Cable-stayed bridges with timber supporting structure

Pylon bridges are optimally suitable for span widths from 30 m

The main supporting structure consists of a roadway support, one or several pylons and steel anchoring. The pylons are made from timber or steel and are back-anchored in the roadway support or separately. The anchoring on the roadway supports replace the supporting structures and allow for particularly high span widths. The roadway supports generally consist of block-bonded laminated timber and can run on either a single-axis or curved double-axis basis.

Attributes of pylon bridges:

• Sophisticated supporting structure with low girder heights
• Wide variety of designs
• Variable in terms of height and layout
• The roadway surface runs over the covered main supporting structure
• Design of the road surface in the form of mastic asphalt, alternatively with concrete components or large-format natural stone slabs

Protected main supporting structure

Structural timber protection is the key to the longevity of a timber bridge. Structural timber protection intends for all structural timber components to be completely protected. In this respect, the following steps are taken into consideration: Installation of technically dried timber with a timber humidity of 12% in order to prevent insect infestation, protection against weathering, ingress of moisture, UV rays due to the installation of projections and skirting in the design as well as good air circulation to encourage drying out. Constructions designed in this way satisfy the requirements of protected timber bridges pursuant to DIN EN 1995-2 NA. This means that loss events are prevented and maintenance costs are minimised, and the use of timber preserving chemicals can be reduced and/or avoided. Structures protected according to DIN EN 1995-2 have a service life of 60 - 80 years*.

* Source: Redemption amounts calculation regulations - ABBV, BMVBS, status 2010 and study of DGfH 2006

Advantages of the pylon bridge:

• optimum cross-section use for individual span widths of 10.0 m to approx. 15.0 m with total span widths of over 70m
• Considerable leeway of design such as S-shaped or circular layouts
• Pylons in the form of pin pylons or in H or A shape with recognition value
• Streamlined construction height of the horizontal supporting element
• Relocation of the main supporting structure to the river banks (with bridges over water)

References:

Here is a selection of pylon bridges with timber supporting structures.