The Midwest Roadside Safety Facility was contracted by Will Stein of the Iowa Department of Transportation to conduct dynamic bogie testing of a recyclable rubber guardrail spacer block manufactured by Welch Products, Inc. The scope of the work included the setup of both a standard, wood guardrail post blockout and the Welch Products recycled rubber blockout on a standard W150x13.5 steel post, as well as two component tests using a bogie vehicle. The bogie tests were conducted in accordance with previously accepted procedures to evaluate the performance of guardrail post blockouts made of non-standard materials

Bielenberg, Bob W.

Faller, Ronald K.

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Final Reports & Technical Briefs from Mid-
America Transportation Center Mid-America Transportation Center 
2003 
PERFORMANCE ANALYSIS OF WELCH PRODUCTS RECYCLED 
RUBBER SPACER BLOCK 
Bob W. Bielenberg 
Ronald K. Faller 
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PERFORMANCE ANALYSIS OF WELCH PRODUCTS
RECYCLED RUBBER SPACER BLOCK
Submitted by
Bob W. Bielenberg, M.S.M.E., E.I.T.
Research Associate Engineer
Ronald K. Faller, Ph.D., P.E.
Research Assistant Professor
MIDWEST ROADSIDE SAFETY FACILITY
University of Nebraska-Lincoln
527 Nebraska Hall
Lincoln, Nebraska 68588-0529
(402) 472-6864
Submitted to
MIDWEST STATE’S REGIONAL POOLED FUND
Nebraska Department of Roads
1500 Nebraska Highway 2
Lincoln, NE 68502
MwRSF Research Report No. TRP-03-132-03
March 16, 2003
March 13, 2003
Mr. Howard Block
Welch Products, Inc.
205 S. Garfield
Carlisle, Iowa 50047
Phone - 515-989-0829
Fax - 515-989-0344
Subject: Summary Report on the Performance Analysis of Welch Products Recycled
Rubber Spacer Block
Dear Mr. Block:
The Midwest Roadside Safety Facility was contracted by Will Stein of the Iowa Department of
Transportation to conduct dynamic bogie testing of a recyclable rubber guardrail spacer block
manufactured by Welch Products, Inc. The scope of the work included the setup of both a
standard, wood guardrail post blockout and the Welch Products recycled rubber blockout on a
standard W150x13.5 steel post, as well as two component tests using a bogie vehicle. The bogie
tests were conducted in accordance with previously accepted procedures to evaluate the
performance of guardrail post blockouts made of non-standard materials.
On February 28, 2003, MwRSF performed two dynamic bogie tests on two spacer blocks, a
routed, wood spacer block and a recycled rubber spacer block.
Wood Routed W-beam Spacer Block
Bogie test no. WB-1 was performed at 32.2 km/h and 0 degrees on a routed, wood spacer block
mounted on a W150x13.5 steel post at a mounting height of 550 mm. A 305-mm long piece of
W-beam guardrail was mounted on the front of the spacer block. The system description, design
details, and test results for the routed, wood spacer block are included in Attachment No. 1.
Recycled Rubber Routed W-beam Spacer Block
Bogie test no. WB-2 was performed at 31.9 km/h and 0 degrees on a routed, recycled rubber
spacer block mounted on a W150x13.5 steel post at a mounting height of 550 mm. A 305-mm
long piece of W-beam guardrail was mounted on the front of the spacer block. The system
description, design details, and test results for the routed, recycled rubber spacer block are
included in Attachment No. 1.
Discussion
Based on the results of the crash tests, obvious differences were observed in the performance of
the wood and recycled rubber blockouts. While both blockouts displayed similar levels of
permanent damage after impact, the recycled rubber blockout was observed to be much less stiff
than the wood blockout during the impact. Analysis of the high speed film showed that the
recycled rubber blockout crushed approximately 76 mm during the impact, thereby reducing the
effective depth of the spacer block to 127 mm. The reduced depth of the spacer block causes an
increased potential for wheel snag because the guardrail would no longer be spaced 203 mm in
front of the post as in standard W-beam guardrail systems. It is believed that the increased
potential for wheel snag may pose a hazard if the recycled rubber blockout were installed on a
standard W-beam guardrail. 
A second area of concern with the recycled rubber blockout design pertained to installation. Due
to the lower relative stiffness of the recycled rubber blockout and the offset post bolt on the
W150x13.5 post used in the testing, tightening of the post bolt to secure the W-beam to the post
and blockout caused one side of the blockout to compress. This prevented the W-beam from
being mounted on the system perpendicular to the post. It is believed that this phenomena could
cause some problems installing the blockout on W-beam installations in the field.
In light of the comparison of the crash test results, the researchers recommend that the Welch
Products recycled rubber blockout be subjected to full-scale crash testing on a standard W-beam
system to alleviate the previously mentioned concerns with stiffness and construction. The bogie
tests detailed herein demonstrated that the performance of the recycled rubber blockout was
substantially different under load than the standard wooden blockout. As such, it is not possible
to accurately predict the performance of the blockout when installed in a full-scale system
without further testing. 
If you have any questions regarding this information, please feel free to contact me at (402) 472-
9064.
Sincerely,
Bob Bielenberg, M.S.M.E., E.I.T.
Research Associate Engineer
Enclosures: (1) One CD-ROM containing digital still photographs, slow-speed  footage, and
high-speed footage of the two bogie tests.
Attachment: (1) Performance Analysis of Welch Products Recycled Rubber Spacer Block
x.c. - Ronald Faller, Ph.D., P.E., Research Assistant Professor
ATTACHMENT NO. 1
PERFORMANCE ANALYSIS OF WELCH PRODUCTS RECYCLED RUBBER
SPACER BLOCK
Bogie Test WB-1 (Wood Spacer Block Baseline Test)
1. System:
• Wood spacer block for steel post W-beam system
• 200-mm x 150-mm x 360-mm spacer block with 10-mm x 100-mm x 360-mm
router on back face
• Southern Yellow Pine
• Mounted on W150x13.5 steel post in rigid foundation with a 305-mm long
section of 12 gauge W-beam guardrail on the front face
• Standard mounting height (550 mm to post bolt)
2. Bogie Vehicle Weight: 992 kg
3. Impact speed: 32.2 km/hr
Impact orientation: 0 degrees
Bogie Impact Height: 550 mm
4. System performance – The wood spacer block displayed minor damage due to the impact
of the bogie vehicle. Some cracking and chipping of the wood on the front face of the
block was observed. A portion of the routed edge on the rear of the block was disengaged
as to bogie rolled over the post.  No crushing or change in the depth of the spacer block
was observed during the impact. The spacer block remained attached to the post.
Bogie Test WB-2 (Recycled Rubber Spacer Block Test)
1. System:
• Recycled rubber spacer block for steel post W-beam system
• 213-mm x 140-mm x 360-mm spacer block with 10-mm x 111-mm x 360-mm
router on back face
• Recycled Rubber (rubber material and resin compound)
• Mounted on W150x13.5 steel post in rigid foundation with a 305-mm long
section of 12 gauge W-beam guardrail on the front face
• Standard mounting height (550 mm to post bolt)
2. Bogie Vehicle Weight: 992 kg
3. Impact speed: 31.9 km/hr
Impact orientation: 0 degrees
Bogie Impact Height: 550 mm
4. System performance – The recycled rubber spacer block displayed minor damage due to
the impact of the bogie vehicle. The front face displayed slices near the top and bottom of
the block where the W-beam guardrail penetrated into the rubber during impact. An
approximately 76 mm x 76 mm section of the block near the top-left corner on the rear of
the block was disengaged as the bogie vehicle rolled over the post. Significant crushing
of the spacer block was observed during the impact. The depth of the spacer block was
reduced a maximum of approximately 76 mm.  The spacer block remained attached to the
post.
It should be noted that the field crew noticed that the W-beam rail would not
mount perpendicular to the W150x13.5 post. The relatively low stiffness of the spacer
block, combined with the offset post bolt location on the steel post, caused one side of the
spacer block to compress more than the other. This prevented installation of the W-beam
at the correct angle.
Figure 1. Wooden Spacer Block Details, Test WB-1
Figure 2. Wooden Spacer Block, Test WB-1
Figure 3. Wooden Spacer Block Impact Location, Test WB-1
Figure 4. System Damage, Bogie Test WB-1
0.000 sec
0.008 sec
0.016 sec
0.024 sec
0.040 sec
0.076 sec
0.104 sec
0.150 sec
Figure 5. Sequential Photographs, Test WB-1
Figure 6. Documentary Photographs, Test WB-1
Figure 7. Recycled Rubber Spacer Block Details, Test WB-2
Figure 8. Recycled Rubber Spacer Block Details, Test WB-2
Figure 9. Recycled Rubber Spacer Block Details, Test WB-2
Figure 10. Recycled Rubber Spacer Block Material Specifications
Figure 11. Recycled Rubber Spacer Block Material Specifications
Figure 12. Recycled Rubber Spacer Block Material Specifications
Figure 13. Recycled Rubber Spacer Block Material Specifications
Figure 14. Recycled Rubber Spacer Block Material Specifications
Figure 15. Recycled Rubber Spacer Block Material Specifications
Figure 16. Recycled Rubber Spacer Block, Test WB-2
Figure 17. Recycled Rubber Spacer Block Impact Location, Test WB-2
Figure 18. System Damage, Bogie Test WB-2
Figure 19. System Damage, Bogie Test WB-2
Figure 20. System Damage, Bogie Test WB-2
Figure 21. System Damage, Bogie Test WB-2
0.000 sec
0.008 sec
0.016 sec
0.040 sec
0.076 sec
0.104 sec
0.150 sec0.024 sec
Figure 22. Sequential Photographs, Test WB-2
Figure 23. Documentary Photographs, Test WB-2
Force vs Deflection Curves, Test Nos. WB-1 and WB-2
-100
-50
0
50
100
150
200
250
0 500 1000 1500 2000
Deflection (mm)
Fo
rc
e 
(k
N
)
WB-1 WB-2
Figure 24. Force vs Deflection, Test Nos. WB-1 and WB-2


PERFORMANCE ANALYSIS OF WELCH PRODUCTS RECYCLED RUBBER SPACER BLOCK

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PERFORMANCE ANALYSIS OF WELCH PRODUCTS RECYCLED RUBBER SPACER BLOCK

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