Assessing the durability and residual carrying capacity of a prestressed footbridge built in Brussels (Belgium) in 1944

Abstract

<p>In October 1944, a 20.9m span footbridge was built in Brussels (Belgium) across the Canal Charleroi-Brussels: it was the first applications of prestressing by post-tensioning to a concrete bridge-type structure in Belgium, and one of the earliest worldwide. The tendons consisted of high strength steel wires 5mm in diameter anchored in so-called « Sandwich » anchorages, a system of post-tensioning developed in Belgium from 1942 onwards by Professor Gustave Magnel with the Blaton-Aubert Company. This system will be extensively used in Belgium during the next 20 years, and was also applied to build the first prestressed concrete bridge in the US in 1949 (Walnut Lane, Philadelphia). The dead weight of the footbridge is 60 tons. Some years ago, the local Authority had decided that this footbridge had to be replaced. This 1944 prestressed concrete footbridge was obviously an engineering heritage structure, but preserving it in use somewhere else raised many problems in terms of reliability. The authors therefore proposed to the Authority to study in depth this historical structure in order to collect information that could be useful to assess the durability and actual carrying capacity of concrete structures built with the same prestressing technology in the period 1945-1965, many of them still standing. The paper presents the main findings from the load testing of this footbridge, that took place in October 2018, and the results from the characterization of its materials.</p>

Determination of object‐specific traffic‐load‐models for existing road bridges based on traffic data

“…For a prestressed concrete bridge built in 1944 by Gustave Magnel (1889-1955) in Brussels, Bernard Espion measured about five times the live load as still being tolerable. 3 Oliver Fischer's large-scale test at the Saale bridge in Hammelburg also showed similar reserves. 4 It was found that overall, the hidden safeties for steel bridges are considerably lower than for prestressed concrete bridges (Figure 2).…”

“…The difference is thus expected to be considerably larger. For a prestressed concrete bridge built in 1944 by Gustave Magnel (1889–1955) in Brussels, Bernard Espion measured about five times the live load as still being tolerable 3 . Oliver Fischer's large‐scale test at the Saale bridge in Hammelburg also showed similar reserves 4 .…”

Verkehrsdatengestützte Ermittlung von objektspezifischen Lastmodellen für Bestandsbrücken

“…Für eine 1944 von Gustave Magnel (1889–1955) in Brüssel errichtete Spannbetonbrücke konnte Bernard Espion rd. die fünffache Verkehrslast als noch verträglich messen [3]. Auch der Großversuch Oliver Fischers an der Saalebrücke Hammelburg zeigte ähnliche Reserven [4].…”