Yannick Martin, ing. jr. Chuck A. Plaxico, Ph.D. Charles-D. Annan, - - PowerPoint PPT Presentation

Yannick Martin, ing. jr. Chuck A. Plaxico, Ph.D. Charles-D. Annan, Ph. D, P. Eng Mario Fafard, Ph. D., ing .

21e Colloque sur la progression de la recherche québécoise sur les ouvrages d’art May 7, 2014

 Mise en contexte  Pratiques au Canada  Pratiques aux États-Unis  Synthèse  Conclusion

 Dispositif de retenue: Limite infranchissable de la

voie carrossable

• Atténue les conséquences d’une sortie de route de véhicule
• Directement lié à la sécurité des usagers

[Kimball et al. 1999]

 Conception: nouveaux systèmes testés à grandeur

réelle

• Testés selon rapport 350 du NCHRP (Ross, 1993)
• CSA-S6 s’appui sur AASHTO

 Plusieurs dispositifs standards déjà approuvés

• Commentaire CSA-S6, Manuel du MTQ

 Nécessité de les modifier?

• Améliorer la performance
• Réduire les coûts de fabrication
• Adapter le dispositif à une structure particulière

 Les modifications sont permises seulement si on

peut démontrer que celles-ci n’affectent pas l’interaction entre le dispositif et le véhicule lors de l’impact.

• Identifier l’effet de la modification
• Démontrer que la performance de la barrière est conservée
• Outils: Rapport de l’essai de collision et notes de calcul

 Approprié pour les changements mineurs avec un

effet positif

 L’ancrage d’un dispositif doit résister aux charges

de l’essai d’impact

• L’ancrage doit pouvoir développer la résistance maximale du

poteau OU résister aux charges prescrites

• Charges tirées de la 2e version de AASHTO LRFD (1998)

 Brief History of Accepted Evaluation

Practices

 Current Policy of FHWA

• New Hardware Designs
• Modifications to Existing Designs

 Example - Modification to Bridge Rail Mount

 As of January 1, 2011

• All new hardware must be

full-scale crash tested according to MASH criteria.

• Existing hardware with

Report 350 approval status may remain in place and may continue to be manufactured and installed.

 Existing systems are often modified for a variety of

reasons, for example to:

• Improve crash performance,
• Reduce manufacturing cost,
• Accommodate installation/mounting to a different structure, etc.

 How do such changes get approved under the new FHWA

requirements?

• Does the system have to be retested?

 If so, which crash test procedures are required?

 The new (more severe) crash testing criteria of MASH?  Or, the test procedures for which the system was previously approved (e.g., Report 350)?

• Could alternative methods be used to evaluate the modification?

Test Vehicles

Report 350 / AASHTO ‘98 MASH

22 kip 56 mph 15 deg. 18 kip 50 mph 15 deg. 2.4 kip 62 mph 25 deg. 1.8 kip 62 mph 20 deg. 5.0 kip 62 mph 25 deg. 4.4 kip 62 mph 25 deg.

20 40 60 80 100 120 140 160 180

Report 350 (TL-4) AASHTO '98 (PL-2) MASH (TL-4) Impact Severity (kip-ft) Test Procedure small car test pick-up test SUT test

54%

2nd Ed.

 On May 12, 2012, the FHWA instituted a new

Federal-Aid Reimbursement Eligibility process.

 All New Hardware ➔ MASH Full-Scale Testing  Modifications to already accepted hardware

were categorized into three categories:

• 1. Significant
• 2. Non-Significant: Effect is Positive or

Inconsequential

• 3. Non-Significant: Effect is Uncertain

Full Scale Testing (MASH) Petition FHWA for Approval

http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/acceptprocess/

(2) (1) (3)

Exam ample les

• System height
• Barrier face geometry
• Material Type
• System components (e.g.,

different post size)

Full Scale Testing (MASH) Petition FHWA for Approval

http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/acceptprocess/

(2) (1) (3)

Exam ample les

• Increase gauge thickness
• f rail element
• Modify barrier face

geometry within a “known” tolerance

• (All are reviewed on a case

by case basis)

Full Scale Testing (MASH) Petition FHWA for Approval

http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/acceptprocess/

(2) (1) (3)

Exam ample les

• Dissimilar method of

fastener (e.g., welded vs. bolted)

• Substitute successfully

crash tested component into system for identical use

• Change in component

design (e.g., bridge rail mount)

(3) (3)

 (3

(3) ) No Non-Significan Significant: t: Ef Effect fect is is Unce Uncertain rtain

• Acceptable evaluation procedures:

 Performing full-scale crash testing under MASH criteria  The LS-DYNA non-linear, dynamic finite element code

• Report 350 testing is no longer permitted
• So at the moment, modifications to a Report 350

system design can only be evaluated through FEA – or in some cases, dynamic component testing.

• Evaluation of the system must be “independently

certified” by an organization that is on the FHWA’s list of accredited laboratories.

FEA Full-Scale Testing

Laboratory Contact(s)

Dip ipartimen timento to di i Sc Scienze ienze e Tecnologie

• logie Aer

erosp

• spaz

azial iali

Milano- ITALY Marco Anghileri Phone: +39 02 2399 8316-7162 -7152 marco.anghileri@polimi.it

E-Tech ch Testin ting g Se Servi vice ces, s, Inc. c.

Rocklin, California John LaTurner Phone: (916) 644-9146 John.laturner@trin.net

Ge George ge Mason Un Univ iver ersi sity

Center for Collision Safety and Analysis Fairfax Virginia Dhafer Marzougui Phone: (703) 993 4680 dmarzoug@gmu.edu

Mid idwes west t Roadside ide Sa Safet fety Facili ility

University of Nebraska-Lincoln Lincoln, Nebraska Ronald K. Faller Phone: (402) 472-6864 rfaller@unl.edu

George Washington University

National Crash Analysis Center Ashburn, Virginia Umashankar Mahadevaiah Phone: (703) 726 8326 ushankar@ncac.gwu.edu

RoadSafe LLC

Canton, Maine www.roadsafellc.com Chuck A. Plaxico Phone: (614) 578-1942 chuck@roadsafellc.com

Texas A&M Transportation Institute

Texas A&M University College Station, Texas

• D. Lance Bullard, Jr.

Phone: (979) 845-6153 l-bullard@tamu.edu

Modifications to the Design of an Existing Report 350 Test Level 4 Bridge Rail to Accommodate Installations on Through Truss Bridges.

Concrete Bridge Structure NETC 4-Bar Bridge Rail (PL-2 / Report 350 TL-4) Steel Through-Truss Bridge

1) 1) Dev evel elop

• p a fi

fini nite te element ment mo model of f an n existing isting ha hardwa ware re th that t is Re Repo port t 350 0 or

• r

MA MASH H com

• mpliant

nt. FEA Model Concrete Bridge Structure NETC 4-Bar Bridge Rail (Report 350 TL-4)

1) Develop a finite element model of an existing hardware that is Report 350 or MASH compliant.

2) 2) Va Validate te th the e model by by com

• mparing

ng th the mo model re resu sults ts to to an ex n existing isting fu full-sca cale le crash sh te test st on

• n the

the syste ystem, us using ing th the proc

• cedures

dures ou

• utl

tlined ned in N n NCHRP HRP Doc

• cum

umen ent t 179. 79.

1.1 seconds 1.2 seconds 1.3 seconds 1.4 seconds 1.0 seconds

Test NETC-3 FEA

1) Develop a finite element model of an existing hardware that is Report 350 or MASH compliant.

2) 2) Va Validate te th the e mo model by by co comp mparing ng th the mo model re resu sults ts to to an ex n existing isting fu full-sca cale le crash sh te test st on

• n the

the syste ystem, us using ing th the proc

• cedures

dures ou

• utl

tlined ned in N n NCHRP HRP Doc

• cum

umen ent t 179. 79.

1) Develop a finite element model of an existing hardware that is Report 350 or MASH compliant. 2) Validate the model by comparing the model results to an existing full-scale crash test on the system, using the procedures outlined in NCHRP Document 179.

3) 3) In Incor

• rpor
• rate

te desi sign gn mo modifi ficati tion(

• n(s)

) int nto

• th

the FE mo model (e (e.g., cha hange nge mo moun unt t desi sign gn). ).

 In this case, the modifications included only those necessary for attachment to the bridge structure.

Original Mount

50.8 mm 137 mm

Original Mount Design Modified Mount Design

50.8 mm 137 mm

1) Develop a finite element model of an existing hardware that is already a Report 350 or MASH compliant system. 2) Validate the model by comparing the model results to an existing full-scale crash test on the system, using the procedures outlined in NCHRP Document 179. 3) Incorporate design modification(s) into the FE model (e.g., change mount design).

4) 4) Use e FEA EA to to simula mulate te th the requi quired red fu full- scale le te tests sts and nd eva valua uate te the system’s perfo form rmance. ance.

1) Develop a finite element model of an existing hardware that is already a Report 350 or MASH compliant system. 2) Validate the model by comparing the model results to an existing full-scale crash test on the system, using the procedures outlined in NCHRP Document 179. 3) Incorporate design modification(s) into the FE model (e.g., change mount design). 4) Use FEA to simulate the required full- scale tests and evaluate the system’s performance.

5) 5) Com

• mpare results

esults to to t the he or

• rigi

gina nal l desi sign gn to to ensu nsure re th that t th the e cha hange nge wa was pos

• siti

tive ve

• r “insignificant” regarding crash

perfo form rmance. ance.

Full Scale Testing (MASH) Petition FHWA for Approval

http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/acceptprocess/

Modification mineure Nouvelle conception Analyse EF dynamique

• Constitue un outil pour les chercheurs
• Permet d’éclairer les concepteurs
• Ouvre des portes à l’innovation

Analyse statique

Analyse dynamique

 Développement d’ancrage pour un tablier

• rthotrope en acier

30

 Élimination des contraintes plastiques à l’aide de

plaques d’appuis

Comparaison des modèles

Modèle de base Plaxico & Ray Modèle sur tablier

• rthotrope en acier

31

Comportement similaire

 Les pratiques américaines apportent une nuance

entre la nouvelle conception et la modification mineure

 L’analyse dynamique par éléments finis et les

procédures V&V permettent d’évaluer une nouvelle gamme de modification

 Ces nouvelles opportunités ouvrent la porte à

l’innovation dans les ouvrages d’art

33

Date: 11/22/2013 Comparison: Device Name:/Variant: Submissions Type: Non-Significant -- Effect is Uncertain Testing Criterion: Non-Significant -- Effect is Positive Test Level: Non-Significant -- Effect is Inconsequential FHWA Letter: X Baseline Validation of Crash Test to FEA Analysis. Test Number: Test FEA Occupant Risk (cont.) Test FEA Vehicle: A1 - Acceptable perf.? Yes Yes L1 – Long. OIV 1.7 m/s 2.4 m/s Vehicle Mass: A2 – Permenant 0.51 in 0.66 in L1 – Lat. OIV 2.9 m/s 5.5 m/s Impact Speed: A3 – Contact Length 40 ft 35 ft L2 – Long. ORA 8.95 g 9.4 g Impact Location: A5 – Comp. Failures? No No L2 – Lat. ORA 14.3 g 14.6 g Tested Hardware: Original Design A6 – Connection Failure? No No Vehicle Trajectory FEA Hardware: Original Design A7 – Wheel Snagging? No No M2 – Exit Yaw Angle 4.1 deg 0.5 deg A8 – Vehicle Snagging? No No M3 – Exit Velocity 35.8 mph 39.6 mph Total Energy: 5.0% Pass Occupant Risk Test FEA Hourglass Energy: 0.0% Pass D – Detached elements? No No Sprague-Geer Magnitude < 40 19.7 Pass Mass Added: <1% Pass F2 – Max. Vehicle Roll Unk Sprague-Geer Phase < 40 26.1 Pass Shooting Nodes: No Pass F3 – Max. Vehicle Pitch Unk ANOVA Mean 2 Pass Negative Volumes: No Pass F4 – Max. Vehicle Yaw Unk ANOVA Standard Deviation 25.9 Pass (FHWA Memorandum) W-179 Table E-5: Roadside PIRTS Finite Element Analysis Determination of Elibibility for Reimbursement under the Federal-Aid Highway Program SwRI NETC-3 8000S NETC 4-Bar w/ Side Walk NCHRP Report 350 TL 4 B50 Crash tested original design to FEA of original design Structural Adequacy Bridge Rail System Type: Baseline Crash Test W-179 Table E-1: Verification Evaluation Summary W-179 Table E-3 (Multi-Channel Method) 17,875 lb 49.8 mph / 15 deg 27 in. upstream of Post 6

0.40 sec 0.60 sec 0.80 sec 1.00 sec 0.20 sec

FEA Analysis Crash Test

The he fi fina nal st step p in t n the he pr proc

• cess

ess is t s to:

• :

 Submit the complete

analysis report to FHWA and

 Fill out the required forms

Category AASHTO Guide Spec ‘89 NCHRP Report 350 AASHTO MASH Test Vehicles Report 350 MASH

Test 4-10

Mass (lb) 1,800 1,807 2,425 Impact Speed (mph) 60 62.1 62.1 Impact Angle (deg) 20 20 25 Impact Severity (kip-ft) 25.3 27.3 56.0

Test 4-11

Mass (lb) 5,400 4,400 5,000 Impact Speed (mph) 60 62.1 62.1 Impact Angle (deg) 20 25 25 Impact Severity (kip-ft) 76.0 101.6 115.4

Test 4-12

Mass (lb) 18,000 18,000 22,046 Impact Speed (mph) 50 50 56 Impact Angle (deg) 15 15 15 Impact Severity (kip-ft) 100.1 100.1 154.5

TL TL-4 PL PL-2

1) Develop a finite element model of an existing hardware that is Report 350 or MASH compliant.

2) 2) Va Validate te th the e mo model by by co comp mparing ng th the mo model re resu sults ts to to an ex n existing isting fu full-sca cale le crash sh te test st on

• n the

the syste ystem, us using ing th the proc

• cedures

dures ou

• utl

tlined ned in N n NCHRP HRP Doc

• cum

umen ent t 179. 79.

 Qualitative Validation :  Verify overall model response through a general comparison with a full-scale crash test.  Quantitative Validation:  Solution verification  Time-history evaluation  Phenomena Importance Ranking Table (PIRT)