Issue 10

Push tests in Australia have suggested that studs welded in modern trapezoidal decks possess lower resistances and slip capacities than expected. This paper presents the results from a comprehensive research programme consisting of full-scale composite beam and companion push tests. The beams exhibited excellent ductility, and the slip capacity at the shear connection far surpassed the levels considered obtainable by current British and European Standards. Comparisons of load-slip performance show that any brittleness exhibited in push tests is as a result of a deficiency in the standard push specimen rather than the shear connection. For single studs, the beam tests demonstrate that the current UK design practice of using the shoulder height of the deck in BS 5950 to be the most appropriate. Conversely, the performance of pairs of studs in the current research appears to be adversely affected by longitudinal connector spacing. Interim design guidance is proposed for studs in this arrangement. Stephen Hicks, BEng(Hons), PhD(Cantab) Manager, Building Engineering, The Steel Construction Institute, Silwood Park, Ascot, Berks

The New Rewa River Bridge crosses the Rewa River just downstream of the old steel truss girder bridge at Nausori, a busy market town located 15km north west of Suva, the capital of Fiji. The new bridge was opened to traffic by the President of Fiji in August 2006 and is the longest bridge of its type in the South Pacific. It carries a dual two-lane carriageway with wide footways, and provides a much needed improvement in access to Nausori town and to the island’s second airport. The new bridge has an overall length of 425m, comprising seven internal spans of 49.5m and end spans of 39.25m. The post tensioned concrete box girder superstructure was constructed from the west (Suva) side of the river using the incremental push launch method. The wide single cell box girder is post tensioned longitudinally for launch conditions and live loading, and is transversely prestressed in the top slab to eliminate the need for an internal web. The paper describes the construction of the bridge and gives details of the bottom driven steel tubular pile foundations, the proprietary launch bearings, and the launch method, which were key features of the contractor’s alternative tender. The project was co-funded by the European Union (EU) and the Government of Fiji. Roger Buckby, MSc, CEng, FIStructE, MICE, FIHT Halcrow Group Ltd, UK David Phillips, BSc, MSc, CEng, MICE, MIStructE Halcrow Group Ltd, Fiji Mark Essam, BSc, MEng Halcrow Group Ltd, Fiji Ruwan Sahabandu, BSc(Eng), PG Dip (Hyd), MSc(Struct), MIE(SL), CEng Ministry of Works and Energy, Fiji