Cable-stayed bridges

Cable-stayed structures are a type of structure that use cables, stays, tendons and other items submitted to traction.

This type of structure refers, almost exclusively, to structures whose deck is suspended by one or various pilings by means of cables, such as bridges. In these structures, the piling (made in a plant) works under compression, while the cables support traction force

We have a wide range of patents for tensioning steel cables, and we are especially known for our cable-stayed bridges system. These are often used in large constructions for road infrastructure (such as viaducts), cutting-edge airports or singular buildings.

Construction with suspension cables or tendons

Nevertheless, cable-stayed structures include more than just bridges and footbridges, they also make use of tendons:

• The roof of the Heathrow airport or the Terminal 4 at Barajas Airport also used these types of structures to help distribute internal tension.
• Train catenaries.
• Lighting for large areas.

All cables — generally braided steel cables or cross-section tubular cables — assume a polygonal shape when the load is concentrated, a catenary shape when acting under its own weight, or parabolic when subjected to a uniformly distributed load. These types are shown in the image below:

When used in bridges, large structures or singular construction, the most common turnbuckle is a braided steel cable. Leading companies in the sector, such as Tecpersa, use individual steel tendons that are individually protected by means of high-density polyethylene sheath and wax, which are also contained in collective sheaths.

Benefits of cable-stayed structures

The main reason we work with this specific method is to add protective barriers against corrosion that increase the resilience and final quality of the infrastructure. In addition to gradual detensioning, cable corrosion is one of the largest maintenance expenses for cable-stayed structures.

In the first phase, the tensioning of steel tendons is carried out by means of a unitary jack to ensure that all the cables maintain the same level of tension and that none of them are supporting an excessive load. Throughout successive testing phases (tendon by tendon or by means of a multiple jack), the tension of each cable is regulated until the hypothesis of the final load of the structure is obtained.