Our services
Cable-stayed and suspension bridges
We build cable-stayed and suspension bridges in places where significant spans need to be crossed while minimising visual interference within the environs. The prestressed concrete structure itself is made using one of the techniques used for building monolithic bridges. In a deviation from the standard procedure, we build pylons to carry the structure by means of special cables. Depending on the actual arrangement, the bridge, when completed, is described either as a cable-stayed bridge (the supporting cables terminate directly in the superstructure) or a suspension bridge (the main cables are tensioned between the pylons with the superstructure being carried by suspenders attached at intervals to the main cables).
Monolithic bridges
When building monolithic bridges, we rely mainly on four tried and tested techniques. Short- and medium-span bridges, usually featuring a lower number of girders, are cast using fixed falsework carried by a system of auxiliary supporting structures consisting of assembled PEINER- and PIŽMO-type supports. In some cases, rolled steel or welded beams are used. Where suitable, we alternatively use modern, light box systems. We have modified this technique for use in building multi-span bridges where we use fixed falsework and movable formwork.
Building monolithic bridges by casting in-situ on movable falsework achieves the lowest cost per square metre for multi-span bridges. This cost efficiency comes from the technique’s relatively low demands in terms of material, equipment and labour. What’s more, the cost efficiency increases with the number of spans, which makes it especially suitable for long bridges, e.g. spanning valleys at heights of up to 20 metres above the terrain. Typically, such bridges would use girders of a TT section design.
Bridges of medium to long spans are often built using cast-in-place segmental construction. In our practice, this approach is usually applied when building bridges with spans from 100 to 150 metres. Using this method, individual spans are cast in place from a pier advancing symmetrically in both directions. This approach offers several benefits: there is no interference with the space between piers, the decks can be shaped as required, and the approach can be used for building bridges of considerable heights.
When using the incremental launching method to build a monolithic bridge, the deck is cast in-situ, usually close to one of the future bridge’s abutments. Using hydraulic jacks and a movable structure, the cast section is pushed into position. This technique was especially beneficial, for example, when building the new bridge across the Vltava River in Davle, just south of Prague.
Prestressed bridges assembled in-situ
We also build bridges by assembling them from individual pre-cast girders. It is a quick and cost-efficient method, highly suitable, for example, for the construction of long viaducts. Individual segments are cast using high-quality concrete and subsequently installed on piers, usually by means of a heavy mobile crane. Once in place, adjacent segments are tied by means of a monolithic slab of reinforced concrete.
Steel bridges
The superstructure of steel bridges, which have a long tradition, most especially in railway construction, is made of steel girders in various designs, such as truss, beam or arch. The speed of assembly, the possibility of prefabrication with little impact on existing traffic, and lower weights compared to reinforced-concrete structures make steel bridges suitable candidates also for reconstructions.
Bridge repairs and reconstructions
At present, we most often perform repairs on bridges erected in the 1960s to 1980s. Bridges dating to this period often manifest defects caused by component malfunctions, insufficient protection of reinforcements and/or low quality of the concrete used. Bridges can also become outdated in terms of current demands on the load rating. When repairing or reconstructing bridges, we can deliver a completely new roadway including insulation layers, reinforce superstructures by means of composite slabs, or replace bearings. Repairs often also include the restoration of the concrete surfaces of bridge components. Where necessary, we can replace the complete superstructure.
Footbridges
We always design our footbridges with respect to the surroundings. So that they blend in naturally, we may use timber, steel, reinforced concrete or high-strength concrete to achieve the best result. Some of our footbridges feature steel suspension systems. We are often tasked with repairing or reconstructing footbridges damaged or destroyed by floodwaters. A fitting example of our capabilities is provided by the footbridge crossing the Těchlovický brook in the municipal park in Stříbro. Building the footbridge was quite a challenge due to the limited space that precluded the use of heavy machinery. We therefore used smaller equipment and transported the footbridge superstructure to the site by means of a funicular.
