Infante Bridge - Design and Construction

The Infante D. Henrique Bridge, spanning the Douro River and linking Porto and Gaia, sits between the Luiz I and Maria Pia bridges, presenting technical and aesthetic qualities that rival these iconic engineering feats. Named after Infante D. Henrique, a prominent historical figure from Porto and Portugal, the bridge played a vital role in renewing vehicular traffic by taking over road traffic from the Luiz I Bridge to make way for Porto’s Metro.

Led by Prof. Adão da Fonseca and developed by Eng. Renato Bastos, the bridge’s design is distinguished by its simplicity and respect for the historic landscape and the UNESCO World Heritage urban core. Its nearly linear form maintains harmony with neighbouring bridges, resting on the elevated slopes. This approach achieved a world record known as the "boldness coefficient," measuring the ratio of the arch’s rise to span, reflecting the project’s innovative scale.

The bridge features a prestressed concrete box girder, 4.5 metres high, supported by a flexible reinforced concrete arch 1.5 metres thick. The arch span measures 280 metres, with a rise of 25 metres between the arch crown and supports, yielding a ratio exceeding 11:1. This design gives the structure a unique behaviour, with the rigid deck bearing loads while the arch primarily works in compression. Its construction required advanced techniques, including the use of rock masses and inclined prestressed cables, as well as temporary structures tailored to the construction segments.