How do I design an overpass bridge

First integral pre-stressed carbon concrete bridge

In the Peter-Behrens-Halle of the Institute for Civil Engineering at the TU Berlin, the prototype of what is said to be the world's first integral pre-stressed carbon concrete bridge was built. Now the tests begin.


It will take a while before the first carbon-reinforced bridge with a six-lane motorway and a clearance height and width of 4.70 x 36 meters spans a street or a river, and it will take a few more tests. Among other things, such tests are now taking place in Berlin-Wedding, in the Peter-Behrens-Halle of the Institute for Civil Engineering at the TU Berlin on the historic AEG site.

2019 | OriginalPaper | Book chapter

Reinforced concrete

Similar to other composite materials, the composite partners steel and concrete are each assigned specific tasks.

A 20-meter-long test bridge with carbon concrete reinforcement was built there, on which short and long-term experimental studies are carried out. Among other things, weights that weigh tonnes will be stored on the test bridge for around a year. Dr.-Ing. Alex Hückler from TU Berlin says: "For the investigations, the pre-tensioned carbon strands are located in a thin channel across the bridge. From time to time, mini cameras can be used to check how the material inside the bridge behaves under load. what signs of fatigue occur, etc. "

Corrosion-free and economical

The Department of Design and Construction - Solid Construction is a partner of the BMBF joint project "C³ - Carbon Concrete Composite", at the TU Berlin it is coordinated by Prof. techn. Mike Schlaich. One of the aims of the project is to replace steel reinforcement. Because: Corrosion damage is one of the most common types of concrete damage, as Dr. Michael Stahr writes in the chapter "Concrete and Reinforced Concrete" of the Springer textbook "Bausanierung". Even the smallest cracks in the concrete can penetrate water and damage the steel reinforcement. The problem affects tunnels, roofs, building facades and large systems. And bridges. In Germany, around half of the bridges built between 1960 and 1985 are damaged, so that they will have to be replaced in the near future, according to the scientists at the TU Berlin.


Up to five times stronger than the steel reinforcement

The solution could be bridges reinforced with carbon, such as Silke Scheerer, Harald Michler and Manfred Curbach in the section "Bridges made of textile concrete" in the chapter "Bridge building on the way from antiquity to modern bridge construction. Current developments" in the Springer book "Bridge Handbook" (P. 120) write. The lack of corrosion is only one advantage of the composite material. "It is hard-wearing, robust, conserves resources and is therefore particularly economical," says Hückler. Less concrete is needed for the cladding, which makes buildings lighter. And the carbon reinforcement is up to five times stronger than the steel reinforcement, he continues.

Yes, according to José Luis Moro in the "Reinforced concrete" chapter of the Springer specialist book "Building Construction - From Principle to Detail": "At present, we only have experience in individual cases." Hence the tests and detailed investigations in Berlin. Alex Hückler from the TU Berlin: "The pre-tensioning of the ribbons and ropes made of carbon embedded in the concrete must support the entire length of the bridge, allow vibrations, guarantee breaking strength and stability." But he is also certain: "The future will belong to slim, material-reduced and thus not only more cost-effective, but also more environmentally friendly structures for roads, bridges and buildings."