Monitoring the behaviour of MEO Arena roof

Abstract

The roof structure of MEO Arena (previously known as Atlantico multipurpose Pavilion) is a pioneering example of large glued laminated timber (glulam) structures. At the time of its construction (1995) for the EXPO’98 world exhibition, this was the first large glulam structure ever built in Portugal, it had the longest single span glulam arch (122m) in the world and it was the first large timber structure designed according with an early version of Eurocode 5 (European Standard ENV 1995-1-1(1994): Design of timber structures). This timber roof structure, shaped like the shell of a horseshoe crab and covered with an oxidized zinc sheet, stands more than 40m above the arena and is independent from the concrete building underneath. LNEC was requested to carry out systematic inspections and monitoring of the roof structure after its construction and the follow up of its performance still continues. In this scope, the geodetic monitoring set on a regular basis (twice a year) allows the assessment of three dimensional displacements of selected points of the timber arches. The analysis of this data has allowed to distinguish normal variations throughout the year from those resulting from the initial settling and climatic adjustment of the structure and will allow identify any abnormal movements that may be due to accidental or exceptional circumstances. The good knowledge of the structure behaviour has also been an important basis to a pioneer study of the behaviour of the zinc roof cover based on multitemporal InSAR techniques. In this paper, we describe the geodetic monitoring system and an analysis of the behaviour of the glulam structure as well as of the roof cover based on the geodetic and InSAR data.