Talbrücke Kattenohl, A45 — steel superstructure BIM and Stahlbaupläne
One of the ageing A45 valley bridges in the Sauerland, carrying far more traffic than it was built for, replaced without closing the motorway.
- Location
- Germany
- Our services
- Steel BIM · Construction staging · Shop drawings
The bridge is rebuilt half at a time, and the new steel superstructure is moved into position rather than assembled in place. We built the BIM model of the steel structure, including every construction stage, and produced the Stahlbaupläne from it.
The stages are the structure
A superstructure that is moved into place is not one structure but a sequence of them. In its final position it sits on its permanent bearings; at every step before that it is held somewhere else, spanning differently, with different reactions and different forces in every member. Each stage was modelled in the order it will be built, with the temporary supports and the launching equipment alongside the permanent steelwork, so the geometry exists for every stage and not only for the finished bridge.
The steel model
Webs, flanges, stiffeners, diaphragms and bracing, splices, bearings and the connection to the deck — modelled as the pieces that will actually be fabricated, in the lengths they will be made in and delivered in. The model is built to be cut from, not to be looked at.
Stahlbaupläne
The drawings come out of the model: general arrangement, assembly and part drawings, with weld and bolt information, part marks and weights. Drawings and model are the same object, so a change to a plate is a change to every sheet that shows it.
Built over a live motorway
The staged model is what lets the erection sequence be checked before any steel is cut — the temporary condition at each step, the clearance to the structure still carrying traffic, and the position of the new bridge at every stage of the move.