1200 New Jersey Ave., S.E. 

Washington, DC 20590

January 24, 2008 

In Reply Refer To: 

HSSD/WZ-266 

Mr. Andrew Markunas, P.E. 

Manager, Work Zone Traffic Control Section 

Bureau of Highway Safety and Traffic Engineering 

Pennsylvania Department of Transportation 

400 North Street 

Harrisburg, PA 17120 

Dear Mr. Markunas: 

In your letters of December 1 and December 20, 2007, you requested the Federal Highway 

Administration’s (FHWA) acceptance of the Pennsylvania Department of Transportation’s 

(PennDOT) H-base and X-base portable sign stands as a crashworthy traffic control device for 

use in work zones on the National Highway System (NHS). Accompanying your letter was the 

FHWA Office of Safety Design form that included a drawing and a detailed description of the 

sign stands, test report, and videos of the crash tests and LS-DYNA crash simulations. The 

drawings and detailed descriptions are enclosed with the acceptance form for the H-base and 

X-base portable sign stands. You requested that we find these sign stands acceptable for use on 

the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) 

Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway 

Features". 

This letter is the acknowledgement of the FHWA's acceptance of your requests. The original 

completed forms have been modified by the addition of the FHWA acceptance letter number, the 

date of our review, and minor editorial changes. The form will be posted on our website in the 

near future. 

Please note the following standard provisions that apply to the FHWA letters of acceptance: 

• This acceptance is limited to the crashworthiness characteristics of the devices and does not 

cover their structural features, nor conformity with the Manual on Uniform Traffic Control 

Devices. 

• Any changes that may adversely influence the crashworthiness of the device will require a 

new acceptance letter. 
1200 New Jersey Ave., S.E. 

Washington, DC 20590

January 24, 2008 

In Reply Refer To: 

HSSD/WZ-266 

Mr. Andrew Markunas, P.E. 

Manager, Work Zone Traffic Control Section 

Bureau of Highway Safety and Traffic Engineering 

Pennsylvania Department of Transportation 

400 North Street 

Harrisburg, PA 17120 

Dear Mr. Markunas: 

In your letters of December 1 and December 20, 2007, you requested the Federal Highway 

Administration’s (FHWA) acceptance of the Pennsylvania Department of Transportation’s 

(PennDOT) H-base and X-base portable sign stands as a crashworthy traffic control device for 

use in work zones on the National Highway System (NHS). Accompanying your letter was the 

FHWA Office of Safety Design form that included a drawing and a detailed description of the 

sign stands, test report, and videos of the crash tests and LS-DYNA crash simulations. The 

drawings and detailed descriptions are enclosed with the acceptance form for the H-base and 

X-base portable sign stands. You requested that we find these sign stands acceptable for use on 

the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) 

Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway 

Features". 

This letter is the acknowledgement of the FHWA's acceptance of your requests. The original 

completed forms have been modified by the addition of the FHWA acceptance letter number, the 

date of our review, and minor editorial changes. The form will be posted on our website in the 

near future. 

Please note the following standard provisions that apply to the FHWA letters of acceptance: 

• This acceptance is limited to the crashworthiness characteristics of the devices and does not 

cover their structural features, nor conformity with the Manual on Uniform Traffic Control 

Devices. 

• Any changes that may adversely influence the crashworthiness of the device will require a 

new acceptance letter. 
2

• Should the FHWA discover that the qualification testing was flawed, that in-service 

performance reveals unacceptable safety problems, or that the device being marketed is 

significantly different from the version that was crash tested, it reserves the right to modify or 

revoke its acceptance. 

• You will be expected to supply potential users with sufficient information on design and 

installation requirements to ensure proper performance. 

• You will be expected to certify to potential users that the hardware furnished has essentially 

the same chemistry, mechanical properties, and geometry as that submitted for acceptance, 

and that they will meet the crashworthiness requirements of the FHWA and the NCHRP 

Report 350. 

• To prevent misunderstanding by others, this letter of acceptance, designated as number 

WZ-266, shall not be reproduced except in full. This letter, and the test documentation upon 

which this letter is based, is public information. All such letters and documentation may be 

reviewed at our office upon request. 

• If proprietary devices are specified by a highway agency for use on Federal-aid projects, 

except exempt, non-NHS projects, they: (a) must be supplied through competitive bidding 

with equally suitable unpatented items; (b) the highway agency must certify that they are 

essential for synchronization with the existing highway facilities or that no equally suitable 

alternative exists; or (c) they must be used for research or for a distinctive type of 

construction on relatively short sections of road for experimental purposes. Our regulations 

concerning proprietary products are contained in Title 23, Code of Federal Regulations, 

Section 635.411. 

• This acceptance letter shall not be construed as authorization or consent by the FHWA to use, 

manufacture, or sell any patented device for which the applicant is not the patent holder. The 

acceptance letter is limited to the crashworthiness characteristics of the candidate device, and 

the FHWA is neither prepared nor required to become involved in issues concerning patent 

law. Patent issues, if any, are to be resolved by the applicant. 

Sincerely yours, 

David A. Nicol 

Director, Office of Safety Design 

Office of Safety 

Enclosures 

FHWA:HSSD:MLupes:tb:x66994:1/9/08 

File: s://directory folder/mlupes/WZ-266(PennDOT).doc 

cc: HSSD (Reader, HSA; Chron File, HSSD; M.Lupes, HSSD; 

 M.Bloschock, HSSD; M.McDonough, HSSD) 

 
PENNSTATE

~

.

TEL:

FAX:

E-Mail:

(814) 863-7925

(814) 865-3039

zrado@psu.edu

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

20 I Research Office Building

University Park, PA 16802-4710

Federal Highway Administration

Office of Safety Design

Category 2 Work Zone Device Acceptance Letter

Letter Number:

Date:

f)/Z -2c'b

(/3/Z0o<t?

CONTACT !Petioner / Developer Name:

INFORMATION: !

I

Andrew Markunas, PE

I

[Street:

ICity,State, and Zipcode:

I

II herby certify that the device(s) covered by this Acceptance Letter meet(s) the crash -

;..orthiness test and evaluation requirements of the FHWA and NCHRP Report 350.

!Signature: ~~ ;Telephone Number:

IE-mailAddress:

I

IEngineer Name:

ILaboratory Name:

IStreet:

ICity,State, and Zipcode:

;Check

pne:

Manager, Work Zone Traffic Control Section

Pennsylvania Department of Transportation i

Bureau of Highway Safety &Traffic Engineering

Work Zone Traffic ControlSection --J

400 North Street, 6th Floor I

Harrisburg, PA 17120 -<

itle:

r::--

'Company:

~

(717) 783-6080

amarkunas@state.pa.us

Dr.Zoltan Rado

The Pennsylvania Transportation Institute

201 Transportation Research Bldg.

University Park, PA, 16802

I

I hereby certify that the testing that supports this Acceptance Letter was

!conducted in accordance with NCHRP Report 350 guidelines, that the

;deViCe(S)tested is/are accurately described on this form, and that the test "

results indicate that the device meets all applicable NCHRP Report 350

,evaluationcriteria.

IIhave evaluated the requested modificationsto these devices previously I

!foundacceptable by the FHWA in Acceptance Letter WZ--, and hereby '

I

certify that, in my opinion, the modifications do not adversely affect the crash I

I

performance of the devices. I also certify that these devices are accurately

,describedonthisform. .

i

~ --:: ~

(814)-863-7925

zxr100@psu.edu

r

jSignature:

rrelephone Number:

IE-mailAddress:

Page 1 of9
PENNSTATE

~

.

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

'KEvWORDSiPlease-selectfrom thefollowing Keyworcisfor"Type of

iDevice":

ILongitudinal Channelizing Barricade

'Curb (Curb channelizer system with or without road tubes or

other channelizers) Drum

H-Footprint Sign Stand

lx-FootprintSign Stand

ITrailerMounted Signs (Does not include arrow boards or

Ivariablemessage signs or other Category 4 trailer mounted

,devices.)

!AutomatedFlagger Device (not trailer mounted)

!TripodSign Stand

!TypeI Barricade

lType II Barricade

!TypeIII Barricade

Vertical Panel

!IntrusionDetector

Ballast (Action relates to ballast on one or more devices)

!Channelizer(Individual units unlike cones, road tubes, or drums)

IOther(Please describe on form)

TEL:

FAX:

E-Mail:

(814) 863-7925

(814) 865-3039

zrado@psu.edu

The Pennsylvania State University

201 Research Office Building

University Park, PA 16802-4710

Type of Device:

H-Footprint Sian'

Stand

leaseSelectfrom the following Keywords for Composition

f Sign or Rail Substrate:

IRoll-up/ Fabric (with fiberglass spreaders - aluminum or steel

spreaders are not allowed.)

Plywood

Aluminum - Solid

'Aluminum- Laminate

Corrugated Plastic

IExtrudedPlastic

Waffleboard Plastic

Wood / Lumber

Compositon of Sign or

Rail Substrate:

IAluminum -Solid

Page 2 of9
12 to 18

inches

above the

pavement

20 to 24

inches

above the

pavement

25 to 36

inches

above the

pavement

37 to 59

inches

above the

pavement

60 to 71

~"

.

"

.T~ above inchesthe

pavement

, . 72 inches Oversized

and taIIer

PENNSTATE

~

.

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

" ;Thicknessof s~ubstrate(ind,es):

""[Indicatethe height of sign from the ground

i(inches), if applicable: Low

i r

Mid-A

:Mid-B i

,Mid-C I

TEL:

FAX:

E-Mail:

(814) 863-7925

(814) 865-3039

zrado@psu.edu

The Pennsylvania State University

20 I Research Office Building

University Park, PA 16802-4710

Height of Sign: tvif

r

test? Indicate number of each:

°l!i~hts: 1 ofl~ghts:-~a. 2Ib:>- - "~..~

DEVICE]Provide Detailed Description of Device, Materials, sizes. Fasteners, Substrates: Foundation, ""

'NAME: 'Aux. Features Ballast, etc. (May be attached on separate page(s) )

pescription:

~he sign's horizontal support legs consist of ASTM A500 Grade B steel tubes that are 44.5mm

1(1.75in)x 44.5mm (1.75in) x 2.78mm (0.11in) thick. The cross member used for the H-shaped

base is 610mm (24in) in length. The two side members of the H-shaped base are both 914mm

1(36in)in legth. The aluminum sign panel fastened onto the vertical support beam is 914mm

i(36in)x 914mm (36in) square x 5.54mm (0.22in)thick. The sign panel is rigidly bolted to the

;verticalpost made of ASTM A500 Grade B steel tubing. The vertical post is 50.8mm (2in) x

i50.8mm (2in) square x 2.78mm (0.11in)thick and 2438mm (96in) in height. The sandbags used

for temporary stabilization of portable sign structure are placed on the end of each of the four

horizontalegs. Eachsandbagis406mm(16in)widex 2.?3(8in) mm in height x 101mm (4in) in

Page 3 of9
PENNSTATE

~

. TEL:

FAX:

E-Mail:

(814) 863-7925

(814) 865-3039

zrado@psu.edu

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

201 Research Office Building

University Park, PA 16802-4710

'1IengiFi:The"'safeiyiigh~fh~as~aradiusof1'8Y:3mmri'.4inrand "isposiiioneci'on"io'pofiFie"'sign.

180ltsthatattachedthesignpanelto theverticalpostaremadeof nylon6/6materialandarefully.

~hreaded.Thediameterof eachheadandthreadis 12mm(OA7in),and7mm(O.28in).

I

i

iMateriallist:

I

IMast slides outside vertical stub fastened with 5/16" (0.3125") diameter 2 1/4" (2.25") long :stainless steel or grade 5 zinc plated bolts and nylon insert lock nuts. Use 3/8" steel and nylon

washers under both the bolt and nut.

The sign panel is placed on the vertical sign post with top edge aligned with post top end and

,fastenedwith 5/16" (0.3125") diameter 21/4" (2.25") long nylon 6/6 fully threaded hex headed

ibolts and nylon insert lock nuts. Use 3/8" steel and nylon washers under both the bolt and nut.

,

i

D . i rawlngs:

~he engineering drawings are attached separately.

~,--"-,..,'~ ..

Page 40[9

Part Description Dimensions Material Qty

1 Verilcal steel tubular stub 1.75" sq. x 0.109" wall x 16" long ASTM A500 Grade B s1eel tubing 1

2 Leos cross member 1.75" sq. x 0.109" wall x 24"lono ASTM A500 Grade B s1eel tubinq 1

3 Legs 1.75" sq. x 0.109" wall x 36" long ASTM A500 Grade B s1eel tubing 2

4 Vertical uprioht mast 2.0" Sq. x 0.109" wall x 96" lono ASTM A500 Grade B s1eel tubinq 1
PENNSTATE

~

.

... .., ,'''' . .....

MANDATORY

ATTACHMENTS:

The Pennsylvania Transportation Institute

VehicIe Systems & Safety Program

TEL:

FAX:

E-Mai):

(814) 863-7925

(814) 865.3039

zrado@psu.edu

The Pennsylvania State University

201 Research Office Bui1ding

University Park, PA 16802-4710

iPle'aseinclude"ihosepages as'separate electronic files as they willbe

Ipostedon the FHWAwebsite in lieuof the entire finalreport.

Attachm~r'I~~~:T~~t ~CltasLJmrT1arypag~(s).. ...

IAttach. #1 a ITest #: Penn DOT 02

[~~~cb."iHbm.e~!~.,,,~. "

Attach. #1c est #-

iAttach.#1d -]Test#~.

,..O'.. "'-,,- ,.. _._~

I

F'.-m.' ' ,.."""""""" '..'mm' '.'..,--""", m"_""_'m'~_'m... ,

'Alternative-"~~ ""-~~- -.. ..--..-.-

:Attachment #1: Description and discussion of modification(s) to crash teste

[Clnd(~rac.~ep~~d~!::l,Ii~~:m_.~ .

.Attach. #2b

iAttach. #2d

.'_'m_.. '-"

-

;Date:

~iiachmeni'#2:"POFdrawing(s)"of'device(s) ~'MandatorYAtiachments:"'Please

linclude those pages as separate electronic files as they will be posted on

ithe FHWAwebsite in lieu of the entire final report.

IAttach.#2a 'l[)rawin~Title: H-Stand

iDra",:-,in!)#: S-H-001

:Dra",:-,il1~Titl~:- ..

,Drawing #:- ..

,Attach.#2c IDrawingTitle:-

r-""""--" "[Orawing#:=- ...

TDrawing Title:-

.. "~awning #::.. --

.~m- wing Title:- -....-

#:-

I~CI",:-,ingI~le:-

Drawing #:-

~ttach."#2g"'" '--IDrawi~gTiile:~-

m ''' ''''

--m- --"""'~"""'-' ~-'--'

Page 5 0[9
PENNSTA TE

.. The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

201 Research Office Building

University Park, PA 16802-4710

Attachment #1a: (a) Test summary sheet 0 degree Sign Post

0.03s 0.06s 0.08s O.13s

0.03s 0.06s 0.08s 0.13s

General Information

Test Agency............................................

Test No.

Date .....

Test Article

Type.

Pennsylvania Transportation Institute

PennDOT 02

28 September 2007

Impact Conditions

Speed (kmlh)...........................................

Angle (deg)

100.4 km/h (62.4 mi/h)

0 degrees

Penn DOT - H Portable Sign Post

Test Article Deflections (m)

Dynamic ..........

Permanent

See Evaluation and Assessment of Test Results

See Evaluation and Assessment of Test Results

Test Vehicle

Type........................................................

Designation .

Model .

Mass (Kg)

Test Inertial

Gross Static

820C

Oeo Metro

1945 Ibs (882 kg)

1780 Ibs (807 kg)

Page 6 of9
PENN STATE

~

.

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

201 Research Omce Building

University Park, PA 16802-4710

Attachment #1a: (b) Test summary sheet 90 degree Sign Post

0.03s 0.06s 0.08s O.13s

0.03s 0.06s 0.08s O.13s

General Information Impact Conditions

Test Agency."."".""...

Test No.

Date ..."

Test Artide

.." ,...".""""""". Pennsylvania Transportation Institute

PennDOT 02

28 September 2007

Speed (km/h)

Angle (deg)" """"". ". """" "" """".""" """"..

100.4 kmlh (62.4 milh)

90 degrees

PennDOT - H Portable Sign Post

Test Article Deflections (m)

Dynamic ..""."""..""""".

Permanent.." "" "..""" """ " .

See Evaluation and Assessment of Test Results

See Evaluation and Assessment of Test Results

Test Vehicle

820C

Designation

Model...........................................................

Mass (Kg)

Test Inertial

Gross Static

Geo Metro

1945 lbs (882 kg)

1780 lbs (807 kg)

Page 7 of9
PENN STATE

.. The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

201 Research Office Building

University Park, PA 16802-4710

Test Article Damage and Vehicle Damage

Sign and vehicle crash performance was visually addressed through crash and post-crash images.

In addition, crash performance from LS-DYNA simulations and full-scale crash testing were

compared and assessed following evaluation criteria fromNHCRP 350.

Post-crash performance photographs are shown in Figure I. The pictures in Figure 1show that

both the 0 and 90 degree H-base structures were severely deformed approximately 43 em (l7in)

in height above the ground, which was approximately equal to the front bumper height. It can be

seen that horizontal legs were also severely deformed at their connectionjoint. The deformations

of the two signs were very similar. Both sign posts buckled at the point where the bumper of the

crash vehicle came into contact with the vertical poles. One of the signs bent to almost 90

degrees while the other suffered a similar but somewhat smaller deformation. Both of the signs

show that the base structure which carried all of the weights from the stabilizing sand bags

became fractured and separated from the sign posts. Figure 2shows that the 820C vehicle was

damaged mildly according to expectations. The front bumper on both sides near the quarter

points suffered small dents and also the hood of the vehicle was dented by the buckling sign posts

to a small degree.

Attachment #1a: (c) Evaluation and Assessment of Test Results

I ~ ~' ,- ~.. ...1i~1

I~ p,r~~.. c"

. ':", ~;'II\)

.~,., '

Figure 1. Crash performances for H-base sign structures.

i!!

~

J

Figure 2. Post-test photographs oftest vehicle.

Windshield Deformation and Damage Assessment

Windshield Damage Index according to WOI procedure:

Zone: 1 (Left 1/3 quadrant), Vertical Position: C (center horizontal slice),

Horizontal Position: R (Right side of slice), Shape: E (Elliptical)

Depth ofIndentation: 3 (I<01<1 y;,"),Extent ofIndentation: 3 (20<EI<50 in2)

WDI: 441CRE33

-, '., --,~>~

.

-\Io.;--t:{ '\ .~:\

-" \; 'J.. '-f.:.~~:?' '\~~?:"

-,- .,' -:r" ~ }l1 t . ~~-~- ,.7': ..;,\< (/:=~IT~_f:"?";:~~~~--' . ,- - .1 .' '" ! 1 'L...' " .. i '." + ,-, "-.."

Figure 4. Case 5: Significant local damage

Page 8 of9

-- -- n - n'.mn---

Location Vertical Ref. Horizontal Crash Vehicle Ref. Vehicle Deformation # Dim. Ref. Dim. Meas. Meas.

I 14" ISv.." S '/.," 4 1116" 12/16"
PENNSTATE

..

Attachment #2a

The Pennsylvania Transportation Institute

Vehicle Systems & Safety Program

The Pennsylvania State University

201 Research Office Building

University Park, PA 16802-4710

~ ;oo~r ~l -- -- - -- -9600 -- --- - - - - I

0~r -,'- ~"~ -~ --- j--- -- - - --- --- I

.1-00.40

l

11 :

,(-0040

-t

,3 )

12 ,

3 )

~- --

- 1

36.00

Part Deseri tion 1 Ve'." ,lee' 'ubulw,Iub

2 "'''' membe, 3 le, 4 Ve"~" u , hi me,1

5 l>Jum'oum "00 p""e'

(4)

-~ ,---

--- - - - -- - -

Peoo"'''o,, DOT Po""b'e 5'go Po"

H stand

at ;

ill",7 5-H.001

- -

I

3600

I

__I

I

_J E70 Ih

1800

Alum'oum"go p,ool ',pl,,,d 00 Ih, ""',,' "'0 po'l withlop ,d" 'Ii,ood withpoollop ""d

end 'e,I,,," wHh5116"(03125") d'emel" 2 114"(225") lon, nylon6/6lull, Ih,eeded he,

h"d,d bolt, eod 0,100,,,," looknul, U.. 3/8",1.., eod o,'on w"h,,, uod" bolhIh, bolt eodoul

Me,t ,lide, out,ide ",'',,' otub ...te"d w ith 5116" (03125", d',met" 2 114"1225""00'

,"e'o'ess ".., °' ",ed, 5 "nk pl",d bolts ,nd nyloo 'n,," look nuts Use 3/8" sl..1 ,nd oyloo

h"",

1.2

E70-1-

E70 ij12.00 -- j - -24.00--

Page 9 of9
Federal HighwayAdministration

Office of Safety Design

Category 2 Work Zone Device Acceptance Letter

CONTACT !PetionerI Developer Name:

INFORMATION'

LetterNumber:vJl: 2/ob

Date: 1/3/2008'

Andrew Markunas, PEl

,Street:

jCity,State, and Zipcode:

Manager, Work Zone Traffic Control Section

Pennsylvania Department of Transportation

Bureau of Highway Safety &Traffic Engineering

Work Zone Traffic Control Sectionl 400 North Street, 6th Floor

Harrisburg, PA 171201

IIitle:

r---

:Company:

II herby certify that the device(s) covered by this Acceptance Letter meet(s) the

crash - worthiness test and evaluation requirements of the FHWA and NCHRP

,Report 350.

!Signature:

'-elephone Number:

E-mailAddress:

(717) 783-6080

amarkunas@state.pa.us

Dr. Zoltan Radot

The Pennsylvania Transportation Institute

201 Transportation Research Bldg.

University Park, PA, 16802

:Engineer Name:

!Laboratory Name: =-= :-

jStreet:

~tate, and Zipcode:

!Check '

One:

I hereby certify that the testing that supports this Acceptance Letter

I

as conducted in accordance with NCHRP Report 350 guidelines,

hat the device(s) tested is/are accurately described on this form, and

~hat the test results indicate that the device meets all applicable ' NCHRP Report 350 evaluation criteria. . I

) have evaluated the requested modifications to these devices

previouslyfound acceptableby the FHWAin AcceptanceLetterWZI -' and hereby certify that, in my opinion, the modifications do not

:adversely affect the crash performance of the devices. I also certify

~hat these devices are accurately described on this form. , It: "

,Signature: ~ ~.

I elephone Number: (814)-863-7925

E-mail Address:zxr100@psu.edu

10

1
KEYWORDSjPlease select from the following Keywords for "Type

f Device":

Longitudinal Channelizing Barricade

Curb (Curb channelizer system with or without road tubes

pr other channelizers) Drum

H-Footprint Sign Stand

:-Footprint Sign Stand

railer Mounted Signs (Does not include arrow boards or

ariable message signs or other Category 4 trailer

mounted devices.)

,utomated Flagger Device (not trailer mounted)

ripod Sign Stand

ype I Barricade

ype II Barricade

ype III Barricade

ertical Panel

Intrusion Detector

Ballast (Action relates to ballast on one or more devices)

Channelizer (Individual units unlike cones, road tubes, or

Idrums)

Other (Please describe on form)

IPlease Select from the following Keywords for

'Composition of Sign or Rail Substrate:

Roll-up / Fabric (with fiberglass spreaders - aluminum or

teel spreaders are not allowed.)

Plywood

lIuminum - Solid

lIuminum - Laminate

Corrugated Plastic

Extruded Plastic

affleboard Plastic

ood / Lumber

2

Type of Device:

X-Footprint Sian

Stand

Compositon of Sign or

Rail Substrate:

Aluminum -

Solid
12 to 18

inches

above the

pavement

20 to 24

inches

above the

pavement

25 to 36

inches

above the

pavement

37 to 59

inches

above the

pavement

60 to 71

inches

,

--- abovethe

pavement

I . 72 inches Oversized

and taIIer

hickness of substrate (inches):

Indicate the height of sign from the ground

(inches), if applicable: Low

Mid-A

Mid-B

Mid-C

Height of Sign: 6D f/

Flags and or lights present during test? Indicate number of each:

of flags: 0 1#of lights: 1 Iweight of lights: ea. 21bs

DEVICE l

provide Detailed Description of Device, Materials, sizes, Fasteners, Substrates,

NAME: Foundation, Aux. Features Ballast, etc. (May be attached on separate page(s) )

Description:

he sign's horizontal support legs consist of ASTM A500 Grade B steel tubes that are

A.5mm (1.75in) x 44.5mm (1.75in) x 2.78mm (0.11in) thick. The four cross members of

he X-shaped base are both 914mm (36in) in length. The aluminum sign panel fastened

l

onto the vertical support beam is 914mm (36in) x 914mm (36in) square x 5.54mm

(0.22in) thick. The sign panel is rigidly bolted to the vertical post made of ASTM A500

Grade B steel tubing. The vertical post is 50.8mm (2in) x 50.8mm (2in) square x

.78mm (0.11in) thick and 2438mm (96in) in height. The sandbags used for temporary

tabilization of portable sign structure are placed on the end of each of the four

horizontallegs. Eachsandbagis 406mm(16in)wide x 203 (8in) mm in height x 101mm

(4in) in length. The safety light has a radius of 187.3mm (7.4in) and is positioned on top

f the sign. Bolts that attached the sign panel to the vertical post are made of nylon 6/6

material and are fully threaded. The diameter of each head and thread is 12mm

(0.47in), and 7mm (0.28in).

3
4

Material list:

Part Descriotion Dimensions Material QN

1 Veritcalsteeltubularstub 1.75"so.x 0.109"wallx 17.75"IanASTMA500GradeBsteeltubina 1

2 Lens 1.75"so.x 0.109"wallx 21"lana ASTMA500GradeBsteeltubina 4

3 Verticaluriaht mast 2.0"so.x 0.109"wallx 96"lona ASTMA500GradeB steeltubina 1

4 Aluminumsinnoanel 36"x 36"x 0.22"thick ASTMB221MulbnurnoseAluminumIAliov6061\ 1

Mast slides outside vertical stub fastened with 5/16" (0.3125") diameter 21/4" (2.25")

long stainless steel or grade 5 zinc plated bolts and nylon insert lock nuts. Use 3/8" steel

and nylon washers under both the bolt and nut.

he sign panel is placed on the vertical sign post with top edge aligned with post top end

and fastened with 5/16" (0.3125") diameter 21/4" (2.25") long nylon 6/6 fully threaded

hex headed bolts and nylon insert lock nuts. Use 3/8" steel and nylon washers under

both the bolt and nut.

Drawings:

The engineering drawings are attached in Attachment 2a.
jPlease include those pages as separate electronic files as they willbe I .iposted on the FHWAwebsite in lieu of the entire final report.

.ttachment #1: Test datasummarypage(s)

!Attach.#1a :Test#: FEAAnalysisof PennDOTSignStructure

Attach. #1b 'rest #-

!Attach.#1c ;Test#-

!Attach.#1d ;Test#-

I

IAlternative

;Attachment#1: Descriptionand discussionof modification(s) to crash

!:::~andlor accepted device I

~ttachment # 2: PDFdrawing(s)of device(s)- Mandatory Attachments:

iPlease include those pages as separate electronic files as they will be

,posted on the FHWAwebsite in lieu of the entire final report.

!Attach.#2a !DrawingTitle:X-Stand

I IDrawing #: S-X-001

!Attach. #2b ,Drawing Title:-

: :Drawing #:-

:Attach. #2c ,Drawing Title:-

I iDrawing#:-

!Attach. #2d IDrawing Title:-

I [Drawing #:-

:Attach. #2e :Drawing Title:-

, :Drawing #:-

IDrawing Title:-

!Drawing #:-

'Drawing Title:-

MANDATORY

ATTACHMENTS:

/Attach. #2f

r

[Attach.#2g

5
Attachment #1a:

FEA Analysis of PennDOT Sign Structure

Background

To evaluate the perfonnance of the "X" based portable sign post a three tiered modeling

and analysis approach was taken first a complete FEA analysis of the "H" based structure

was undertaken where all the characteristics of a full scale NCHRP 350 crash test were

computed. Te second phase was to conduct the actual full scale crash test of the physical

"H" based structure built to the exact specifications used in the LS-DYNA modeling.

Using the results of the full scale crash test the parameters predicted by the FEA analysis

were verified. The validated model of the sign structure then was modified to the "X"

shaped base and tested in the FEA analysis software.

This approach guarantees the high fidelity of the evaluation of the modified sign post

structure and delivers very high confidence in the simulation results.

Numerical crash-testing was perfonned using LS-DYNA for each of the two PennDOT

structures the "H" footed and the "X" footed structures. Each sign structure was

subjected to virtual crash tests identical to those perfonned in NCHRP 350 Level 3-71

crash tests, using a Geo Metro vehicle (a standard 820C vehicle according to NCHRP

350 designation) with the sign oriented facing the vehicle and at 90° with respect to the

vehicle. These tests were run with the top of the sign placed at 96"(2438mm) from the

ground.

Model Construction

SignStructureConstruction

The horizontal legs and vertical stands having 0.109" (2.77mm) thickness were modeled

using shell elements provided by LS-DYNA. The aluminum sign panels consisting of a

36" (914.4mm)x36" (9l4.4mm) square plate with a 0.1" (2.54mm) thickness were also

created using shell elements. The steel H-support, vertical mast and sleeve with 0.109"

(2.77mm) thicknesses were modeled using shell elements. The steel stands were

modeled using nominal A36 steel properties available in LS-DYNA and standard

aluminum properties (i.e., 6061-T6) were used for representing the aluminum panels.

All sign structures were constructed according to the design plans. All sign panels were

modeled separately from their support structures and placed onto them using constrained

rivets provided by LS-DYNA, which couple the models together. The safety light placed

on top of the sign was modeled matching published dimensions and weights to represent

a worst case scenario with respect to low speed crash tests. It was modeled using a hard

plastic material and affixed to the top of the sign using the constrained rivets.

6
VehicleModelConstruction

A standard NCHRP approved vehicle model developed by the FHWAlNHTSA National

Crash Analysis Center (NCAC) was used for the numerical crash tests. Model

information is as follows:

1. Number of Parts

2. Number of Nodes

3. Number of Solids

4. Number of Springs

5. Number of mass elements

6. Number of Elements

230

100348

1209

8

76

16000

The vehicle model can be observed in Figure 1.

Figure 1. Detailed vehiclemodel (http://www.ncac.gwu.edu/vml/models.html)

Crash Scenario Modeling

The crash scenarios were selected using the NCHRP 350[1]Section 3.2.3, "Support

Structures, Work Zone Traffic Control Devices, and Breakaway Utility Poles". Using a

test matrix from the guide it was decided to employ Level 3 test requirements of the

"support Structures" category with test level 3-71.

These tests include a high speed crash scenario as described below:

Test Level 3-70. The test comprised two separate full crash scenarios at 100 kmIh

(62 mph) with the 820C vehicle (Geo Metro) using sign impact

angles of 0 and 90 degrees as described above. Each portable sign

structure crash scenario was analyzed twice. The first analysis was

performed with the sign structure facing the approaching vehicle

and impacting its front either at the vehicle's geometric middle or

7
at one of the quarter points with respect to its longitudinal

centerline. The second analysis had the sign structure rotated 90

degrees from its initial position and placed at the middle or at the

other quarter point of the approaching vehicle.

The virtual crash scenarios were developed following these conditions. The model was

created so that each support structure was placed at the geometric longitudinal middle of

the approaching vehicle to represent the critical scenario for each individual crash test.

The structures were placed a short distance from the original location of the vehicle to

ensure that the vehicle was in a dynamically stable condition with a constant direction

and speed free from dynamic effects before impact. The structure was placed on an

infinitely rigid smooth surface representing the ground and was given a nominal

coefficient of friction of 0.3 at contact locations with the ground. The portion of the

structure in contact was then loaded with a model representing four sand bags on the end

of each support leg. The incorporation of the sand bags represented real life conditions.

Prior to the numerical crash test the vehicle was initialized to the following conditions:

. Initial speed of all components was set to the desired nominal test speed.

. Rotational speed of the tires was set to matching angular velocities to avoid

differential frictional and inertial effects from the moving vehicle.

. The vehicle, at its defined initial speed and tires angular velocities, was placed on

a perfectly smooth and level infinitely rigid surface with a friction coefficient of

0.3.

Results

Since the actual dimensions, materials and construction of the signposts were kept

identical to the original structures the inertial and kinetic properties of the crash with

regard to vehicle deceleration, vehicle trajectory and occupant aggregate risk factors

caused by vehicle dynamics remained statistically the same.

The results from the FEA analysis for the four scenarios are depicted in Figure 2, Figure

3, Figure 4, and Fi2Ufe 5:

t=O.OOs t=0.03s t=0.06s t=0.08s

Figure 2. Crash Behavior of "H" footed sign at 0 degree

t=O.13s

t=O.00s t=O.03s t=O.06s t=0.08s

Figure 3. Crash Behavior of "H" footed sign at 90 degree

t=O.13s

8
t=O.OOs t=O.03s t=O.06s t=O.08s

Figure 4. Crash Behavior of "X" footed sign at 0 degree

t=O.I3s

t=O.03s t=O.06s t=O.08s

Figure5. CrashBehaviorof "X" footedsignat 90degree

In all four virtual crash scenarios for both structures (the "R" shaped foot and the "X"

shaped foot structures) the virtual crash simulation indicated the expected crash behavior

of the structure. In all four cases the aluminum sign panels have separated from the

vertical sign post upon impact. The fastening bolts from the nylon material have failed as

expected.

In the zero degree crash setup where the sign posts are facing the approaching crash

vehicle the tensional forces created by the impact acceleration and inertial forces of the

solid aluminum sign panel exceeded the tensile strength of the new bolt material and the

screw on both the upper and lower fastening points of the sign panel broke. The sign

panel become separated from the rest of the sign structure and in its free fall to the

ground has cleared the vehicle moving underneath. The vertical sign post free from the

relatively high inertial forces that would have been caused by a non-separated sign panel

are showing buckling but with a much slower rate and the damage to the front bumper

and hood of the vehicle also reduced substantially.

In the 90 degree crash setup where the sign posts are turned parallel to the approaching

crash vehicle the shear forces created by the impact acceleration and inertial forces of the

solid aluminum sign panel exceeded the shear strength of the new bolt material and the

screw on both the upper and lower fastening points of the sign panel broke. The sign

panel become separated from the rest of the sign structure and in its free fall to the

ground has cleared the vehicle moving underneath. The vertical sign post free from the

relatively high inertial forces that would have been caused by a non-separated sign panel

are showing buckling but with a much slower rate and the damage to the front bumper

and hood of the vehicle also reduced substantially.

Figure 6 shows the comparison of the FEA analysis predicted behavior of the "R" based

sign structure in relation to the actual behavior captured throughout the actual crash test

executed after the FEA analysis was completed.

t=O.OOs t=O.I3s

9
(/.) M

...... 0

(/.)

0000

(/.)

1.0 00

(/.) M

c: 0

(/.) M...... 0

~~0

=-- =

bf)

02

1

00

0 "CI . ~ 0 ~~

,l;j

"'~~

-=

.....

14-< 0Q~ee=~=0...

..... ~

(/.)

1

=

1.0e c: ... 0 00

..c

Q,j t.=~~

0

......

(/.) M00
As it can easily be observed from the time sequences of the LS-DYNA produced results and the

actual crash test in Figure 6 the simulation predicted behavior of the sign structure matches the

actual observed real crash behavior to a very large degree.

Conclusion

Based upon the conducted analysis, full scale crash test, and analysis validation using both the

"H" and "X" shaped sign structures it can be concluded that both of the structures have proven to

~xhibit the same crash performance subjected to the NCHRP 350 crash test. The evaluation of

the modification to the PennDOT "H" based portable sign structure replacing the base to an "X"

shaped base do not adversely affect the crash performance of the device.

It can be concluded based upon the engineering analysis and the executed crash test that both

structures pass the necessary criteria set forth by the NCHRP 350 guide.

Page 11of 12
Attachment #2a

17s--.j

~.00 l 12.0

L 6.0

r- ;r'"~ ,. ,.~'-'"., ''0

00.40

21.0'

1.75-+1

36.00

-.l

11.75

21.00

-.L

T1.75

E70

Pennsylvania DOT Portable Sign Post

21.00 I

A1Uinln"m sign panal Is placed on Ihe vertical slgnposl with lop adgaiilignad with post lop and

and faslenad wilh 5116" (0.3125") dlamatar 2 1/4" (2.25") long nylon 6/6 f""y Ih",adad hax

haadad bolls and nylon Insart lock n"'s. Usa 3/8" staal and nylon washars onder both tha boll

and not X Stand Masl slides o"tslde vartlcal sl"b faslenad with 5116" (0.3125") dlemeler 2 1/4" (2.25") long

slalnless sleel or grada 5 zlnk plaled bolls and nylon Insert lock n"ts. Use 3/8" steel and nylon

17&-+j

1

£"X17

1

jlSCALE

owo NO

0.1

rPart

'1

'2

'3

'4

Description

Veritcalsteel tubular stub

LeQs

Vertical uprlQhlmast

Aluminumsian panel

Dimensions Material

I.7S" sa. x 0.109" wall x 17.7S" Ion ASTM ASOO Grade B steel tubln

1.75" sn. X0.109" wall x 21" lonn ASTM ASOO Grade B steel tubln

2.0" so. x 0.109" wall x 96" lonn ASTM ASOO Grade B sleel tubin

36" x 36" x 0.22" thick ASTMB221 MultipurposeAluminum(Allov6061

Q

S-X-001

Page 12 of 12