Construction Stage Analysis of Cable-Stayed Bridges

Marko Justus Grabow

"Abstract

Different means and methods exist in the construction industry for the erection of bridges. In the
planning and the execution of the complex construction operations, the effects of the chosen
erection methods need to be taken into consideration to achieve a safe and economical process.
For a defined span range, the cable-stayed structure is a bridge type which offers an aesthetic
shape and also a cost-effective solution for crossing rivers and valleys. The Cantilevering
Method is a widely used procedure for the construction of the superstructure.
In the structural analysis of this process, changes in the geometry and boundary conditions as
well as the material properties and other structural details must be considered. Temporary
construction loads and boundary conditions act only during the construction, depending on the
method and the sequence of the erection. However, these construction loads can produce
considerable stresses in the unfinished structure. Due to its lack of resistance against failure, a
detailed investigation prior to the construction is essential.
Not only the influence of individual structural elements, such as the non-linear behaviour of the
stay cable, but also the performance of the composed structure in the various stages must be
taken into account. Furthermore, time dependent material properties such as creep and shrinkage
play a major role, especially in the case of bridges where the main girder is fabricated of cast-in
situ concrete segments or composite sections. The issues and considerations required to develop
a save and economical construction sequence are expatiated in this thesis.
An example of a construction stage analysis is provided in detailed for the Second Jindo Bridge.
This bridge is a steel cable-stayed bridge with a main span of 344 metres, and is erected with the
Cantilever Construction Method. The overall construction process is modeled and analysed."