Flared Approach Guardrail Transition: Test No. FLAGT-2

Report Number(s): TRP-03-439c-25

Description: The flared AGT test installation was approximately 81 ft – 6 in. long and consisted of five main components: (1) a concrete buttress, (2) a thrie-beam AGT, (3) standard MGS, (4) a guardrail anchorage system, and (5) a flared AGT connector plate. Design details for test no. FLAGT-2 are shown in Figures 4 through 31. Photographs of the test installation are shown in Figures 32 through 34. Material specifications, mill certifications, and certificates of conformity for the system materials are shown in Appendix A. Note, the test installation was identical to the one evaluated previously in test no. FLAGT-1 except the posts supporting the nested thrie beam (post nos. 16 through 20). The downstream end of the installation consisted of a concrete parapet with dimensions matching those of the standardized concrete buttress [1]. The buttress was 84 in. long and 36 in. tall. To prevent vehicle snag on the buttress above the thrie-beam rail, the upstream end of the buttress was 32 in. tall and incorporated a 24-in. long slope to bring the barrier height up to 36 in. The upstream end of the standardized buttress utilized a dual tapered design, or dual chamfer, as shown in Figure 13. The lower tire chamfer was 18 in. long by 4½ in. wide by 14 in. tall and was designed to reduce the propensity for wheel snag on the buttress. The upper chamfer measured 4 in. long by 3 in. wide and extended vertically 18 in. along the remaining height of the buttress. The upper chamfer was designed to limit vehicle snag on the buttress, prevent the guardrail from bending around a rigid corner, and to limit the unsupported span length of the rail upstream from the buttress. The buttress was reinforced with Grade 60 rebar, as detailed in Figures 14 through 17, and the vertical steel in the buttress was anchored to the tarmac using an epoxy adhesive, as detailed in Figure 14

Test Level: 3

System Type: Guardrail to Concrete

MASH Test Number: 3-21

Proprietary/Non-proprietary: Proprietary

Pass/Fail: Fail

Evaluation: Testing + Engineering Analysis

Sponsor: Midwest Pooled Fund Program