The Colorado Department of Transportation (CDOT) utilizes both guardrail Type 7 F-Shape concrete barriers, as well as precast Type 7 concrete barriers. Guardrail Type 7 F-Shape barriers may be cast-in-place or slip formed and do not typically require connecting or stabilization pins. However, for precast Type 7 concrete barriers, CDOT utilizes a design that does require barrier connecting pins and stabilization pins. Connecting pins are galvanized, high strength ASTM A449 pins with either a forged head or a welded circular washer and threads for a lifting nut. Stabilization pins are made from galvanized ASTM A36 steel with a welded washer on one end and may have an optional tapered end to facilitate driving into the asphalt or soil.
Connecting Pin – PB Part #18359
The Colorado barrier connecting pin is a galvanized, high-strength ASTM A449 rod with thread on the top and a circular washer fillet welded to the rod. Alternately, a one piece, forged head may be used in place of the welded washer design.
The purpose of the round washer/forged head is to rest on the top most connecting loop on the barrier to keep the pin in place. The purpose of the threads is to facilitate removal using a special lifting nut that is screwed onto the pin. In lieu of the threads and lifting nut, the forged head alternative may feature a horizontal hole through the head or a second lip on the head to facilitate removal.
An optional 1/2″ bevel may be added to the bottom of either style for ease of placement. Both styles can be seen on Colorado Standard Plan No. M-606-14, Sheet 2.
For anchoring precast barrier sections, Colorado utilizes a stabilization pin made from 1″ diameter ASTM A36 steel round bar with a 3/8″ thick x 2-1/2″ diameter round plate washer welded near one end. The other end may be given an optional 3″ maximum bevel to facilitate placement. The entire stabilization pin assembly is required to be hot dip galvanized after fabrication and welding. The length of the stabilization pin varies from 30-42″ depending on what type of surface the barriers are being anchored to. The details of the stabilization pin can be seen on Colorado Standard Plan No. M-606-14, Sheet 3.