Anchor: #CIHHIGEA

Section 2: Bridge Railing Upgrade Requirements

Anchor: #i999419

FHWA Policy

The Federal Highway Administration (FHWA), in its November 20, 2009, implementation plan for MASH, requires that bridge railing on the National Highway System (NHS) meet requirements of MASH or NCHRP Report 350:

    Anchor: #CHDGGGHG
  • "Highway safety hardware installed on new construction and reconstruction projects shall be those accepted under NCHRP Report 350 or MASH."

and

In the January 7, 2016, MASH implementation memo, agencies are again encouraged to upgrade existing highway safety hardware, with the additional requirement that only MASH-approved devices are allowed for bridge railing installations with contract letting after December 31, 2019.

Anchor: #i999459

Texas Policy

TxDOT requirements for treatment of existing railing for various project classifications are outlined in the table below.

Anchor: #i1012507Table 4-1: TxDOT Requirements Upgrading Bridge Railing Current Standards

Project Classification

Railing Action

Preventive Maintenance (PM) and 2R

Replacement of traffic railing not complying with MASH or NCHRP Report 350 is recommended but not required as long as the minimum rail height requirement is met.

Existing traffic railing complying with MASH, NCHRP Report 230, or NCHRP Report 350 may be raised to meet the minimum rail height requirement.

Existing rail that does not meet the minimum rail height and does not comply with MASH, NCHRP Report 230, or NCHRP Report 350 must be upgraded to comply with MASH or NCHRP Report 350.

3R

If the structure is not widened and if no work affecting the existing railing is done as part of the 3R project.

Replacement of traffic railing not complying with MASH or NCHRP Report 350 is recommended but not required as long as the minimum rail height requirement is met.

Existing traffic railing complying with MASH, NCHRP Report 230 or NCHRP Report 350 may be raised to meet the minimum rail height requirement.

3R

If rehabilitation work is scheduled or performed which widens the structure to either side or redecks (full-depth) any complete span of the structure, or if any work affecting the rail is done to the existing structure as part of the 3R project.

All traffic railing on the structure must comply with MASH or NCHRP Report 350. Railing adjacent to pedestrian walkways must comply with requirements in Chapter 3.

Exceptions by approval of Design Exception or Design Waiver Request.

Exceptions to compliance with MASH or NCHRP Report 350:

  1. Design Exception approval required if ADT is greater than 1,500 VPD.
  2. Design Waiver approval required if ADT is less than 1,500 VPD.

4R

Traffic railing must comply with MASH or NCHRP Report 350. Railing adjacent to pedestrian walkways must comply with requirements in Chapter 3.

Exceptions by approval of Design Exception Request.

Hazard Elimination Program (HES) Projects

3R or 4R criteria as applicable to the elements affected by the programmed scope of the HES project.

All Project Classifications

When traffic rail is upgraded to MASH or NCHRP Report 350, adjacent MBGF and guard fence transitions must also be upgraded.



NOTE: For project classifications and work that does not require the bridge rail to be upgraded, MBGF and MBGF transitions may be upgraded without upgrading the bridge railing provided no work is done to the bridge railing other than the connection of the bridge railing to the transitions or guard fence.

Rails that meet NCHRP Report 230 requirements include Types T202, C202, T6, T411, T421 and C411.

Anchor: #i1013659

Existing Railing Meeting Current Standards (NCHRP Report 350)

Existing railing types that are no longer used for new construction but are considered to meet the crash test criteria in NCHRP Report 350 are summarized in the following table.

Anchor: #i1013948Table 4-2: Acceptable Railing No Longer Used for New Construction

Railing Type

NCHRP Report 350 Approval Level

Nominal Height

Minimum Height

Description

T101

TL-3

27 in.

27 in.

Steel rail with two rectangular tubes and W beam, and with W6x20 posts.

T101RC

TL-3

27 in.

27 in.

A version of T101 rail for retrofitting on bridges with curbs. Superseded by T131RC.

C101

TL-2

42 in.

42 in.

Same as T101 rail with additional steel pipe rail; designed for vehicular and pedestrian traffic.

T2

TL-3

27 in.

27 in.

Vertical faced concrete parapet with W-beam fascia; designed for vehicular traffic. Superseded by T201.

C2

TL-2

39 in.from sidewalk

39 in.from sidewalk

Vertical faced concrete parapet with W-beam fascia and steel pipe rail; designed for vehicular and pedestrian traffic. Superseded by C201.

T201

TL-3

27 in.

27 in.

Vertical faced concrete parapet; designed for vehicular traffic. Superseded by T221.

C201

TL-2

42 in.

42 in.

Vertical faced concrete parapet with steel pipe rail; designed for both vehicular and pedestrian traffic. Superseded by C221.

B201

Not applicable*

63 in.

63 in.

Vertical faced concrete parapet with chain-link fence; designed for bicycle and pedestrian use. Superseded by B221.

*The presence of chain-link fence makes this railing only approved for speeds of 45 mph and below.

T202

TL-2

27 in.

27 in.

Concrete posts with concrete beam rail; designed for vehicular traffic. Superseded by T203.

C202

TL-2

42 in.

42 in.

Concrete posts with concrete beam rail; designed for vehicular traffic. Superseded by C203.

T203

TL-3

27 in.

27 in.

Concrete posts with concrete beam rail; designed for vehicular traffic. Superseded by T223.

C203

TL-2

42 in.

42 in.

Concrete posts with a steel pipe rail between each post, a concrete beam rail and a steel pipe rail; designed for both vehicular and pedestrian traffic. Superseded by C223.

B221

Not applicable*

63 in.

63 in.

Vertical faced concrete parapet with chain-link fence; designed for bicycle and pedestrian traffic. *The presence of chain-link fence makes this railing only approved for speeds of 45 mph and below.

T4 (A)

TL-3

33 in.

31 in.

Concrete parapet with aluminum railing; designed for vehicular traffic. Superseded by T401.

C4 (A)

TL-2

42 in.

42 in.

Concrete parapet with aluminum railing; designed for vehicular and pedestrian traffic. Superseded by C402. There are two heights of C4 rail-39 inches and 42 inches. The 39 inch tall version is acceptable for traffic only.

T4 and T4 (S)

TL-3 or TL-2

33 in.

(27 in.)

31 in.

(27 in.)

Concrete parapet with steel railing; designed for vehicular traffic. Superseded by T401. Earliest version of T4 rail had 12 inch tall concrete parapet and 27 inch overall height, which is not considered to meet TL-3 requirements but is considered to meet TL-2 requirements. Subsequent version of T4 rail had 18 inch tall parapet and 33 inch overall height; this version meets TL-3 requirements.

C4 and C4 (S)

TL-3

42 in.

42 in.

Concrete parapet with steel railing; designed for both vehicular and pedestrian traffic. Superseded by C402. There are two heights of C4 rail-39 inches and 42 inches. The 39 inch tall version is acceptable for traffic only.

T421

TL-2

32 in.

30 in.

Slanted steel posts with large round tubular rails; designed for vehicular traffic.

T5

TL-4

32 in.

29 in.

Concrete safety shaped parapet; designed for vehicular traffic. Superseded by T501. Needs a 3 foot long vertical taper at toe of rail on upstream rail end to meet NCHRP Report 350 criteria.

T501

TL-4

32 in.

29 in.

Concrete safety shaped parapet; designed for vehicular traffic. Superseded by T551.

C501

TL-2

42 in.

42 in.

Concrete safety shaped parapet with steel pipe railing; designed for both vehicular and pedestrian traffic.

T502

TL-4

32 in.

29 in.

Concrete safety shaped parapet with multiple drain slots; designed for vehicular traffic. Superseded by T552.

C502

TL-2

42 in.

42 in.

Concrete safety shaped parapet with multiple drain slots and with steel pipe railing; designed for both vehicular and pedestrian traffic.

T503

TL-4

32 in.

29 in.

Precast concrete safety-shaped parapet bolted to slab; designed for vehicular traffic.

T504

TL-4

32 in.

29 in.

Precast concrete safety-shaped parapet bolted to slab and designed for box-beam and slab-beam structures; designed for vehicular traffic.

T6

TL-2

27 in.

27 in.

Steel rail with two W-beam members welded back to back and with breakaway posts.

C6

TL-2

42 in.

42 in.

Same as T6 rail with additional steel pipe rail designed for vehicular and pedestrian traffic.

HT

TL-5

50 in.

47 in.

Modified concrete safety-shaped parapet with steel railing; designed for heavy truck traffic. Superseded by T80HT.

TT

TL-6

90 in.

90 in.

Modified concrete safety-shaped parapet with concrete posts and concrete railing; designed for heavy tank truck traffic. Never issued as a standard rail type. Superseded by T80TT.

T501SW

TL-4

Not applicable

Not applicable

8-foot reinforced concrete safety-shaped parapet and vertical wall; designed for use on bridges and on pavement. Never issued as a standard rail type. May also be referred to as T501NB and in heights other than 8-feet.

TW3

TL-3

29 in.

27 in.

Concrete curb with steel posts and two steel tube rails, designed for vehicular traffic. Never issued as a standard rail type. Superseded by T1W.

CW2

TL-2

42 in.

42 in.

Concrete curb with steel posts and four steel tube rails, designed for vehicular and pedestrian traffic. Never issued as s standard rail type. Superseded by C1W.

T412

TL-4

42 in.

42 in.

Concrete with 6-inch windows; designed for vehicular traffic. Never issued as a standard rail type. Superseded by C412.

T414

TL-4

42 in.

42 in.

Concrete with 6-inch windows; designed for vehicular traffic. Never issued as a standard rail type. Superseded by C412.



Anchor: #LNHYUMRQ

Minimum Bridge Railing Height

Minimum heights for most bridge railing types are documented in Appendix A, "Current Standard Bridge Railings in Texas" and Table 4-2. If the railing is not shown in this Manual, the minimum allowable height is 27 inches for traffic railing and 42 inches for combination and pedestrian railings.

Anchor: #i1017372

Measuring Bridge Railing Height

If there is no overlay or seal coat, measure the bridge railing height at its top inside face to the top of the roadway surface, as shown in Figure 4-1.

Measuring bridge railing height with no
overlay (click in image to see full-size image) Anchor: #LLIQEOPRgrtop

Figure 4-1. Measuring bridge railing height with no overlay

If there is an overlay or seal coat, measure the bridge railing height at its top inside face to the bottom of a 10 ft. straightedge placed flush on the pavement in front of the rail and perpendicular to the rail, as shown in Figure 4-2.

Measuring bridge railing height with overlay
or seal coat (click in image to see full-size image) Anchor: #YIAQTUDBgrtop

Figure 4-2. Measuring bridge railing height with overlay or seal coat

Anchor: #i999469

Bridge Railing Height in Pavement Overlay Projects

Minimum railing heights must be maintained, even during subsequent bridge maintenance overlays. In order to achieve minimum railing height, the following actions are available: Mill the existing overlay prior to new overlay application; taper the new overlay at a maximum 1 to 10 slope over the width of the shoulder to zero depth at the rail; or both.

If minimum railing height cannot be achieved with milling or tapering the overlay, the railing must be retrofitted to its minimum height when allowed by the criteria in Table 4-1. The Bridge Division is available to assist when details for raising railing heights are required.

Anchor: #i999538

Transition Upgrades

When roadway guard fence is upgraded, but existing bridge railing will remain in place, customized bridge-rail-to-guard-fence transitions may be required. The Bridge Division is available to advise Districts on options.

Anchor: #i999548

Recommendations

Consider the following aspects of the project in the selection of a retrofit railing when planning for a bridge that will be widened or rehabilitated:

Elements of the bridge structure

    Anchor: #JNPSSQWO
  • Review details of the slab and curb reinforcement of the existing bridge to determine if the slab edge is capable of being retrofitted with an adequate new railing. Note in particular:
    Anchor: #MNJXTKWO
  • Evaluate the effect of a full-strength retrofit on the shoulder width of the bridge. Ensure that a reduction in effective shoulder width or in sight distances at adjacent intersections will not affect safety. Also consider the following:

Characteristics of the bridge location

Features of the retrofit designs


Previous page  Next page   Title page