2017

Innovative Wood Technologies have been Used in the Restoration of the Bridge over the River Menčupīte

At the end of the last year, a 11.3 metre-long bridge over the River Menčupīte reconstructed by JSC "Latvia's State Forests" (LVM) was opened in Kocēni Municipality Zilaiskalns Rural Territory. In the reconstruction process, the historical values and characteristics of the bride have been preserved. This is the first bridge in Latvia that is intended for road traffic and is made of prestressed glued wooden structures, in the construction of which two natural materials - stone and wood - have been used.

"It once again demonstrates the ability of the Latvian forest industry to ensure good quality results in a short time, using wood. Wood is a renewable resource, and any object in which it is used, promotes development of the forest industry. Using glued and bent wooden structures, it is possible to perform construction works much faster and cheaper than with the classical methods, at the same time meeting the load-bearing capacity, durability and other essential requirements," says Andrejs Domkins, Director of the Forest and Wood Products Research and Development Institute (MeKA).

At the crossing point of the River Menčupīte, there were stone pillars of the narrow-gauge railway line Smiltene - Valmiera - Ainaži built at the beginning of the 20th century. The cultural heritage - the historic rubble pillars - has been preserved in the bridge restoration process. In addition, innovative wood technologies have been employed in the bridge construction: the span was made of prestressed glued wooden structure, and the roadway – of a double plank deck. Wood has also been used in other bridge structures: glued wood bridge railings, a wood shielding barrier in the bridge access area, road sign shields made of plywood, wooden traffic sign poles. The bearing capacity of the bridge is 60 tons.

Such construction projects had not been implemented in Latvia before; therefore constructors had to search for new technical solutions, study the building materials available on the market and the experience of other countries in the construction of similar facilities. In Scandinavia and Western Europe bridges of a similar type are built already for more than 20 years.

The glued wooden beams were manufactured in Lithuania, while beams were impregnated (treated against moisture and fire) in a factory in Jēkabpils, to ensure timber longevity and resistance to stress and external environmental effects. After impregnation, beams were delivered to the construction site in Kocēni Municipality to set up the slab and insert and tension the reinforcement bars.

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The bridge construction design was developed by LLC "Inženierbūve". LLC "Limbažu ceļi" won the tender for construction works and entered into a partnership of suppliers, entrusting the bridge construction works to LLC "Viadukts". Construction works at the site were launched on 27 September 2016, and completed - on 9 December.