As part of the efforts of the federal and state governments to promote digital design and construction, a large number of infrastructure projects are currently underway and the foundations for BIM standards are being developed – including the right software.
In the Lower Saxony BIM pilot project "Highway A1: Replacement of the bridge over the Hase and the Stichkanal" near Osnabrück, the modeling software was replaced by Allplan Bridge in the middle of the project.
Due to the high volume of traffic, the A1 highway has been widened from 4 to 6 lanes. This expansion in six construction phases includes a seven-span bridge built in 1969. A structural analysis showed that the bridge does not have sufficient load-bearing capacity in the longitudinal and transverse directions. According to the expert opinion, the target load level could only be achieved by a new replacement structure.
Preferred variant: Canal and foreshore bridge
The client, the Lower Saxony State Authority for Road Construction and Traffic (NLStBV), commissioned THORMÄHLEN + PEUCKERT with a variant investigation in the course of the preliminary planning as well as with the modeling of the preferred variant for the construction of the new replacement. The engineers calculated a total of nine variants, in each of which the structure was separated into a canal bridge and a foreshore bridge.
Preference was given to a variant consisting of a tied arch bridge with a span of 68.0 m in the area of the canal crossing and a subsequent foreshore bridge as a two-span plate girder with two integral support axes and variable headroom. The individual spans of the foreshore bridge vary between span widths of 25.8 and 56 meters.
A change to Allplan Bridge
Once the preferred variant had been decided, it still had to be modeled. The alignment axes in particular posed an enormous challenge, as they differed in the 2 directional lanes and required a complicated cross-section widening of the RF Dortmund. The engineers soon realized that the software they were using was not up to the complexity of the task and that too much time would have to be invested in modeling. Thus, they decided to switch to Allplan Bridge during the ongoing project.
Hendrik Martin, project manager for structural engineering/bridge construction at THORMÄHLEN + PEUCKERT, is enthusiastic: "By switching to Allplan Bridge during ongoing project processing, we have succeeded in achieving error-free modeling of the new replacement canal and foreshore bridge in the course of the motorway A1 near Osnabrück. Allplan Bridge makes it possible to implement complex structural designs and to adapt them to demanding route layouts. Arched structures in composite construction with subsequent semi-integral and haunched prestressed concrete structures could thus be harmonized despite differently routed gradient girder axes."
Editor's Note: Scranton Gillette Communications and the SGC Infrastructure Group are not liable for the accuracy, efficacy and validity of the claims made in this piece. The views expressed in this content do not reflect the position of the Roads & Bridges' Editorial Team.