Development of a Safe End Treatment for W-Beam-on-Barrels ... · LIST OF FIGURES (C.onti nued) Figure Page 22 SeqlJenti a 1 Photographs for Test 12. 33 23 Sequential Photographs for

TECHN.lCAL REPORT STANDARD TITLE PAGE

1. Report No. 2. Gov.rnm"nt Acce .. ;on No. 3. Recipient'. Ca'olog No.

FHWA/TX-85/35+262-6F i--4.·-=-T,-,"-e -an-d-Su...,-b-'H..,-'e--------..L..-..--------'-------+-S=-. -=R"'-ep-a-rt--::"O-,,'-e ---- ._. "- ,. "',--

Development of a Safe End Treatment For W-Beam-On-Barrels Barrier

November 1984

--o--------------------.~-------".-------'- ----" "-----1 7. Autho,1 sl 8. Pe,forming O,gan. ~otion R"p"~1 N<!

Dean L. Sicking, Hayes E. Ross, Jr. and Bill Gaugler Research Report 262-6F ~------------------------------------------~~---~-------------~ 9. P"rforming 0'90nizollon Name and Add,!!.. 10. War" Unit No.

Texas State Department of Highways porta t ion; T ran sporta t i on P lamting P. O. Box 5051

and Public Trans-D;-vis i o-n ------ -tl-:--Cl>ntrlJrt-or-lYront-th'7-

Stud'y No. 2-18-79-262 13. Type 0'1 Repor' ond Pe,iod Cove,ed Austin, Texas 78763

---------------------~ September 1978 November 1984

12. Sponsoring Agency Nom .. and Addre"

Texas Transportation Institute The Texas A&M University System College Station, Texas 77843

'5, ~upp'emento'y No'",

Final -

14. Sponsoring Agency Cod.

Research performed in cooperation with DOT, FHWA. Research Study Title: Safety Devices for Highway Work Zones

16. Abs'roct

The objective of this study was to develop a safe end treatment for W-BeamOn-Barrels Barrier (WBBB). The WBBB terminal currently used in Texas was first tested and found to be unacceptable in terms of impact performance. A modified terminal consisting of a stand up barrier end attached to a steel drum by a W-beam end section (buffer) was then developed.

Two full scal e vehi cul ar crash tests were conducted to evaluate the impact behavior of the design. Since the WBSB is a low performance level, temporary barrier it was decided that test conditions (vehicle weight, impact speed and impact angle) recommended for higher performance level permanent roadside appurtenances were not appropriate. The basic difference between the selected conditions and those recQmmended for permanent installations involved the impact speed. A 50 mph (80.5 km/h) impact speed was used in lieu of the 60 mph speed used for permanent installations. As a result of the crash testing it was concluded that the design was acceptable in terms of impact performance.

17. Key Words

End Treatment(s), Crash Test(s), .Construction, Work Zone(s), Temporary Safety, Low Performance Level, Barrier(s).

18. Dis'ribution Statement

No restriction. This document is available to the public through the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161.

19. Security Clossif. (af 'his report) 20. Security C'ossil. (ol this page) 21. No. of Pages . 22. Prj ce

Unclassified Unclassified 63 Form DOT F 1100.1 18.691

DEVELOPMENT OF A SAFE END TREATMENT FOR W-BEAM-ON-BARRELS BARRIER

by

Dean L. Sicking Hayes E. Ross, Jr.

and Bill Gaugler

Research Report 262-6F

Research Study No. 2-18-79-262 Safety Devices for Highway Work Zones

Sponsored by

Texas State Department of Highways and Public Transportation in cooperation with

U.S. Department of Transportation Federal Highway Administration

November 1984

TEXAS TRANSPORTATION INSTITUTE The Texas A&M University System

College Station, Texas

DISCLAIMER

The contents of this report reflect the views of the authors,who are

responsible for the opinions, findings, and conclusions presented herein.

The contents do not necessarily reflect the official views or policies of

the Federal Highway Administration. This report does not constitute a

standard, specification, or regulation.

KEY WORDS

End Treatment(s), Crash Test(s), Construction, Work Zones(s), Temporary

Safety, Low Performance Level, Barrier(s)

ACKNOWLEDGMENTS

This research study was conducted under a cooperative program between

the Texas Transportation Institute, the Texas State Department of Highways

and Public Transportation, and the Federal Highway Administration. Harold

Cooner of the SDHPT worked closely with the researchers, and his comments

and suggestions were appreciated.

ii

I NTRODUCTI ON

TEXAS WBBB END TREATMENT

IMPACT PERFORMANCE CRITERIA

CRASH TEST RESULTS

Test 12

Test 13

Test 14

Test 15

SUMMARY AND CONCLUSIONS

TABLE OF CONTENTS

APPEND IX A. SEQUENTI AL PHOTOGRAPHS

APPENDIX B. ACCELEROMETER TRACES AND PLOTS OF ROLL, PITCH, AND YAW RATES

REFERENCES

iii

2

6

7

7

12

12

24

30

32

41

58

LIST OF FIGURES

Fi gure Page

1 Existing W-Beam on Barrel Configuration 3

2 Existing W-Beam on Barrel End Treatment 4

3 Sand Level in Barrels -- Existing End Treatment 5

4 Summary of Test 12 8

5 Test Vehicle Before Test 12 9

6 Test Vehicle After Test 12 10

7 Existing WBBB After Test 12 11




11 Existing WBBB After Test 13 16

12 Construction Drawings of Modified WBBB Terminal 17

13 Modified WBBB Terminal 19




17 Modified Barrier Before and After Test 14 25




21 Modified WBBB After Test 15 29

iv

LIST OF FIGURES (C.onti nued)

Figure Page 22 SeqlJenti a 1 Photographs for Test 12. 33

23 Sequential Photographs for Test 12. (cont. ) 34

24 Sequenti al Photographs for Test 13. 35


26 Sequential Photographs for Test 14. 37


28 Sequent; al Photographs for Test 15. 39

29 Sequential Photographs for Test 15. (cont.) 40

30 Vehicl~ Longitudinal Accelerometer Trace for Test 2262-12. 42

31 Vehicle Lateral Accelerometer Trace for Test 2262-12. 43

32 Vehicle Vertical Accelerometer Trace for Test 2262~12. 44

33 Vehicle Angular Displacements for Test 2262-12. 45

34 Vehicle Longitudinal Accelerometer Trace for Test 2262-13. 46


36 Vehicle Vertical Accelerometer Trace for Test 2262-13. 48





LIST OF FIGURES (Continued)

Figure Page 41 Vehicle Angular Displacements for Test 2262-14. 53





vi

INTRODUCTION

A W-beam-on-barrels barrier (WBBB) has been successfully crash tested

for use in construct ion zones CD and is currently used wi dely across

Texas. However, a safe end treatment for the WBBB has never been

developed. The end treatment currently used in Texas has never been crash

tested, and some contractors have reportedly installed the end treatment

incorrectly thereby significantly reducing its effectiveness. This study

was undertaken to evalute potential safety and construction problems

associ ated with the W-beam-on-barre 1 s ba rri er end treatment current ly used . .

on Texas highways and, if necessary, develop a safe alternative to the

existing design.

Prior to the start of the study, a survey was taken to determine the

nature and extent of construction problems associated with the existing WBBB

terminal. Three major metropolitan highway districts within Texas were

contacted and it was reported that although the end treatment was difficult

to install, the terminal was constructed correctly at most sites. Visits to

five construction sites utilizing the WBBB confirmed the results of the

survey. Thus it was concluded that the existing end treatment for the WBBB

is generally installed correctly, and its crashworthiness should be studied

further.

1

TEXAS WBBB END TREATMENT

The WBBB end treatment currently used in Texas is essentially a tapered

terminal where the end of the W-beam rail is bent down to the ground. In

addition to the taper, the rail end is flared away from the travelway

approximately 4 ft (1.2 m) over a distance of approximately 50 ft (15.1 m).

The end of the W-beam is hel din pl ace by three steel drums at the nose

containing 4 in. (10.2 em) of sand. A 25 ft {7.l m) section of unsupported

rai 1 separates the three steel drums at the nose of the treatment and the

beginning of the length of need for the barrier. Figure 1 shows drawings of

the existing WBBB terminal design and Figure 2 shows photographs of the

constructed end treatment. Note that steel barrels at the beginning of the

length of need of the barrier are full of sand as shown in Figure 3.

Preliminary analysis of the impact performance of the existing end treatment

for WBBB was inconclusive. Therefore, full-scale crash testing of the

design was undertaken to accurately determine the crashworthiness of the

termi na 1.

2

AcNCHOR OR SPLICE BOLT 5/e" NUT POST SOL T: SirrlHo; ucept lu"t"

(7/s&Hex bOn, requltf!o for r"tmioQl COflfttclQi'l

1~2". 4"~ ~';'(Mjn.) $1 •• 1 PIQ!tWCllh.r lor Ecc~ eor~.1

DETAIL OF RAIl. ELEMENT CONNECTION to B_L

PLAN VIEW

ATTACHMENT TO BRIDGE RAIL OR CONCRETE MEDIAN BARRIER

PLAN VIEW

NORMAL BARREL SPACING

SECTION A-A

~!S GoII<:m Stu! Borrlfl. FItt.d with SQ~d tlnlul Olht;.",j •• $hc ..... nan Ille. PI(ln~.

SECTION C-C

6'-3" Soocmq

GUQrd Fence

2-2" ~ 4" 'It 3;je" (MIr'lJ SIte I Plale Wastier

I-$/et Dio, Soli with Hell Nut

HO" )( to" 1, o/~ iMird Steel Plote

TERMINAL DETAIL

1. RAIL ;L~I!T MY BE tiTHER 1,'Si Ill! 25 FOOT I.t'lGnfS ANtI tlMR );j ~ 12 aAlJGt.

Z. !lIUHMOH LENGTH Qf FVlC£"IEHT ft;(lALS 100 F£Ef.

), fikTHE JIAl\l)WA'I' SJ~F~ !SI.S~ALT. Pt'litllCO SHALL liE PLAtEtlllKO[RTIl[ IM,Fl.P!LS

TO PIIE~E~ !.!AMeE TO 1'1<£ PAVf)tEhT.

4, lOCATlOM OF BARREL/ItOIJIITt[l 3UARC FENCE ISSItO'JlNaSElitlEP.£ IIITKE PLAIIS.

5. flAIL £~EJII£t«' SPL1'~S SHALL 8E LAPPED IN THE OIRECiION OF TRAme.

(;. RAil sPt.ictS SHALL B~ CONNECTED Ir/!T~ THE NO~ £IGMT llr." LONG OVA\. SHOUU)!l~

BUTTOItHtA.I)OOl'TSlltI.lCH'IIRE6/B" I'! DIAMETER,

1. BIIRREl SPA(;fIlG :w.LL BE S.'~3·. U:CEn ELOSER :SPACtll:i SliALL BE IJW} AS ~ TO

TRA!(Sa:~ rll'l'O II CO""EtnOft WITH II BRIDGE P.A!L. COIiCRtrE "£OlAA eAAAIER, OI!

SIII1LAPfUEOoa..:ECT,

8, OAA:NAG( HOLES SHf<Ll Sf Dlm"LEO tN TH£ sorrow OF * 8ARREtS TO I\lUIW FOR

IlAAUiA\i£OF iiATeR,

9, M~~H EIQ OF TilE TEMPGAAJrr 8AARIU SHALL BE Ft.AA£I) AllAY ~ !!.OAQWAT

Al4l SHAll. ~ T!i{ATEU .nH THREE W!ill.S AS SkOIm 1't* AVOla AI< U?CStO WR/II)

Of 12~' WITII II %S fOOT LOlfG SECTlOIl Of G'JARO ((He!, UOl Of Tilt WflEU

Slt4l.tll( fllUO ltlHl APPlWXjV,lTE~'t 4" OF 5.A!'t~, TM£ ThIIlU DARIIEL Sl'A\.l BE

ATTACHfll USIH~ '1~R m,Ul(TE~ SOLTS ,r~ oftX ""TS AII~ Wt~£RS

10. IF nit eAIiRIER IS USEOASA CHAr-r.'l':l!ZIItG 1)<;'O!c£ INHIGHnII'IE SITlJATlOtlS,

IT SIl~L 6£ Sl$PLEi'lEMTEoIlV OElINEATloNOR:ChANNELlZAHON/llAllklNGSOIi

l)~v!<ES. R£f'J!t.1'ORIZ(O MARKING.S ON DIWMS AS DETAIlED ON THE Be STANOARD

SHHTS, OR V£RHCAL PME~S. OR DELINEATORS SHALL BEUSEO TOPRQV!OE

SUPPLE'I£~TAL DEL1MtiATlOIf.

I" CIC, 1'101 ••

{t~~~o::~;~=)( ~~T::~~:~ F'O~r ''l;. ".x. .JI"ICI'IQr !;tQ!!, .... ,11'11'1",1$ Qno wash*" ,~ql..,red,

ATTACHMENT TO BRIDGE RAI,L OR CONCI'IET€ M£DlAcN &AIiIR+ER

SECTIO'N a-a

! "''''''''''''L''''''''''''''AU..«_J TERMINAL CONNECTOR (10 GAGE MINIMUMt

B STATE DEPARTMENT OF HIGHWAYS ~ AIID PUBLIC TlIANSPORTATIOH

TEMPORARY BARRIER BARREL-MOUNTED GUARD FENCE

TB (BMGF) -83

Figure 1. Existing W-Beam on Ba~rel Configuration

Flared Offset

Figure 2. Existing W-Beam on Barrel End Treatment

3-Barrel Nose Terminal

W-Beam Drop From 2711 to 12.75 11

Typical Level-Full

Nose Terminal Level-4 inches

Figure 3. Sand Level in Barrels Existing End Treatment

IMPACT PERFORMANCE CRITERIA

Present test standards contained in NCHRP Report 230 (~) recommend that

temporary barriers be designed for impact conditions equal to those for

permanent barriers. However, the W-beam-on-barrels barrier is a low service

level, temporary barrier capable of redirecting a 4500 1b vehicle impacting

at 45 mph and 15 deg (~). Although NCHRP Report 230 recommends test

standards for a low service level barrier, no test standards are given for

barriers of the level of service offered by the WBBB. Therefore, selection

of crash test conditions (vehicle size, impact speed, and impact angle) was

made jOintly by TTl and SDHPT engineers. Factors considered in the

selection process included the level of service of W-beam-on-barrels

barrier, test standards for higher service end treatments, traffic speeds in

work zones, and the state of the art regarding temporary end treatments. As

a result of this process, test conditions described in the following section

were chosen. Results of each test were evaluated ; n terms of the

recommended performance criteria (~tructural adequacy, severity, and post

impact trajectory) presented in reference 2.

6

CRASH TEST RESULTS

Two full-scale crash tests were conducted to evaluate the performance

of the W-beam-on-barrel end treatment shown in Figure 2. Sequential photos

of the tests are given in Appendix A. Appendix B shows accelerometer traces

and roll~ pitch~ and yaw angles versus time after impact.

Test 12*. In the first test a 2410 lb (l095 kg) vehicle impacted the

three-barrel end cluster at 48 mph (77 km/h) and an impact angle of 0°. The

centerline of the impacting vehicle was offset 15 in. (38 cm) from the

center nose of the end treatment. Upon impact the 25 ft (7.7 m) section of

unsupported W-beam buckled through the bolt holes midway between the end of

the terminal and the beginning of the length of need. The vehicle then rode

up onto the clustered barrels and dragged them along as the test vehicle

continued to travel behind the barrier. The test vehicle came to rest

approximately 55 ft (17 m) from the point of impact. Figure 4 summarizes

the results of test 12.

The longitudinal occupant impact velocity measured during the test was

31 ft/sec (9.6 m/sec). This value is only slightly higher than the

recommended maximum longitudinal impact velocity of 30 ft/sec (9.3 m/sec)

and is much lower than the maximum allowable limit of 40 ft/sec (12.3 m/sec)

tV. The measured lateral occupant impact velocity was 6 ft/sec (1.9

m/sec), which is much lower than the recommended limits (1). Longitudinal

and lateral ridedown accelerations of 3.8 and 2.1 gls~ respectively, were

also well below recommended limits (,g). Figures 5 and 6 show the test

vehi cl e before and after the test. Fi gure 7 shows the damage to the test

*Tests 1 through 11 were conducted during previous research (see Research Reports 2262-1 through 2262-5), and were unrel ated to the work reported herei n.

co

0.822 s~c.

Test No. Q ••

Date • . • . • • . Install ation

Drawing No • Beam Rai 1

Member • • • • • • • • • Length of Segments-ft(m)

First Segment ...... Remaining Segments ••

Maximum Deflection. Vehicle

0 ... 548 sec.

2262-12 6-11-84

TB(BMGF)-83

12 gao W-Beam

25(7.62) 6.25(1091) 18(5.49)

Model ••••• Mass--Ib(kg) ••

r,1aximum Roll Angl e

1975 Pontiac Astre • •• 2410(1095)

(degrees). 23

0.274 sec. _

Speed-mph(kph) Impacto • • Exit. 0 ••

Angle-deg . . . . . .

Impact. • • • • • • • • • • Occupant Impact Velocity-fps(m/s)

Forward • • • • • • • • • • • • Lateral • • ••• Q •• 0 •••

Occupant Ridedown Accelerations-g's Forward • • • • • • •• Lateral ••••••••••••

Vehicle Damage TAD • • • • • • • • . .

0.000 sec.

..47.6(76.7) 17.8(28.7)

0.0

31.07(9.47) 6.01 (1.83)

3.76 2.03

l-FR-3 VOl Q • • • . . . . . . . . . . 01 FRMW2

Figure 4. Summary of Test 12

Figure 5. Test Vehicle Before Test 12

9

_"" .. +, __ .. or< .. i

Figure 6. Test Vehicle After Test 12

10

Figure 7. Existing WBBS After Test 12

11

installation. This test was considered to be a success since impact

severity measures were within acceptable limits and the test passed normal

structural adequacy and post impact vehicle trajectory criteria.

Test 3 The second test involved a 2250 lb (1021 kg) vehicle

impact i ng the end treatment mi dway between the nose and the begi nni ng of

the length of need. The test vehicle impacted the terminal at 49.7 mph (80

km/h) and an angle of 15 deg. relative to the longitudinal barrier. Upon

impact, the W-beam at the poi nt of contact was pushed down to the ground

where it remained in an upright position. The test vehicle's left front

tire then climbed over the~uardrai1 and the rail lifted the front of the

vehicle off the ground. As the vehicle approached the beginning of the

length of need, the front bumper was raised to a height of approximately 27

in. (69 cm). The test vehicle's front bumper struck the first barrel full

of sand near the top of the steel d rum. The vehi c 1 e then ramped over the

barrier and rolled a complete revolution before coming to rest on its tires

approximately 75 ft (23 m) from the point of impact.

Figure 8 summarizes the results of test 13. Although, as shown in

Figure 8, impact severity evaluation criteria were within recommended

limits, the test was considered to be a failure since the vehicle rolled

over. Figures 9 and 10 show the test vehicle before and after the test, and

Figure 11 shows test installation damage.

Test 14. After review of the results of test 13, it was concluded that

the WBBB end treatment must be modified to prevent impacting vehicles from

mounting the bent down guardrail. The end treatment was then modified as

shown in Figures 12 and 13. As shown in Figure 12 the bent down rail was

raised to the normal height of the W-beam, and the cluster of barrels at the

nose of the terminal was replaced with a single barrel. A standard W-beam

12

0.522 sec. . 0.420 sec. 0.210 sec. 0.000 sec.

1 , ..

2:.1.....----_ -O...~~:t::=:::=-'-~ Test No. • • • • ••• o • •

Date • • • • • . . . Installation

Drawing No ••••••• Beam Rai 1

Member • • • • • • • • • Length of Segments-ft(m)

First Segment •••• Remaining Segments ••

Maximum Deflection • Vehicle

2262-13 6-14-84

TB{BMGF)-83

12 gao W-8eam

25(7.62) 6.25(1.91) 9.20{2.80)

Mode 1. • • • • • • • •• 1977 Ponti ac. As tre Mass-lb(kg) •• 0 • • •• 2550(1159)

Note: Vehicle Rolled Over

Speed-mph(kph) Impact. • • • • • • • • • • Exit •••••••••••

• • 49.7(80.0) 28.0(45.0) . . .

Angle-deg Impact. • • • • • • • • • • • •

Occupant Impact Velocity-fps(m/s) Forward • • • • • • • • • • • Lateral ............. .

Occupant Ridedown Accelerations-g's Forward • • • • • • • • • • 0 0

Lateral • 0 0 • • • 0 • 0 • 0 0

Vehicle Damage TAD • • • • 0- • • • • • • • • • • •

VOl 0 • • • • • • • . . . . . .

15.0

27.06(8.25) 6.29(1.92)

6.27 8.59

10-L&T-4 10LYA03



14

Figure 10. Test Vehicle After Test 13

15

Figure 11. Existing WBBB After Test 13

16

,

NORMAL 5_3"

SPACING

I

I I

I

I

6'-3"

I

I

...

I

I

Beginning of Length of Need

SAND FILLED BARRELS

6'-3" S.EE DETAILS ~--ja+:::==~~~-----~ (TYPICAL)

- ........ ----- DIRECTION OF TRAVEL - .... ------

PLAN

6'-3" (TYPICAL) 25'-0" W':BEAM seCTION

I I I I I I I I I I" :>

I I I '\ I 1_, I I 'I' '--- "- 350+ S~NDBAGS

IN" EACH OF THE DIRECTION OF TRA VEL LIIIIf FRONT THREE BARRELS.

SEE DETAILS.

ELEVATION

I !': I

iii". I I~

J

a _I <or

TeXAS TRANSPORTATION INSTITUTE

Scal~~ . 0 1 2 5

1 of 2

Figure 12. Construction Drawings of Modified WBBB Terminal

3/4" PLYWOOD

NOTE:

'b 2"x4"x 1'-0 114" .'

-', t:l

3 Required per Tripod 14-25+ SANDBAGS

-r---W..----J~::p:mI=P,,'" TRIPOD SUPPORT

. _-#' o ...!.

+I' .. ... .J..

It . smE VIEW TRIPOD DETAILS

sIDe VIEW ". HOU;SFOR SANDBAG SUPPORT SYSTEM , 29/3a-lIl!ra" :\ 518·+~ (TYP.'1

H/8" DIA. BOLTS 11/4"LONG 'wl WASHER ON OUTSIDE AND

, PLATE WASHER ON INSIDE OF BARREL

scale~ __ ~L 02 8 i' .2'

2"x4"x3/1S- STEEL. PLATE WASHER

W-aEAM END SECTION (BUFFER) _ RE-7[24] -79 "

BUFFER DETAIL . Scale I"IJ" ___ ----.:

0:1 8' l' 2' (6 REQUIRED)

I---"'T'"%-f-I

-.:-_ 0 ,=*,0 ~TYP.l )_-1 ______ __.- '

:-~---~-----J=C:-:'-'l8UFFER

I 0 '

, RE-1 24 -19 BUFFER i ,I"

W-SEAM , NOTE:

518" OVAL SHOULDER SUTT~O~N:.... _______ ...... _ .... 6-3/4- DIAMETER HOIJiS':"rO BE DRlLL.ED IN BARRELS.. LOCATE HOLES BY FrrTINa BUFFER AROUND BARREL. AND MARKING BARREL TO ENSURE PftOPER , FIT.

HEAD $Puce BOLT (4 ReauIRED)

BARREl. CONNECTION DETAILS TEXAS TRANSPORTA nON I NSTinrre

2 ttt 2

Figure 12. Construction Drawings of Modified WBBB Terminal (cont.)

~"~. -.....-.,:::;::::-, :;;''..,h~ .... ~_

...

Figure 13. ~lodified WBBB Terminal

19

buffered end section normally used in the breakaway cable terminal was

wrapped around the leading barrel to prevent the end of the rai 1 from

spearing impacting vehicles. Further, 350 lb (159 kg) of sand was placed in

the leading barrel and the first two barrels after the beginning of the

length of need. The sand in these barrels was put in bags for ease of

handling and the bags were placed on wooden pedestals to raise the center of

gravity of the barrels to a height of approximately 22 in. (56 cm). Raising

the center of gravity of the leading barrels should reduce the possibility

of an impacting vehicle vaulting over the barrels and becoming airborne.

The beginning of the length of need for the modified terminal is the point

of attachment of the second steel drum.

Test 13 was then repeated to determine if the modifications to the WBBB

terminal would prevent vehicle rollover. A 1974 Chevrolet Vega weighing

2453 lb (1115 kg) impacted the modified end treatment at 47 mph (76 km/h)

with an impact angle of 15° relative to the centerline of the road. The

impact point was midway between the nose of the terminal and the beginning

of the length of need. Upon impact the test vehicle began to redirect while

pushing the light barrel away from the roadway. The test vehicle was then

traveling parallel with the roadway approximately on the centerline of the

W-beam-on-barrels barrier. The test vehicle then impacted the first barrel

full of sand head-on and was brought to a quick stop. A summary of test 14

is shown in Figure 14.

The forward and lateral occupant impact velocities were 16.7 and 8.4

ft/sec (5.2 and 2.6 m/sec), respectively, while the forward and lateral

ridedown velocities were 11.4 and 9.2 gIs, respectively. These values are

well below the recommended values cited in NCHRP Report 230. Figures 15 and

16 show the test vehicle before and after testing. As illustrated, the

20

.881 sec .. 414 sec .000 sec

Test No. . · · . · · · · 2262-14 Speed-mph(kph) N Date • . . · · · · · 8-10-84 Impact. · · · · 47.3(76.2) --' Installation Exit. 11.9(19.2) · · · · 0 · 0 · .. • .

Drawing No • Angle-deg Beam Rai 1 Impact. · · · · · · • · · • · 15.0

Member • · . · · · · · · 12 gao W-Beam Occupant Impact Ve1ocity-fps(m/s) Length of Segments-ft(m) Forward · · • · · • · · · · · 0 16.69(5.09)

First Segment ••• · 25{7.62) Lateral · .. · · · · · • · · · · 8.41 (2.56) Remaining Segments. · 6.25(1.91 ) Occupant Ridedown Accelerations-gls

Maximum Deflection. 30.5(9.30) Forward • · · · · · · · · 11.43 Vehicle Lateral · · · • · • · 9.24

Model. · · . · · · · · · 1974 Chevrolet Vega Vehicle Damage Mass-1b(kg). · · · · · · 2453(1115) TAD • • · · • · · · • · • • · • • . l-FR-5

fvlaximur,l Roll Angle (degrees). 4. 1 VDI . · · · • · · · 01 FZMW3


Fig u r e 15. T est V e hie 1 e Be for e T est 1 4

22

Figure 16~ Test Vehicle After Test 14

23

vehicle suffered extensive damage to the front and was not operable. Figure

17 shows photos of the test installation before and after impact. This test

was determined to be successful because all measures of impact severity were

within acceptable limits. the modified terminal exhibited no structural

inadequacy. and vehi c1 e post impact trajectory was acceptable.

Test 15. The final test of the WBBB end treatment investigated the

head-on impact characteristics of the modified terminal. This test

involved a 2453 1b (1153 kg) vehicle impacting the nose of the end treatment

at 46 mph (74 km/h). The angle of impact was 0° with respect to the roadway

and the point of impact was offset 15 in. (38 cm) to the right of the

vehicle centerline. When the test vehicle impacted the terminal. the 25 ft

(7.7 m) section of unsupported rail buckled at the quarter point between the

leading barrel and the beginning of the length of need for the barrier. The

test vehicle was then redirected behind the barrier and dragged the leading

barrel to a stop approximately 65 ft (20 m) from the point of impact.

Figure 18 shows a summary of test 15. As shown in this figure the

longitudinal occupant impact velocity was 35 ft/sec (10.8 m/sec). which is

above the recommended limit of 30 ft/sec (9.3 m/sec) but below the maximum

allowable limit of 0 ft/sec (12.3 m/sec) (.?). All other measures of impact

severity shown in Figure 18 were well below the recommended values. Figures

19 and 20 show the damage incurred by the test vehicle, and Figure 21 shows

the damage sustained by the test installation. Although the longitudinal

occupant "impact velocity was above recommended limits for this test, the

test was considered to be a success because the impact velocity was within

maximum acceptable limits and the test passed all other methods of

evaluation.

24

Figure 17. Modified Barrier Before & After Test 14

25

", , 'f' .,: to;l""""' ________ "':--:_"., , ___ ;

.953 sec .363 sec .095 sec

---1-1 -

Test No. . · · · · · 2262-15 Speed-mph{kph) Date • . . · · · · · · · · · 8-14-84 Impact. 0 · · · · · · · · · 45.5(73.3)

N Installation Exit. . '. G · · · · · . . 20.6(33.2) m Drawing No Angle-deg · · · · Beam Rai 1 Impact. · · · · · • · · · • · · 0.0

Member • · · · · · . · · 12 gao W-Beam Occupant Impact Velocity-fps(m/s) Length of Segments-ft(m) Forward · · · · · · · · · · · 34.81 (10.61)

First Segment ••• · 25(7.62) Lateral · · · · · · · · · · · · . . 6.39(1.95) Remaining Segments. · 6.25(1.91) Occupant Ridedown Accelerations-g's

Maximum Deflection 40.0(12.2) Forward · · · · · · 4.08 Vehicle Lateral · · · 1.50

Model. · · · · · · · · · 1975 Chevrolet Vega Vehicle Damage Mass-lb(kg). · 0 · · · · 2453(1115) TAD • . · · · 12-FC-4

~1ax i mum Ro 11 Angle (degrees). 3.6 VOl ... · · · · • · · · · · 12FC~1N5



27

Figure 20~ Test Vehicle After Test 15

28

Figure 21. Modified WBBB After Test 15

29

SUMMARY AND CONCLUSIONS

The W-beam-on-barre1s barrier has been shown to be a cost beneficial,

low service, temporary barrier and is used widely across Texas. No safe end

treatment for the WBBB had been previously tested successfully. The end

treatment currently used in Texas, shown in Figures 1, 2, and 3, utilized a

bent-down guardrail element with a cluster of three steel drums at the end

to hold the rail in place and cushion head-on impacts. This end treatment,

although difficult to construct, was found to be installed correctly by most

contractors using the WBBB, and it contains no obvious safety problems.

Therefore, this end treatment was selected for full-scale crash test

evaluation.

Two full-scale crash tests were conducted to evaluate the impact

behavior of the existing terminal. Since the W-beam-on-barre1s barrier is

intended for low service level applications, it was decided that test

conditions (vehicle weight, impact speed, and impact angle) recommended for

permanent barri ers were not appropri ate. The basi c difference between the

selected conditions- and those recommended for permanent installations

involved the impact speed. A 50 mph (80 km/h) impact speed was used in lieu

of the 60 mph (97 km/h) speed used for permanent barriers. The second crash

test of the terminal resulted in test vehicle rollover.

The end treatment design was modified as shown in Figures 12 and 13 to

prevent vehicles impacting the side of the terminal from becoming airborne

and rolling over. Important features of the modification include raising

the end of the rail to a height of 27 in. (69 cm) and replacing the three

barrel cluster at the nose of the terminal with a single barrel. As shown

in Figure 12, a W-beam buffer end section was used to prevent the guardrail

from spearing an impacting vehicle. Two crash tests of the modified end

30

treatment verified the crashworthiness of the new design. In conclusion,

the modified end treatment developed under this study has been shown to be a

crashworthy termi nal for the W-beam-on-barre 1 s barri er.

31

APPENDIX A - SEQUENTIAL PHOTOGRAPHS

32

0.000 sec

0 .. 135 sec

0.273 sec

0.409 sec

Figure 22~ Sequential Photographs for Test 12.

33

0.549 sec

0.684 sec

0.822 sec

1.000 sec

, -.-,.;

li&itrie~-::: 'iI- '-{.;WJ

Figure 23. Sequential Photographs for Test 12. (cant.)

34

0.000 sec

0.106 sec

0.209 sec

0.315 sec

Figure 24. Sequential Photographs for Test 13.

0.419 sec

0.522 sec

0.633 sec

0.744 sec

Figure 25~ Sequential Photographs for Test 13. (cant.)

36

0.000 sec

0.103 sec

0.203 sec

0.309 sec

Figure 26. Sequential Photographs for Test 14

37

0.414 sec

0.546 sec

0.881 sec

. ~,----........

,.i\ " ., ....... ~ • .aJ.:..;a "MId"~~!!~ 1.213 sec

Figure 27. Sequential Photographs for Test 14 (cont.)

0.000 sec

0.095

0.215 sec

_cd ,..)c-

0.364 sec

Fiqure 28. Sequential Photoqraphs for Test 15

39

0.511 sec

0.660 sec

0.807 sec

0.953 sec

Figure 29. Sequential Photographs for Test 15 (cont.)

40

APPENDIX B - ACCELEROMETER TRACES AND ROLL, PITCH, AND YAW RATES

41

z o 1-1 I-

~ lJ.J -' lJ.J

10

o

~ -]0 c:(

-' ;2 1-1 Cl ::;:) I-1-1

§g -20 :3 I

-30

--i I

0.00

Class 180 Filter

. . , ......... :' ................ " ..... : ..... " ......... ' .. "

I . l··· .... ····j········ I :

.... , ............. " .... ,:,', ..................... : ... " ....... . : : . .

k-N~X. I ~

0.050 se~ Avg. = -11~3 g

0.20 0.40 0.60 0.80

TIME (SECONDS)

Figure 30. Vehicle Longitudinal Acce1 erometer Trace for Test 2262...,12.

42

1.00

-20

-40

.I. .... I I I

0.00

Class 180 Filter

0.050 sec Avg. = 3.1 ~

....................................... ", ..... ,. , ......... , ... , ...... " .... ".,', ........ , ...... .

0.20 0.40 0.60 0.80

TIME (SECONDS)

Figure 31. Vehicle Lateral Accelerometer Trace for Test 2262-12.

43

1.00

Class 180 Filter 40~~~--~----~~------------------------~

I ~ --",,--I ~.c: .......... ----..., fviax. o. ClSp sec Avg. ~ 6.8 g

1 I

§: 20'1· z o .......

~ W ....J W U U c:(

....J c:( U ....... b2 w :> -20

I I

I I: : i . . . . . . .. I···· '1' ....... ~ . . . . . . . . . . . . . . . . . . . . . ... ; . . . . . . . . . . . . . . . . . . . . . . .. ; . . . . . . . . . .. . . . . . . . .. ......................... .. .

I I l ~ . I I ~ I I ~

-40 ~~~--~------~--------~------~------~ 0.00 0.20 0.40 0.60 0.80 1.00

TIME (SECONDS)

Figure 32 .• Vehicle Vertical Accelerometer Trace for Test 2262~12.

44

lIZ

~ dbVAW

~~

,.-,.

Q

o · If)

if) 0

we: WIf) a:: I

C)

w 00 """"0 · 0 1- ...... Zl W :::E Wo WD a: . .-.-l~ 0.... I if) 1--1

00 0

· 0 (\J

I

0 0

· l.Il (\J

I

Axes are vehicle fixed. Sequence for determining orientation is:

1. Yaw 2. Pitch 3. Roll

Pitch

Yaw

Roll

Figure 33. Vehicle Angular Displacements for Test 2262-12.

45

..-.. ~ -z: 0 ....... l-e( 0::: I..LJ ....J I..LJ U U e(

~ ....J 0'1 e( Z ....... Cl => I-....... ~ z: 0 ....J

Class 180 Filter 40 ,-----~------~---.--~11------~------~------~----~

I 0( ~Io(

I d Max; 0.050 sec Avg~ = -8.5 d

, .

I d 20 .. ····· .... · .............. ".,'" '''''' '"'''''~I''''' ." .. , I ~ I

, , ........ , .. , .. ; .... , ..... , . ~ ...... , .. " ....... , ... , ... ,

I q I :1 I :

: \

o

-20 ""'''''''''''''',,,, ... ,, ..... , .. ,,,

-40 0.00 0.10 0.20 0.30 0.40 0.50

TIME (SECONDS)

Figure 34. Vehicle Longitudinal Accelerometer Trace for Test 2262-13.

0.60 0.70

VI VI ~ ,.....

u

~ ..... ~ ....... ~ . ~ . , ,

-~

<> ~

':;::>

~i> , .... ~ .... , .................. : ........................... , ........ ..,.,. ...... ""

c> c;;""

:=

N I

II

· O'l >

c:( ~~ .

.................................... ,.. .<: ........................... , .... " .. , ............... : ............ (,) ......... .

..,;;~~g~~~~-- . . ~ ~3

;;::>

.......... ~ ....... ..

-

I--

· o

· x . •. , .. , ...... " .... ", ................ , .. tIS .... ·

:;:

--..................................

- --

=--,""'"

............... , ........ :' .......... ~, .. ,~.~~, .. ~,.~ .. "." ............ " " ......... , ....... , ....................... .

c;

0 0 0 0 0 0 N ,..... ,..... N (V)

I I I

(:J) NOIIV~313JJV lV~31Vl


47

· o

o \0

o

o 10 · o

0 '<:T · 0

o (V)

· o

o N · o

o ,..... · o

8 · 0

......... Vl CI Z 0 U LLJ Vl .........

s.. Q) co +> r-- .... ~ ... ~ ................ : .... ~ ......... .

M

o CO r-

VI

II

~ U r- Q) . U ............ V/ ...... " ... : ...•....••...•..•••.....

o L()

o . o . X to

· o

· o

o .~ o

o .......... ~ ........... : ................. '""".-~~ ................................. """

--~-~--~~-----................................. :::=::::~""' ........................................... .. --:---_.:::-:::-=_-.....j....-,.",....---:----

· o

o M · o

o N .......... ~ .............. _ ... ~ .. ~ , . . . .. . . . . . . . . . .' .

0 0 0 0 0

""" N N """ I I

(9) NOI'lVCl313:l:lV lV:lIHI3A

Figure 36. Vehicle Vertical Accelerometer Trace for Test 2262-13.

48

o

o ...-· o

0 0 · 0

..-.,. (/) Cl z: o U L.1J (/) .........

liZ

~dbVAW ~

IZ

o a · o

en

o o · o

Wo

"p.O\..\..

Axes are vehicle fixed. Sequence for determining orientation is:


Roll Yaw

2::: 0 wo~,~~--~~------~,---------,-------~

U 0.00 0.40 0.60 0.80 S SECONDS) D-0 tn~ I--iO

o~

o a · a ru

I

Pttch

Figure 37. Vehicle Angular Displacements for Test 2262-13.

49

z o .......

~ LLJ ....J LLJ U

10

o

~ -10 ....J c:r: Z ....... Cl :::::> I-....... c..!J

B -20 ....J

-30 0.00 0.20

Fi gure 38.

Class 180 Filter

I : ", ..... .1.. ... L .. ,,,.... , .. ,,' ".""."

I I ~ ~ 'I+- Max.

I Il O.O~O sec Avg. -9.7 9

0.40 0.60 0,,80 1.00

TIME (SECONDS)

Vehicle Longitudinal Accelerometer Trace for Test t262-14.

50

z o ....... ~ IX LLl .....J LLl U U c::(

Cl ass lS0 Fil ter 40 .-----~~------_c--._._~--------------~

0.050 s~c Avg. = 2 .. 9 -.j f.-- Max. I I ~ I I ~

20 , ................... ,' ............ , ........ , ... ········l·····I"·····'~····"·······'·'·· .,.,", ..... , .. .

. I I .

-200. 00 ..

0.20 0.40 0.60 O.SO

TIME (SECONDS) <


51

1.00

z o ....... I-

~ LU -I LU U U c.:(

-I

5 ....... Iex! LU :>

Class 180 Filter 30

--I r--Max. b.050 sec A g. I I . .

20 ..................................................................... .1. .... I.. .............. '.J ................... . I i I ~ Ij I

~ I 10 ........... " .......... " ............ " ...................... " ...... [ '"1'''''''''''''''''''[''''''''''''''''''''' ..

o

-10

-20

I I

I I

. I ........................ : ............. " ......... : ... · .. · .. ···· ........ ·l .. ··I .. ···· .. · .. "· .... ·j .. ,, ................. .

0.00

I j I : I ~ I

0.20 0.40 0.60 0.80

TIME (SECONDS)

Figure 40. Vehicle Vertical Accelerometer Trace for Test 2262-14.

52

1.00

= 5.7 g

o o o :::f'

o o . o

...-.. (T')

en w w a:o (.:)0 W •

o 0(\1

I--20 Wo :a:: , wS u IT -.J (L

eno

Axes are vehicle fi~e~. S quence for determl mng e .. orientatlon 1S:


Yaw

~Ol~~ __ ~~ __ ~~~ __ ~ ... . 0 0.90

~Roll o o . o -' I

Vehicle Angular Displacements F,igure 41.

53

Pitch

for Test 2262-14.

z o ........ f-

~ L.LI -l L.LI U U c::c -l c::c Z ........

20

o

Cl -20 ~ f-........ t.!J Z o -l

C1 ass 180 Fil ter

t-1~-_iOl-l~~~ - Max. 0.050

I I I I

sec Avg. ~ = -14.1 g

····I···i························f···················· .... : ............................................... .

I : : : : · . : :

I ~ [ · . : : · . -40 .. - ,.:~ ....... c .... _. ___ •. __

0.00 (). 1 0

Figure 42.

0.20 0.30 0.40

TIME (SECONDS)

Vehicle Longitudinal Accelerometer Trace for Test 2262~15.

54

0.50

Glas~ 180 Fj] ter 40 ~r---~----------------------------~--------,

I I I

;;- 20 .HII························ ........................................................... .

o

-40

I I

I

·+1··················································· ... I I ~ 1-- ~I":

0.00 0.10

Figure 43.

Max. 0.P50 sec Avg.[ = 2.3 9

0.20 0.30 0.40

TIME (SECONDS)

Vehicle Lateral Accelerometer Trace for Test 2262-15.

55

0.50

40

........ CD 20 ......... z: 0 ..... l-e:::( e:::: I..L.I -! I..L.I U 0 U e:::(

-! e:::( U ..... l-e:::: I..L.I ::::-

-20

-40

Class 180 Fi lter

I I .. [~r Max. 0.050 sec Avg. = 8.7 9

I • I • ............... ..1.. ·( .. 1 .................. ·( ................................................................ ..

I . .

0.00

I ~ I ~

0.10 0.20 0.30 0.40

TIME (SECONDS)

Figure 44. Vehicle Vertical Accelerometer Trace for Test 2262~15.

56

0.50

o o · t.n

§J.O · a

'-"0 (f)a LtJ. Wlf) eel C)

W 00 '-'0 · a 1-- ..... Zl W L We UO cr:~ --.J..--. 0-. 1

en 00

o · o

C\l I

o o · t.n ('\J

I

Figure 45.

, are vehicle fixe~. Axes for determin1ng Sequence. '. orientatlOn 1S.

1. Yaw ) Pitch t:...

3. Roll

ECCJNDS) ,'Pi.tc~.60

011

Yaw

~ .. , 'r Test 2262-15. -r Di spTacements fo Vehicle Angu ar

57

REFERENCES

1. Ross, H. E., Jr., and Sicking, D. L., "Guidelines for Use of Temporary

Barriers in Work Zones," Research Report 4151-1, Texas Transportation

Institute, Texas A&M University, July 1983.

2. Michie, Jarvis D., "Recommended Procedures for the Safety Performance

Evaluation of Highway Appurtenances," National Cooperative Highway

Research Program Report 230, March 1981.

3. Bronstad, M. E. and Kimball, C. E., "Temporary Barriers Used in

Construction Zones, II FHWA/RD-80/095, Southwest Research Institute,

Dec. 1980.

58

Documents

Development of a Safe End Treatment for W-Beam-on-Barrels ... · LIST OF FIGURES (C.onti nued) Figure Page 22 SeqlJenti a 1 Photographs for Test 12. 33 23 Sequential Photographs for