested beam, which demonstrates proper interaction between the layers. The results obtained in the present study enable the recommendation of CTLBs for practical application as effective and economical continuous bending elements. K E Y W O R D Scontinuous two-layer beams, interaction between concrete layers, steel-fiber high-strength concrete | INTRODUCTIONAs is known, the main drawback of simply supported reinforced concrete (RC) beams is the relatively large moments in the span, which leads to large deflections and extensive cracking. Moreover, in simple statically determinate RC structures there is no internal moment redistribution, so the section in which the moment is maximum determines the load-bearing capacity of the structure. A solution to this problem is the use of continuous (statically indeterminate) RC structures that allow reduction of the maximum moment and deflection. In continuous beams, the moments above the supports and those in the span are redistributed, permitting the use of typical longitudinal reinforcement.One of the first theoretical works on continuous RC beams was carried out by Gvozdev, 1 which was focused on the load-bearing capacity of such beams. According to this method, each of the beam bays is loaded and the corresponding load-bearing capacity for the loaded bay is found. An equation for the calculation of the external bending moment in a certain loaded bay was proposed. The problem was solved for a beam with constant section dimensions by maximizing the internal forces. In a more general form, the problem of maximization of the internal forces for continuous RC beams was recently solved theoretically. Two-layer high-performance RC beams can be used in the traffic (longitudinal) direction of long-span bridges. The beam section consists of two parts: a bottom part made of normal-strength concrete (NSC), and an upper one made of steel-fiber-reinforced high-strength concrete (HSC). Using two-layer beams (TLBs) is logical because, as the beam span beco...

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Section: Introductionmentioning

confidence: 81%

Experimental investigation of continuous two-layer reinforced concrete beams

Iskhakov

Ribakov

Holschemacher

2017

Structural Concrete

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“…A previously developed numerical model [24] is used here to conduct the parametric evaluation of the redistribution of moments in continuous concrete beams prestressed with external CFRP tendons. The time-dependent effects are neglected in the present study, but the modeling of these effects can be found elsewhere [25]. The proposed model is based on the finite element method, and accounts for both geometric and material nonlinearities.…”

Section: Nonlinear Modelmentioning

confidence: 99%

Factors affecting moment redistribution at ultimate in continuous beams prestressed with external CFRP tendons

Lou

Lopes

2014

Composites Part B: Engineering

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Please cite this article as: Lou, T., Lopes, S.M.R., Lopes, A.V., Factors affecting moment redistribution at ultimate in continuous beams prestressed with external CFRP tendons, Composites: Part B (2014), doi: http://dx. Abstract: A numerical investigation of redistribution of moments in continuousconcrete beams prestressed with external carbon fiber reinforced polymer (CFRP) tendons at failure loads is described. A finite element analysis (FEA) model is introduced, and an extensive parametric study is carried out on two-span continuous beams. The factors examined in this study include the content of non-prestressed steel, tendon eccentricities, tendon area, effective prestress, span-to-height ratio, concrete strength, CFRP modulus of elasticity and load type. The results obtained from FEA are compared with those obtained from various codes. The study shows that the importance of some factors is not reflected in the codes. When used to calculate the degree of moment redistribution in these beams, the parameter ε t (net strain in extreme tension steel) seems to be more reasonable than the parameter c/d (ratio of neutral axis depth to section effective depth). A simplified equation for calculating the degree of moment redistribution at ultimate is proposed.

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“…A finite element model has been 24 developed and is validated against the available test data. A numerical test is carried out on two-span 25 continuous bonded prestressed concrete beams.…”

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confidence: 99%