In June 2017, Hessen Mobil Strassen- und Verkehrsmanagement Kassel awarded PORR the construction contract for the new Goldbachtal Bridge.
Using a precise cost estimation which took PORR’s complete value chain into account, we were able to offer the best price for the complete contract. In order to ensure optimal project execution, the construction aids were developed and built from scratch.
In 2017, Hessen’s Road and Transport ministry in Kassel (Hessen Mobil Strassen- und Verkehrsmanagement Kassel) appointed PORR as the main contractor for construction of the 285 m long Goldbachtal Bridge, which forms a component of the new section of the A49 national motorway. The contract covers setting up the construction site, earthworks and foundation work for the bridge columns, and the abutment embankments. It also incorporates manufacturing the superstructure as a composite cross-section with steel box girder and reinforced concrete slab carriageway, and constructing a concrete trough for drainage. Finally, the passive concrete and steel protection system for the parapets and the establishment of noise barriers around the abutments also form part of the contract. PORR was able to offer the best price for the complete contract by taking the company’s complete valuechain into account. PORR Deutschland GmbH’s Steel Construction and Civil Engineering departments were involved in the special civil engineering cost estimations, along with PORR subsidiary Stump. The Steel Construction and Infrastructure departments at PORR Deutschland are also working closely together during project implementation.n.
As soon as the contract had been awarded, planning work began on the electricity supply to the construction site, site facilities and access roads. The client had made available their verified structural analyses and object planning, including the material distribution plan for the steel superstructure, meaning that PORR was also able to make an immediate start on execution planning and designs for the steel construction, substructures and construction aids. The decision was made to design and build our own components for the incremental launch procedure. These include the launch rockers used on the abutments and columns, and in the prefabrication area. We also created a launching nose for launching the steel base, plus the launching system itself, which includes a lateral slide strand jack of our own design. These will eventually become part of the PORR inventory, enabling us to deepen our value chain for future similar construction schemes by using our own equipment.
As soon as the preliminary work was complete, the Special Civil Engineering department began work manufacturing the bored piles along the lines where the columns would emerge. Although the drilling team had to battle through unusually hard rock, the special civil engineering works were completed on time in May 2018. Meanwhile, work on the columns had begun in parallel with the bored piles in March 2018. The columns were manufactured using a climbing formwork with climbing section lengths of 5 m, then reinforced and concreted. The exposed formwork was created using a board structure with a rough-sawn surface.
March 2018 also saw the start of work on the 160 m long and 30 m wide prefabrication area where the steel structure was assembled. At the same time, the embankment for the abutments was being constructed. The foundation for the abutment was integrated into the embankment. It is founded on the load-bearing colluvial deposit and made from unreinforced concrete. This foundation was built in during construction of the embankment as underfill for the abutment foundation. Around 3,000 m³ of concrete was built into each abutment for this purpose.
In the middle of April 2018, the time came to set in place the eleven prefabricated steel components for launch cycle 1 of the first section of the eastern superstructure. Delivery of the steel components, weighing up to 85 t and measuring 35 m in length, represented an enormous logistic challenge for this process.
The steel components for the second section of the superstructure were unloaded in the middle of July, following the successful first launch section; these were then assembled and launching continued until September. Due to the height of the launch rockers, the eastern superstructure was launched into a position elevated by around 30 cm. Once the launch was complete, the structure was lowered to its final position, and the prefabrication area was converted ready for work to begin on the western superstructure.
The abutments and columns have now been completed. The steel components for the western superstructure have been shifted already or are on-site ready for assembly. The formwork carriage for creating the carriageway slabs has been assembled; production of the slabs began in December 2018 using a back-and-forth process where the carriageway slab in the centre of the bridge area is concreted first of all, followed by the slabs above the columns.
Manufacture of the parapets will start in spring 2019, using PORR’s own parapet formwork carriage, specially designed in 2018 for the Rothof Valley and Goldbachtal bridges. Corrosion protection work on the inside and outside of the steel box girder will likewise take place. In summer 2019, the cladding work will be carried out and the superstructure kitted out.
Exciting projects from the World of PORR.