Interaction between the Local and General Zone for the Post-tensioned Girder Anchorage Zone

Ghassan M Werdina,Omar Q Aziz

doi:10.2174/1874149502115010050

Abstract

Background: The use of post-tensioning in girders causes high bearing and compressive stresses in the anchorage zone. In this study, the behavior of the anchorage zone and the interaction between the local and general zone are investigated. The variables included different reinforcements for both the local and general zones for a block of two anchorage devices. Methods: Both experimental and numerical methods have been applied to study the behavior of the anchorage zone. The experimental part of the study involved laboratory testing of sixteen specimens, and the numerical study was conducted using ABAQUS non-linear finite element analysis. Results: Tie reinforcement provided additional confinement for the local zone, and this confinement was more for the specimens with originally less confined spiral reinforcement strength. There was a slight or no effect of the local zone reinforcement on the general zone strength and ultimate load of the anchorage zone when the failure was in the general zone. Conclusion: Confinement of the local zone prevented the brittle bearing and compression failure of this zone.

Highlights

In pre-stressed concrete, internal compressive stresses are induced by means of pre-stressed reinforcement to reduce tensile stresses in the concrete due to applied loads
The ultimate load increased from 1190 kN (SP11) to 1341 kN (SP9) by increasing the tie bar size from φ4 mm to φ6 mm, representing an increase of 12.7%, which was more than the increase in group G2
This influence was more when the spiral bar size was less. This indicated that the tie reinforcement provided additional confinement for the local zone, and this additional confinement was more for the specimens with originally less confined spiral reinforcement strength

Summary

Introduction

In pre-stressed concrete, internal compressive stresses are induced by means of pre-stressed reinforcement to reduce tensile stresses in the concrete due to applied loads. The use of post-tensioned concrete allows for longer spans and smaller cross-sections in structures, especially bridges. Post-tensioned girders are subjected to a high concentration of compressive stresses at the anchorage zone due to the transfer of prestressing force at the girder end through bearing plates and anchors [1 - 3]. A local failure may occur in the immediate vicinity of the anchorage device if. The bending theory is not valid because the ordinarily assumed linear strain. The use of post-tensioning in girders causes high bearing and compressive stresses in the anchorage zone. The behavior of the anchorage zone and the interaction between the local and general zone are investigated. The variables included different reinforcements for both the local and general zones for a block of two anchorage devices

Methods

Results

Conclusion