Anchored Log Decks
Murison, Evangeline Rivera
To improve the performance of the conventional nail laminated bridge deck, three generations of innovative decks have been developed during the last three decades: (a) the stress laminated wood deck, (b) the stressed log bridge, and (c) the grout laminated wood deck. The grout laminated wood deck, the most recent wood deck, consists of trimmed logs interconnected with internal grout cylinders, in compression or tension. Previous research has shown that the grout cylinders have superior load distribution characteristics, but the cost of trimming the treated logs was found to be relatively high. Recently, research has been conducted to develop the next generation of the bridge wood decks, called the anchored log decks. The anchored log deck, meant for use as decking of steel girder bridges, consists of untrimmed discarded utility timber poles which have been treated with preservatives. The logs are held together by means of unstressed transverse proprietary Cintec anchors. The anchors consist of stainless steel rods encased in grout cylinders. Panels, each comprising of 5 to 6 logs, are preassembled to fit on a flatbed trailer for shipping. The smooth wearing surface over the log deck is provided by longitudinal sawn timber planks, with high-density foam filling the gap between the logs and the planks. The panels are inter-connected through inclined anchors passing through adjacent logs. At the University of Manitoba, an anchored log deck with five preassembled panels was constructed and tested to failure at several locations under both static and fatigue loads. The test results have shown that anchored log decks have the potential of being economical preassembled decks for steel girder bridges.
Bridge, Timber, Log, Anchor, Grout