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Texas Bridge Rails June 2019
TEXAS BRIDGE RAILSJamie F. Farris, P.E.
June 2019
Texas Bridge Rails 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 Bridge Rails June 2019
Texas Policy
Bridge Railing Manual
First published in 2001
http://onlinemanuals.txdot.gov/txdotmanuals/rlg/rlg.pdf
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Texas Bridge Rails June 2019
Texas Policy
Bridge Railing Manual
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 Bridge Rails June 2019
Texas Policy
Bridge Railing Manual
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 Bridge Rails June 2019
Texas Policy
Bridge Railing Manual
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 Bridge Rails June 2019
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 Bridge Rails June 2019
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 Bridge Rails June 2019
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 Bridge Rails June 2019
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
Texas Bridge Rails June 2019
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
Texas Bridge Rails June 2019
Crash Testing Process
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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Texas Bridge Rails June 2019
Crash Testing Process
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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Texas Bridge Rails June 2019
Crash Testing Process
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Circa 1983 – Monster Rail Test – 80k Tanker
Texas Bridge Rails June 2019
Crash Testing Process
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Crash Testing
Circa 1989
Appr GF Tests using
tubular W-Beam
Texas Bridge Rails June 2019
Crash Testing Process
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
Texas Bridge Rails June 2019
TxDOT Bridge Rail Standards
http://www.dot.state.tx.us/insdtdot/orgchart/cmd/cserve/standard/bridge-e.htm
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TxDOT Bridge Rail Standards
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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Texas Bridge Rails June 2019
TxDOT Bridge Rail Standards - Newer Rails
T2P– 42” tall, MASH TL-4
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C2P – 42” tall, MASH TL-4
Texas Bridge Rails June 2019
TxDOT Bridge Rail Standards - Newer Rails
T222 - 36” tall, MASH TL-4
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MASH
Texas Bridge Rails June 2019
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
Texas Bridge Rails June 2019
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
Texas Bridge Rails June 2019
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
Texas Bridge Rails June 2019
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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Texas Bridge Rails June 2019
MASH Crash Testing – C402 – Box Truck
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Texas Bridge Rails June 2019
MASH Crash Testing – C402 – Pickup
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Texas Bridge Rails June 2019
MASH Crash Testing – C402 – Car
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Texas Bridge Rails June 2019
MASH Crash Testing – Damage
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Texas Bridge Rails June 2019
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.
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WHAT’S NEXT?
Texas Bridge Rails June 2019
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
Texas Bridge Rails June 2019
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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Texas Bridge Rails June 2019
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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Texas Bridge Rails June 2019
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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Texas Bridge Rails June 2019
What’s Next?
On-Going Research
CIP Retaining walls – evaluating load response to rail impact at top
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Texas Bridge Rails June 2019
Questions?
Taya Retterer, P.E.
TxDOT Bridge Standards Engineer
Taya.Retterer@txdot.gov
Jamie F. Farris, P.E.
TxDOT Bridge Division Deputy Director
Jamie.Farris@txdot.gov
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Texas Bridge Rails June 2019
Copyright Notice
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Copyright 2019 • Texas Department of Transportation
• All Rights Reserved
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