Shear Carrying Capacity of Segmental Prestressed Concrete Beams

Abstract

This paper describes the results of an experimental study and nonlinear finite element method in order to examine the shear failure mechanism of segmental prestressed concrete beams by varying the length of segment, prestressing force and loading position. It is observed that after the opening of the segmental joints, the stiffness of such beams considerably decreases and the tendon stress is caused to increase significantly. The simplified truss model and other existing prediction methods for shear carrying capacity have been applied in this study in order to examine their applicability and accuracy. The simplified truss model can provide reasonable accuracy under the limitation of applied prestressing force.

Mechanical Behavior of Widening Prestressed Concrete Deck Slabs under Concentrated Load

“…When an interface element is introduced in a finite element model, the major prerequisite is that no additional deformation be introduced in the elastic stage. For this reason, the values of initial stiffness k n and k t have to exhibit a sufficiently high value to reproduce the continuous geometry of segmental concrete beams before the joint opening (Turmo et al 2006;Sivaleepunth et al 2009). However, the values of initial stiffness have to be small enough to avoid numerical problems during analysis.…”

Shear Carrying Capacity of Segmental Concrete Beams With Draped External Tendons

“…The behavior of concrete in compression and tension is modeled according to the model proposed by Thorenfeldt et al 9) and Hordijk To represent the interfacial behavior between external tendons and deviators or the concrete beam, the two-node interface element is applied. In order to neglect the friction between tendons and deviators or concrete at the beam ends the stiffness of the interface element is adopted from Sivaleepunth et al 11) . Two-node interface element is also provided in some positions to model the unbonded internal tendon as shown in Fig.…”

“…The diagonal crack from the deviator to the loading point was not formed in segmental beams with straight external tendons 1), 11) . In segmental beams with draped external tendons the diagonal cracks from deviators, however, were formed before the occurrence of the dominant diagonal crack from the segmental joint to the loading point.…”

“…(1), in the horizontal distance from the loading point. The tension members [11] and [14] from the draped tendon are formed to balance the prestressing force. The model can be …”

“…The cross sectional area of the flexural compression members is set as t f b f , where t f and b f are the thickness and the width of top flange, respectively. The cross sectional area of external tendons, A ps , is employed as the cross sectional area of members [11] and [14] in Model I and members [9], [11] and [14] in Model II. The cross sectional area of longitudinal tensile bars, A s , is provided for member [7].…”