Stress-laminated-timber decks: state of the art and design based on Swedish practice

Stress-laminated-timber (SLT) bridge decks are a valid alternative to conventional short- and medium-span bridges in terms of cost and performance. SLT decks are made from a number of planks or glulam beams positioned side by side and stressed together using high-strength steel bars. A concentrated load can therefore be distributed from the loaded beams onto adjacent beams due to the resisting friction caused by the pre-stressing of all beams in the deck. This paper describes the state of the art of SLT bridge decks, with special emphasis on Swedish practice. The effect of butt joints on deck deflection and solution applied to accommodate the loss of pre-stress are shown. Simple design tools for the preliminary design of road bridges are illustrated. Best practice with regard to some detailing, water protection and durability is also discussed. Finally, possible developments of SLT bridges are discussed.