Year: 2007

Location: Vintirov

Country: Czech Republic

Volume: 2.980 m³ expanded clay 4-8 mm

Owner Builder: Národná diaľničná spoločnosť, a. s.

Contractor: Stavby mostov Slovakia, a.s

Designer: Valbek s.r.o.

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Problem / Solution

To build a so called “green” bridge it is often necessary to use long span bridge construction (in that case 36 m). Therefore it is up to the planners to reduce the weight of each layer by finding the right choice for materials. To reduce vertical load and high vertical forces on top by covering and greening was the aim. This could be achieved on a high quality level by using expanded clay which is also a high effective material for greening.

Experience

After finishing the bridge construction a geotextile on bottom and- to prevent water penetration- a very special insulation on the wood construction where applied. The resulting horizontal forces where derived into the subsoil by backfilling with normal materials. They were used in the lower regions. Then expanded clay was delivered by truck and could be poured directly out of the track. Because of its size composition and the manipulation by caterpillars no additional compaction was necessary, so the load for the construction was a minimum.

Why expanded clay?

Using expanded clay means less weight, simply application, less efforts for compacting and therefore less dynamic load for the construction. Resistances against freezing and humic acid are additional ideal features for greening. By driving directly on and distributing the material with caterpillars it was easy to handle and to reach the right stabilization.