On the construction site HWS Baltschiederbach the existing dam will be raised to protect the inhabitants of Baltschieder from future storms.
Where slopes descend, water penetrates or corrosion sets in, where vehicles drive through continuously and heavy traffic increases steadily, structures can be heavily stressed over the years and damaged over time. Reinforcement measures are needed everywhere. The Volken Group also offers strong services in this area. The latest findings in technology, standards and materials science are always incorporated.
Whether we are maintaining bridges, renovating galleries or rehabilitating tunnels: When it comes to rehabilitating engineering structures for our mobility, the Volken Group brings many years of experience and strong know-how to the table – throughout the Valais and far beyond. We have planning, logistics and execution for a wide range of measures under control and carry out repairs even with heavy traffic.
Maintenance work is always an issue. But no one likes to be disturbed on the road. When roads and their engineering structures are being renovated, there is often no way to get around them. That's why this work often takes place during heavy traffic. A number of safety regulations must be observed at all times.
The restoration program has a number of key objectives. The main objectives are to preserve the structure, to ensure adequate safety, to maintain or restore serviceability and to optimize maintenance operations cost-effectively. Today, most of the structures have reached the end of their useful life and have to cope with the current and future increase in traffic, especially heavy traffic. Therefore, structures such as galleries or bridges have to be strengthened and damaged sections, waterproofing or drainage systems have to be repaired.
Ongoing periodic inspections are carried out to check the condition of the structures and initiate appropriate action. Today, for example, bridges show signs of corrosion of the reinforcement as well as corroded, worn and leaking expansion joints. Chlorides have partially reached the reinforcements, which can lead to pitting. Through the development of rehabilitation and reinforcement concepts, an intervention-free operating time of approx. 15 to 20 years is guaranteed today.
Concrete ages - this is not new. Due to weathering or road salt, concrete corrosion begins, carbonation of the outer concrete layers follow, leading to a reduction in alkalinity and thus to corrosion of the steel reinforcements. The smaller the cover, the quicker the concrete needs to be rehabilitated. However, this is not the only problematic aging phenomenon. There is also the alkali aggregate reaction (AAR), which starts deep in the structure of the concrete. The phenomenon is quickly described - and once again a problem of moisture. Depending on the water exposure, it penetrates the concrete at different rates, where it forms alkalis with the alkaline constituents of the cement. These in turn react with the silicate aggregates sand, gravel, quartz, feldspar. The result is the aforementioned alkali-calcium-silicate hydrate, which is capable of storing further water. This in turn results in an increase in volume of the concrete structure, which becomes visible as cracks. Our mission is to remove the damaged areas and stop the concrete corrosion. This is done by applying new reinforcement protection and concrete re-profiling using repair mortar or concrete. This can be done by spraying or conventionally (pre-concreting with vibration). At the end, a surface protection is applied.
In order for replacement and protective coatings to be applied, the substrate must be load-bearing. Damaged concrete usually does not meet these requirements. In this case, its surface must be free of friable parts, cracks, cavities or foreign substances such as rubber abrasion. Depending on the degree of damage, we remove concrete down to the surface or even to the outer reinforcement. Our partner companies use hydrojetting for this purpose: This high-pressure process works with a punctiform water jet that hits the concrete with several hundred bars of pressure. This does not trigger any vibrations and does not damage the components to be preserved. Once a substrate has been prepared accordingly, we apply additional layers, if necessary also with additional reinforcement.
Artificial structures have to withstand a lot. Galleries, for example, protect road users from avalanches and rockfalls. To prevent such risks, the Volken Group carried out reinforcement measures on the "Meggeri-Kapf-Schallbett" section of an existing gallery on the Simplon by anchoring the gallery roof back into the rock with additional anchors and reinforcing the roof structure with reinforced supplementary concrete. In addition, we installed glass ballast on the gallery roofs to dampen the impact of rock fragments.
Heavy traffic, in particular, causes severe damage to road surfaces. If the damage exceeds a certain level, it is no longer sufficient to repair only the top layer of a surface. Heavily damaged roads require complete rehabilitation: all asphalt layers are removed and then a new base, binder and surface course is paved.
When roads are comprehensively rehabilitated, the drainage systems are often renewed as well, and new shafts are built for the infrastructure of operating equipment or for telecommunications. In addition, the safety of road users is increased with hydrant lines that meet new standards.