Section 3: Metal and Concrete Railing
Anchor: #i1007267Traffic Railing Type T4 (S)
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This railing is 33 inches high with an 18-inch concrete parapet and a steel ellipse 15 inches above the concrete. It has twin one-inch cut-plate posts spaced a maximum of 10 ft. apart. Its minimum height after maintenance overlays is not yet established. NOTE: This railing is no longer used for new construction. It has been superseded for new construction by the T401 railing. |
The 33-inch T4 (S) railing has not been crash tested; however, TxDOT considers it as equal in strength and geometry to the Type T4 (A) railing, which was crash tested in 1999 and is approved for TL-3 use. See Figure 2-4, below.
Figure 2-4. 33-inch Type T4 (S) Railing
Anchor: #i1007292Traffic Railing Type T4 (A)
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This railing is 33 inches high with an 18-inch concrete parapet and an aluminum, bullet-shaped ellipse 15 inches above the concrete. It has thick, cast aluminum posts spaced a maximum of 8.33 ft. apart. Its minimum height after maintenance overlays has not yet been established. NOTE: This railing is no longer used for new construction. |
The T4 (A) railing was crash tested in 1999 with a 4,409-lb. pickup truck at 62 mph and at an angle of impact of 25 degrees. It is approved for TL-3 use. See Figure 2-5, below.
Figure 2-5. T4 (A) Railing
Anchor: #i1007312Combination Railing Type C4 (S)
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This railing is 42 inches high with a 24-inch concrete parapet, a steel ellipse at 18 inches above the concrete, and a pipe rail between the steel ellipse and the concrete. It has twin one-inch cut-plate posts spaced a maximum of 10 ft. apart. Its minimum height after maintenance overlays is 42 inches. NOTE: This railing is no longer used for new construction. It has been superseded for new construction by the C402 railing. |
TxDOT considers the 42-inch C4 (S) railing acceptable for TL-3 use. However, its pipe rail should be removed when the C4 (S) is used in high-speed applications.
Anchor: #i1007326Traffic Railing Type T401
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This railing is 33-inches high with an 18-inch concrete parapet and a steel ellipse 15 inches above the concrete. It has twin one-inch cut-plate posts spaced a maximum of 10 ft. apart. It features a bolt anchorage system for the steel rail posts that may be drilled and epoxy-anchored allowing slip-forming of the concrete parapet. Its parapet is thicker than the T4(S) rail, from which its design is derived. |
TxDOT considers this railing equal in strength and geometry to the Type T4(A) railing, which was crash tested in 1999 and is approved for TL-3 use.
Anchor: #i1007335Traffic Railing Type T402
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This railing is 42 inches high with a 24-inch concrete parapet and a steel ellipse 18 inches above the concrete. It has twin one-inch cut-plate posts spaced a maximum of 10 ft. apart. It features a bolt anchorage system for the steel rail posts that may be drilled and epoxy-anchored allowing slip-forming of the concrete parapet. Its parapet is thicker than that of the C4(S) rail, from which its design is derived. |
TxDOT considers this railing equal in strength to railings of like geometry that have been crash tested and approved for TL-3 use.
Anchor: #i1007344Combination Railing Type C402
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This railing is 42 inches high with a 24-inch concrete parapet and a steel ellipse 18 inches above the concrete. It also includes a 2-inch pedestrian pipe rail between the parapet and the steel ellipse to be used on the sidewalk side of the rail. It has twin one-inch cut-plate posts spaced a maximum of 10 ft. apart. It features a bolt anchorage system for the steel rail posts that may be drilled and epoxy-anchored allowing slip-forming of the concrete parapet. Its parapet is thicker than that of the T4(S) rail, from which its design is derived. |
TxDOT considers this railing equal in strength to railings of like geometry that have been crash tested and approved for TL-3 use.
Anchor: #i1007353Traffic Railing Type T77
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This railing is 33 inches high with a 9-inch sloped concrete rail parapet and with two steel ellipses centered at 18 inches and 30 ½ inches above the roadway surface. The steel ellipses are supported by 1 ¼-inch cut-plate posts spaced a maximum of 8 ft. apart. |
The T77 railing has been successfully crash tested for TL-3 use.
NOTE: Significant restrictions based on bridge geometry on the use of this railing are documented on the T77 standard drawing, posted on the internet at: http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve /standard/bridge-e.htm#Railing.
Figure 2-6. Type T77 Railing.
Anchor: #i1007376Heavy Truck Railing Type HT
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This railing is a 32-inch high concrete safety-shaped parapet with elliptical heavy steel railing mounted 18 inches above the concrete. Posts are twin one-inch steel-cut plates and are spaced a maximum of 8.33 ft. apart. The minimum height of the concrete parapet after maintenance overlays is 29 in. NOTE: See standard drawing for overhang requirements. |
This railing has had limited use in Texas. It was crash tested in 1984 with an 80,000-lb. semi-truck at 48 mph and at an angle of impact of 15 degrees. It was approved for TL-5 use after evaluation of results from the 1984 crash testing. See Figure 2-7, below.
Figure 2-7. Type HT Railing
Anchor: #i1007396Pedestrian Railing Type PR2
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This railing is 42 inches high with a short concrete parapet and steel posts and rails. It has four pipe rails, with 3-inch standard steel pipe for the top rail and 2-inch standard steel pipe for the lower rails. Its 5-inch wide steel plate posts are spaced a maximum of 10 ft. apart. Its minimum height after maintenance overlays is 42 inches. |
The PR2 railing is designed for pedestrian loads only. It has not been crash tested and is not intended for exposure to traffic. If this railing is used on a bridge or culvert, it must be protected from vehicular impact by an approved bridge railing. See Figure 2-8, below.
Figure 2-8. Type PR2 Railing