Cité Footbridge

The small concrete pedestrian bridge with integral abutments is an innovative and efficient design solution created for crossing a four-lane highway. It stands out as a lightweight, elegant alternative to the heavy, joint-based pedestrian bridges typically seen in Germany.

The bridge’s total length is 37.10 meters, divided into two spans. These spans are supported by a central Y-shaped column, which not only provides essential structural support but also enhances the aesthetic character of the bridge.

The rigid connection between the concrete deck and the end walls eliminates the need for traditional expansion joints. This design reduces long-term maintenance costs and simplifies inspections throughout the bridge’s lifecycle.

A critical element of the design is the soft sandwich geotextile drainage layer placed between the end walls and the stabilized earth-fill dams. This 20 mm thick interlayer allows the bridge to expand and contract safely due to temperature fluctuations.

In summer, the bridge experiences thermal expansion, and this flexible detail prevents cracking or stress buildup. In winter, the structure responds differently but remains within safe operational limits, verified through extensive calculations.

The iconic Y-shaped column was intentionally chosen to reflect concrete’s malleability and to create a visually appealing feature that complements the minimalist form of the structure.

Advanced finite element analysis was used to model load cases, including dead load, live load, temperature variations, and different earth pressure scenarios. This helped in optimizing the deck thickness and structural reinforcements.

The use of a Y-shaped column reduces negative bending moments in the deck when compared to traditional vertical columns. This optimization allowed the concrete deck thickness to be minimized to around 30 cm.

High-performance concrete (C40/50) and S500 reinforcement steel were used for the deck, walls, and the column, ensuring strength, durability, and longevity for the structure.

The column was fabricated on-site in a horizontal position, ensuring perfect concrete finish and quality control. After curing, it was carefully lifted into its final position by crane, demonstrating precise construction logistics.

The concrete deck and end walls were cast in situ using temporary steel structures to support the deck during construction. This approach enabled highway traffic below to continue without interruption.

The construction methodology highlights how modern techniques allow safe building above active highways, with minimal disruption to daily traffic flow and public use.

The final pedestrian bridge represents a tailored solution that blends structural engineering excellence with architectural simplicity and clarity.

Beyond aesthetics, the design is also highly functional, accommodating temperature-induced movements and earth pressures without the need for complex expansion joints or bearings.

The project’s success shows how integral abutments can be applied to smaller pedestrian bridges, making them more elegant, maintenance-friendly, and cost-efficient over their entire lifespan.

Various earth pressure distributions were analyzed in both summer and winter scenarios, demonstrating that the bridge could operate safely and efficiently under changing environmental conditions.

The formwork and reinforcement for the Y-shaped column required high precision, and the finished column adds sculptural elegance to the overall bridge design.

The end result is a sleek, minimalistic pedestrian bridge that not only fulfills structural requirements but also serves as a design landmark for the area.

This project serves as an example for future pedestrian bridges and could inspire lighter, more efficient highway overpasses in both Germany and other countries.

The bridge is a symbol of engineering ingenuity, combining technical mastery with visual refinement, offering both function and form in perfect balance.