PSI - Issue 5

Tiago Mendonça et al. / Procedia Structural Integrity 5 (2017) 48–54 Mafalda Monteiro et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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process has yet started and real deficiencies are covered with paint, the thorough work necessary to add the compulsory resistance preserving its aesthetic and heritage, among other remarks. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017.

Keywords: Old steel bridges, spacial steel truss, masonry piers

1. Introduction

The bridges of Abrantes, Chamusca and Belver on the Tagus River have great importance in the daily life of the neighboring populations, since they ensure vital communications between the settlements located on its banks. These structures are crossed intensely and daily in successive pendulum movements since their construction. These centennial bridges were designed for other use that the one currently required whether under load and horizontal actions or frequency of passage. Initially they were designed for smaller platforms and executed in wood. Due to the degradation of this material wood platforms were modified to concrete but weightier. These structures exhibit global wear, chemical changes of materials, and damages on elements, non-genuine repair interventions and local reinforcements. To ensure the high flow of traffic of heavy vehicles over long-lasting bridges it is desirable to know its state of conservation and to evaluate its structural capacity. The rehabilitation process of each bridge has comprised several phases. Particular conditions and design concepts of each structure are developed in the following document. The peculiar structural solutions that were executed are also reported.

2. Brief description of bridges’ structures and damages 2.1. Centennial steel bridges main characteristics

The Abrantes Bridge was designed and built by the company Jean François Cail & Cie and the Compagnie de Fives-Lilles . The construction dates from 1870. It has a trussed deck with upper platform that defines a continuous box-girder with 7 spans. It is supported on masonry piers. In the 60's the wooden platform was replaced by another one made of reinforced concrete. This new platform had sliding characteristics and was much heavier than the original one. So, Professor Edgar Cardoso has designed a reinforcement-type with independent external pre-stress cables that were placed on the steel truss (Fig. 1).

Fig. 1. Abrantes bridge over Tagus river.