Title:
Structural Behavior of Tendon Coupling Joints in Prestressed Concrete Bridge Girders
Author(s):
Byung Hwan Oh and Sung Tae Chae
Publication:
Structural Journal
Volume:
98
Issue:
1
Appears on pages(s):
87-95
Keywords:
construction joint; coupler; prestressed concrete; stress; tendon
DOI:
10.14359/10150
Date:
1/1/2001
Abstract:
Recently, segmental construction of prestressed concrete (PSC) girder bridges has been widely employed in many countries. In these segmentally constructed prestressed concrete bridges, many construction joints exist, and these construction joints require coupling of tendons to introduce continuous prestress through the superstructures of bridges. The purpose of this paper is to investigate in detail the complicated stress distributions around the tendon coupling joints in PSC girders. A comprehensive experimental program has been set up, and a series of test members have been tested to identify the effects of tendon coupling. The present study indicates that the longitudinal and transverse stress distributions of PSC girders with tendon couplers are quite different from those of PSC girders without tendon couplers. The longitudinal compressive stresses in concrete introduced by prestressing are decreased by approximately 35% in the vicinity of tendon coupling joints for the coupling ratio of 50%, and this reduction of compressive stresses reaches up to 70% around the coupling joint of fully coupled members. Large reduction of compressive stresses in concrete around the coupled joints may cause serious cracking problems in PSC girder bridges due to tensile stresses when live loads, shrinkage, and temperature effects are superimposed. The analytic results by finite element analysis correlate very well with test data on the complex strain distributions of tendon coupled members. This paper indicates that approximate amounts of reinforcements are required around the coupled joint to avoid deleterious cracking. This fact is not reflected realistically in the current design codes and must be taken into account correctly for the safe and reliable design of PSC bridge girders.