Three-dimensional integration of power electronic converters on printed circuit board

Abstract

This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-known example of fatigue cracks are those observed in the deck plate of the Van Brienenoord bascule bridge in 1997, at that time a 7 year old bridge. The renovation techniques are part of a proposed maintenance philosophy for steel bridge decks. Lifetime calculations, inspections and renovation techniques are the three essential parts of this philosophy. A reliable lifetime calculation model for fatigue damage in the deck plate is described, including the influence of the asphalt surfacing. Accurate calculation results are obtained, both for movable and fixed bridges. Inspection programs can be based on the lifetime calculation results. Several innovative inspection techniques are presented briefly. For fixed bridges the replacement of the asphalt surfacing with a reinforced high performance concrete surfacing is an effective renovation method. For movable bridge decks three solutions that extend the lifetime of the orthotropic deck structure were researched in this thesis.