The bridge was designed by Virginia Tech personnel using standard bridge design procedures (Ritter, 1990). The overall span was 31 ft and crossed a stream with a watershed of 6500 ac. The central bent was pre-constructed in the workshop (28 hours). The stream was ditched to lower the water level, the road was cleared and trees felled and removed for the new approaches (26 hours). The headwall trenches were dug and the headwall assembled and then backfilled (32 hours) and the sides of the headwalls completed to retain the soil for the road approach (8 hours). The trench for the central bent was dug and the bent placed and supported (16 hours). Concrete bags were placed around the central bent to anchor it (8 hours).

Figure 3: Timber stringers placed across abutent and supported
by a central bent oon the 31 foot two-span timber bridge.

Finally the 16 stringers were put in place (Figure 3, 12 hours) and the decking nailed onto it (12 hours).

Rehabilitation work around the bridge included placing straw and sowing grass seed on exposed soil, which took 6 hours. Costs of the timber bridge are provided in Table 3 and the finished bridge is shown in Figure 4.

Figure 4: Finished two-span 31 ft long timber stinger stream crossing.

Labor and Machinery
156 hours @ $12.50/hour on bridge	$ 1950
24 hours @ $16.00/hour on plates, threaded rod, etc	$ 384
40 hours of backhoe @ $45/hour rented	$ 1800
Materials (bent)
8 in. x 8 in. x 12 ft ties @ $60 each	$ 300
80 feet 3/4 in. threaded rod @ $2.50/ft	$ 200
20-ft2 1/4 in. steel plate @ $5.00-ft2	$ 100
84 washers, and nuts @ $1.50 each	$ 126
50 60lb bags of pre-mix @ $3 each	$ 150
Materials (beams and decking)
16 8in. x 8 in. x 16 ft ties @ $79 each	$ 1264
45 2 in. x 8 in. x 12 ft boards @ $1.50 each	$ 67
150 bridge spikes @ $0.50 each	$ 75
3 boxes of 16d nails @ $5.00 each	$ 15
Materials (headwalls)
10 8 in. x 8 in. x 16 ft ties @ $79	$ 790
24 2 in. x 8 in. x 12 ft boards @ $1.50	$ 36
10 8 in. x 8 in. x 12 ft ties @ $60	$ 600
100 feet of 1/2 in. rebar @ $0.30/ft	$ 30
Total	$7,887
Table 3. Estimated costs for the 31 ft two-span wooden stringer timber bridge.