Renovation of the Dresden Central Station Roof

Description

Overview
The ongoing renovation project, led by DB Station & Service AG, aims to replace the damaged membrane and reinforce the steel structure. General planning is managed by EHS, with IF Group, that provided the IFC (Issue For Construction) design. PFEIFER Structures, is responsible for the implementation, working as a General Contractor to DB. formTL is doing the workshop design with PFEIFER. The chosen Verseidag material is fabricated in PFEIFER’s own workshops.

Technical Challenges and Modifications
A crucial aspect of the new design is the rotation of the membrane's warp and weft directions by 90 degrees. Initially, the warp direction ran along the hall arches; it now runs from arch girder to arch girder, enhancing tension distribution and stability. Additionally, a comprehensive 3D survey revealed that the truss girders are not perfectly parallel but follow an S-shaped spline. This data was crucial for accurate form-finding and structural alignment.

Skylights and Snow Management
Steel skylights with glass covers are installed over the existing inlet funnels. These constructions allow snow to accumulate on the skylights, melting and draining through 60mm wide joints between the glass panes into the funnels. This innovation prevents membrane damage caused by freeze-thaw cycles, a frequent issue with the previous design.

Steel Structure Adaptation and Membrane Fastening
The steel structure required extensive reinforcement in the areas of new Skylight load introduction. Approximately 4000 drill holes were made to attach L-profiles and reinforce specific beam areas. Also the membrane connection detail was redesigned to allow tension adjustment and tolerance adjustment, improving durability and structural integrity.

Construction and Quality Control
Extreme focus is placed on ensuring the quality and integrity of the membrane. This involves meticulous handling during transport from PFEIFER’s workshops and installation on site to prevent damage. The installation methodology emphasizes that new membrane sections are temporarily secured over the old membrane before the old panels are fully removed. Special attention is given to edge areas and temporary openings to prevent water ingress as the station is almost under full operation. Construction is conducted "under rolling wheels," with train operations continuing during the renovation. This necessitates stringent safety measures, including the installation of work platform nets below the membrane and additional safety nets under the working platform nets. Regular inspections and quality controls by site supervisors and specialists ensure adherence to high standards.
Strategic use of cranes is vital for the project. Two cranes, a mobile construction crane on the north side and a crawler crane on the south side, are used to lift materials and steel components in tightly scheduled time windows. These operations are confined to predefined track closures, making them highly time-sensitive and challenging for the team and construction management.
To protect passengers from water ingress during construction, an extra concept for temporary drainage was implemented. This involves various measures to ensure that the station's interior remains dry despite ongoing roof work. For instance, partially temporary membrane is installed to manage construction-phase water runoff.
The complex scaffolding logistics were fully planned using Building Information Modeling (BIM) to avoid collisions with stairways, signs, and other installations. This careful planning ensures efficient and safe scaffolding erection and minimizes disruption to station operations.

Completion and Future Prospects
The third construction phase has commenced in 2024, involving the installation of 14.500m² of membrane and 10 skylights. Completion is expected by spring 2025. Post-installation, safety nets will be removed, and snow guards installed. This project exemplifies modern membrane construction technologies in historical buildings, showcasing the potential of textile membranes as sustainable roofing materials.

Conclusion
Combining modern technology, extensive expertise, and innovative solutions ensures that Dresden Central Station remains a functional and aesthetic landmark. PFEIFER Structures provides the necessary proficiency and innovation in membrane construction, contributing to the quality and durability of the refurbished roof structure.

Description of the environmental conditions

General comments, links

www.fosterandpartners.com/projects/dresden-central-station
www.sergeferrari.com/references/membrane-roof-renovation-dresden-central-station