Timber bridge over the Vircava

Our services:
  • Location
    Jelgava County, Latvija
  • Year of construction
  • Dimensions
    Length: 23.4 m, span: 16 m, width: 7,9 m
  • Client
    Municipality of Jelgava County
  • Built by
  • Design
    ZAZA TIMBER Engineering SIA

During the construction of the bridge, the old road bridge was completely dismantled and a new bridge was built. The bridge is made of timber and has a stress-laminated timber deck (SLTD) covered with asphalt concrete. The beams are stressed together using 66 high-strength steel tensioning cables.

The span of the bridge is 16.00 m, providing a bridge without intermediate supports to improve the flow of the river, as well as reduce the formation of ice congestion and river sediments. The bridge is designed to support up to 60 tons load and last at least 100 years.

Besides chemical protection the stress-laminated timber deck also is protected mechanically - with waterproofing layer under asphaltconcrete and plank cladding with stainless steel sheeting on longitudinal sides.

The shore support is made of monolithic reinforced concrete with 4 CFA type drilling piles with a diameter of 880 mm and a length of 9 m on the right bank and 11 m on the left bank.

“This is the largest stress-laminated timber deck transportation bridge in Latvia and the first this kind of bridge with asphalt concrete wearing surface in the country. Although in Scandinavia these types of timber bridges are designed and built for almost 30 years, there is minimal experience in Latvia. So we used extensively handbooks, publications and reference projects from Sweden and Norway to be able to design and assembly prestressing systems, connections, barriers, asphalt concrete layers, foundations and curbs. Also, waterproof layer and barriers specially made for stress laminated timber deck bridge were available only in Scandinavia," comments bridge engineer Rainers Daugava.

For the stress-laminated timber deck we manufactured 61 glued-laminated timber beams (each beam width 115 mm and height 880 to 964 mm). The glulam beams, made of pine (strength class GL28H), had undergone pressure treatment twice – before and after gluing. The beams include CNC-milled condensation drainage system.

Both kerbs of the bridge too are manufactured from glulam. The total glulam volume in this project was 111 m3, the largest parts were 115 x 970 x 16600 mm.

We also produced panels of plank cladding for both sides of the bridge; the panels can be detached and reattached to the deck to facilitate inspection and maintainance works.