Optimum Bridge Renewal Project

Case Study

Traffic is to be diverted onto this superstructure (left) by November 2008. Then, the whole existing structure, which is no longer able to cope with the growing amount of traffic, can be demolished.
This 35 million Euro motorway project is due for completion by 2011. The design, engineering and construction companies are on the building site practically non-stop.

Smooth project management in structural engineering

Bridging the Rush Hour

New bridge over the River Main relieves congestion on A3 motorway at Randersacker exit

SRP Schneider & Partner Ingenieur-Consult GmbH in Kronach, Germany, was commissioned to plan the execution of a new bridge on the A3 motorway. RIB software systems – from the design to the calculation of complex bridge structures made of reinforced concrete, prestressed concrete or composite steel – ensure smooth handling of all structural engineering tasks.

Founded in 1969, SRP Schneider & Partner Ingenieur-Consult operates nationally and internationally in consulting, planning, project management and training. Experts in CAD, GIS and bridge engineering, the company offers customised solutions for far-reaching clientele. SRP’s strength stems from the expert knowledge of its staff, the use of modern hardware and software and the extensive network it has built through its involvement in numerous professional associations.

The company is dedicated to providing its customers with cost-efficient solutions. SRP also respects the protection of the environment by ecological use of resources in design and construction. Solutions for international customers are also developed on site or in foreign branches from the Baltic via Turkey to Egypt.

End of congestion in sight

On the A3 motorway from Nuremberg to Frankfurt am Main, motorists have come to expect long tailbacks near the Randersacker exit. One of the reasons is the nearby bridge over the River Main, a bottleneck that has long been unable to cope with the growing amount of motorway traffic. Besides this, major damage to the main bridge makes new building urgently necessary. Steel wires used in the sixties have proved particularly prone to material fatigue due to the high traffic load. The motorway maintenance authority of Northern Bavaria noticed this problem a few years ago and placed an order for a new six-lane bridge in May 2007. SRP was commissioned to perform structural engineering. The 35 million Euro motorway project is scheduled for completion by the year 2011. Consultant Dr.-Ing. Heinrich Hochreither has been engaged as inspection engineer. The construction work is being performed by DYWIDAG Bau GmbH, while the field inspection is the job of the Würzburg department of the North Bavarian motorway maintenance authority.

Free six-lane traffic flow

Last July, SRP engineers under project manager Peter Borsboom began designing the superstructure for the new bridge. In the first construction phase, the temporary substructure next to the existing bridge and the northern superstructure of the road in Frankfurt direction are being built. The prestressed concrete superstructure is being produced with the cantilever method over the River Main and with the conventional falsework method on the river bank.

Traffic is to be diverted onto this superstructure until November 2008. Afterwards, the entire existing structure will be demolished. This step is scheduled for November 2008 to April 2009. Following the demolition, the project team will be given the job of building the pillars and abutments and building the southern superstructure. The six pillars and two abutments of the new bridge are roughly in the same positions as the old ones. After the new building of the bridge in the direction of Nuremberg, all traffic will be diverted onto this road. Finally, the northern superstructure of the 540 metre long bridge over the Main valley, which also spans Federal road 13, State road 2418, a two-track railway line and the Main valley cycle path, will be moved sideways into its ultimate position. After this, the temporary substructures can be removed and then the way is clear for a scheduled opening in June 2011.

The northern superstructure consists of two cantilevered and four falsework sections, of which two have already been completed and concreted. The cantilevered sections are being built by incremental launching using launching waggons to which the cantilever scaffold and formwork is attached. “On average, two new cycles are built per week,” says project manager Borsboom. “The finished cantilevered sections are composed of a total of 32 cycles.” As well as this, the first cantilevered section is already connected to the first falsework section of the new bridge. Thirty per cent of cantilevered section number two is now also complete.

Field-proven IT systems for new challenges

Peter Borsboom and his team at SRP are working with field-proven software systems for this complex bridge construction project. SRP Schneider & Partner Ingenieur-Consult GmbH has relied on structural engineering software from RIB for almost 20 years, using almost the entire range of the RIBTEC portfolio. For example, the engineers at SRP produced the design for the new Randersacker bridge with the design system ZEICON. “The reinforcement modules of the construction software are particularly reliable,” comments the project manager. And RIB systems are not only being used for design, but also for calculating the entire bridge structure.

It was particularly helpful that the bridge could be fully calculated with RIB software due to the cantilevered construction process. All 32 construction cycles were captured as construction states in one computing operation. Peter Borsboom entered the extensive system and load specifications for the different systems with the software solution PONTI Expert, which is specifically designed for bridge construction projects.

The calculation of the box and the dimensioning of all the cross girders was done with the support of the RIB system TRIMAS. The software allows all types of load cases to be combined for the complex computing methods. “The stress analysis systems of RIBTEC support us for the entire duration of the project,” the project manager sums up. “As our company usually has an extremely tight time frame for the design and engineering, we need reliable IT systems and have never been disappointed with the RIBTEC products of RIB Software AG.”



Industries>Architecture, Engineering & Construction>Architects and Engineers>SRP - Schneider & Partner

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