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Texas Bridge Rails June 2019

TEXAS BRIDGE RAILSJamie F. Farris, P.E.

June 2019


Summary

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Texas Policy

Crash Testing Process

TxDOT Bridge Rail Standards

MASH

What’s Next?

Questions?

Texas Bridge Rails June 2019 3

TEXAS POLICY


Texas Policy

Bridge Railing Manual

First published in 2001

http://onlinemanuals.txdot.gov/txdotmanuals/rlg/rlg.pdf

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Texas Policy


Summarizes current policies governing the use of bridge

railing in Texas

Provides information on acceptable Texas bridge railing

types

Update will occur in Fall 2019

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Texas Policy


Overview – federal and state policies

Policies on the Use of Bridge Railing for Vehicular Traffic

Pedestrian, Bicycle, and ADA Requirements for Bridge

Railing

Treatment of Existing Railing

Temporary Bridge Railing

Current Standard Bridge Railings in Texas

Acceptable Placement of Bridge Railing for Vehicular and

Non-vehicular Traffic

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Texas Policy


Crash testing requirements

Approval of bridge railing

Rail type selection

Allowable uses of bridge railing for specific installations

Required crash tests

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Texas Policy

Rail Certification

In accordance with the May 21, 2012 memo "Roadside Safety Hardware - Federal-Aid

Reimbursement Eligibility Process,"

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– TxDOT certifies that all traffic and

combination railings included in the

Bridge Railing Manual - Appendix A,

"Acceptable Bridge Railing in Texas,"

– Rails have been crash-tested by an

accredited test facility or evaluated to be

equal to a crash-tested railing,

– Bridge railings are eligible for federal-aid

reimbursement.


Texas Policy

All bridges require bridge railing.

Bridge-class culverts require safety end treatments,

metal beam guard fence, or bridge railing.

Roadways elevated by retaining walls require bridge

railing or metal beam guard fence for the entire

length of the retaining walls.

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Texas Policy

New bridges - Texas bridge railing on new construction must meet FHWA crash-test

criteria as specified in MASH 2016. (this update will be in Fall 2019 Manual)

Existing bridges - TxDOT has developed a range of procedures for retrofitting existing

structures with railing types that have performed well and are reasonably economic to

install.

– Procedures for retrofitting bridge railing on existing structures are published with the

TxDOT Bridge Standards.

– Texas policy - Upgrading rails depends on the project classification

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Example – Retrofit Guide for

Concrete Rails


Texas Policy

Approval of Bridge Railing

A bridge railing type can be approved for use on Texas bridges in any one of the

following ways *:

– It has been successfully crash tested in accordance with MASH 2016.

– It has been approved for specific uses by FHWA after evaluation of results from

successful crash testing.

– It has been evaluated by TxDOT and identified as similar in strength and geometry

to another rail that has been successfully crash tested in accordance with MASH

2016 criteria.

* Further evaluation by Bridge Division may be required before approval can be given.

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CRASH TESTING

PROCESS



How does TxDOT choose what bridge rails to test or research to do?

– For MASH testing – goal to maintain current rails

– Knowledge for retrofits and rail foundations

How does TxDOT decide on what to design?

– TxDOT develops rails to meet a need, such as:

• Historic look

• Aesthetics

• Better drainage

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• Lighter

• Higher test level

• Precast or Rapid construction



Crash testing and analytics are

done through TxDOT’s

research program

TxDOT research problem

statements become research

projects through the research

proposal evaluation process

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Most of the crash testing has been done by

Texas A&M Texas Transportation Institute

(TTI) dating back to the early 1980’s

– This partnership has been the key to a

successful bridge rail program

– https://static.tti.tamu.edu/tti.tamu.edu/d

ocuments/tti-crash-testing.pdf

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https://static.tti.tamu.edu/tti.tamu.edu/documents/tti-crash-testing.pdf



17

Circa 1983 – Monster Rail Test – 80k Tanker



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Crash Testing

Circa 1989

Appr GF Tests using

tubular W-Beam



Researchers analyze and evaluate the data collected in the crash tests and prepare

reports documenting the test procedures and results

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TXDOT BRIDGE RAIL

STANDARDS



http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/bridge-e.htm

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http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/bridge-e.htm



Traffic Rails – 18

Combination Rails – 8

Miscellaneous Rails – 12

– Includes rail retrofit guidance

– Pedestrian rails

– Traffic rail foundation

– Chain link fence for RR Overpass

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TxDOT Bridge Rail Standards - Newer Rails

T2P– 42” tall, MASH TL-4

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C2P – 42” tall, MASH TL-4


TxDOT Bridge Rail Standards - Newer Rails

T222 - 36” tall, MASH TL-4

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MASH


MASH Deadline

Manual for Assessing Safety Hardware (MASH)

– On January 7, 2016, AASTHO and FHWA issued the

“AASHTO/FHWA Joint Implementation Agreement for Manual

for Assessing Safety Hardware (MASH)” memorandum. The

memorandum outlines a staged plan, which requires that

permanent installations of safety hardware be evaluated using

MASH 2016 criteria by the following dates:

• December 31, 2019: bridge rails, transitions, all other

longitudinal barriers (including portable barriers installed

permanently), all other terminals, sign supports, and all

other breakaway hardware

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Status – MASH Crash Testing - Texas

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Rail MASH Test

Level

Tests Performed

T402 & C402 TL-4 Car, Pickup, Box Truck

T411 & C411 TL-2 Car, Pickup (low speed)

C412 TL-5 18 wheeler

T1W TL-3 Car, Pickup

C1W TL-4 Box Truck

T66 & C66 TL-3 Car, Pickup

Total = 11 Crash Tests

Completed MASH crash testing - tested in the last year


Which crash tests are run?

Not all crash tests are run. Some are skipped based on evaluation, tests on other

systems, or previous data from tests using an older requirement.

Example - T1W and C1W rails

– T1W - Crash tests for the car and pickup (full suite)

– C1W - only the box car (skipped car and pickup)

– Tests for the T1W were used to evaluate the C1W

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T1W C1W


Which crash tests are run?

Why?

T1W

Shorter with fewer pipe runners

Opening between runners larger than

C1W

Same type of post and post spacing

as C1W

Similar enough rail with a more

critical intrusion potential

Since T1W passed, C1W passes

Small car and pick-up tests for T1W are

applied to the C1W

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T1W C1W


MASH Crash Testing – C402

Use Current standard railing

Classification Combination

Description

24 in. concrete parapet with 18 in.

steel ellipse or rectangular HSS rail

with 2 in. pedestrian pipe rail between

parapet and top rail

Approximate Period of

Installation2005 – Present

Nominal Height / Min.

Height42 in. / 40 in.

Approved Test CriteriaSuccessfully crash-tested and approved

for MASH TL-4

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MASH Crash Testing – C402 – Box Truck

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MASH Crash Testing – C402 – Pickup

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MASH Crash Testing – C402 – Car

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MASH Crash Testing – Damage

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Current Texas Bridge Rails that meet MASH

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TL-2 TL-3 TL-4 TL-5 TL-6

T631LS T1F T2P / C2P T224 T80TT *

T411 T1P* T222 T80HT

C411 T1W T402 / C402 T80SS

T221 / C221 SSTR C412

T223 / C223 C1W

T551 / T552

T66 / C66

T131RC

T221P

3 total 13 total 7 total 4 total 1 total

* Available as working drawings.


WHAT’S NEXT?


What’s Next?

Update TxDOT Bridge Railing Standards

– Change general notes from NCHRP 350 to

MASH

– Other minor changes to reinforcement, concrete

type, sleeve members

Update TxDOT Bridge Railing Manual

– Reflect updates

– Finish conversion to MASH

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When? – Actively working on, planning no later than October.

http://mtvcog.org


What’s Next?

On-Going Research

54” TL-5 Rail on a Structurally Independent Foundation

– Computer simulations and design done

– Crash test in June

– Project finishes in August

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What’s Next?

On-Going Research

TL-4 TRF – Traffic Rail Foundation

– Computer simulations and design done

– Crash test in June

– Project finishes in August

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What’s Next?

On-Going Research

C-RAIL-R – Retrofit Guide for Concrete Rails

– Evaluating for TL-4 and adding curb rails (T1F, T2P,

T1W, etc.)

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What’s Next?

On-Going Research

CIP Retaining walls – evaluating load response to rail impact at top

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Questions?

Taya Retterer, P.E.

TxDOT Bridge Standards Engineer

[email protected]

Jamie F. Farris, P.E.

TxDOT Bridge Division Deputy Director

[email protected]

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mailto:[email protected]

mailto:[email protected]


Copyright Notice

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Copyright 2019 • Texas Department of Transportation

• All Rights Reserved

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is distributed without profit and is being made available

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