Maillart bridges: From structural concept to strengthening

Abstract:

Structural schemes using a thin arch stiffened by a deck placed at the extrados were one of the most successful innovations in bridge construction. In the last century, after significant development of construction materials, several reinforced concrete (RC) deck-stiffened arch bridges were built with an open-spandrel configuration. The importance of these structures is related not only to their functionality but also to their architectural and historical value. In recent years, due to increased loads and material degradation, several bridges have had to be strengthened without loss of their fine architecture. Traditional strengthening techniques may be inadequate from this point of view, especially when architectural and landscape requirements need to be respected. This paper presents an innovative strengthening concept for openspandrel RC deck-stiffened arch bridges, known as 'Maillart bridges' all over the world. The strengthening concept and design equations are presented for a real bridge of span length 60 m built in southern Italy in 1965. Theoretical concepts related to the mechanical behaviour of the bridge are presented using traditional structural analysis based on the influence line theory. This paper shows how such a method can easily highlight the parameters necessary to define a strengthening strategy that should preserve architectural aspects of a bridge. To meet the new load-bearing capacity derived from new traffic needs, the arch strength should be increased by 17% while the shear and flexural strength of the deck should be increased by 35%. The strengthening concept involves increasing the arch thickness by 5% by using fibre RC (which will also improve the durability of the structure), increasing the flexural strength of the deck with the use of unidirectional fibre reinforced polymer (FRP) epoxy-bonded laminates and increasing the local shear strength of the deck with bidirectional FRP epoxybonded sheets.

Año de publicación:

2009

Keywords:

• Maintenance & inspection
• Concrete structures
• bridges

Fuente:

scopus