Publications

The decay phase can have an important role in the behaviour and failure of the structure during and after a fire, and therefore, it should be properly defined. The most commonly used method to define natural fire exposure, the Eurocode parametric fire curve (EN 1991-1-2:2002), adopts a simplified linear approximation of the fire decay phase with a constant cooling rate defined in function of compartment characteristics. In this study an analysis of the influence of the decay phase cooling rate assumption on structural behaviour is made, considering the case of a simply supported reinforced concrete slab exposed to fire from the bottom side. It is demonstrated that the cooling rate of the decay phase can have a significant effect on the reduction of the slab s bending capacity. It is also shown that the magnitude of this influence is affected by both the temperatures during the heating phase and the size of the concrete cover. The case study demonstrates that the difference between the cooling rates from the Eurocode parametric fire curve and available experimental test results are significant, and that this can have a significant effect on the assessment of the slab's structural performance.

No abstract is provided for this article.

During a storm in October 2002, wind induced ovalling oscillations were observed on several empty silos of a closely spaced group of 8 by 5 silos in the port of Antwerp (Belgium). Present day standards describe only basic wind load cases, unable to explain this ovalling phenomenon. In order to improve the design of engineering structures with cylinders placed in groups, a thorough understanding of the fluid flow around such groups is required. 2D unsteady Reynolds averaged Navier-Stokes (URANS) equations usingMenter’s shear stress transport turbulencemodel were performed, considering the wind flow around the rectangular group for a range of angles of incidence (0  a  90). The 2D highly turbulent post-critical flow (Re = 1.24×107) around a single cylinder was computed to elucidate the influence of the applied turbulence model and to validate the spatial and temporal discretization. Since, the flow regime around and within the silo group is similar to the flow around rectangular cylinders and the flow within tube arrays (e.g. heat exchangers), similarities and differences are used to assess the influence of the angle of incidence on the flow pattern around the cylinder group. The large velocities in the interstitial flow between cylinders as well as the formation of large scale vortex shedding in the wake of the group are discussed for various angles of incidence. Static and dynamic loadings on separate silos of the group are studied to explain the existence and the location of ovalling oscillations in closely spaced silo groups.

No abstract is provided for this article.

Abstract The Øresund Bridge opened in July 2000. It is the most striking part of the fixed link across the Øresund connecting Copenhagen (Denmark) and Malmø (Sweden), which further includes a tunnel and an artificial island. The bridge is equipped with a PC-based continuous monitoring system, capable of measuring both static and dynamic quantities such as temperatures, wind characteristics, air humidity, strains and accelerations. The challenges for the design of the monitoring system were the long distances between the monitoring points and the variety of sensors. This paper describes the bridge and the monitoring system components. Some typical measurement data are presented. Finally, the modal parameters of the bridge are extracted from the deck, cable and tower vibrations. This shows that the system does not only give information about sudden events that exceed a certain threshold, but can also be used as a health monitoring system by tracking the evolution of the modal parameters. Keywords: Øresund Bridgestructural health monitoringoperational modal analysis Acknowledgements The authors would like to thank Mr Svensson from Øresundsbro Konsortiet ( www.oeresundsbron.com) for granting us the right to use monitoring data and photographs of the Øresund Bridge. The present research is conducted in the framework of the European Commission fifth framework programme projects SAMCO ( www.samco.org) and IMAC ( www.vce.at/imac.htm).