TECHNICAL RepORT STANDARD TITLE PAGE

1. Report, No. r;",'

I

2. GcY.~nm.nf Accessio~ No, 3. Rel!iplent's Coiolo,g HI).

FHWA/TX-84/62+262-5 ...... ... __ .. _- - _._- --

4. Title ohd Subtitle 5. R~port Dote

Development of a Truck-Mounted Portable May 1984 Maintenance Barrier T-PCTtorffling Otgoni1t11ion coJ;- ----

--c;--,-------------.--.. " ,-.~,-.... , ---.---- -----7, Avthor's) a, P~rforrni('j9 O,gonuor,on R~!'ldri N~

W. Lynn Beason and H. E. Ross, Jr. Resea rch Report 262-5

-9_ • '" Organi:r:alion NQffl4! and AdduI'S!I' 10. WorJ.c Unit No . :

Texas Transportation Institute The Texas A&M University System 11. Contract or Ceonl NQ,

College Station, Texas 77843 Study No. 2-18-79-262 13, Type 01 Rep-ott and Period Cr'i!-fed -- Interim _ September 978 12. SpOn~bfin9 Agency Nome ond Addreu

Texas State Dept. of Highways and Public Transpor- May 1984 tati on; Transportation Planning Division ---..

P.· O. Box 5051 14. Sponsoring Agency Code

Austin. Ie)(as Z8Z63 15. Supplementary Noti!-~

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

16. Abshact

A truck-mounted portable maintenance barrier is described in this report. The barrier is designed to provide a reasonable degree of positive protection in short duration work zones where it is not practical to use conventional barriers. The barrier consists of a steel barrier section which is supported between two maintenance trucks. The barrier section is towed to the work zone on a specially fabricated transport dolly. On-site deployment can be accomplished by a crew of two men in 15 minutes or less. The barrier is highly maneuverable in the deployed configuration so that it can be easily repositioned as the work progresses. Three full-scale tests were conducted to demonstrate the impact performance of the barrier.

17. Key Words 18. Di,tribufion S'atement

Portable Barrier, Crash Test(s), No restriction. This document is available to the public through the National Techni-Construction. Work Zone(s), Temporary, cal Information Service, 5285 Port Royal Safety. Road, Springfield, Virginia 22161.

19, S~eufit:t' Clouif. (of thi. repo,t) 20. Security Clossif, {.of fhi So pogei I 21. NQ. of Pages 22. P,ictl

Unclassified Unclassified I 80

Form DOT F 1100.1 1.· •• 1

j j j j j j j j j j j j j j j j

j j j j j j j j

j j j j

j j

j j j

DEVELOPMENT OF A TRUCK-MOUNTED PORTABLE MAINTENANCE BARRIER

by

W. Lynn Beason Engineering Research Associate

and

Hayes E. Ross, Jr. Research Engineer

Research Report 262-5 on

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

Sponsored by State Department of Highways and Public Transportation

i n coope rat i on wit h U.S. Department of Transportati on Federal Highway Administration

Apri 1 1984

Texas Transportation Institute Th'e Texas A&M University System

College Station, Tx

DISCLAIMER

The contents of thi s report reflect the vi ews 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

Portable Barrier, Crash Test(s), Construction, Work Zone(s), Temporary,

Safety

ACKNOWLEDGMENTS

This research study was .conducted under a cooperative program between

the Texas Transportation Institute, the Texas State Department of Hi ghways

and Public Transportation, and the Federal Highway Administration. David

Hustace, Hunter F. Garrison and William V. Ward of the SDHPT worked closely

with the researchers, and their comments and suggestions were appreciated.

i i

DEVELOPMENT OF A TRUCK-MOUNTED

PORTABLE MAINTENANCE BARRIER

ABSTRACT

A truck-mounted portable mal ntenance barri er is descri bed in thi s

report. The barrier is designed to provide a reasonable degree of positive

protection in short duration work .. zones where it is not practical to use

conventional barriers. The barrier consists of a steel barrier section

which is supported between two maintenance trucks. The barrier section is

towed to the work zone on a specially fabricated transport dolly. On-site

deployment can be accomplished by a crew of two men in 15 minutes or less.

The barrier is highly maneuverable in the deployed configuration so that it

can be easily repositioned as the work progresses. Three full-scale crash

tests were conducted to demonstrate the impact performance of the barrier.

iii

TABLE OF CONTENTS

I NTRODUCTI ON

CONCEPT

PERFORMANCE CRITERIA

BARRIER ANALYSIS AND DESIGN

Preliminary Analysis

Final Analysis and Design

TEST RESULTS

Test 9

Test 10

Test 11

Maneuverability Tests

CONCLUSIONS

APPENDIX A. BARRIER DEPLOYMENT

APPENDIX B. SEQUENTIAL PHOTOGRAPHS

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

REFERENCES

iv

Page

1

3

18

20

20

25

29

29

32

36

36

44

46

50

57

72

Ll ST OF FIGURES

Fi gure No. Page

1 Truck-Mounted Portable Maintenance Barrier 4

2 Single lane Barrier Deployments 5

3 Barrier Components 6

4 Fabrication Details of Front and Rear Hitches 8

5 Fabrication Details of Side Hitches 9

6 Fabri cati on Detail s of lateral Support Members 10

7 Fabrication Details of Longitudinal Support Members 11

8 Fabrication Details of Barrier Section 13

9 Side View of Barrier Section 14

10 Barri er Sect; on on Transport Dolly 15

11 Fabrication Details of Transport Dolly 16

12 Idealized Impact 21

13 Idealized Barrier Force Deformation Relationship 23

14 Computer Model of Ba rri er 26

15 Summa ry of Test 9 31

16 Barrier and Automobile Prior to Test 9 33

17 Barr; er and Automobile After Test 9 34

18 Summa ry of Test 10 35

19 Barr; er and Automobil e Pri or to Test 1037

20 Barrier and Automobile After Test 10 38

21 Summary of Test 11 39

22 Barrier and Automobile Prior to Test 11 40

23 Barrier and Automobile After Test 11 41

24 Barrier Configuration for Maneuverabi 1ity Test 43

v

Fi gure No.

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

LIST OF FIGURES (continued)

Sequential Photographs for Test 9

Sequential Photographs for Test 10

Sequential Photographs for Test 11

Vehicle Longitudinal Accelerometer Trace for Test 9

Vehicle Lateral Accelerometer Trace for Test 9

Vehicle Vertical Accelerometer Trace for Test 9

Vehicle Resultant Accelerometer Trace for Test 9

Vehicle Angular Displacements for Test 9

Vehicle Longitudinal Accelerometer Trace for Test 10

Vehicle Lateral Accelerometer Trace for Test 10

Vehicle Vertical Accelerometer Trace for Test 10

Vehicle Resultant Accelerometer Trace for Test 10

Vehicle Angular Displacements for Test 10

Vehicle Longitudinal Accelerometer Trace for Test 11

Vehicle Lateral Accelerometer Trace for Test 11

Vehicle Vertical Accelerometer Trace for Test 11

Vehicle Resultant Accelerometer Trace for Test 11

Vehicle Angular Displacements for Test 11

vi

Page

51

53

55

58

59

60

60

61

62

63

64

65

66

67

68

69

70

71

LI ST OF TABLES

Tabl No.

1 Summary of Crash Test Statistics 30

vii

DEVELOPMENT OF A TRUCK-MOUNTED

PORTABLE MAINTENANCE BARRIER

I NTRODUCTI ON

There is an increasing number of high volume, multilane expressways

where it is not practical to stop traffic across all lanes during mainte­

nance operations. The current approach to this problem is to close only

those lanes which are under repair and redirect traffic into adjacent

lanes. The problem with this approach is that the work zone is adjacent to

a traffic lane thus exposing the workers to the risk of being struck by an

errant vehicle. This situation is particularly hazardous during times of

heavy traffic flow when the loss of even one lane of traffic can create

severe local traffic congestion. There is an urgent need to increase the

protection of workers in this situation.

In some instances, the nature of the maintenance operation is such that

the work zone is occupied for weeks or months. In such cases, it is

possible to install portable concrete barriers (1). In other instances, the

time required to acomplish the maintenance is only a few hours. In the

latter case, it -takes substantially more time to deploy portable concrete

barriers than it does to perform the maintenance. In addition, the widths

of the portable concrete barriers are such that they encroach into either

the work zone or the adjacent traffic lane.

Research presented in thi 5 paper was di rected toward development of a

t ruck-mounted po rtab 1 e mai ntenance barrier for use in short-term hi ghway

maintenance operations. The portable maintenance barrier developed provides

a reasonable degree of protection for the workers; it can be easily

deployed; and once deployed, it remains highly maneuverable so that it can

be easily repositioned in the work zone. This report presents a discussion

of the concept of the portable maintenance barrier, a discussion of the

performance criteria, a discussion of the design approach, and results of

both strength and maneuverability tests.

2

CONCEPT

It is common practice in highway maintenance to station supply trucks

and other maintenance vehicles ;n the work zone lane immediately upstream

and downstream of the work zone. This is done to provide ready access to

maintenance suppl ;es and to prevent unnecessary blockage of additional

traffic lanes. A side benefit of this practice is that the maintenance

vehicles afford the workers protection from in-lane impacts. The purpose of

the research reported herein is to develop a barrier system which enhances

the protection afforded by in-lane maintenance vehicles without introducing

new hazards to impacting vehicles. The portable maintenance barrier

developed is intended for use in short-term, less than one day, maintenance

operations such as guardrail replacement, pothole repair, etc. Major

emphas 1 s was placed on devel opi ng a barri er that is eas ily transported and

deployed.

The truck-mounted, portable maintenance barrier developed consists of a

steel barrier section which is supported between two support trucks as shown

in Figure 1. Figure 2 shows planned deployments of the portable maintenance

barrier in a work zone. The support trucks provide protection against

in-lane impacts, while the barrier section provides protection against

lateral impacts. The major components of the portable maintenance barrier

are: the support trucks, the hitch assemblies, the support members, the

barrier section, and the transport dolly (ref. Fig. 3). Each of these

components is discussed below.

The support trucks used in the prototype are standard 5 cubic yard

State Department of Highways and Public Transportation (SDHPT) dump trucks.

The trucks were obtained from the SDHPT surplus property department. The

major modification to the trucks consisted of the installation of a frame

3

Figure 1. Truck-Mou t ~1aintenan~ eBd Po~tab1e earner

4

9 Q Q Q Q Q g Q 0' Q Q 0 Q

EXTERIOR LANE WORK ZONE

~I

INTERIOR LANE WORK ZONE

Figure 2. Single Lane Barrier Deployments

5

.lr

"f\ ~

SIDE HITCH

,REAR HITCH fRONT HITCH '" -T ,.-

LEAD SUPPORT TRUCK LATERAL

SUPPORT .- MEMBER

-, 1/

I l BARRIER SECTION

lLONGITUDINAL SUPPORT MEMBER

Figure 3. Barrier Components

- l'

LONGITUDIN~ SUPPORT MEMBER

REAR SUPPORT TRUCK

~ SIDE HITCH

plate to increase the in-plane stiffness of the truck frames. The purpose

of stiffening the truck frames is to assure that the support trucks can

survive the design impact with no damage. The frame plate consists of a 1/2

in. (1.27 cm) steel thick plate which is mounted between the frame members

of the truck and the dump bed in a horizontal plane. The plate was welded

in place in the prototype. However, it will probably be necessary to attach

the plate with bo 1 ts on newer trucks with hi gh-strength frames.

Installation of the frame plate does not interfere with the dump mechanism.

Two different types of hitch assemblies were developed to attach the

support members to the trucks: a front/rear hitch and a Side hitch. The

front/rear hitches were welded to the truck frames on the prototype. As

before, it may be necessary to bolt these hitches onto newer trucks with

high-strength frames. The side hitches were bolted to the truck frame with

twelve 1 in. (2.54 cm) diameter bolts for each hitch. Fabrication details

of the hitches are presented in Figures 4 and 5. The lead support truck is

equipped with a rear and side hitch, while the rear support truck is

equipped with a front and side hitch. The support members attach to the

hitches with pins and bolts.

Two types of support members were developed to attach the ba rri er

section to the hitch assemblies: longitudinal support members and lateral

support members. The purpose of the support members is to transfer the

impact forces from the ends of the barrier section to the hitches mounted on

the support trucks. The longitudinal support members connect the side

hitches to the ends of the barrier section. The lateral support members

connect the barr; er ends of the 1 ongi tudi na 1 su pport members to the rea rand

front hitches of the front and rear support trucks, respectively. Fabrica­

tion details of the support members are presented in Figures 6 and 7.

7

24" MAX. (CUT TO FIT) 24" MAX.(CUT TO Fin

4"

3" 1-1/4"4>

I~ I" Ie.

PLAN VIEW

I :.; I ~I"

T

END VIEW

Figure 4. Fabrication Details of Front and Rear Hitches

8

4"x 6"x 1/4" STR. TUBE

,

3 1-6"

2-1/2"I 4"

2-1/2"

4'- 2."

. .. ..... II ..

6"

I 13" I 13" I ,3",3",3"13"14" 13"13"14" 13"13"1"f,r, 6"

o o o

2-1/6"

... +/:::=:)~:;;;;;_ 4 "x 6". 1/4 " STR. TUBE

PLAN VIEW

ELEVATION

gure 5. Fabrication Details of Side Hitches

9

7/8" II!.

3-1/2" -0---+-+- 3 _ 1/ 2 "

DEPENDS ON _~...!-,.;T.;.;RUCK HEIGHT

2"

.. 4'-6" (CUT TO FIT)

2 Ilx2 n xl/4 11

STR. TUBE r 2- 1/ 4 "

3,;-r'l;:;1,:\%f~/~'"T' -rL -j-=1 ("~ -, -_ -_ -_ -_ -_ 1...J1-,,---~T ------------------------.:t'~::::::::::::::=::[====:~tj

1-1/4" 4> USE H/8"4> BOLT OR PIN

12- 3/4"

3--3/4" 3 11 6"

PLAN VIEW

I- 1/4" 4> ---­USE 1-1/8"4> BOLT OR PIN

11-1/4"

3':r-E~~;:::t=======H=========~~ I-~ 1/2" Ie. 1/2" 12.

ANGLE TO FIT ELEVATION ANGLE TO FIT

Figure 6. Fabrication Details of Lateral Support t~embers

2-1/4"

1/2"

~" ====t=;;f.

4"

~

~

112",* I" 2

6" 5" III 2.1 I

I/i'

1'-7-3/4" •

1-3/4" .p USE 1-9/16" PIN

," 1'-7-3/4"

511 .3".1/4" STR. TUBE

PLAN VIEW

"'9'-0" (CUT TO FIT)

SS

M -I I-I I

I \ :~

\/2" It.

'\1" It.

ELEVATION

Figure 7. Fabrication Details of Lcmgitudinal Support Members

1'-7-3/4"

4"

USE 1-9/16" PIN

I' -7- 3/4" ~I

I -I

The barrier section is fabricated using two parallel sections of 6 x 6

x 1/4 in. (15.24 x 15.24 x .64 cm) structural steel tubes welded together as

shown in Figure 8. The weight of the barrier section is supported by two

swivel casters which are permanently mounted on the underside of the barrier

section as shown in Figure 9. In addition, two screw jacks are permanently

mounted on the barrier section to aid in handling. The ends of the barrier

sections are equipped with single pin connections that mate with the ends of

the longitudinal support members. These connections are designed to allow

180 degrees of yaw and nominal amounts of pitch and roll between the barrier

secti on and the support trucks. The combined effects of these features

result in a highly maneuverable barrier which can be easily moved through

short distances in the work zone.

The barrier section is towed to and from the work zone using a detach­

able transport dolly (ref. Fig. 10). Fabrication details of the transport

dolly frame are presented in Figure 11. The barrier section is loaded and

unloaded onto the transport dolly by alternately using the two barrier

section screw jacks. An experienced crew of two men can load or unload the

barrier section in a period of 15 minutes or less. Complete details for the

1 oadi ng and un load; ng operat ions are presented in Appendi x A. When not in

use, the transport dolly is connected to an auxiliary hitch point located on

the rear of the front truck.

12

w

1'-0"

II_a"

4"

1-3/4"4>

8" 3-1/2"1

c/;-I I Z -1/8" i::::i:.:=;;::;~

1'_0"

[ 7/8"

1-1/4" ¢ PLUG WELDS

2'-1"

1'·0"

::::44 1-0"

r-3-1/ 2 "

~~--~~~=~~.~ii:====~~~A.~ " -y-

511

5 11

PLAN VIEW

=:44 1 -0 11

1/2" It

3-1/2".11-1/2".1/4" It SlOP WELO- IZ"WELO-IZ"CLEAR 1/4"

2"x 2·1/8"x 4" STEEL SPACER

7/8" It 1/411

f:L.EVATION

Figure 8. Fabrication Details of Barrier Section

DOLLY LUG

CASTORWHEEL

I--- 7' ------l 2' ~ 2'-1

Figure 9. Side View of Barrier Section

Figure 10.

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

Barrier 5 Transport eoction on ally

15

4"

1/2." It 4"=C= ~---r4----r-rr--:-';"""'-J--~ ~ __ 5u~ 'I'I'If'--_ 5 11 )1;2"x 1/4"

4" I STR, TU'BE

211 X 2." X 1/4'1 ",-__ """ STR, TUBE

/see Details

PLAN VIEW

Figure 11. Fabrication Details of Transport Dolly

16

I 4" /- 4" -14"

TOP HITCH PLATE :

2"

2"

2"

2"

I ~ 2."x 2." X V4i-,,----...:.-----I.--+-:I---i I I~_~" STR. TUSE

1/2."

~LO~ITCH PLATE 1/4"

SECTION "A-A"

4" I" 3"

I" 450 1/2."12:

2"

I"

TOP HITCH PLATE

3"

I" 1/2."1t.

2"

I"

1-1/4"«.>

LOWER HITCH PLATE

Figure 11. Fabrication Details of Transport Dolly {continued}

17

PERFORMANCE CRITERIA

Performance criteri a for guardrail s, traffic barriers, and other types

of highway appurtenances are presented in NCHRP Report 230 tV. The

criteria presented in this report are the result of a consensus process

involving interested experts and professionals. While it is not explicitly

stated in the report, the primary use of NCHRP Report 230 has been to

establish performance criteria for permanent appurtenances.

The proposed portable maintenance barrier is not intended to be perma­

nently deployed. Therefore it is not exposed to the continual risk asso­

ciated with a permanent barrier or semipermanent portable barrier. Further,

it must be recogni zed that the mai ntenance workers are cu rrent ly work i ng

with a limited amount of protection. These factors combine to suggest that

it is reasonable to employ design criteria which are less stringent than

performance criteria presented in NCHRP Report 230 (I).

The criteri a for permanent guardra il i nsta 11 at ions presented in NCHRP

Report 230 is intended to evaluate the following three principal performance

factors: structural adequacy, occupant risk, and vehicle after-collision

trajectory (I). Permanent guardrail i nsta 11 ati ons must be desi gned to

safely redirect a 4500 lb (2043 kg) automobile traveling at 60 mph (96.6

km/h) and impacting at an angle of 25 degrees. In addition, permanent

guardrail installations should be able to smoothly redirect compact

automobiles (2250 and 1800 lb) (1022 kg and 812 kg) traveling at 60 mph

(96.6 km/h) and impacting at an angle of 15 degrees. The first criterion

establishes the required strength of the barrier and evaluates the occupant

risk factors. The second criterion evaluates the barrier's potential for

destabilizing errant automobiles.

18

Based upon input received through discussions held with SDHPT engineers

and researchers, coupled with the judgment of researchers at TTl, the

following performance criteria was established for the truck-mounted

portable maintenance barrier. The portable barrier was designed to redirect

a 4500 lb (2043 kg) automobile with a velocity of 50 mph (80.5 km/h) and an

impact angle of 15 degrees. The destabilizing potential of the portable

maintenance barrier was evaluated using an 1800 1b (812 kg) automobile

traveling at 50 mph (80.5 km/h) and impacting at an angle of 15 degrees. It

was the consensus of all professionals contacted that these are reasonable

performance criteria for the truck-mounted portable maintenance barri er

presented herein.

19

BARRIER ANALYSIS AND DESIGN

The structural design of the portable maintenance barrier was

accompl i shed in two stages. Fi rst, a simplified analysis was used to

determine the relative effects of varying barrier length, stiffness, and

mass. Results of this preliminary study were then used to develop a

preliminary portable maintenance barrier design. The performance of the

preliminary design was further examined using a computer Simulation, Barrier

VII (1). Based upon results from the computer simulation, a refined barrier

desi gn was, advanced. The refi ned desi gn was revi ewed by SDHPT engi neers,

and suggested changes were incorporated. This section presents pertinent

details of the design of the portable maintenance barrier.

PRELIMINARY ANALYSIS

To simplify analysis of the portable maintenance barrier, the following

idealized impact is assumed. First it was assumed that the support trucks

do not slide laterally during the impact. This assumption leads to

consi derati on of the barr; er sect; on as a simply supported beam between the

support trucks. Further, it is assumed that the automobile is a point mass

impacting the barrier section with a velocity, Vi, and with an angle of

impact, e (ref. Fig. 12). The impact is considered to be perfectly plastic

so that the automobile is redirected parallel to the barrier face. Finally.

it is assumed that the force between the barri er and the automobile acts

normal to the barrier section and is the result of the flexural stiffness of

the barrier. Other forces such as friction and intertia forces are ignored.

Using the principle of impulse and momentum, the exit velocity, Vf, of

the automobile is calculated as follows:

Vf = Vi cos e (1 )

20

...., u

'" 0-S ...... -0 <IJ N .~

~

'" <IJ -0 ......

N ~

<IJ ... ::>

"" .~

I.L.

\

21

The change in kinetic energy of the automobile during this idealized impact

is referred to as the impact severity, IS, in NCHRP Report 230 (l). The IS

energy is calculated as follows:

IS = 1/2 m Vi 2 sin2 e (2)

where Vi is the impact velocity and m is the mass of the automobile.

When the automobil e impacts the ba rri er secti on, a force develops

between the barrier and the impacting automobile and energy is absorbed

through several different mechani sms i ncl udi ng: deformati on of the automo-

bi le, deformation of the barrier, friction, etc. In the preliminary analy-

sis, it is assumed that the barrier absorbs a percentage, fl, of the IS

energy in an e1asto-p1astic flexural response.

Figure 13 presents the idealized elasto-p1astic force displacement

relationship between the automobile and the barrier. The total amount of

energy, Ut, absorbed by the barrier is given as follows:

Ut = 1/2 Py 8y + Py 8p (3)

where Py and 8 yare the force and disp1acment corresponding to the elastic

limit of the barrier, and 8p is the plastic deformation of the barrier. The

first term in equation (3) is the elastic response, and the second term is

the plastic response.

The ratio of the plastic deformation, op' to the elastic deflection,

8y , is the ductility ratio and is a measure of the barrier's capacity for

plastic deformation. A maximum allowable value of 5 was assumed for the

ductility ratio in the preliminary analysis. Substitution of this value

into equaton (4) results in the following expression for the total amount of

energy that a given barrier section can absorb:

V =llp 0y t 2 y

22

(4)

w U 0::: o u....

I- 8y . I . 8 p -I

Figure 13.

DISPLACEMENT

Idealized Barrier Force Deformation Relationsfuip

23

Using elementary concepts of mechanics of materials and equation (4), the

following expression for the total amount of energy that can be absorbed by

the barrier section is developed:

11 cr} Ii Vt

= - ( J )

6 c2E (5 )

where I is the moment of inertia of the barrier section, i is the barrier

section length, cry is the yield strength of the barrier section, c is the

distance from the neutral axis to the extreme fibers of the barrier section,

and E is the modulus of elasticity of the barrier section.

The optimum use of material results when the energy absorption capacity

of the barrier section is set equal to the percentage of energy that must be

absorbed by the barrier as follows:

11 cr 2 Ii 6' (Y2 ) = s(IS)

c E (6)

Equation (6) can be rearranged so that the cross-section properties of the

barrier section appear on the left side of the equation while the automobile

characteristics, the barrier section length, and the properties of the

barrier section material appear on the right side of the equation as

follows:

(7)

Equation (7) was used to perform feasibility studies and the prelimi­

nary barrier design. During the preliminary studies a wide range of values

of S were assumed. Subsequent experi ence in the testi ng phase of the

project suggests that values of S ranging from .30 to .40 are reasonable for

analysis of this type of barrier.

24

FINAL ANALYSIS AND DESIGN

The preliminary analysis presented above was used to establish the

feasibility of the proposed portable maintenance barrier and to develop

preliminary barrier designs. The preliminary designs were then examined

using a crash simulation program, Barrier VII (~). Modifications to the

ba rri er design were made based on i nformati on generated usi ng the computer

analysis.

Because of the complexities and uncertainties associated with the

problem, a simplified model of the barrier was used in the computer study

(ref. Fig. 14). In the simplified computer model, the support member

attachment points (hitch points) are assumed to be immovable. In the real

situation, the support trucks allow the hitch points to translate as a

result of sliding of the trucks and truck suspension deflections. It is the

opinion of the writers that the assumed model provides conservative

estimates of the impact forces. Major points of the design are discussed

be low.

The portable maintenance barrier was designed to withstand the impact

of a 4500 lb (2043 kg) automobile traveling at a velocity of 50 mph (80.5

kg/h) and impacting at an angle of 15 degrees. The barrier section was

designed to experience plastic deformation when exposed to the design

impact, while the support trucks, support members, and hitches were designed

to remain elastic. The barrier section should be repaired or replaced after

a design hit, while the rest of the barrier can be reused.

An approximate analysis of the truck frame using the impact forces

determi ned from the computer ana lysi s suggests that the unrei nforced truck

frame would be subject to plastic deformation at the design impact. There­

fore, the stiffness of the frame was increased by coupling the primary frame

25

N 0'1

LEGEND

o POSTS

• HINGES

= MEMBERS

Figure 14. Computer Model of Barrier

members together usi ng a hori zonta 1 frame plate. The effect of the frame

plate is to trans form the truck frame into a hori zonta 1 plate gi rder wi th

the frame plate serving as the plate girder web and the truck frame members

serving as the plate girder flanges. The frame plate modification adds

sufficient stiffness to the truck frame to prevent permanent deformation of

the truck frame.

The support members and hitch configurations were designed so that the

1 ongitudi na 1 and the lateral support members are two-force members. As

stated earlier, the support members and the hitches were designed to remain

elastic during impact. Results of the computer analysiS show that the

lateral support members experience compression during impact, whi le the

longitudinal members experience tension. In addition to the tension force,

the longitudinal members were designed to withstand a direct impact from the

automobile.

Of primary concern with the design of the barrier section was lateral

torsional stability. An approximate analysis of different proposed barrier

sections suggested that barrier sections with open cross sections such as

wide flanges, I beams, etc .. would be susceptible to lateral torsional

buckling. The torsional rigidity of closed sections such as the one used in

the prototype is sufficient to prevent lateral torsional buckling. An

additional concern with the design of the barrier section was local buckling

of the barri er secti on si dewa 11 • It is the opi ni on of the writers that a

barrier section made of a single rectangular tube would have a tendency for

local buckling of the sidewall at the point of impact. Therefore a double

structural tube section was selected to reduce the propensity for local

buckli ng.

27

Major emphasis was placed on specifying commonly avai lable materials

for construction of the portable maintenance barrier. Two types of

structural steel were used in the design of the portable maintenance

barrier: structural tubes and flat steel. Structural tubes are most

commonly available with a mimimum yield strength of 46 ksi. All structural

tubes are of this type. The most commonly available structural steel used

for bars and plates has a minimum yield strength of 36 ksi. All flat steel

used in the barrier was designed on this basis. The bolts and pins used in

the portable barrier were sized using minimum available strengths. This

should preclude problems if field substitutions are made.

28

TEST RESULTS

Three full-scale crash tests were conducted on the truck-mounted

portable maintenance barrier. The purpose of the tests was to establish the

redirective capabilities of the barrier and to determine its destabilizing

effect on compact cars. The impact point in all of the tests was located

one third of the length of the barrier section ahead of the rear support

truck. This impact point was selected to maximize the flexural loading on

the barrier section. It is recognized by the writers that direct impact

into the supporting trucks would be much more serious for the errant

vehicle. However, there is no reason to think that such an impact would be

more serious than an impact with a free standing maintenance vehicle. It is

recommended that one of several different types of rear crash cushions be

towed behind the rear support truck to reduce the consequences of a vehicle

impact at that point.

Table 1 presents a summary of pertinent test statistics. The tests

were conducted in order of i ncreasi ng severity. Sequenti a 1 photos of the

tests are presented in Appendix B. Appendix C presents accelerometer traces

and plots of roll, pitch, and yaw angles. In addition, tests were conducted

to evaluate the maneuverability of the barrier. Short discussions of both

the strength and maneuverability tests are presented below. Results

presented in this report are a part of an ongoing research. The three crash

tests are the 9th through 11th tests of this series.

TEST 9

In this test, a 4500 lb (2043 kg) vehicle impacted the barrier at 50.9

mph (81.95 km/h) with an angl e of impact of 7.3 deg. The automobile was

smoothly redirected with relatively minor damage. Figure 15 presents a

29

TABLE 1. CRASH TEST SUMMARIES

Test 9 10 11

Vehi cl e Wei ght, 1b (kg) 4500 (2043) 1765 (801) 4500 (2043)

Impact Speed, mph (km/h) 50.9 (81.95) 50.9 (81.95) 49.7 (80.02)

Impact Angle, deg. 7.3 14.0 15.0

Exit Angle, deg. .5 1.3 1.0

Barrier Displacement, in. (cm) 11.2 (28.45) 13.0 (33.02) 24.0 (60.96)

Occupant Impact Velocity f Is (m/s)

Longitudinal 6.7 11.3 10.0 Latera 1 0 0 0

Occupant Ridedown Accel., g's

Longitudi na 1 .87 1.58 1.34 Lateral 0 0 0

Vehicle Damage Classification

TAD 2-RFQ-l 2-RFQ-2 2-RFQ-2 VDI 02RFMW5 02RFMW6 02RFMW9

30

Test No .... . Date ..... . Installation

Drawing Nos. Length-ft (m)

Beam Ra il Member. . . . . . . . .. Length of Segment-ft (m). i'1axilnum Deflections

Dynamic - in. (cm). , Permanent - in. (cm).

Vehicle Mode 1 . ~1ass-lb (kg).

II Lrr= . ~ Od

2262-9 Speed-mph (kph) 8/22/83 Impact.

Exit. 2262-5(3-9,11) Angle - deg 88 (26.8) Impact.

Exit. 2 6x6xl/4 in. St1. Tubes Occupant Impact Velocity fps (m/s) 44 (13.4) Forward

La tera 1 11 .2 (28.3) Occupant Ridedown Accelerations - g's

.5 (1 .3) Forward . Lateral

1977 Plymouth Gran Fury Vehicle Oamage* 4500 (2045) TAD

VOl

Figure 15. Summary of Test 9

50.9 (81.9) 46.2 (74.4)

7.3 .5

6.69 (2.04) N/A .. '

", .87

N/A

2RFQ- 1 02RFMW5

summary of the results of this test. All measured occupant risk values and

vehicle trajectory characteristics are well below the values recommended by

NCHRP 230 CV. Figure 16 presents photographs of the barrier and the automobile prior

to impact. Figure 17 presents photographs of the barrier and the automobile

after impact. The barrier section sustained 1/2 in. (1.27 cm) of permanent

lateral deflection. The support trucks, hitches, and support members were

not damaged. Most of the damage to the right front of the automobile

visible in Figure 17 occurred when remotely controlled safety brakes failed

to stop after impact. As a result, the automobile crashed into a concrete

medi an barri er downstream from the barri er. The primary damage to the

automobile as a result of contact with the portable barrier occurred when

the right front tire and rim struck the barrier section supp~rt caster as

the autombile slid along the harrier section. This occurred because the

caster pivoted outward as the steel barrier section underwent lateral

deformation. Similar damage occurred in all three tests. Failure of the

tire and rim did not destabilize the impacting vehicle. The damage ratios

presented in Figure 15 reflect the damage before the secondary impact.

TEST 10

In this test, a 1765 lb (801 kg) vehicle impacted the barrier with a

ve 1 ocity of 50.9 mph (81 .95 km/h) wit h an angl e of 14.0 deg. The same

barrier section used in the first test was reused in this test. The

previous 1/2 in. (1.27 cm) of permanent deformation was not removed. Figure

18 presents a summary of the results of this test. Again the vehicle was

smoothly redirected. The measured occupant risk values and the vehicle

trajectory characteristics were well below the values recommended by NCHRP

230 (l).

32

Figure 16. Barrier a d A p . n utomobi 1 rlor to Test 9 e

33

Figure 17. Barrier and Automobile After Test 9

34

w U1

................. ~- ..•.. -- .-... _-_ .. - -.. ~-.•....•....... ---

Test No •.... Date ..•... Installation

Drawi ng Nos. Length-ft (m)

Beam Rail Member. . . . . . . . • . Length of Segment-ft (m). Maximum Deflections

Dynalllic - in. (em). • Permanent - in. (em).

Vehicle ~1ode 1 • • . • Mass-lb (kg).

JB dd ____ • un ____ un~~

2262-10 8/24/83

2262-5(3-9, 11) 88 (26.8)

2 6x6x1/4 in. Stl. Tubes 44' (13.4)

13.0 (32.9) .5 (1.3)

1979 Honda Civic 1765 (801)

I[ In

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

Angle - deg Impact. . Exit. . • • . • • • " •

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

Occupant Ridedown Accelerations - 9'S Forward .. Latera 1 • •

Vehicle Damage TAO .• VDI .••.

Fi gure 13. Summary of Test 10

50.9 (81.9) 42.6 (68.6)

14.0 1.3

11.3 (3.5) N/A

1.58 N/A

2RFQ-2 02RFMW6

Figure 19 presents photographs of the barrier and the automobile prior

to impact. Figure 20 presents photographs of the barrier and the automobile

after impact. The barrier section experienced another 1/2 in. (1.27 cm) of

permanent deflection d~ring this test, resulting in a total of 1 in. (2.54

cm) permanent deformation. The support trucks, hitches, and support members

experienced no damage. The automobile experienced damage to the right front

fender and scratches down the right side, damage to the right front tire and

rim, and the ri ght front headl i ght.

TEST 11

In this test, a 4500 (2043 kg) vehicle impacted the barrier with a

velocity of 49.7 mph (80.02 km/h) and an angle of 15.0 deg. Again, the same

barrier sections used in the previous two tests were reused in this test.

The accumulated in. (2.54 cm) of lateral deflection was not removed.

Figure 21 presents a summary of the results of this test. The vehicle was

smoothly redirected. The measured occupant risk values and the vehicle

trajectory characteristics were well below recommended values.

Figure 22 presents photographs of the barrier and the automobile prior

to the impact. Figure 23 presents photographs of the barrier after the

impact. The barrier section experienced another 3 in. (7.62 cm) of perma­

nent deformation during this test. The support trucks, hitches, and support

members experi enced no damage. The automobil e experi enced damage to the

right front fender and bumper, scratches down the right side, and damage to

the right front tire and rim. Following the crash test, the spare tire was

mounted on the right front of the car and the automobile was able to operate

at low speeds under its own power.

MANEUVERABILITY TESTS

In addition to the three full-scale crash tests discussed above, maneu­

verability tests were conducted using the truck-mounted portable maintenance

36

Figure 19. Barrier and Automobile Prior to Test 10

37

Figure 20. Barrier and Automobile After Test 10

38

Test No. . . . . Date ..... . Installation

Drawl ng Nos. . Length ft (m)

Beam Rail 11eClbe r. . . . . . . . . . Length of Segment-ft (m). I',aximum Deflections

Dynamic - in. (em) .• Permanent in. (em).

Vehicle l~ode 1 . . . • • . I-lass - lb (kg). .

2262-11 8/26/83

2262-5(3-9, 11) 88 (26.8)

2 6x6x1/4 in. St1. Tubes 44 (13.4)

24 (61.0) 3 (7.62)

1978 Plymouth Salon 4500 (2045)

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

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

Occupant Impact Velocity - fps (m/s) Forward . • . . • . • Latera 1 • . . ••••.

Occupant Ridedown Accelerations - 9'5 forward •. Lateral . .

Vehicle Damage TAO VOl

Figure 21. Summary of Test 11

49.7 (80.0) 40.6 (65.4)

15.0 1.0

9.96 (3.0) N/A

1. 34 N/A

2RFQ-2 02RFMW9

,,'

Figure 22. Barrier and Automobile Prior to Test 11

40

Figure 23. Barrier and A.utomobile After Test 11

41

barrier using professional truck drivers employed by TTl. It was found that

the barrier section mounted on the transport dolly and hitched to the center

of the lead truck for highway transport had handling characteristics similar

to a tractor-trailer rig of similar length. There were no special problems

noted by the drivers in maneuvering the system set up in this fashion.

The fully deployed system (ref. Fig. 1) consisting of both trucks, the

barrier section, and two drivers had a surprising amount of maneuverability

with forward speeds up to 15 mph (24.15 km/h). When deployed in this

fashion the lead truck provides the power. The forward thrust is trans­

ferred through the barrier section to the rear truck whose transmission is

in neutral. The driver in the lead truck is responsible for controlling the

application of power and braking. The responsibility of the driver in the

rear truck is simply to guide the rear truck along the desired path.

Because the barrier is supported on pivotal casters, the barrier offers no

restraint to the maneuverability of the rear truck. The only constraint on

maneuverability is that the trucks are forced to remain a constant distance

apart. The drivers reported no special problems with the system.

In addition to the general maneuverability tests discussed above, the

following test was conducted to simulate an actual maintenance operation. A

30 ft (9.15 m) long section of pavement was marked off between the trucks to

simulate an area of pavement under repair as shown in Figure 24. The pur­

pose of the test was to demonstrate that upon completion of the maintenance

in the 30 ft (9.15 m) zone it is possible to move the portable maintenance

barrier forward without encroaching into the repair zone. The objective was

accomplished by moving the lead truck forward while the rear truck was

steered around the repair zone. The maneuverability of the portable mainte­

nance barrier around such objects is hindered only by the base-l ine maneu­

verabil ity of the rear truck.

42

44'

" " " n

~I ID -III

. ~BARRIER SECTION

Figure 24. Barrier Configuration for Maneuverability Test

CONCLUSIONS

Recent experiences with injuries and fatalities among SDHPT maintenance

personnel suggest that there is a need for increased personnel protection in

short-term work zones. One way to reduce the risks is to use portable main­

tenance barriers. The problem is that most portable maintenance barriers

that are available require too much setup time or too much work zone space.

A new truck-mounted portable maintenance barrier design that overcomes both

of these difficulties is presented in this report.

The truck-mounted portable maintenance barrier consists of a steel

barrier section which is supported between two support trucks. The

barrier section was designed to smoothly redirect a 4500 lb (2043 kg)

automobile impacting at a velocity of 50 mph (80.5 km/h) with an angle of 15

degrees. This design criteria reflects a consensus among SDHPT and TTI

engineers on a reasonable design criteria for the portable maintenance

barrier. Results of three crash tests conducted on the prototype

substantiated that the barrier section can successfully redirect the design

impact. It is clear that if an errant vehicle di rectly impacted either of

the support trucks the outcome would not be as favorable as the impact with

the barrier section. However, it is the contention of the writers that such

an impact would be no more severe than an impact with any other maintenance

vehicle. It is recommended that normal procedures involving the use of

towed crash cushions and proper delineation of the work zone hazard be used

with the truck-mounted portable maintenance barrier.

Of equal importance with the redirective characteristics of the por­

table maintenance barrier is the time required for on-site deployment and

the ease of handling. The barrier is towed to the work zone on a specially

fabricated transport dolly. Experience with the system shows that the

44

barrier can be deployed by an experienced team of two men in less than 15

minutes. Approximately the same amount of time is required to transfer the

system back to the transport dolly. In addition, tests show that the

deployed portable maintenance barrier can be easily maneuvered around

simulated obstacles that might be encountered in a work zone •

. The approximate cost of the barrier system excl usive of the cost of the

trucks, which can be mUltipurpose vehicles, is $8,000 for a 44 ft (13.42 m)

barrier section. This translates to an approximate cost of $182 per ft. A

substantial portion of the fabrication cost is involved in the construction

and installation of hitches, support members, and the truck frame-plate.

However, in the event of a design impact, only the barrier section will have

to be replaced or repaired. Therefore, the economics of the system seem to

be favorable.

It is therefore concluded that a workable, affordable portable mainte­

nance barrier for use in short-term work zones has been successfully devel­

oped. The portable maintenance barrier is capable of providing a reasonable

degree of protection for maintenance personnel, it can be conveniently

transported to the work zone, easily deployed, and once deployed it can be

easily maneuvered in the work zone.

A second version of the portable maintenance barrier has been construc­

ted and delivered to the Houston area SDHPT office which plans to put it

into service shortly. Hopefully the system can be easily integrated into

routine operations and help to reduce maintenance personnel injuries and

fat a 1 it i es.

45

APPENDIX A

BARRIER DEPLOYMENT

46

BARRIER DEPLOYMENT

There are two basic configurations for the portable maintenance barrier

presented in thi s report: the transport confi gu rati on and the deployed

confi guration. This appendix presents the steps necessary to transfer the

portable maintenance barrier from the transport configuration to the

deployed configuration, and vice versa.

In the transport configuration, the transport dolly is placed under one

end of the barrier section, and it is secured to the barrier section with a

post tension chain assembly. The other end of the barr; er secti on is

attached to the main rear hitch point on the lead truck as shown in Figure

10. The front 1 atera 1 support member is connected to an auxi 1 iary rear

hi tch poi nt. The front 1 ongi tudi na 1 support member is connnected to the

side hitch and lateral support beam. This entire assembly is supported by a

turnbuckle support. The support members on the rear truck are attached to

the front hitch and side hitch and supported by a turnbuckle support. The

trucks are driven to the work zone independently.

Once at the work zone, the following steps are necessary to transfer

the barrier from the transport configuration to the deployed configuration,

1. The lead truck is positioned ahead of the rear truck.

2. The front barrier section jack is engaged and the barrier section

is detached from the lead truck. The lead truck is moved forward a

few feet, and the lateral support member is transferred to the main

rear hi tch.

3. The front barrier section jack is then disengaged and the barrier

; s allowed to rest on the front caster wheeland the transport

dolly.

47

4. Next, the barrier section is manually pushed into line with the

hitch point provided by the longitudinal support member on the lead

truck. The lead truck is then backed into position, and the

connection pin is put into place. Vertical adjustments of the

longitudinal support member during this hitching operation are made

using the turnbuckle support.

5. With the connection to the lead truck completed, the tie-down

apparatus on the transport dolly is released, the barrier section

is lifted from the transport dolly with the rear barrier section

jack, and the dolly is removed.

6. The rear jack is then disengaged, allowing the rear caster wheel to

contact the pavement. The wei ght of the barri er secti on is now

completely supported by the caster wheels. Stability is afforded

by the front lateral support member.

7. The transport dolly is then moved to an auxiliary hitch point on

the lead truck.

8. Finally. the rear truck is pulled forward and the barrier section

is connected to the hitch point on the rear longitudinal support

member. During this operation the barrier section end can be

manually pivoted laterally, and/or the vertical height of the

1 ongitudi na 1 support member attached to the rear truck can be

adjusted using the turnbuckle support.

A reverse procedure is foll owed to transfer the barri er from the deployed

confi gurati on back to the transport confi gurati on.

The connections between the longitudinal members and the side hitches,

and between the barrier section ends and the longitudinal members, are made

using 1 9/16 in. (3.97 em) diameter steel pins. The connections between the

48

longitudinal and lateral support members are made with 1 1/8 in. (2.86 cm)

diameter steel bolts. This connection should be kept tightened. Finally.

the connect; ons between the 1 atera 1 support members and the rear and front

hitches are made with 1 1/8 in. (2.86 cm) diameter steel pins. It is not

necessary to use high strength bolts or pins.

49

APPENDIX B

SEQUENTIAL PHOTOGRAPHS

50

;

0.000 sec

0.161

0.241 sec

Figure 25. Sequential Photographs for Test 9

51

0.322

-0.402

0.483 sec

0.550 sec

Figure 25. Sequential Photographs for Test 9 (continued)

52

//' .. I

0.000 sec

0.0063 sec

0.189 sec

Figure 26. Sequential Photographs for Test 10

53

sec

0.315 sec

0.378 sec

0.433 sec

Figure 26. Sequential Photographs for Test 10 (continued)

54

/

0.000

0.181 sec

0.272 sec

Figure 27. Sequential Photographs for Test 11

55

,.

Figure 27.

/l1Z.{. .I

0.363

0.454

0.544 sec

0.633 sec

Sequential Photographs for Test 11 (continued)

56

APPENDIX C

ACCELEROMETER TRACES AND

PLOTS OF ROLL, PITCH. AND YAW

57

Class 180 Filter

20 ,-------------~------~--,_--,,----_,----~

'" ~ 10 ~ ~

S LU ....I LU U

:.! 0 ....I

"" Z ~

'" => I­~

'-" B -10 ...J

I

~1.25 !f

-20 ~ ____ ~ _______ ~ ___________ .~ __ ~ ____ ~ ____ ~

0.00 0.10 0.20 0.30 0.40 0.50 0.60

TIME (SECONDS 1

Figure 28. Vehicle Longitudinal Accelerometer Trace for Test 9

58

Class 180 Filter

5 . . . . . . . I

-10 ~ ........... ~~~ __ ~~ __ ~~~ ____ ~~ ____ ~~ ___ ~ 0.00 0.40 0.50 0.60

TIME (SECONOS)

Figure 29. Vehicle Lateral Accelerometer Trace for Tes·t 9

59

15

Class 180 Filter

I! '. i . . ~ ,-1 Hax. 0.050 sec Avg. = 0.41 9 .

II '. • • I /Y'~~. WvI!iJ.A .• .•

"' ... -'-"1......... '. m J\.!v),J "1 (""n JI-'L;.,. '1.,., I, °l~;' !d1~Prl¥-\ftf\;M-p.qf~\-II ,... , , ,"V 1 ,''i1\i"i' "V llr"

0.00

I· ' • . I' I'

0.10 0.20 0.30 0.40

TIME (SECONDS)

Figure 30. Vehicle Vertical Accelerometer Tra,ce for Test 9

0.50

Class 180 Filter

0.10 0.20 0.30 0.40

TIME (SECONDS)

Figure 31. Vehicle Resultant Accelerometer Trace for Test 9

60

0.50

0.60

0.60

I'X

.~~'~~ Axes are vehicle fixed. Sequence for determining orientation is:

1. Yaw

a a · a -

o a · ro

rna Wa W .~

a:(O I

CJ , W ' o

(Lru

en ...... 0

0 a · "'0

0 0

N I

00

.. ~o\..\.. 2. Pitch 3. Roll

Yaw

Pitch

~.4lJ_.~60 0.20 TIME [SECClNDS) Roll

Figure 32. Vehicle Angular Displacements for Test 9

61

~

'" :z a ~

~ '" w.J ..J w.J U u <C

..J <C :z ~

"" => I-~

'" :z a ..J

Class 180 Filter

10 ,-------~------~------~,---,-~--------------,

5

0

-5

-10

H tlax. 0.050 sec Avg. = -1. 4 9 I I· . II. I I

I 1

1

I I I I 1 1 1·······1· . I I 1 1

I 1 -15 L.--------------~------~~--~~------------.--~

0.00 0.10 0.20 0.30 0.40 0.50 0.60

TIME (SECONDS)

Figure 33. Vehicle Longitudinal Accelerometer Trace for Test 10

62

'" ~ z 0 -~ I.U -' I.U U U

"" ...J

"" ~ !;;: ...J

20

10

0

-10

-20 0.00

Class 180 Filter

I . . HMax. 0.050 sec Avg. = 4 9

I 1

.. 1 ....... 1

I 1

I 1

0.30 0.40

Figure 34. Vehicle Lateral Accelerometer Trace for Test 10

63

0.50 0.60

10 ,_------~------~------~----,_--~------~-------,

-5 0.00 . 0.10 0.20 0.30 0.40

TIME (SECONDS)

Figure 35. Vehicle Vertical Accelerometer Trace for Test 10

64

0.50 0.60

20

(;;- 15

o 0.00

Class 180 Fl1ter

' , , . • I'·, , .,

, : .. : : :

0,.10 0.20 0.30 0.40

TIME (SECONDS)

Figure 36. Vehicle Resultant Accelerometer Trace for Test 10

65

0.50 0.60

j'Z

~~ ... ~

t:)

W o

Cl

co Cl . In

Cl Cl

(\j

co co . (C) ,

,f'O\..\.

0.20 TIME

Axes are vehicle fixed. Sequence for determining orientation is:

1. Yaw 2. Pitch 3. Roll

Yaw

Fi~ure 37. Vehicle Angular Displacements for Test 10

66

Class T80 FiTter 10 r-----~------~------~_,--_c------~~~~~~~_,

Max. 0.050 sec Avg. = .56 9

.,.0 ..••.•

I

-10 L~~_~~~~~ __ ~~ __ ~ __ L-___ ~~~ ___ ~~~~ 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

TIME (SECONDS)

Figure 38. Vehicle Longitudinal Accelerometer Tract for Test 11

67

10

<!>

'" 5 0 -..... "" '" w ...J u.J U U

"" 0 ...J

"" '" u.J ..... cc ...J

-5 0.00 0.10

Class 180 Filte'r

0.20 0.30 0.40 0.50 0.60

TIME (SECIINOJ;)

Figure 39. Vehicle Lateral Accelerometer Trace for Test 11

68

0.7{)

10

~ 5 (.:;t ~

~ .... .,. :e Litl ...J .... 0 u u

"" § ~ '" - 5

-10

Class 180 Filter ,----~---~--~ ..... -~ ..... ~---,---~---

0.00

,Max. 0.050 ec Avg. ~ - .17 g

I •

0.10 0.20 0.30 0.40

TIME (SECONOS)

,

·...1 , I I

,

1/

I I

0.50

Figure 40. Vehicle Vertical Accelerometer Trace for Test 11

69

0.60

15

o 0.00

Class 180 Filter

0.10 0.20 0.30 0.40 0.50

TIME (SECONDS)

Figure 41. Vehicle Resultant Accelerometer Trace for Test 11

70

0.60 0.70

a a . 0 (\J

a a . tJ)

~~

(J)

w W 0::0 CJO W' O~

1-Z

W· U1

U IT -1 (L

ui:o ...... 0

Axes are vehicle fixed. Sequence for determining orientation is:

1. Yaw 2. Pitch 3. Roll

Yaw

~mh o· _ .... j

9J .00 0.80

0 a tJ)

I

Figure 42. Vehicle Angular Displacements for Test 11

71

REFERENCES

1. Ivey, D. L., H. E. Ross, T. J. Hirsch, C. E. Buth, and R. M. Olson, "Portable Concrete Median Barriers: Structural Design and Dynamic Performance," Transportation Research Record 769, 1980, pp. 20-30.

2. Mi chi e, Jarvi s D., "Recommended Procedures for the Safety Performance Eva 1 uati on of Hi ghway Appurtenances," NCHRP Report 230, March 1981.

3. Powell, G. H., "Barrier VII: A Computer Program for Evaluation of Automobile Barrier Systems," FHWA-RD-73-51, Federal Highway Administra­tion, Office of Research and Development, Washington, D.C., April 1973.

72