TIMBER BRIDGE CONSTRUCTION IN N.S.W. XI, 
windbracing and the triangulation lines of the truss members 
would intersect at a common point in the bottom chord. 
3rd. The distribution of the load, so as to get each pair of the 
floor beams to act as one. 
4th. The necessity of concentrating the loads at the apices, as, 
with the Section employed, two 14” by 7” timbers, no additional 
stress was permissable in the bottom chords. 
The deck adopted consists of 4” tranverse planking spiked to 
12” by 6” longitudinal stringers, seated on the lower lateral struts. 
The lower lateral strut is 12” wide by 8” deep at centre, adzed 
down on top surface to 6 inches at ends (to give camber in deck), 
the centre line of strut being placed in the same plane as the 
centre line of the bottom chord. The ends of the lateral strut 
are secured to bottom chords by wrought-iron brackets, and to 
these brackets are attached the diagonal tie rods, the centre lines 
of which, if produced, would intersect at the centre of bottom 
chord; the triangulation lines of the wind-bracing and truss mem- 
bers thus intersecting at a common point and avoiding all bending 
stress. 
The lateral struts are tightly dapped one inch over nine 12” by 
4” sawn packing blocks 2’ 5” long, resting on the floor beams. 
These blocks not only pack the lateral struts up to the same 
plane as the centre line of chord, but what is of just as much 
importance, equally distribute the whole load over the pair of 
floor beams. ; 
With a panel length of 15’ 9” and a span of 27 feet the 
resulting load is so great as to necessitate the use of two floor 
beams, each 14” wide by 16” deep, spaced one inch apart (to 
permit of a current of air and avoid boring for stringer bolts), 
and connected together with 11 {” bolts passing through one inch 
cast-iron distance washers. 
As the overall width of these two floor beams is 2’ 5” it was 
impracticable, without fouling the braces and suspension rods, to 
rest them on the upper edge of the chord. They are therefore 
