Specifications include, but are not limited to: scription
This work shall include all Timber materials, including ties, timber bridge spacers, backwall timbers
as shown on the Plans and described in this Specification
A. Timber. All ties and timbers shall be solid-sawn and treated Southern Pine (5”x5” or larger) or
Douglas Fir (beams and stringers) Grade No. 1 or better. All ties and timbers shall meet the
requirements of Chapter 7, Section 1.7 “Specifications for Timber Bridge Ties” of the AREMA
Manual. All ties and timbers shall meet or exceed the allowable unit stress values for wet
conditions, visual grading shown in AREMA Table 7-2-9. Bridge ties shall be surfaced two sides
(s2s) on the top and bottom sides, and dapped (notched) on the bottom side as shown in the Plans.
B. Preservative Treatment. All timber shall be Dual treated with 1# Borate and 6# Creosote
preservative in accordance with the requirements of Chapter 30, Section 3.6 “Wood Preserving”
and Section 3.7 “Specifications of Treatment” of the AREMA Manual. Minimum creosote
preservative retention shall be 6 pounds creosote per cubic foot of timber for all members. The
preservative treatment to be used shall be Borate/Creosote as outlined above.
Submittals and Fabrication Requirements
Written certification shall be submitted including treatment reports demonstrating that the timbers
and ties meet the species, grading, and treatment requirements of this Specification.
Holes for bolts connecting bridge ties to top flanges shall be prebored during fabrication and before
treatment of the bridge ties. Prebored holes shall be 1/16” larger than the diameter of the bolt. Bridge
tie to top flange connectors shall be installed in accordance with the manufacturer’s instructions.
Holes for all lag screws shall be predrilled with a bit not larger than the body of the screw at the
base of the thread.
Each bridge tie shall be permanently tagged identifying the respective bridge number and dapping
pattern. Ties, timbers, and associated hardware shall be grouped and packaged for delivery to each
Anti-splitting gang nail end plates shall be installed on the ends of all bridge ties. End plates shall
meet all of the applicable requirements of Chapter 30, Section 3.1.6 and Section 3.1.7 of the AREMA
Manual. End plates shall cover a minimum of 75% of the end are of the tie, shall be 18-gauge
galvanized steel and shall have teeth extending at least 3/8 inches beyond the end of the plate. End
plates shall be installed centered on the end of each tie and fully driven with no evidence of excessive
bending or mashing of teeth.