Double Mailbox with Thin-Wall Galvanized Support Posts in Type 4 Foundation

Report Number(s): 0-6946-R2

Description: Two Elite No. 1-A (Model #E1600B00) standard arched-top medium size mailboxes from Solar Group, Inc., a division of Gibraltar Industries, were attached to the top of a galvanized, thin-wall steel support post at a height of 42 inches above grade. The mailboxes, which weighed 7 lb, had approximate dimensions of 11 inches tall × 8¾ inches wide × 21½ inches deep. A mailbox bracket (DHT #161443) and extension bracket (DHT #148938) was attached to the bottom of each mailbox using SAE grade 5 bolts, nuts, and washers. Attachment of the Elite mailboxes to the post was accomplished using a bracket (DHT #162323) that consisted of a horizontal steel plate and tubular socket. The mailboxes were bolted to the horizontal plate at a center-to-center spacing of 10 inches. The bracket socket was then placed over the end of the support post and secured using a ⅜-inch diameter × 3½-inch long SAE grade 5 hex bolt, flat and lock washers, and nut. The galvanized steel support post (DHT #143426) was fabricated from 2-inch nominal 16 gauge (2⅜ inches outside diameter × 0.109-inch wall thickness) thin wall ASTM A513 Type 5 DOM steel tubing. The support post, which had a length of 57 inches and weighed 7.5 lb, was inserted into a Type 4 foundation socket (DHT #160891) and secured with a tapered semicircular HDTP wedge (DHT #160892) on the impact side. The foundation socket was installed flush with the surface of a 12-inch diameter × 30-inch deep unreinforced concrete foundation. The concrete was specified as TxDOT Class B having a minimum 28-day unconfined compressive strength of 2000 psi. The total mass of the two mailboxes, connection hardware, and support post assembly was 31 lb.

Test Level: 3

MASH Test Number: 3-61

Proprietary/Non-proprietary: Non-proprietary

Pass/Fail: Pass

Evaluation: Full-Scale Crash Testing

Sponsor: Texas Department of Transportation