3412Wood Guardrail Posts

3412.1SCOPE

Provide preservative treated wood posts for use in guardrail construction, including round posts and sawed timber posts with rectangular cross-sections and offset blocks.

3412.2REQUIREMENTS

A Round Posts A.1 Species of Wood Provide treated round posts made from any of the following species of wood:

A.2 Seasoning Air-season wood for treated posts. The wood may be conditioned as part of the treating process for penetration of preservative without damage to the posts. A.3 Dimensions and Finish Provide naturally round posts. Shave off inner bark and closely trim knots.

Saw the bottom end of the posts square. Provide posts in the length, Nominal diameter, and with a top finish as shown on the Plans. Complete debarking, trimming, and sizing of posts before applying the preservative treatment. A.4 Quality Do not use wood with any of the following defects:

outside the center of the post by more than 2 percent of the post length

3/8 inch in diameter in the top of the post

Northern White Cedar

post as determined by the Engineer

B Sawed Timber Posts B.1 Species and Grade Provide sawed timber posts made from any of the following species of wood:

Provide sawed timber posts in the grade meeting the following requirements and characteristics:

to half of the post thickness

For rectangular post sizes, use the wider face to determine the maximum size of the knots permitted.

B.2 Dimensions Saw the posts and offset blocks to the Nominal dimensions as shown on the Plans. The Engineer will not require surfacing. Do not allow the sawing dimensions for dry Material to vary from the Nominal dimensions by greater than −1/4 inch or +1/2 inch. C Preservative Treatment Treat posts and offset blocks in accordance with 3491, “Preservatives and Preservative Treatment of Timber Products.” Provide treated posts and offset blocks with a dry surface and free of excess preservative.