Regional Rail Project - Rare Detailing and Design for Geelong Road bridge
Bruce Gibbens - Technical Lead: Bridges - Regional Rail Project Package C
The provision of new rail tracks and grade separations through central Footscray necessitated unusual bridge forms to accommodate tight clearances. Three skewed through- girder rail bridges, as well as a steel-truss road bridge, and a steel-arch road bridge were adopted. The road bridges measure transversely almost 20 m between deep trusses/arches, while minimising structure depth under the roadway.
The presentation will outline the genesis of the rare details chosen for each bridge, including approaches investigated but discounted. Topics will include: detailing for fatigue, including fatigue-life enhancement; the (magnetic) induction –bending of steelwork; the sliding into place of bridges built off-line; the use of plastic formwork; and unusual steel detailing. Examples of finite element modelling of hollow-section truss connections, and flexible bolted-connections will be discussed, as well as the approaches to shop fabrication of the steelwork and erection on site.
The piers of the Geelong Road bridge were strengthened to resist train collision. The presentation will describe the merits of the carbon-fibre-laminate and post-tensioning solutions which were investigated before finally adopting a steel-plate (jacketed) solution. To overcome the need to excavate pile caps between existing tracks – bored piles were strengthened by steel sections rather than reinforcement.
Bruce Gibbens graduated Monash University in 1995. His experience encompasses all aspects of the bridge life-cycle, from concept studies and independent verification, to the load-rating, strengthening, and material condition assessments of existing bridges, as well as providing technical support during the construction phase.
He specialises in segmental box girders, including those built in balanced cantilever, steel box girders, and integral bridges, as well as the widening of bridges (e.g. Gardiner’s Creek Viaduct, Melbourne), and railway structures including the Port River Expressway bridge in Adelaide which utilises hydraulic shock-transmission units in order to achieve a varying articulation of the structure.
Bruce also worked in support of the Independent Reviewer – assessing bridge designs for Eastlink project.
His experience working in California introduced him to the tortures of high-level earthquake design as well as the use of foreign codes of practice such as the AASHTO, Canadian, and British approaches.
This event will start at 6:15pm in the Turner Theatre at The University of Melbourne, Botany Building, Parkville (Building 122, Grid E13 on this map.)
Refreshments will provided from 5:30pm in Room C301, 3rd Floor, Engineering Block C (Building 174, Grid L17 on this map.)
All of the IStructE Evening Technical Meetings are free to attend unless stated otherwise.