In the west of the municipality of Schweppenhausen, the K29 road includes a bridge over the Guldenbach stream which must be torn down and rebuilt. The new bridge construction comprises elements of prefabricated parts, onto which a slab of road with lateral caps is concreted on site. The Project Department of the German scaffolding manufacturer ALFIX GmbH developed a scaffolding construction that enables pedestrians to cross the stream even while bridge repairs are underway. They chose to use the versatile ALFIX MODUL METRIC modular scaffolding system, which is able to be implemented for work on façades and complex industrial scaffolding or, in this case, used as an elaborate support structure. Assembled as a lengthwise free-standing scaffold, a makeshift bridge with a minimum walking surface width of 1.10 m was planned, calculated and erected. The required span over the water of 18.0 m was achieved. In order to avoid heavy steel sections such as HEM or IPE beams, lengthwise load transfer was obtained using two connector discs installed on either side of the walking surface. The diagonal braces were arranged for optimal tension and were also doubled. In this way, a scaffold construction suitable for crane handling (weighing merely approx. 7 tonnes) was able to be planned using a 3D CAD program.
Assembly was able to be completed entirely on the ground adjacent to the installation site with the help of Kleid Gerüstbau GmbH, and a crane was used to lift the construction into its final position.
The scaffold bridge was anchored into the foundations prepared by the client, where the concrete foundation served as both support and ballast for structural stability. In order for the scaffold construction to be suitable for public use, the pedestrian bridge was equipped with ALFIX MODUL METRIC child-safe guardrails. Additionally, the bridge construction had to be assessed for a live load of 500 kg/m2 and the use of steps avoided in order to ensure accessibility.
The service life of the scaffold bridge was estimated at approximately one year, making it also necessary to take into account the static calculation of the seasonal snow load. This combination of live load and snow load was managed by the use of two ALFIX MODUL METRIC vertical diagonal braces and two ALFIX MODUL standards. It was necessary to shorten the field length of the scaffold fields in the direction of the middle of the bridge from 2.50 m to 2.00 m in order to not surpass the maximum allowable compressive force of the ALFIX MODUL METRIC tube ledgers.
When the makeshift bridge is dismantled, the scaffolding material is able to be reused for a new construction project right away, providing a long-lasting and sustainable alternative to wooden constructions or heavy steel sections.
The economical number of prefabricated construction components of the ALFIX MODUL METRIC system make it possible to plan efficient and secure scaffolding solutions for every construction need. ALFIX systems offer flexible options for component arrangement, for example when combining tube ledgers (in lengths ranging from 0.25 m to 4.00 m) in a 0.5 m grid with our selection of standards (in lengths ranging from 0.5 m to 4.00 m). The makeshift bridge in Schweppenhausen was able to be erected using the load-bearing capabilities of the construction materials and node connections in an optimal way. Since the middle of last year, the ALFIX MODUL MULTI 4.0 and ALFIX MODUL METRIC 4.0 modular scaffolding systems now feature higher connected loads and target higher static values than nearly all market-standard scaffolding systems. These values are outlined in the approval documents available in the Download section of our website at https://www.alfix-systems.com/en/downloads/. The further developed modular scaffolding systems are also compatible with prior models and able to be combined with standard market systems.