Kruunuvuorensilta Bridge Construction-Design Story Pt. 2

Dear bridge engineering community!

As announced in pt.1 (10/28/2022) I promised that we discuss a little bit about the installation method. The cable-stayed part of Kruunuvuorensilta bridge was originally designed to be constructed with the cantilever method. It was later decided by the contractor that the construction method is changed, and temporary supports will be used. The main reason for this change was to save time because the pylon and the deck can be built simultaneously. ?The bridge site is also well suited for this method because the sea is relatively shallow here. The steel segments are brought to site with barge and lifted in-place with marine crane in four (≈50 m) pieces per span. While the pylon is being built up the deck slab is being casted simultaneously. Then starts the cable works. Cables are installed starting from the West side and after two cables are installed the corresponding cables are installed on the East side. This sequence is repeated until all the cables are installed. Finally, the main spans are connected into the approach spans. Further details about the construction design of the cable-stayed part will be discussed in future releases which I will be sharing with you later.

The approach spans will be incrementally launched which has already started from the East (Kruunuvuori) side. So far, three spans have been launched and the measurements show that those have gone well. The interesting part about the incremental launching of Eastern approach spans, and even a little challenging as well, has been the bridge geometry. The geometry of the Eastern approach spans is in constant slope in elevation-plane, but this is not all. In plan-view, the geometry is S-shaped and made from polygonal segments, so let me tell you, these two items combined brought a few additional things to consider. I will explain and discuss this with you more thoroughly in the next part.

Until then, stay tuned!!!