Abstract
Research efforts to improve the ability of timber to satisfy deflection criteria and to be economical for longer spans are leading to composite timber-steel deck bridges with transverse prestressing. The use of small size and length timbers is imperative because, quite simply, small-to-medium size trees are much more plentiful than large trees. A bilayer timber bridge model that employs both timber and steel is shown here to perform quite well. Results show that despite numerous butt joints and reliance on steel for horizontal shear, loads in excess of required magnitudes may be taken safely without undue deflections or stresses.