Testing criteria and test levels for bridge railings are the same as previously discussed for roadside barriers (Art. 6.4). The FHWA maintains a list of designs that have been tested to NCHRP Report 350 levels, as well as designs that were tested to earlier guidelines and have been assigned an equivalent Report 350 test level. Railings are seldom evaluated for TL-1. Examples of railings designs that meet higher levels are as follows:
TL-2. Thrie-beam bridge railing, side mounted. Consists of a thrie-beam rail centered 22 in (550 mm) above the deck, supported on steel or wood posts mounted on the side of the bridge. It is intended for use on lower-volume secondary roads. Actually tested only to NCHRP 230 criteria, it is considered to meet TL-2.
TL-3. Wyoming Two-Tube bridge railing. Consists of two horizontal tubular rails, 6 X 2 X 0.25 in (152 X 51 X 6.4 mm), supported by fabricated steel posts on 10-ft (3-m) centers, mounted on and flush with concrete curb. Height of top rail is 29 in (740 mm) and height of bottom rail is 16 in (405 mm). A heavier version meets TL-4.
TL-4. (1) Solid concrete railings. The current New Jersey, F-shape, single-slope, and
vertical wall types meet TL-4 when adequately reinforced and built to a minimum height of 32 in (810 mm). (2) Massachusetts S3 Steel Bridge Railing. This is a beam and post system with three tubular rails on W6 X 25 (W150 X 37) posts, mounted flush on the outside edge of a sidewalk or on top of a curb. The tube size varies. Steel tube pickets are bolted to the back to provide an aesthetic look. (3) Wyoming Two — Tube bridge railing. Consists of two horizontal tubular rails, 6- X 4- X 0.25-in (152- X 102- X 6.4-mm) top rail and 152- X 76- X 6.4-mm (6- X 3- X 0.25-in) bottom rail], supported by fabricated steel posts on 10-ft (3-m) centers, mounted on and flush with concrete curb. Height of top rail is 33 in (830 mm) and height of bottom rail is 19 in (480 mm). (4) BR27C railing. This railing may be mounted on a curb or flush mounted
on the bridge deck. The lower portion consists of a concrete parapet, 24 in (610 mm) high by 250 mm (10 in) thick. The upper portion consists of steel tube posts 4 X 4 X 3/16 02 X 102 X 4.8 mm)/6.5 ft (2 m) spaced at on center. A horizontal steel tube
rail [4 X 3 X 0.25 in (102 X 76 X 6.4 mm)] is mounted to the face of the posts.
TL-5. Solid concrete railings. The current New Jersey, F-shape, single-slope, and vertical wall types meet TL-5 when adequately reinforced and built to a minimum height of 42 in (1070 mm).
TL-6. Texas Type TT (Tank Truck). This system consists of a very heavily reinforced and widened concrete safety shape, with a heavily reinforced continuous concrete member and post system above.
