WEGH Group has designed and developed a system of railway bridges and viaducts which use one single element filling a structural function – normally the decking – and the railway superstructure, which is usually implemented with sleepers and the ballast. This system enables Wegh to minimise the idle times of the bridge, thus dramatically reducing traffic problems. The range of railway superstructure products is completed by noise barriers which are made of special lightened concrete panels coupled with “tympanum” devices.
This type of railway bridge can be used for spans from 3.5 to 11.00 m and it consists in a set of prestressed reinforced concrete slab tracks. One self-bearing slab track serves as structural element equipped with the fastening systems to the rails; a side service slab track, which is supplied with a compartment for the cable runways and railing mounting plates, is used as sidewalk and it is designed to contain derailments, if any. In lines with two tracks the slab placed between the two rails provides for surface continuity. Each slab track in the system is placed on the existing shoulders. Its height changes according to the calculated span – from 45 cm to 84 cm. The times for PTA bridge replacement are reduced to create minimum upheaval to rail traffic overnight.
This system consists of a set of prefab elements that are assembled during the installation steps. These include an L-shaped girder made of prestressed reinforced concrete, which is the load-bearing structural element, self-bearing slab tracks of variable length depending on the bridge span, which are equipped with the fastening systems to the rails, connection beams, which are used to create a network of collaborating sleepers, and the side service walkways. The slab tracks are placed in such way that their bottoms form a continuous line at the sides of the L-shaped girders which, on their turn, sit on existing or new shoulders. Once fastened, resin is filled in the gaps between the slab tracks and the girders. Vibrations are damped through the elastomers in the fastening systems, the structure of the prefab elements that work as energy accumulators, and the application of reinforced neoprene packs on the shoulder mounts. The LPTA system is suitable for spans between 12 and 18 metres. The time for replacement of LPTA bridges with two rails or a dual span is 48 hours.
Noise barriers are made of special lightened concrete panels coupled with “tympanum” devices, which use the principle of interference while preserving a pleasant appearance. The features of the constituting materials of the noise barriers ensure a practically unlimited life cycle of the system, low maintenance costs, and a high level of self-cleaning. This is one of the best systems to solve the problem of noise pollution, especially in sensitive areas. Once installed, the barriers reduce the noise generated by trains by 5 to 15 dB, based on the dimensions of the barrier and the distance between the noise source and the individuals receiving the noise waves.