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CILLEY (LOWER) BRIDGE

Year Built:	1883
Bridge Type:	Multiple King Post
Span:	67 feet
Vertical Clearance Over Water:	8'5"
One Lane
Skew:	7 Degrees
Posted:	3 Tons
Traffic Data:	1994: 50 Vehicles Per Day	2012: 70 Vehicles Per Day
Detour Length:	2.1 miles
Existing Species For Structural Timbers:	Eastern Hemlock
Abutment No. 1:	Concrete
Abutment No. 2:	Laid up Stone

Items Common to All Options:

Remove guy wires, replace tie beam and knee bracing, and plumb up the end of bridge at abutment no.2
Replace damaged interior knee brace
Replace siding with 1" shiplap (eadsting is two layers of 1/4" hemlock)
Restore abutment no. 1 to its original floor system configuration
Replace end of the bottom chord at abutment no. 1
Rechink abutment no. 2 as required
Remove top layer of stone (some not original) at abutment no. 2 and replace with concrete bridge seat and backwall
Install new approach rail(HDSB Weathering Steel)

Existing Bride Rating:

Truss capacity is 20,000 lbs at a posted rating governed by the end diagonal
Floor system capacity is 12,000 lbs at a posted rating governed by the floor beam

Options For The Floor System Rehabilitation:

Option 1:
- Replace approximately 50% of floor beams in kind and move to even spacing. Replace plank decking in kind with Eastern Hemlock less than 3". With this option the floor system would rate 12,000 lbs at an inventory rating and the truss would rate 20,000 lbs at a posted rating.
Option 2:
- Replace floor beams with Select Structural Douglas fir
- Replace plank decking in kind with Eastern Hemlock
- With this option the floor system would rate 20,000 lbs at a posted rating and the truss would still rate 20,000 lbs at a posted rating.
Option 3:
- Replacing floor system with glue laminated floor beams and a nail laminated deck. This does not retain the engineering of the floor system and would decrease the vertical clearance by approximately 3" to 10'5". The reduction in dead load would increase the capacity of the truss, but it would be minimal.