Chapter 2: Acceptable Bridge Railing in Texas
Anchor: #CHDFIAHGSection 1: Overview
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All new Texas bridge railing must meet FHWA crash-test criteria as specified in NCHRP Report 350. The following tables identify bridge railing that will be coded as acceptable in TxDOT bridge inspections. Except where noted in individual railing type descriptions, these railing types meet crash-test criteria for use at the level specified in Sections 2 through 4 of this chapter.
Texas bridge railing type names use alphanumeric sequences in which the following conventions are usually observed:
- T indicates railing for vehicular traffic.
- P indicates railing for pedestrian traffic.
- C indicates railing for a combination of vehicular and pedestrian traffic.
- B indicates railing for bicycle traffic.
- R indicates retrofitted railing.
- HT indicates heavy truck railing.
- TT indicates tank truck railing.
- SSTR indicates single slope traffic railing.
- S indicates steel railing.
- A indicates aluminum railing.
NOTE: The “nominal face of railing” is one foot from the outside edge of bridge slabs, regardless of actual physical dimensions.
Texas currently uses standard metal railing summarized in the following table.
|
Railing Type |
Approval Level |
Description |
|---|---|---|
|
T101 |
TL-3 |
Steel posts and tubular rails with W beam; designed for vehicular traffic. |
|
T6 |
TL-2 |
Steel breakaway posts with tubular W-beam railing; designed for vehicular traffic. |
|
PR1 |
Not Applicable |
Steel post and pipe railing; designed for pedestrian use only. |
Texas currently uses standard metal and concrete railing summarized in the following table.
|
Railing Type |
Approval Level |
Description |
|---|---|---|
|
T401 |
TL-3 |
Concrete parapet with steel railing; designed for vehicular traffic. |
|
T402 |
TL-3 |
Concrete parapet with steel railing; designed for vehicular traffic. |
|
C402 |
TL-3 |
Concrete parapet with steel railing; designed for both vehicular and pedestrian traffic. |
|
T77 |
TL-3 |
Short concrete parapet with steel railing; designed for vehicular traffic. |
|
HT |
TL-5 |
Modified concrete safety-shaped parapet with steel railing; designed for heavy truck traffic. |
|
PR2 |
Not Applicable |
Short concrete parapet with steel posts and pipe railing; designed for pedestrian use only. |
Texas currently uses standard concrete railing summarized in the following table.
|
Railing Type |
Approval Level |
Description |
|---|---|---|
|
T203 |
TL-3 |
Concrete posts with concrete railing; designed for vehicular traffic. |
|
C203 |
TL-2 |
Concrete posts with concrete railing; designed for both vehicular and pedestrian traffic. |
|
T221 |
TL-3 |
Concrete parapet; designed for vehicular traffic. |
|
C221 |
TL-2 |
Concrete parapet; designed for both vehicular and pedestrian traffic. |
|
B221 |
Not Applicable |
Concrete parapet with chain-link fence; designed for bicycle and pedestrian traffic. |
|
T411 |
TL-2 |
Concrete with 6-inch windows; designed for vehicular traffic. |
|
C411 |
TL-2 |
Concrete with 6-inch windows; designed for both vehicular and pedestrian traffic. |
|
T501 |
TL-4 |
Concrete safety shaped parapet; designed for vehicular traffic. |
|
T501SW |
TL-4 |
8-foot reinforced concrete safety-shaped parapet and vertical wall; designed for use on bridges and on pavement. NOTE: This railing is intended to protect highly vulnerable sites beneath a bridge. |
|
C501 |
TL-2 |
Concrete safety shaped parapet; designed for both vehicular and pedestrian traffic. |
|
T502 |
TL-4 |
Concrete safety shaped parapet with multiple drain slots; designed for vehicular traffic. |
|
C502 |
TL-2 |
Concrete safety shaped parapet with multiple drain slots; designed for both vehicular and pedestrian traffic. |
|
T503 |
TL-4 |
Precast concrete safety-shaped parapet bolted to slab; designed for vehicular traffic. |
|
T504 |
TL-4 |
Precast concrete safety-shaped parapet bolted to slab and designed for box-beam and slab-beam structures; designed for vehicular traffic. |
|
SSTR |
TL-3 |
Constant slope concrete parapet similar to single slope concrete median barrier; designed for vehicular traffic. |
|
TT |
TL-6 |
Modified concrete safety-shaped parapet with concrete posts and concrete railing; designed for heavy tank truck traffic. NOTE: This railing is intended to protect highly vulnerable sites beneath a bridge. |
Acceptable rails no longer used for new construction are summarized in the following table.
|
Railing Type |
Approval Level |
Description |
|---|---|---|
|
T421 |
TL-2 |
Slanted steel posts with large round tubular rails; designed for vehicular traffic. |
|
T4 (S) |
TL-3 |
Concrete parapet with steel railing; designed for vehicular traffic. NOTE: This railing has been superseded for new construction by the T401 railing. |
|
T4 (A) |
TL-3 |
Concrete parapet with aluminum railing; designed for vehicular traffic. |
|
C4 (S) |
TL-3 |
Concrete parapet with steel railing; designed for both vehicular and pedestrian traffic. NOTE: This railing has been superseded for new construction by the C402 railing. |
|
T201 |
TL-3 |
Concrete parapet; designed for vehicular traffic. NOTE: This railing has been superseded for new construction by the T221 railing. |
|
C201 |
TL-2 |
Concrete parapet; designed for both vehicular and pedestrian traffic. NOTE: This railing has been superseded for new construction by the C221 railing. |
|
B201 |
Not Applicable |
Concrete parapet with chain-link fence; designed for bicycle and pedestrian use. NOTE: This railing has been superseded for new construction by the B221 railing. |
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C Railing Types
Combination railing types C201, C203, C221, C501, and C502 are considered acceptable only for slow-speed use (TL-2) with a design speed of 45 mph or less because their pipe rail presents an occupant compartment intrusion threat to high speed vehicular traffic. However, the C4 (S) and C402 railing types are considered acceptable for higher speed use (TL-3) with a design speed greater than 45 mph.
Anchor: #i1007150Sound Walls
Recent years have produced interest in sound barriers for the sides of highways and on bridge overpasses, particularly in suburban areas. The Traffic Railing Type T501SW is approved for TL-4 use on Texas bridges. TxDOT does not recommend installation of concrete sound barriers mounted on top of concrete bridge railing for these reasons:
- The sound barrier mass changes the vehicle impact behavior with the railing.
- The sound barrier connections at the top of the railing cannot be acceptably anchored.
Open Bridge Railing
Open rails on Texas bridges enhance the bridge user’s view from the bridge and often improve the appearance of the bridge. TxDOT encourages the use of open bridge railing on Texas bridges whenever possible. The cost premium of open bridge railing can usually be offset by increased positive perception of the public.
Anchor: #i1007172More Information
See the following sections for descriptions of these bridge railing types. For more detailed information on Texas bridge railing, refer to TxDOT Bridge Division Railing Standards. http://www.dot.state.tx.us/insdtdot/orgchart /cmd/cserve/standard/bridge-e.htm
For information about crash-tested railing currently available or about railing currently under design, contact the TxDOT Bridge Division.