The 25 de Abril Bridge is an iconic symbol of Lisbon and holds a special place in the collective imagination of all Portuguese people. For this reason, any intervention on such a landmark structure presents a particularly significant challenge.

Intervention goal

The main objective of the intervention was to repair anomalies in both the reinforced concrete and the metallic elements, in order to ensure the proper functioning of the structural components and affected systems. The project also provided an opportunity to introduce improvements in certain areas of the bridge, mainly related to accessibility and safety for the teams involved in its ongoing maintenance.

Intervention Stages

Improvements to accessibility and enhanced protection included the installation of both fixed and removable coverings over various openings in the towers and the piers of the northern access viaduct. These piers were also upgraded with the installation of new stairways. The works further included the installation of safety railings on vertical ladders, the replacement of some of these ladders, and the addition of protective elements on several platforms. Additionally, the project involved the re-tensioning of bolts securing the clamps that fix the suspenders to the main and secondary suspension cables. Due to the limited accessibility of these bolts, it was necessary to install mobile platforms to allow the work to be carried out.

Applied Technique

The concrete rehabilitation works included structural repair using dry-process shotcrete, the sealing and injection of epoxy resin into structural cracks, and finally, the application of a protective coating with a high solids content - thus ensuring the longevity of the intervention on the structure.

Additional information

The works were carried out by Stap in partnership with AMAL – Construções Metálicas. Stap was responsible not only for the structural repair of the reinforced concrete but also played a key role in coordinating the entire project.

Given the specific characteristics of the 25 de Abril Bridge, the works had to be planned with great precision. A multidisciplinary and highly experienced team was involved to ensure the success of the intervention across multiple work areas, including the tops of piers P2 and P3, all piers of the northern viaduct, the expansion joints of the northern viaduct, and, of course, the bridge's suspension cables.