|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1996 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1995 : ¥1,300,000 (Direct Cost : ¥1,300,000)
In this study, an effective arrangement of the external cables was, first, determinated after the discussion of numerical results using force method. Next, the fundamental relationships between stress and strain in concrete for the analysis of long-term behavior due to dreep and shrinkage were derived. The stress resultants and its changes of concrete slab and steel girder in composite girder, where sustained bending moment and normal force force apply at the neutral axis of the composite section, were also derived. The stiffness matrix method, in which an eccentrical connection of the cable to the girder is taken into account, was applied for the analysis of behaviors in whole structure.
On the other side, in oder to verify the propriety of analytical method, comparativelly a large test specimen of two-span continuous composite girder was fabricated and the tests of introducing of prestressing force by the cables and long-term behavior were carried out.
The main results in this study are summarized as follows :
1) Introducing of prestressing force to the composite girder can be done easily by using external cable.
2) Long-term behaviors of composite girder can be evalusted comparativelly with good accuracy by analytical method which developed in this study.
3) Long-term behaviors of multi-span continuous composite girder bridges with external cables are estimated using the analytical results of four-span continuous one.
4) The loss of prestressing force of the cable due to creep and shrinkage may be englected in designing of composite girder bridge.