M.A.S.H.: The New Safety

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26 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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M.A.S.H.: The New Safety
Hardware Crash Testing
Criteria

Idaho Transportation Department

2011 Project Development Conference

Richard Albin

Federal Highway Administration

Resource Center Safety and Design Team

April, 2011


Crash Testing
-

History

Crash Testing has been used as a tool for evaluating the
safety performance of roadside features for many years.

History of Testing Procedures


Highway Research
Correlation Services
Circular 482 (1962)


NCHRP Report 153
(1974)


NCHRP Report 230
(1980)


NCHRP Report 350
(1993)

Procedures for how to perform crash tests have
evolved

NCHRP 350

NCHRP Report 350, was
formally adopted by FHWA
for the NHS

This was the first time that
FHWA adopted these
procedures

An implementation date was
established in 1998 for new
installations on the NHS.


Practical Worse Case Philosophy

Practical Worse Case Philosophy

Test Matrix


NCHRP Report 350
created 6 Test Levels


Levels 1
-
3 based on
speed


TL1


50 km/h (31 mph)


TL2


70 km/h (43 mph)


TL3


100 km/h (62 mph)


Levels 4
-
6 add large
trucks

Manual for Assessing Safety
Hardware (MASH)


Update of the
evaluation
procedures prepared


Published as
AASHTO document in
October, 2009


Implementation plan
also developed



Manual for Assessing Safety
Hardware (MASH)

Primary Focus of
Update


Update test vehicles &
impact conditions


Eliminated ambiguities


Removed
inconsistencies


Consolidate test
matrices


Tighten reporting
procedures


Most Significant Changes


Small car and Pickup mass increased


TL
-
4, single unit truck test revised


Impact angle for small car increased to 25
o


Impact angle for terminals and crash cushions
raised to 25
o


Small Car


The 820C vehicle specified in Report 350 has
not been manufactured since 2000.


Proposed vehicle is a 1100C (2420 lb)


2001
-
2003 models

curb weight
-

2,765

lb

Small Car Angle


Increase impact
angle from 20
degrees to 25
degrees to be
consistent with
Pickup test


Tested with new
impact vehicle and
angle into a rigid NJ
shaped concrete
barrier

Pickup Truck


The 2000P Pickup specified in Report 350 has not
been manufactured since 2001


Quadcab reflects the 90th percentile vehicle


Proposed vehicle is
a 2270P Quadcab
Pickup (5000 lbs)


Quadcab Pickup
has a higher center
of gravity and more
closely represents
the large SUV’s


Pickup Truck


How does w
-
beam guardrail (27
-
5/8” height,
steel posts) perform with large vehicle?

New Test Matrices added


Variable Message Sign / Arrow Board test matrix
added.


Longitudinal Channelizing Devices category
added.

Test Matrices revised


Pickup Truck Test was added for support
structures and work zone traffic control devices

Test Installations


Installation length
more definitive
(cable barriers 600
ft minimum).


Specified the critical
impact point for
cable barrier testing
to be at a post for
the pickup truck test

Test Installations


Barrier height (max)
small car & (min)
pickup test.


Addition of
performance based
specs for soil.

Evaluation Criteria


Windshield damage criteria to be more objective.


Occupant compartment deformation criteria
more objective and based on NHTSA data


Maximum roll angle set to 75 degrees.


Single Unit Truck Test (TL
-
4)


NCHRP Report
350, the impact
severity of the SU
test (TL
-
4) is less
than the impact
severity of the
Pickup test (TL
-
3)


Intent was to
make the TL
-
4
test more
meaningful.

0
100
200
300
400
500
600
700
1
2
3
4
5
Test Level
Impact Severity, kJ
NCHRP 350

MASH

Single Unit Truck Test (TL
-
4)


Mass increased from 8,000 kg (18000 lb) to 10,000
(22
,000 lb)


Speed increased from 80 km/h (50 mph) to 90 km/h
(56 mph)



32” New
Jersey
shaped
concrete
barrier


Single Unit Truck Test (TL
-
4)


36” Single
Slope
concrete
barrier


What did not change?


Impact speed for high speed test retained at 100
km/h (62 mph)


No Changes to TL
-
5 and TL
-
6


Angle for strength test


Six test levels


Tests Conducted with New Criteria


W
-
Beam Guardrail


Steel
Post (27
-
5/8” height)


Pickup (passed)


W
-
Beam Guardrail


Wood
Post (27” height)


Pickup (failed
)

Tests Conducted with New Criteria


Box
-
Beam Guardrail


Pickup (passed)


Weak Post W
-
Beam


Pickup (passed)


Midwest Guardrail (31”
height)


Pickup (passed)


Small Car (passed)

Tests Conducted with New Criteria


W
-
Beam Guardrail
Median Barrier


Pickup (failed)


Small Car (passed)


Thrie

Beam Guardrail
Barrier


Pickup (failed)



Guardrail Transition


Pickup (passed)


Guardrail Terminal (SKT)


CIP test with small car
(passed)

Tests Conducted with New Criteria


Rigid 32” NJ shape
concrete barrier


Small car (passed)


Single Unit Truck
(fail as TL
-
4)


Precast Concrete
Barrier (Iowa F
Shape)


Pickup (passed)

Tests Conducted with New Criteria


U Channel sign
support


Pickup (passed)


Perforated square
tube sign
suppost


Pickup (failed)

MASH Implementation Plan


AASHTO Technical Committee on Roadside
Safety (TCRS) is responsible for developing and
maintaining MASH.


FHWA shall review and accept highway safety
hardware under MASH.


MASH Implementation Plan


All hardware accepted under Report 350 may
remain in place and may continue to be
manufactured and installed.


Hardware accepted using Report 350 is not
required to be retested using the MASH criteria

MASH Implementation Plan

However …


If hardware that met Report 350 is tested and
fails using MASH…

AASHTO & FHWA
will jointly review
results and
determine a course
of action.

MASH Implementation Plan


Upon adoption new hardware not previously
evaluated shall utilize the MASH criteria


Hardware under development at time of
AASHTO adoption can be completed under
Report 350


FHWA will not consider applications for
acceptance under Report 350 after January 1,
2011.


MASH Implementation Plan


Hardware installed on new or reconstruction
projects shall meet Report 350 or MASH


Agencies are encouraged to upgrade hardware
that does not meet Report 350 or MASH when:


roadway is reconstructed


3R projects


System damaged beyond
repair


MASH Implementation Plan


Hardware not meeting either Report 350 or
MASH and for which there are no suitable
alternatives can remain in place and can
continue to be installed.

Contact Information


FHWA Office of Safety


Nick Artimovich


Phone:202
-
366
-
1331


Email:
nick.artimovich@dot.gov



FHWA Office of Safety


Will Longstreet


Phone: 202
-
366
-
0087


Email:
will.longstreet@dot.gov



FHWA Resource Center


Dick Albin


Phone: 303
-
550
-
8804


Email:
dick.albin@dot.gov



FHWA Roadside Hardware Link

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


A narrated presentation can be viewed by following this link:



https://admin.na3.acrobat.com/_a55098539/mashfinal/