January, 2002
COMPLIANCE CRASH TESTING OF A STEEL VERSION
OF THE TYPE 732 BRIDGE RAIL
STATE OF CALIFORNIA
DEPARTMENT OF TRANSPORTATION
ENGINEERING SERVICE CENTER
MATERIALS ENGINEERING AND TESTING SERVICES
Supervised by ............................................................................................... Dan Speer, P. E.
Principal Investigator .................................................................................. Rich Peter, P. E.
Report Prepared by............................................ Michael White, P. E. and John Jewell, P. E.
Research Performed by.................................................... Roadside Safety Technology Unit
January, 2002
STATE OF CALIFORNIA
DEPARTMENT OF TRANSPORTATION
ENGINEERING SERVICE CENTER
MATERIALS ENGINEERING AND TESTING SERVICES
COMPLIANCE CRASH TESTING OF A STEEL VERSION
OF THE TYPE 732 BRIDGE RAIL
Supervised by ...................................................................................... Dan Speer, P. E.
Principal Investigator ......................................................................... Rich Peter, P. E.
Report Prepared by................................... Michael White, P. E. and John Jewell, P. E.
Research Performed by........................................... Roadside Safety Technology Unit
Dan Speer, Chief Rich Peter, P. E.
Structural Materials Branch Senior Materials and Research Engineer
Phil Stolarski, Chief
Division of Materials Engineering and Testing Services
TECHNICAL REPORT STANDARD TITLE PAGE
i
1. REPORT NO.
FHWA/ CA/ TL- 2001/ 41
2. GOVERNMENT ACCESSION NO. 3. RECIPIENT'S CATALOG NO.
4. TITLE AND SUBTITLE
COMPLIANCE CRASH TESTING OF A STEEL VERSION
OF THE TYPE 732 BRIDGE RAIL
5. REPORT DATE
January, 2002
6. PERFORMING ORGANIZATION CODE
7. AUTHOR( S)
Michael White, John Jewell, Rich Peter
8. PERFORMING ORGANIZATION REPORT NO.
59- 680317
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Materials Engineering and Testing Services
California Department of Transportation
5900 Folsom Blvd.,
Sacramento, CA. 95819
10. WORK UNIT NO.
11. CONTRACT OR GRANT NO.
F2000TL22
12. SPONSORING AGENCY NAME AND ADDRESS
California Department of Transportation
5900 Folsom Blvd.,
Sacramento CA. 95819
13. TYPE OF REPORT & PERIOD COVERED
FINAL
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
This project was performed in cooperation with the US Department of Transportation, Federal Highway Administration, under
the research project titled “ COMPLIANCE CRASH TESTING OF A STEEL VERSION OF THE TYPE 732 BRIDGE
RAIL.”
16. ABSTRACT
A steel version of the Type 732 concrete bridge rail ( Type 732S) was tested in accordance with NCHRP Report 350.
The rail is composed of segments that are each 2.5 m in length and 813 mm high, constructed from 15- mm thick steel plate.
It has a smooth face with a single slope of 9.1 degrees from vertical on the traffic side while the backside is vertical. The
barrier tested was 25 m long and was constructed off- site and later installed at the Caltrans Dynamic Test Facility in West
Sacramento, California. The steel version is approximately 595 kg lighter per linear meter than the concrete version. This
weight saving was critical to the design of the East span of the new San Francisco/ Oakland Bay Bridge.
Two crash tests were conducted under Report 350 test Level 4, one with a 2000- kg pickup truck and one with an
8000- kg single unit van truck. The results of the two tests were within the limits of the Report 350 guidelines.
The Type 732S bridge rail is recommended for approval on California highways requiring TL- 4 bridge rails.
17. KEY WORDS
Barriers, Crash Test, Bridge Rail, Steel, Vehicle Impact Test
18. DISTRIBUTION STATEMENT
No Restrictions. This document is available through the
National Technical Information Service, Springfield, VA 22161
19. SECURITY CLASSIF. ( OF THIS REPORT)
Unclassified
20. SECURITY CLASSIF. ( OF THIS PAGE)
Unclassified
21. NO. OF PAGES
41
22. PRICE
ii
NOTICE
The contents of this report reflect the views of Materials Engineering and Testing
Services, which is responsible for the facts and the accuracy of the data presented herein. The
contents do not necessarily reflect the official views or policies of the State of California or the
Federal Highway Administration. This report does not constitute a standard specification or
regulation.
Neither the State of California nor the United States Government endorses products or
manufacturers. Trade or manufacturers' names appear herein only because they are considered
essential to the object of this document.
English to Metric System ( SI) of Measurement
iii
SI CONVERSION FACTORS
To Convert From To Multiply By
ACCELERATION
m/ s2 ft/ s2 3.281
AREA
m2 ft2 10.764
ENERGY
Joule ( J) ft. lbf 0.7376
FORCE
Newton ( N) lbf 0.2248
LENGTH
m ft 3.281
m in 39.37
cm in 0.3937
mm in 0.03937
MASS
kg lbm 2.205
PRESSURE OR STRESS
kPa psi 0.1450
VELOCITY
km/ h mph 0.6214
m/ s ft/ s 3.281
km/ h ft/ s 0.9113
iv
ACKNOWLEDGMENTS
This work was accomplished in cooperation with the United States Department of
Transportation, Federal Highway Administration.
Special appreciation is due to the following staff members of the Materials Engineering
and Testing Services and the Office of Research for their help on this project:
Michael White, John Jewell, Mike O’Keeffe, Glen Weldon, Larry Moore, Jarvis Mahe,
Steve Hahn and Natane Clarke, test preparation, data reduction, vehicle preparation, and film
processing; Dave Bengel, Independent Camera Operator; Bob Cullen, Eric Jacobson, Ed Ung,
Danny Callaway and Walt Winter, electronic instrumentation; Gene Weyel and Bill Poroshin,
machine shop services.
Other persons from Caltrans who made important contributions include: Francisco
Carpio, Vong Toan, Engineering Services Center - Office of Structures, technical consultation;
Don Fogle, Traffic Operations, technical consultation; Don Tateishi, Herb Holman and Lynn
Harrison, Headquarters Photo Section; Sonny Fereira and Bill Brook, Structures Construction.
T. Y. LIN International under the direction of Tom Ho designed the bridge rail. Christie
Constructors Inc. of Richmond California fabricated the test article under the supervision of Alan
Straub, Vice President.
v
TABLE OF CONTENTS
TECHNICAL REPORT STANDARD TITLE PAGE................................................................................ i
DISCLAIMER ............................................................................................................................... .............. ii
METRIC CONVERSION TABLE............................................................................................................. iii
ACKNOWLEDGMENTS ........................................................................................................................... iv
LIST OF FIGURES........................................................................................................................ ........... vii
LIST OF TABLES......................................................................................................................... ........... viii
1. INTRODUCTION ............................................................................................................................... . 1
1.1. Problem........................................................................................................................ ..................... 1
1.2. Objective ............................................................................................................................... ............ 1
1.3. Background And Significance Of Work ............................................................................................. 1
1.4. Literature Search ............................................................................................................................... 2
1.5. Scope ............................................................................................................................... .................. 3
2. TECHNICAL DISCUSSION................................................................................................................ 3
2.1. Test Conditions - Crash Tests ............................................................................................................ 3
2.1.1. Test Facilities..................................................................................................................... ........ 3
2.1.2. Test Barrier Design and Construction......................................................................................... 3
2.1.3. Test Vehicles .............................................................................................................................. 7
2.1.4. Data Acquisition System............................................................................................................. 7
2.2. Test Results - Crash Tests .................................................................................................................. 8
2.2.1. Impact Description - Test 571 .................................................................................................... 8
2.2.2. Vehicle Damage - Test 571....................................................................................................... 13
2.2.3. Barrier Damage - Test 571........................................................................................................ 13
2.2.4. Impact Description - Test 572 .................................................................................................. 14
2.2.5. Vehicle Damage - Test 572....................................................................................................... 20
2.2.6. Barrier Damage - Test 572........................................................................................................ 20
2.3. Discussion of Test Results - Crash Tests.......................................................................................... 21
2.3.1. General - Evaluation Methods ( Tests 571 and 572).................................................................. 21
2.3.2. Structural Adequacy.................................................................................................................. 21
2.3.3. Occupant Risk........................................................................................................................... 21
2.3.4. Vehicle Trajectory .................................................................................................................... 21
vi
TABLE OF CONTENTS ( cont.)
3. CONCLUSION..................................................................................................................... .............. 24
4. RECOMMENDATION................................................................................................................. ..... 25
5. IMPLEMENTATION................................................................................................................. ....... 25
6. REFERENCES ............................................................................................................................... .... 26
7. APPENDICES..................................................................................................................... ................ 27
7.1. Test Vehicle Equipment.................................................................................................................... 27
7.2. Test Vehicle Guidance System.......................................................................................................... 30
7.3. Photo - Instrumentation ................................................................................................................... 30
7.4. Electronic Instrumentation and Data............................................................................................... 33
7.5. Detailed Drawings ........................................................................................................................... 39
vii
LIST OF FIGURES
Figure 2- 1 Type 732S barrier installation. ................................................................................................................... 4
Figure 2- 2. Second deck assembly of the Type 732S being installed. ......................................................................... 5
Figure 2- 3. Holes being drilled for installation of the vertical threaded rods............................................................... 5
Figure 2- 4. Type 732S barrier installed and ready for asphalt overlay. ....................................................................... 6
Figure 2- 5. Type 732S test article after installation of the asphalt concrete overlay.................................................... 6
Figure 2- 6 Test vehicle for Test 571 ............................................................................................................................. 9
Figure 2- 7 Test article prior to Test 571 ....................................................................................................................... 9
Figure 2- 8 Test vehicle after Test 571 ........................................................................................................................ 10
Figure 2- 9 Right front corner of test vehicle after Test 571 ........................................................................................ 10
Figure 2- 10 Type 732S barrier face after Test 571 ..................................................................................................... 11
Figure 2- 11 Type 732S barrier backside after Test 571.............................................................................................. 11
Figure 2- 12 Impact sequence and diagram for Test 571 ............................................................................................. 12
Figure 2- 13 Test vehicle for Test 572 ......................................................................................................................... 15
Figure 2- 14 Test vehicle for Test 572 ......................................................................................................................... 15
Figure 2- 15 Test article prior to Test 571 ................................................................................................................... 16
Figure 2- 16 Right side of test vehicle after Test 571 .................................................................................................. 16
Figure 2- 17 Left side of test vehicle after Test 571..................................................................................................... 17
Figure 2- 18 Type 732S barrier face after Test 572 ..................................................................................................... 17
Figure 2- 19 Barrier face gouges from vehicle lug nuts after Test 572 ........................................................................ 18
Figure 2- 20 Ballast strapped down in cargo bed of test vehicle after Test 572........................................................... 18
Figure 2- 21 Impact sequence and diagram for Test 572 ............................................................................................. 19
Figure 7- 1 - Camera Locations...................................................................................................................... ............. 31
Figure 7- 2 - Tape Switch Layout......................................................................................................................... ....... 32
Figure 7- 3 - Vehicle Accelerometer Sign Convention ................................................................................................ 34
Figure 7- 4 - Test 571 Vehicle Accelerations Vs Time................................................................................................ 35
Figure 7- 5 - Test 571 Vehicle Longitudinal Acceleration, Velocity, and Distance Vs Time ...................................... 36
Figure 7- 6 - Test 571 Vehicle Lateral Acceleration, Velocity, and Distance Vs Time ............................................... 37
Figure 7- 7 - Test 571 Vehicle Roll, Pitch, and Yaw Vs Time..................................................................................... 38
Figure 7- 8 – As built drawing for the Type 732S........................................................................................................ 41
Figure 7- 9 – As built cross section and attachment detail for the Type 732S ............................................................. 42
viii
LIST OF TABLES
Table 1- 1 - Comparison of Different Test Levels ......................................................................................................... 2
Table 1- 2 – Intended Test Conditions..................................................................................................................... ..... 3
Table 2- 1 - Test Vehicle Masses......................................................................................................................... ......... 7
Table 2- 2 - Test 571 Assessment Summary ................................................................................................................ 22
Table 2- 3 - Test 572 Assessment Summary ................................................................................................................ 23
Table 2- 4 - Vehicle Trajectories and Speeds .............................................................................................................. 23
Table 7- 1 - Test 571 Vehicle Dimensions................................................................................................................... 28
Table 7- 2 - Test 572 Vehicle Dimensions................................................................................................................... 29
Table 7- 3 - Typical Camera Type and Locations........................................................................................................ 30
Table 7- 4 - Accelerometer Specifications ................................................................................................................... 34
1
1. INTRODUCTION
1.1. Problem
The current design for the suspension section of the San Francisco- Oakland Bay Bridge
( SFOBB) is nearly complete. The designers have determined that using a steel version of the
concrete Type 732 bridge rail instead of a Type 25 barrier will reduce the overall cost of this span
by approximately $ 10.8 million by allowing the use of a lighter deck and cables. The Caltrans
Division of Structures has requested a study of the viability of a steel version of the Type 732 for
this reason. A steel version of the Type 732 bridge rail has not been tested for compliance with
Test Level 4 of the National Cooperative Highway Research Program ( NCHRP) Report 350( 1).
1.2. Objective
To crash test a Type 732 bridge rail fabricated from steel plate rather than concrete
( hereinafter referred to as the Type 732S) in accordance with NCHRP Report 350 Test Level 4
criteria for longitudinal barriers. These tests will involve impacts with a 2000- kg pickup truck at
100 km/ h and an impact angle of 25° as well as with an 8000- kg single unit van at 80 km/ h and
an impact angle of 15°.
1.3. Background And Significance Of Work
A Type 25 concrete barrier was chosen for the eastern portion of the SFOBB during the
initial design phase and all the way through the 45% submittal stage. Later in the design process
it became apparent that there was eccentric loading on the tower which had to be alleviated by
adding some counterweight to the westbound deck. This additional load on the cables and
hangers was undesirable and had to be decreased. A logical choice was to change the concrete
Type 25 barrier to some type of steel barrier, which would save approximately 595 kg per linear
meter.
According to calculations done by the designer, the steel version of the Type 732 is
expected to cost approximately $ 1000 more per meter of length when compared to a concrete
Type 732 barrier. The maintenance costs for the steel version are also expected to be higher than
that of a standard concrete version. The savings to Caltrans come from the lower weight per unit
length of the steel version over the concrete version. The lower overall weight will reduce the
size, and therefore the costs, of the supporting sub- structure and super- structure of the bridge.
This saving is projected to be approximately $ 10.8 million.
The State of California tested the Type 70 barrier ( which was later designated the Type
732) in 1997. The Type 70 is a steel reinforced concrete barrier 810 mm high with a single- slope
face that is 9.1° from vertical with the top sloping away from traffic. The Type 70 rail was
originally designed using the American Association of State Highway and Transportation
2
Officials ( AASHTO) “ Guide Specifications for Bridge Railing”( 2) requirements. The AASHTO
Guide Specifications stipulate that bridge rails to be used for high- speed applications must
conform to PL- 2- level testing. According to the FHWA, the PL- 2 test level has since been
replaced by the similar NCHRP Report 350 test level 4. Therefore, the Type 70 rail was tested
according to test level 4 criteria ( TL- 4). Table 1.1 summarizes the testing requirements for
AASHTO levels PL- 1, PL- 2, and NCHRP Report 350 level TL- 4. The TL- 4 impact severity is
higher than that of PL- 2 due to the increased speed and angle, even though the mass is reduced.
The report for the Type 70 concluded that it would successfully contain and redirect the 820C,
the 2000P, and the 8000S vehicles under TL- 4 conditions( 3).
The final design of a steel version of the Type 732 ( the Type 732S) will become a non-proprietary
design, which may be used on other bridge structures where weight savings are
critical or economically sensible. The design may also be useful to other transportation entities.
Table 1- 1 - Comparison of Different Test Levels
Levels Small Automobile Pick- up Truck Single- Unit Truck
PL- 1
( AASHTO)
816 kg ( 1800 lbm)
80 km/ h ( 50 mph) at 20°
2449 kg ( 5400 lbm)
72 km/ h ( 45 mph) at 20°
PL- 2
( AASHTO)
816 kg ( 1800 lbm)
97 km/ h ( 60 mph) at 20°
2449 kg ( 5400 lbm)
97 km/ h ( 60 mph) at 20°
8165 kg ( 18,000 lbm)
80 km/ h ( 50 mph) at 15°
Test Level 4
( NCHRP 350)
820 kg
100 km/ h at 20°
2000 kg
100 km/ h at 25°
8000 kg
80 km/ h at 15°
1.4. Literature Search
A literature search using the TRIS, NTIS, and the Compendex Plus databases was
conducted at the beginning of the project to find research reports or publications related to the
objectives of this project. There were no reports that involved crash testing of steel versions of
either the Type 732 or the Type 70.
3
1.5. Scope
A representative section of Type 732S bridge rail was fabricated by Christie Constructors
Inc. and installed at the Caltrans Dynamic Test Facility in West Sacramento. Data were collected
from two vehicular crash tests under the conditions shown in Table 1- 2. These data were
analyzed to determine if the Type 732S met the criteria set forth in NCHRP Report 350.
Table 1- 2 – Intended Test Conditions
CALTRANS NCHRP Report 350
Test #
Barrier type Mass
( kg)
Speed
( km/ h)
Angle
( deg) Test Designation Vehicle
571 Type 732S 2000 100 25 4- 11 2000P
572 Type 732S 8000 80 15 4- 12 8000S
2. TECHNICAL DISCUSSION
2.1. Test Conditions - Crash Tests
2.1.1. Test Facilities
Each of the crash tests was conducted at the Caltrans Dynamic Test Facility in West
Sacramento, California. The test area is a large, flat, asphalt concrete surface. There were no
obstructions nearby except for a 2 m- high earth berm 40 m downstream from the bridge rail. The
test article was mounted to an existing concrete anchor block, which was approximately 0.9 m
deep by 1.1 m wide by 24.3 m long.
2.1.2. Test Barrier Design and Construction
The Type 732S barrier has the same traffic- side profile as the concrete Type 732 barrier.
Both are 810 mm high as measured from the finished grade to the top of the barrier and both
have a single- slope face, which is 9.1 degrees from vertical. The 732S was designed by T. Y. Lin
International as part of their contract with the State of California for the design of the new San
Francisco / Oakland Bay Bridge ( SFOBB). See Appendix A for design drawings.
The Type 732S was fabricated from 15- mm thick steel plate formed into the appropriate
shape for the barrier face. This face and the supporting gussets on the backside were welded
together to form an individual segment 2.5 m long. Ten of these segments were then bolted to
two separate deck assemblies that had a surface plate of 25- mm thick steel, ( Figure 2- 1 and
Figure 2- 2). A gap of approximately 20 mm was left between segments to allow for expansion of
4
the steel and for ease of removal in the event of damage. The barrier was fabricated by Christie
Constructors Inc. at their Richmond, CA facility and then sent to ABC Paint in Vallejo, CA for
the application of the primer and color coat. It was then transported as two 12.5- m long pieces to
the Caltrans Dynamic Test Facility. The 12.5- m long deck assemblies, with attached 2.5- m long
rail segments, were lifted from the flatbed semi trucks using a high capacity crane. They were
positioned and slid over 25.4- mm diameter threaded rods, which had previously been
horizontally bonded with epoxy resin into the back face of the existing concrete anchor block.
Figure 2- 1 Type 732S barrier installation.
After each section was placed over the threaded rods, alignment was checked and nuts
were tightened to draw the entire assembly tight against the concrete anchor block. The two deck
assemblies were then welded together at their common seam along both the top and bottom side
of this joint. After placing the steel deck assemblies into position, two rows of holes were cored
vertically through existing deck holes into the concrete anchor block with a 241- mm center- to-center
spacing ( Figure 2- 3). These rows were placed at 650 mm and 910 mm out from the traffic
side of the barrier to attach the steel simulated bridge deck to the concrete anchor block.
Threaded rods 25.4 mm in diameter were then bonded with epoxy resin into these holes. After a
curing time of 24 hours, nuts were tightened onto these rods and the protruding threaded rod
sections were cut off flush with the tops of the nuts ( Figure 2- 4). This area was later covered
with a 50- mm thick asphalt- concrete overlay, which completely covered these nuts and vertical
rod ends ( Figure 2- 5). This A/ C overlay tapered down to less than 10 mm at approximately 6 m
from the barrier to provide a smooth transition for the vehicle approach and run- out.
5
Figure 2- 2. Second deck assembly of the Type 732S being installed.
Figure 2- 3. Holes being drilled for installation of the vertical threaded rods.
6
Figure 2- 4. Type 732S barrier installed and ready for asphalt overlay.
Figure 2- 5. Type 732S test article
after installation of the asphalt
concrete overlay.
7
2.1.3. Test Vehicles
The test vehicles complied with NCHRP Report 350( 1). For all tests, the vehicles were in
good condition, free of major body damage and were not missing any structural parts. All of the
vehicles had standard equipment and front- mounted engines. The vehicle inertial mass of the
8000S was within acceptable limits while the 2000P vehicle for Test 571 was slightly overweight
due to its 454 cubic inch big- block engine ( Table 2- 1).
Table 2- 1 - Test Vehicle Masses
Test No. Vehicle Ballast
( kg)
Test Inertial
( kg)
571 1992 Chevrolet 2500 0 2196
572 1992 GMC Top Kick 3049 8111
The Chevrolet 2500 pickup truck and the GMC TopKick single- unit van were self-powered
and used a speed control device to limit acceleration once the impact speed had been
reached. Remote braking was possible at any time during Test 571 via an electric cable tether,
and during Test 572 via a radio- link remote controlled braking setup. A short distance before the
point of impact each vehicle was released from the guidance rail and the ignition system was
deactivated. A detailed description of the test vehicle equipment and guidance system is
contained in Appendices 7.1 and 7.2.
2.1.4. Data Acquisition System
The impact event of each crash test was recorded with 7 high- speed 16- mm movie
cameras, one normal- speed 16- mm movie camera, one Beta format video camera, one 35- mm
still camera with an auto- winder and one 35- mm sequence camera. The test vehicles and the
barrier were photographed before and after impact with a normal- speed 16- mm movie camera, a
Beta format video camera and a color 35- mm camera. A film report of this project was
assembled using edited portions of the film coverage.
Three sets of orthogonal accelerometers were mounted in the 2000P vehicle, two at the
center of gravity and one 600 mm behind the center of gravity. Rate gyro transducers were also
placed at the center of gravity of the 2000P vehicle to measure the roll, pitch, and yaw. The data
were used in calculating the occupant impact velocities, ridedown accelerations, and maximum
vehicle rotation.
Anthropomorphic dummies were not used in any of the tests.
8
A digital transient data recorder ( TDR) manufactured by Pacific Instruments ( model
5600) was used to record electronic data during Test 571. Since accelerometers and rate gyros
are not used on the 8000S vehicle, such data were not acquired during Test 572. The digital data
were analyzed with custom DADiSP workbooks using a Fieldworks Model FW 7666P portable
computer.
2.2. Test Results - Crash Tests
A film report with edited footage from tests 571 and 572 has been compiled and is
available for viewing.
2.2.1. Impact Description - Test 571
The impact angle was set at 25° by placement of the guide rail and the vehicle did not
deviate from this angle prior to impact. The impact speed of 98.2 km/ h was obtained by an
average of two different speed traps located just upstream from the impact point. The test
vehicle impacted the barrier 779 mm upstream of the joint between segments 4 and 5 as
intended. The top right corner of the vehicle hood rode over the top of the 810- mm high barrier
to a maximum extension of approximately 450 mm as measured from the traffic side of the
barrier face. The front tires lost contact with the pavement at approximately 0.125 seconds. The
right front of the vehicle continued to deform moderately as the vehicle began to yaw slightly left
( negative) until the back right side of the vehicle contacted the barrier 0.18 seconds after the
initial impact. This secondary impact by the rear of the vehicle caused slight damage to the rear
quarter section of the truck and also caused both rear tires to lose contact with the pavement. The
vehicle- mounted brake flash erroneously triggered for unknown reasons 0.24 seconds after initial
impact. At 0.30 seconds after initial impact the vehicle lost contact with the barrier at which
time the speed was determined through film analysis to be 81.5 km/ h and the exit angle was 5.8°.
The secondary impact by the rear quarter of the vehicle slowed the negative yaw of the vehicle
and initiated a moderate degree of negative pitch ( nose down). The vehicle obtained a maximum
height of 900 mm as measured from the ground to the undercarriage approximately 0.4 seconds
after the initial impact. The vehicle came back into contact with the pavement in a nose- down
orientation and reached a maximum pitch angle of - 10° and a maximum roll angle of 41° before
it righted itself and continued into the run- out area. The brakes were applied 1.8 seconds after
the initial impact as indicated by the vehicle brake lights, which were visible from the upstream
high- speed camera. The vehicle came to rest against an earthen berm approximately 23 m
downstream from the end of the barrier. Figure 2- 6 through Figure 2- 11 show the pre- test and
post- test condition of the test vehicle and test article. Sequence photographs of the impact for
Test 571 are shown as Figure 2- 12 on the data summary sheet on page 12.
9
Figure 2- 6 Test vehicle for Test 571
Figure 2- 7 Test article prior to Test 571
10
Figure 2- 8 Test vehicle after Test 571
Figure 2- 9 Right front corner of test vehicle after Test 571
11
Figure 2- 10 Type 732S barrier face after Test 571
Figure 2- 11 Type 732S barrier backside after Test 571
12
Data Summary Sheet
t= 0.0 sec t= 0.20 sec t= 0.40 sec t= 0.60 sec
t= 0.80 sec t= 1.00 sec t= 1.20 sec t= 1.40 sec
Figure 2- 12 Impact sequence and diagram for Test 571
Test Barrier
Type: 810- mm high, Type 732S bridge rail, bolted to 25- mm steel plate
Length: 25- m total length consisting of 10 segments of 2.5 m each.
Test Date: August 30, 2000
Test Vehicle:
Model: 1992 GMC 2500
Inertial Mass: 2196 kg
Impact / Exit Velocity: 98.2 km/ h / 81.5 km/ h
Impact / Exit Angle: 25.0° / < 6°
Test Data:
Occ. Impact Velocity ( Long / Lat): 4.64 m/ s / 6.83 m/ s
Ridedown Acceleration ( Long / Lat): - 5.66 g / - 10.18 g
ASI 10.03
Exterior: VDS( 4)/ CDC( 5) FR- 5, RFQ- 5, RD- 2/ 01RFEW3
Interior: OCDI( 1) RF0010001
Barrier Damage: Only superficial marring and less than 4 mm of permanent lateral deflection.
25.0 m
10 9 8 7 6 5 4 3 2 1
25°
20 mm
BARRIER
CONTACT
ON GROUND IN THE AIR
13
2.2.2. Vehicle Damage - Test 571
The right front corner of the vehicle was moderately damaged in the initial impact with
the barrier. The right front fender, hood, bumper, headlamp area, grille, and suspension
components were all affected. The passenger side doorframe was deformed outward but the door
remained latched. The right front tire was also ruptured. Some minor damage along the right
side of the vehicle and to the right rear quarter occurred as the vehicle continued to contact the
barrier after the initial impact. The vehicle become briefly airborne, with the left rear corner
reaching a maximum height of 900 mm. As the vehicle came back into contact with the ground
it was in a nose- down pitch and right roll attitude which placed a majority of the landing force on
the already damaged right front suspension components. This additional force caused the right
front tire to push rearward and slightly into the passenger side footwell area. The maximum
amount of passenger compartment deformation, 127 mm, occurred in the floorboard. This was
within the accepted limit of 150 mm. 1
The longitudinal occupant impact velocity and longitudinal occupant ridedown
acceleration were well below the allowed maximums of 12 m/ s and 20 g, respectively. The
longitudinal occupant impact velocity was 4.64 m/ s and the longitudinal occupant ridedown
acceleration was - 5.66 g. Test results are summarized in Table 2.2 on page 22.
The vehicle used in Test 571 had a test inertial mass that was 151 kg above the upper
limit given in NCHRP Report 350 for the 2000P test vehicle. This was due to the 7.4 liter ( 454
cid) engine in this particular vehicle. Because of the larger mass of this vehicle the impact
speed was adjusted slightly downward to provide an impact severity comparable to a vehicle
that was within the test inertial mass limits. The nominal impact severity value for Test
Designation 4- 11 as given in NCHRP Report 350 is 138.1 kJ with a suggested tolerance of - 10.8
to + 11.6. With a mass of 2196 kg and an impact speed of 98.2 km/ h, the impact severity for this
test was 145.9 kJ, which is below the upper limit of 149.7 kJ.
2.2.3. Barrier Damage - Test 571
There was essentially no permanent damage to the barrier during Test 571. The vehicle
did scrape the paint off the barrier along the length of contact and the vehicle lug nuts created
some minor gouges, which were no more than 5 mm deep. These gouges could be ground and
filled on- site by maintenance crews without removing any barrier segments.
Three measurements were taken at each barrier segment joint before the test to determine
the spatial relationship from one segment to the next. These measurements were later compared
to ones taken after test 571 and it was determined there was no more than 4 mm of permanent
deflection between any two segments at any of the joints.
1 NCHRP Report 350 does not specify a maximum allowable limit for occupant compartment deformation.
However, the Federal Highway Administration has established an informal limit of 150 mm that is generally
accepted by the roadside safety community.
14
The 732S barrier was bolted to 25- mm thick steel plate for this test to simulate the actual
bridge deck that may ultimately be used on the SFOBB. This was done so designers at T. Y. Lin
International could use this test to determine if vehicular impacts on the bridge rail could cause
permanent damage to the bridge deck. To help prevent this possibility from occurring, the
designers used connecting bolts which would essentially act as " fuses" in the event of a severe
impact. None of these bolts were severed or sheared during this test.
2.2.4. Impact Description - Test 572
The impact angle was set at 15° by placement of the guide rail and the vehicle did not
deviate from this angle prior to impact. The impact speed of 82.6 km/ h was obtained by an
average of two different speed traps located just upstream from the impact point. The test
vehicle impacted the barrier 250 mm upstream of the scupper of segment 4 as intended. The
front right corner of the vehicle hood rode over the top of the 810- mm high barrier to a maximum
extension of approximately 320 mm as measured from the traffic side of the barrier face. The
left front tire lost contact with the pavement at approximately 0.10 seconds after impact. The
right front of the vehicle continued to deform as the vehicle began to yaw slightly left ( negative)
until the vehicle became parallel with the barrier 0.30 seconds after the initial impact. At this
point the vehicle had a right ( positive) roll of about 13°. The roll angle reached a maximum of
47.2° approximately 1.15 seconds after initial impact. The vehicle remained in contact with the
barrier until 1.2 seconds after impact at which point the end of the vehicle passed the end of the
barrier. When this occurred the exit angle of the vehicle was less than 2° and the roll angle was
still about 47°. The impact of the right front tire with the barrier caused failure of several
suspension components, including the right- side U- bolts which secure the axle to the leaf
springs. This allowed the front axle to begin to rotate about its connection point on the left side
of the vehicle. The axle continued to rotate as the right front tire passed completely under the
vehicle chassis. The lack of a right front tire and wheel assembly in its normal location helped
contribute to the high roll angle of 47.2°. As the vehicle came to rest against an earthen berm the
front axle had rotated a full 90° and in its final position was still attached to the left shock
absorber and parallel to the longitudinal axis of the vehicle. The vehicle never fully lost contact
with the ground and was able to right itself from its high roll angle as it continued into the run-out
area. The vehicle- mounted brake flash never fired although the brakes were applied
approximately 1.2 seconds after initial impact, at which time the vehicle was approximately 10 m
past the end of the barrier. The brake application was implied from the rotation of the left front
wheel being halted while that wheel was free from contact with any other surface. The berm at
which the vehicle stopped was approximately 23 m downstream from the end of the barrier.
Figure 2- 13 through Figure 2- 19 show the pre- test and post- test condition of the test vehicle and
test article.
The 3049 kg of ballast was comprised of two separate pallets of sandbags and the
associated mounting hardware all bolted and strapped down to the cargo floor. The pallets were
constrained by 150- mm angle iron and the sandbags were held down by 100- mm nylon straps as
shown in Figure 2- 20. The sandbags shifted slightly, but it is unlikely that this affected the test.
None of the sandbags broke lose during the test.
Sequence photographs of the impact for Test 572 are shown as Figure 2- 21 on the data
summary sheet on page 19.
15
Figure 2- 13 Test vehicle for Test 572
Figure 2- 14 Test vehicle for Test 572
16
Figure 2- 15 Test article prior to Test 571
Figure 2- 16 Right side of test vehicle after Test 571
17
Figure 2- 17 Left side of test vehicle after Test 571
Figure 2- 18 Type 732S barrier face after Test 572
18
Figure 2- 19 Barrier face gouges from vehicle lug nuts after Test 572
Figure 2- 20 Ballast strapped
down in cargo bed of test
vehicle after Test 572
19
15°
BARRIER
CONTACT
10 9 8 7 6 5 4 3
20 mm1
2
25.0 m
Data Summary Sheet
t= 0.00 sec t= 0.30 sec t= 0.60 sec t= 0.90 sec
t= 1.20 sec t= 1.50 sec t= 1.80 sec t= 2.10 sec
Figure 2- 21 Impact sequence and diagram for Test 572
Test Barrier
Type: 810- mm high, Type 732S bridge rail, bolted to steel plate
Length: 25- m total length consisting of 10 segments of 2.5 m each.
Test Date: September 13, 2000
Test Vehicle:
Model: 1992 GMC Top Kick
Inertial Mass: 8111 kg
Impact / Exit Velocity: 82.6 km/ h / 76 km/ h
Impact / Exit Angle: 15.0° / < 2°
Test Dummy:
Type: None used
Test Data:
Occ. Impact Velocity ( Long / Lat): not measured
Ridedown Acceleration ( Long / Lat): not measured
Max. 50 ms Avg. Accel ( Long / Lat): not measured
THIV/ ASI not measured
Exterior: VDS( 4)/ CDC( 5) NA / NA
Interior: OCDI( 1) RF0000000
Barrier Damage:
Only superficial marring and less than 4 mm of permanent lateral deflection.
20
2.2.5. Vehicle Damage - Test 572
The right front corner of the vehicle and the fiberglass engine cowling were moderately
damaged in the initial impact with the barrier. The right front bumper and right fender were
pushed rearward. The right front tire and wheel assembly was broken loose from its attachment
to the leaf springs, which allowed it to move rearward. The tire contacted the right- mounted
diesel fuel tank, which damaged it and resulted in a minor leak. The tire also damaged the
battery compartment and ruptured the battery, which was located directly under the passenger-side
door. The passenger- side door remained latched even though film analysis showed a 25- 50
mm gap opening and closing along the top of the door due to flexure of the cab and door. There
was no passenger compartment or floorboard deformation.
2.2.6. Barrier Damage - Test 572
As in Test 571, there was essentially no permanent damage to the barrier during Test 572.
The vehicle did scrape the paint off the barrier along the length of contact and the vehicle lug
nuts created some minor gouges, which were no more than 7 mm deep. These gouges could be
ground and filled on- site by maintenance crews without removing any barrier segments.
Three measurements were taken at each barrier segment joint before the test to determine
the spatial relationship from one segment to the next. These measurements were later compared
to ones taken after Test 572 and it was determined that there was no more than 4 mm of
permanent deflection between any two segments at any of the joints.
The 732S barrier was bolted to 25- mm thick steel plate for this test to simulate the actual
bridge deck that may ultimately be used on the SFOBB. This was done so designers at T. Y. Lin
International could use this test to determine if vehicular impacts on the bridge rail could cause
permanent damage to the bridge deck. To help prevent such damage, the designers used
connecting bolts which would essentially act as " fuses" in the event of a severe impact. None of
these bolts were severed or sheared during this test. Barrier segment number 4 did shift enough
transversely to make removal of these bolts ( for inspection) somewhat difficult.
21
2.3. Discussion of Test Results - Crash Tests
2.3.1. General - Evaluation Methods ( Tests 571 and 572)
NCHRP Report 350( 1) stipulates that crash test performance be assessed according to
three evaluation factors: 1) Structural Adequacy, 2) Occupant Risk, and 3) Vehicle Trajectory.
These evaluation factors are further defined by evaluation criteria and are shown for each test
designation in Table 3.1 of NCHRP Report 350. Test 571 of this report has a NCHRP Report
350 test designation of 4- 11 and for Test 572 it is 4- 12. The evaluation criteria are detailed in
Chapter 5 of NCHRP Report 350 and are summarized in Table 5.1 of that same report.
2.3.2. Structural Adequacy
The structural adequacy of the Type 732S bridge rail is acceptable. There was negligible
movement of the rail during any of the tests. During the time of contact between the test vehicles
and the barriers there were minor amounts of scraping and gouging. A detailed assessment
summary of structural adequacy is shown in Table 2- 2 and Table 2- 3
2.3.3. Occupant Risk
The occupant risk for the Type 732S is also acceptable. In neither one of the tests did any
material from the barrier exhibit any tendency to penetrate the occupant compartment of the
vehicles. All of the calculated occupant ridedown accelerations and occupant impact velocities
were within the “ preferred” range. Please refer to Table 2- 2 and Table 2- 3 for a detailed
assessment summary of occupant risk.
2.3.4. Vehicle Trajectory
The post- impact vehicle trajectory is also acceptable for the Type 732S. The detailed
assessment summary of vehicle trajectories may be seen in Table 2- 2 and Table 2- 3. Vehicle
trajectories and speeds are summarized in Table 2- 4.
22
Table 2- 2 - Test 571 Assessment Summary
Test No. 571
Date August 30, 2000
Test agency California Dept. of Transportation
Evaluation Criteria Test Results Assessment
Structural Adequacy
A. Test article should contain and redirect the
vehicle; the vehicle should not penetrate,
underride, or override the installation although
controlled lateral deflection of the article is
acceptable.
The vehicle was contained and smoothly
redirected
pass
Occupant Risk
D. Detached elements, fragments or other debris
from the test article should not penetrate or show
potential for penetrating the occupant
compartment, or present an undue hazard to
other traffic, pedestrians, or personnel in a work
zone. Deformation of, or intrusions into, the
occupant compartment that could cause serious
injuries should not be permitted.
Only moderate amounts of scraping and
gouging were created during impact.
There was no significant debris from the
vehicle.
The amount of floorboard deformation
was acceptable.
There was moderate occupant
compartment deformation.
pass
pass
pass
F. The vehicle should remain upright during and
after collision although moderate roll, pitching,
and yawing are acceptable.
The observed levels of roll, pitch, and
yaw were deemed acceptable. pass
Vehicle Trajectory
K. After collision it is preferable that the vehicle’s
trajectory not intrude into adjacent traffic lanes.
The vehicle maintained a relatively
straight course after exiting the barrier.
pass
L. The occupant impact velocity in the longitudinal
direction should not exceed 12 m/ sec and the
occupant ridedown acceleration in the
longitudinal direction should not exceed 20 g.
Long. Occ. Impact Vel. = 4.64 m/ s
Long. Occ. Ridedown = - 5.66 g
pass
M. The exit angle from the test article preferably
should be less that 60 percent of the test impact
angle, measured at time of vehicle loss of contact
with test device.”
Exit angle = 6°, 24% of the impact
angle.
pass
23
Table 2- 3 - Test 572 Assessment Summary
Test No. 572
Date September 13, 2000
Test agency California Dept. of Transportation
Evaluation Criteria Test Results Assessment
Structural Adequacy
A. Test article should contain and redirect the
vehicle; the vehicle should not penetrate,
underride, or override the installation although
controlled lateral deflection of the article is
acceptable
The vehicle was contained and
smoothly redirected
pass
Occupant Risk
D. Detached elements, fragments or other debris
from the test article should not penetrate or
show potential for penetrating the occupant
compartment, or present an undue hazard to
other traffic, pedestrians, or personnel in a work
zone. Deformation of, or intrusions into, the
occupant compartment that could cause serious
injuries should not be permitted.
There was not any significant debris
from the test article and negligible
deformation of the occupant
compartment.
pass
G. It is preferable, although not essential, that the
vehicle remain upright during and after
collision.
The vehicle remained upright pass
Vehicle Trajectory
K. After collision it is preferable that the vehicle’s
trajectory not intrude into adjacent traffic lanes
The vehicle maintained a relatively
straight course after exiting the barrier
pass
M. The exit angle from the test article preferably
should be less that 60 percent of the test impact
angle, measured at time of vehicle loss of
contact with test device.”
Exit angle = 2°, 13% of the impact
angle.
pass
Table 2- 4 - Vehicle Trajectories and Speeds
Test
Number
Impact
Angle
( deg)
60% of
Impact
Angle
( deg)
Exit
Angle
( deg)
Impact
Speed, Vi
( km/ h)
Exit
Speed, Ve
( km/ h)
Speed
Change
Vi - Ve
( km/ h)
571 25.0 15 6 98.2 81.5 17
572 15.0 9 2 82.6 76 7
24
3. CONCLUSION
Based on the testing of the Type 732S discussed in this report, the following conclusions
can be drawn:
1. The Type 732S can successfully contain and redirect a 2000- kg pickup truck impacting at 25°
and 100 km/ h. There was moderate occupant compartment deformation, mainly in the cab
floorboard area. This deformation was judged to be insufficient to cause serious injury to
vehicle occupants.
2. The Type 732S can successfully contain and redirect an 8000- kg, single unit, van- bodied
truck impacting at 15° and 80 km/ h.
3. Damage to the Type 732S in accidents similar to the tests conducted for this project will
result in small to moderate amounts of scraping and gouging of the rail. Therefore, the
majority of impacts into the rail will not require urgent repairs. By structurally performing
well at NCHRP Report 350 test level 4, the bridge rail meets the performance level 2
requirements of the 1989 AASHTO “ Guide Specifications for Bridge Railings.”
4. The Type 732S meets the criteria set in the National Cooperative Highway Research
Program’s Report 350 “ Recommended Procedures for the Safety Performance Evaluation of
Highway Features” under test level 4 for longitudinal barriers.
In Test 571 ( pickup truck) all of the barrier structural adequacy, occupant risk, and
vehicle trajectory criteria, as outlined in NCHRP Report 350, were within acceptable limits. The
exit angle was small enough that the vehicle would not impose undue risks to other motorists.
No debris was scattered in such a way that it would create hazards to other motorists. The
vehicle was safely contained and redirected by the barrier and it remained upright throughout the
test.
In Test 572 ( large truck) all of the barrier structural adequacy and vehicle trajectory
criteria, as outlined in NCHRP Report 350, were within acceptable limits. None of the detached
pieces of the vehicle penetrated or even showed the possibility of penetrating the passenger
compartment of the test vehicle.
None of the damage done to the barrier during Tests 571 and 572 would pose safety
concerns for other vehicles which may impact the same location before repairs could be
accomplished by maintenance crews.
25
4. RECOMMENDATION
The Type 732S is recommended for use as new or retrofit bridge railing on high- speed
highways as test level 4.
Vehicle behavior observed during these two tests demonstrated the ability of this barrier
to provide pedestrian protection on the outside of the barrier at the tested speeds and angles. This
vehicle behavior evidence and requirements given in Section 13.4 from NCHRP Project 12- 33
“ Bridge Design Specification” ( 6) and Article G2.7 of the 1989 AASHTO “ Guide Specification
for Bridge Railings” ( 2) clearly specify that a pedestrian sidewalk needs to be separated from
traffic for high- speed applications ( 45 mi/ h or greater). The Type 732S meets this requirement.
5. IMPLEMENTATION
The Office of Structures Design will be responsible for the preparation of standard plans
and specifications for the Type 732S, with technical support from Materials Engineering and
Testing Services and the Traffic Operations Program.
26
6. REFERENCES
1. “ Recommended Procedures for the Safety Performance Evaluation of Highway Features”,
Transportation Research Board, National Cooperative Highway Research Program Report
350, 1993.
2. “ Guide Specifications For Bridge Railings”, American Association of State Highway and
Transportation Officials, 1989.
3. Jewell, John, et al., " Vehicle Crash Tests of Type 70 Bridge Rail", California Department
of Transportation, Report No. FHWA/ CA/ ESC- 98/ 06, January 1998.
4 “ Vehicle Damage Scale for Traffic Accident Investigators”, Traffic Accident Data
Project, National Safety Council, 1968.
5. “ Collision Deformation Classification” - SAE J224 MAR80, SAE Recommended
Practices, 1980.
6. “ Development of a Comprehensive Bridge Specification and Commentary” – Section 13,
National Cooperative Highway Research Program Project 12- 33, 1993.
27
7. APPENDICES
7.1. Test Vehicle Equipment
The test vehicles were modified as follows for the crash tests:
• The gas tanks on the test vehicles were disconnected from the fuel supply line and drained. A
12- L safety gas tank was installed in the truck bed or non- impact cab step and connected to
the fuel supply line. The stock fuel tanks had dry ice or gaseous CO2 added in order to purge
fuel vapors.
• One pair of 12- volt wet cell motorcycle storage batteries was mounted in the vehicle. The
batteries operated the solenoid- valve braking/ accelerator system, rate gyros, and the
electronic control box. A second 12- volt deep cycle gel cell battery powered the transient
data recorder.
• A 4800- kPa CO2 system, actuated by a solenoid valve, controlled remote braking after impact
and emergency braking if necessary. Part of this system was a pneumatic ram that was
attached to the brake pedal. The operating pressure for the ram was adjusted through a
pressure regulator during a series of trial runs prior to the actual test. Adjustments were made
to assure the shortest stopping distance without locking up the wheels. When activated, the
brakes could be applied in less than 100 milliseconds.
• The remote brakes were controlled via a radio link transmitter at a console trailer. When the
brakes were applied by remote control from the console trailer, the ignition was automatically
rendered inoperable by removing power to the coil.
• For tests 571 and 572, an accelerator switch was located on the rear of the vehicle. The
switch opened an electric solenoid which, in turn, released compressed CO2 from a reservoir
into a pneumatic ram that had been attached to the accelerator pedal. The CO2 pressure for
the accelerator ram was regulated to the same pressure of the remote braking system with a
valve to adjust CO2 flow rate.
• For tests 571 and 572, a speed control device, connected in- line with the primary winding of
the coil, was used to regulate the speed of the test vehicle based on the signal from a speed
sensor output from the vehicle transmission. This device was calibrated prior to the test by
conducting a series of trial runs through a speed trap comprised of two tape switches set a
specified distance apart and a digital timer.
• For tests 571 and 572, a microswitch was mounted below the front bumper and connected to
the ignition system. A trip plate on the ground near the impact point triggered the switch
when the car passed over it. The switch would open the ignition circuit and shut off the
vehicle’s engine prior to impact.
Table 7- 1 and Table 7- 2 give specific information regarding vehicle dimensions and
weights for Test 571 and Test 572 respectively.
28
Table 7- 1 - Test 571 Vehicle Dimensions
DATE: 2/ 8/ 00 TEST NO: 571 VIN NO: 1GCGC24N0NE121757 MAKE: CHEVROLET
MODEL: 2500 YEAR: 1992 ODOMETER: 163929 ( MI) TIRE SIZE: L 245 175R16
TIRE INFLATION PRESSURE: 60 ( PSI)
MASS DISTRIBUTION ( kg) LF 609.5 RF 646.5 LR 476.5 RR 457.0
DESCRIBE ANY DAMAGE TO VEHICLE PRIOR TO TEST: Rear Bumper has small dents on face on both sides. Tailgate has small ding on top center.
ENGINE TYPE: Gas V8
ENGINE CID: 454
TRANSMISSION TYPE :
X AUTO
MANUAL
OPTIONAL EQUIPMENT:
Air Conditioning
DUMMY DATA:
TYPE: NA
MASS: NA
SEAT POSITION: NA
A 188.0 D 183.0 G 143.5 K 65.5 N 160.0 Q 44.5
B 91.0 E 136.0 H L 7.3 O 166.5
C 335.5 F 544.0 J 107.0 M 43.8 P 75.0
MASS - ( kg) CURB TEST INERTIAL GROSS STATIC
M1 1256.0 1257.0 1257.0
M2 933.5 939.0 939.0
MT 2189.5 2196.0 2196.0
GEOMETRY ( cm)
29
Table 7- 2 - Test 572 Vehicle Dimensions
DATE: 9/ 7/ 00 TEST NO: 572 VIN NO: 1GDJ7H1P0NJ516558 MAKE: GMC
MODEL: TOP KICK YEAR: 1992 ODOMETER: 88861 ( MI) TIRE SIZE: 11R22.5
MASS DISTRIBUTION ( kg) LF RF LR RR
DESCRIBE ANY DAMAGE TO VEHICLE PRIOR TO TEST: None
A 243.5 D 334.0 G K 47.5 N Q 182.5
B 84.0 E 230.0 H L 107.5 O 58.0 R 103.5
C 533.5 F 837.5 J 177.0 M 95.0 P 201.5 S 59.3
MASS - ( kg) CURB TEST INERTIAL GROSS STATIC
M1 2168 2749 2749
M2 2894 5362 5362
MT 5062 8111 8111
GEOMETRY ( cm)
30
7.2. Test Vehicle Guidance System
A rail guidance system directed the vehicle into the barrier. The guidance rail, anchored
at 3.8 m intervals along its length, was used to guide a mechanical arm, which was attached to
the front left wheel of each of the vehicles. A rope was used to trigger the release mechanism on
the guidance arm, thereby releasing the vehicle from the guidance system before impact.
7.3. Photo - Instrumentation
Several high- speed movie cameras recorded the impact during the crash tests. The types
of cameras and their locations are shown in Table 7- 3 and Figure 7- 1.
All of these cameras were mounted on tripods except the three that were mounted on a
10.7- m high tower directly over the impact point on the test barrier.
A video camera and a 16- mm film camera were turned on by hand and used for panning
during the test. Switches on a console trailer near the impact area remotely triggered all other
cameras. The test vehicle and test barrier were photographed before and after impact with a
normal- speed movie camera, a beta video camera and a color still camera. A film report of this
project has been assembled using edited portions of the crash testing coverage.
Table 7- 3 - Typical Camera Type and Locations
Typical Coordinates, m
Camera Film Size Camera Rate: Test 571
Label ( mm) Type ( fr./ sec.) X* Y* Z*
L1 16 LOCAM 1 400 - 24.8 9.0 1.2
L2 16 LOCAM 2 400 0.0 0.0 9.1
L3 16 LOCAM 3 400 31.6 0.0 1.2
L4 16 LOCAM 4 400 - 0.457 0.0 9.1
L5 16 LOCAM 5 400 - 46.1 - 0.838 2.4
L6 16 LOCAM 6 400 0.457 0.0 9.1
L8 16 LOCAM 8 400 - 1.2 - 24.2 1.7
V 1.27 SONY BETACAM 30 - 2.3 - 27.0 1.7
H 35 HULCHER 40 - 46.3 - 0.254 2.4
Note: Camera location measurements were approximated and are typical for all crash
tests involved in this report.
* X, Y and Z distances are relative to the impact point.
31
Figure 7- 1 - Camera Locations
The following are the pretest procedures that were required to enable film data reduction
to be performed using a film motion analyzer:
1) Butterfly targets were attached to the top and sides of each test vehicle. The targets
were located on the vehicle at intervals of 0.305, 0.610 and 1.219 meters ( 1, 2 and 4 feet.). The
targets established scale factors and horizontal and vertical alignment. The test barrier was
targeted with stenciled numbers every 1 meter.
2) Flashbulbs, mounted on the test vehicle, were electronically triggered to establish 1)
initial vehicle- to- barrier contact, and 2) the time of the application of the vehicle brakes. The
impact flashbulbs begin to glow immediately upon activation, but have a delay of several
milliseconds before lighting up to full intensity.
3) Five tape switches, placed at 4 m intervals, were attached to the ground near the
barrier and were perpendicular to the path of the test vehicle. Flash bulbs were activated
sequentially when the tires of the test vehicle rolled over the tape switches. The flashbulb stand
was placed in view of most of the cameras. The flashing bulbs were used to correlate the
cameras with the impact events and to calculate the impact speed independent of the electronic
speed trap. The tape switch layout is shown in Figure 7- 2.
4) High- speed cameras had timing light generators which exposed red timing pips on the
film at a rate of 100 per second. The pips were used to determine camera frame rates.
L4 L2 L6
L5
H
INTENDED POINT
OF IMPACT
BRIDGE RAIL
+ Y
+ X
L3
L8 G V
L1
32
2nd speed trap
4m O. C.
Three Event
Tape Switches at 4m O. C.
Five Flashbulb Tape Switches at 4m O. C.
Ignition Cutoff Bracket
1st speed trap
4m O. C.
30cm
30cm
30cm
Figure 7- 2 - Tape Switch Layout
33
7.4. Electronic Instrumentation and Data
Transducer data were recorded on a Pacific Instruments digital transient data recorder
( TDR) model 5600 which was mounted in the vehicle for Test 571. The transducers mounted on
the vehicle include two sets of accelerometers at the center of gravity, one set of accelerometers
600 mm behind the center of gravity, and one set of rate gyros at the center of gravity. The TDR
data were reduced using a laptop computer.
Accelerometer specifications are shown in Table 7- 4. The vehicle accelerometer sign
convention used throughout this report is the same as that described in NCHRP Report 350 and
is shown in Figure 7- 3.
Three pressure- activated tape switches were placed on the ground in front of the test
barrier ( see Figure 7- 2). They were spaced at carefully measured intervals of 4 m. When the test
vehicle tires passed over them, the switches produced sequential impulses or " event blips" which
were recorded concurrently with the accelerometer signals on the TDR, serving as " event
markers". A tape switch on the front bumper of the vehicle closed at the instant of impact and
triggered two events: 1) an “ event marker” was added to the recorded data, and 2) a flash bulb
mounted on the top of the vehicle was activated. A time cycle was recorded continuously on the
TDR with a frequency of 500 cycles per second. The impact velocity of the vehicle could be
determined from the tape switch impulses and timing cycles. Two other tape switches,
connected to a speed trap, were placed 4 m apart just upstream of the test barrier specifically to
establish the impact speed of the test vehicle. The tape switch layout for all tape switches is
shown in Figure 7- 2.
The data curves are shown in Figure 7- 4 through Figure 7- 7 and include the
accelerometer and rate gyro records from the test vehicles. They also show the longitudinal
velocity and displacement versus time. These plots were needed to calculate the occupant impact
velocity defined in NCHRP Report 350. All data were analyzed using software written by
DADiSP and modified by Caltrans.
NOTE: There are no data plots for Test 572 because NCHRP Report 350 does not require
accelerometer data for the 8000S test series.
34
TYPE LOCATION RANGE ORIENTATION TEST NUMBER
STATHAM VEHICLE C. G. 100 G LONGITUDINAL ALL
STATHAM VEHICLE C. G. 100 G LATERAL ALL
STATHAM VEHICLE C. G. 50 G VERTICAL ALL
HUMPHREY VEHICLE C. G. 180 DEG/ SEC ROLL ALL
HUMPHREY VEHICLE C. G. 90 DEG/ SEC PITCH ALL
HUMPHREY VEHICLE C. G. 180 DEG/ SEC YAW ALL
ENDEVCO VEHICLE C. G. 200 G LONGITUDINAL ALL
ENDEVCO VEHICLE C. G. 200 G LATERAL ALL
ENDEVCO VEHICLE C. G. 200 G VERTICAL ALL
Figure 7- 3 - Vehicle Accelerometer Sign Convention
Table 7- 4 - Accelerometer Specifications
35
Figure 7- 4 - Test 571 Vehicle Accelerations Vs Time
36
Figure 7- 5 - Test 571 Vehicle Longitudinal Acceleration, Velocity, and Distance Vs Time
37
Figure 7- 6 - Test 571 Vehicle Lateral Acceleration, Velocity, and Distance Vs Time
38
Figure 7- 7 - Test 571 Vehicle Roll, Pitch, and Yaw Vs Time
39
7.5. Detailed Drawings
The following two pages are “ as built” construction drawings of the Type 732S and were
produced by the designers at T. Y. Lin International. Please contact Caltrans, Structures Design
for the most current and complete plans.
California Department of Transportation
Engineering Service Center
Structures Design
1801 30th Street
Sacramento, CA 95816
Nahed Abdin
Telephone: 916- 227- 8805
40
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41
Figure 7- 8 – As built drawing for the Type 732S
42
Figure 7- 9 – As built cross section and attachment detail for the Type 732S