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6 CHAPTER 2 â A SUMMARY OF COMMON NON- PROPRIETARY GUARDRAILS (BASIC DESIGN AND CRASH PERFORMANCE) Crash Testing for Federal Aid Eligibility Full-scale crash testing is the method used by the Federal Highway Administration to ensure that a barrier system is crashworthy for use on federally funded highways. Roadside safety barriers should meet the performance standards accepted by the FHWA. The current procedures are published in the Manual for Assessing Safety Hardware (MASH). [AASHTO09] From the first testing procedures specified in HRB 482 until those of NCHRP Report 350, the 4500-lb (2040-kg) passenger sedan served as the crash test vehicle representing the large end of the passenger vehicle fleet. The large passenger sedan had virtually disappeared from the vehicle population by the late 1980âs and new vehicle types such as minivans, sport utility vehicles and pickup trucks had emerged in their place. Report 350 replaced the large car with a 4409-lb (2000-kg) pickup truck. The challenges that the pickup truck introduced to the crash testing procedures were due to its higher center of gravity, making it much more unstable during impacts than its predecessor, the low center of gravity large car sedan. In Report 350, the 4409-lb pickup was chosen as a replacement for the 4500-lb passenger sedan for several reasons. First, both vehicles had similar mass and were therefore thought to represent similar barrier loadings. Second, the pickup truck was chosen as a surrogate for the much broader class of vehicles known at the time as ISTEA vehicles (e.g., pickup trucks, SUVs, minivans, vans, etc.). The U.S. Congress required the FHWA to address the issue of the crashworthiness of the emerging light truck fleet (e.g., SUV, vans and mini vans) in the ISTEA act. The FHWA responded by adopting the 4409-lb pickup in Report 350 as a surrogate for the entire class of SUVs (e.g., pickup trucks, SUVs, vans, minivans, etc.). There were two tests in Report 350 for evaluating the crashworthiness of guardrail systems for test level three (Report 350 TL-3) which are described in Table 2. In 2002, NCHRP Project 22-14 was initiated to assess the need for updating Report 350. Since publication of Report 350, several changes have occurred in vehicle fleet characteristics, testing technology and crashworthiness research. The result of Project 22-14 was a document with revised criteria for evaluating roadside safety features. The new test guidelines and evaluation criteria were published in 2009 by the American Association of State Highway and Transportation Officials (AASHTO) in the Manual for Assessing Safety Hardware (MASH) and have been adopted by the FHWA for eligibility testing of barrier systems to be installed on federal funded highways.[AASHTO09] The most significant changes in MASH were that both the small car and light truck test vehicles increased in mass, as shown in Table 2.
7 Table 2. NCHRP Report 350 and MASH TL-3 for Guardrail. Report 350 MASH Test 3-10 Vehicle Classification 820C 1100C Mass (lb) 1,807 2,425 Minimum C.G. Height (in) N/A N/A Impact Speed (mph) 62.1 62.1 Impact Angle (deg) 20 25 Test 3-11 Vehicle Classification 2000P 2270P Mass (lb) 4,400 5,000 Minimum C.G. Height (in) 27.6 28 Impact Speed (mph) 62.1 62.1 Impact Angle (deg) 25 25 Summary of Common Non-Proprietary Strong-Post Guardrail Systems Modified G4(1S) with Routed Wood Blockouts The Modified G4(1S) with routed wood blockouts is constructed with 6-ft long W6x9 steel guardrail posts spaced at 6 feet- 3 inches center-to-center; the 12-gauge w-beam rail is offset 8 inches from the posts using routed wood blockouts with dimensions 6 x 8 x 14 inches. The w-beam and blockout are fastened to the post using a 5/8-inch diameter bolt 10 inches long. Drawings for the system (i.e., AASHTO-AGC-ARTBA designator SGR04c) are shown in Figure 5. (AASHTO-AGC-ARTBA designator SGR04c), drawings of the blockout are shown in Figure 6 (PDB01b), drawings of the post are shown in Figure 7 (PWE01), and drawings of the rail-to- post fastener are shown in Figure 8 (FBB03). A photo of the modified G4(1S) with routed wood blockouts is shown in Figure 1. This guardrail system was successfully crash tested at Texas Transportation Institute (TTI Test 405421-1) on November 16, 1995 under NCHRP Report 350 Test 3-11 impact conditions.[Bullard96] A sequence of snapshots from the crash test video is shown in Figure 2. The modified G4(1S) with wood blockouts was also successfully tested under MASH Test 3-11 impact conditions on April 8, 2005 at the Midwest Roadside Safety Facility (MwRSF). A sequence of snapshots from the test video from Test 2214-WB2 is shown in Figure 3. In an earlier test, 2214-WB1, which was conducted under test conditions very similar to the MASH Test 3-11 requirements, the system failed to safely contain and redirect the vehicle.[Polivka06a] The standard test vehicle for MASH Test 3-11 is the 2270P, which is a 5,000-lb ½-ton quad-cab pickup. The test vehicle used in Test 2214-WB1 was a 5,000-lb ¾-ton standard cab pickup. During Test 2214-WB1, the rail ruptured at a w-beam splice connection allowing the vehicle to penetrate behind the system. A sequence of snapshots from the test video for Test 2214-WB1 is shown in Figure 4. The failed test caused many in the roadside safety community to wonder if the modified G4(1S) was being tested very close to its performance limit if a slightly different (but still common) vehicle type resulted in a failed test. This lead to the development of the Midwest Guardrail System (MGS) and other 31-inch w-beam guardrails.
8 Figure 1. Modified G4(1S) with wood blockouts.[Bullard96] Figure 2. Sequential views of Crash Test 405421-1.[Bullard96] Figure 3. Sequential views of Crash Test 2214-WB2.[Polivka06b] Figure 4. Sequential views of Crash Test 2214-WB1.[Polivka06b]
9 Figure 5. Drawing of the strong-post w-beam guardrail (SGR04a-c).
10 Figure 6. Drawing of the 8-inch wood blockout for the modified G4(1S) with wood blockout guardrail (PDB01b).
11 Figure 7. Drawing of the W6x9 guardrail post (PWE01).
12 Figure 8. Drawing of the bolt used to fasten the rail element to guardrail posts.
13 G4(2W) The G4(2W) guardrail is constructed with 6x8-inch rectangular timber posts spaced at 6 feet- 3 inches center-to-center; the 12-gauge w-beam rail is offset 8 inches from the posts using wood blockouts with dimensions 6 x 8 x 14 inches. The w-beam and blockout are fastened to the post using a 5/8-inch diameter bolt 18 inches long. A photo of the G4(2W) guardrail is shown in Figure 9. Drawings for the system are shown in Figure 5 (SGR04b), drawings of the blockout are shown in Figure 6 (PDB01a), drawings of the post are shown in Figure 12 (PDE01 and PDE02), and drawings of the rail-to-post fastener are shown in Figure 8 (FBB04). The G4(2W) was successfully crash tested at Texas Transportation Institute (TTI Test 471470-26) on May 25, 1994 under NCHRP Report 350 Test 3-11 impact conditions.[Mak99] For this test installation the posts were 64 inches long with a 36-inch embedment depth (PDE01). The test, however, was classified as âmarginally acceptableâ due to severe wheel snag and subsequent vehicle instability after redirection from the system. A sequence of snapshots from the crash test video is shown in Figure 10. Figure 9. Photo of the G4(2W) guardrail Test 476460-1-5 test installation.[Bullard10] Figure 10. Sequential views of full-scale crash Test 471470-26.[Mak99] Figure 11. Sequential views of full-scale crash Test RF476460-1-5.[Bullard10]
14 The G4(2W) was also tested (Test RF476460-1-5) under MASH test conditions, in which the guardrail ruptured at a splice connection allowing the vehicle to penetrate behind the guardrail.[Bullard10] Test RF476460-1-5 was conducted at the Transportation Research Institute on March 4, 2009. In this case, the posts were 72 inches long with an embedment depth of 44 inches. A sequence of snapshots from the test video is shown in Figure 11. Figure 12. Drawing of the rectangular wood post used in the G4(2W) and G4(1W) guardrail systems (i.e., AASHTO designator SGR04b).
15 G4(1W) The G4(1W) guardrail is constructed with 6-ft long, 8x8-inch rectangular timber spaced at 6 feet- 3 inches center-to-center; the 12-gauge w-beam rail is offset 8 inches from the posts using wood blockouts with dimensions 8 x 8 x 14 inches. The w-beam and blockout are fastened to the post using a 5/8-inch diameter bolt 18 inches long. Drawings of the G4(1W) guardrail system are shown in Figure 5(SGR04b), drawings of the blockout are shown in Figure 6 (PDB01a), drawings of the post are shown in Figure 12 (PDE05), and drawings of the rail-to- post fastener are shown in Figure 8 (FBB04). While the G4(2W) has been used in a number of states, the G4(1W) is now commonly used only in the state of Iowa. Though the performance of the two guardrails have been presumed to be equivalent, only one full-scale crash test has ever been performed on the G4(1W) and that test was performed over 40 years ago. That successful test involved a 2000-kg passenger car striking the barrier at 100 km/hr and 22 degrees using the recommendations of Highway Research Board Circular 482, the first full-scale crash testing guidelines published in 1962.[Michie71; HRB62] In a study performed by Plaxico, Ray, and Hiranmayee for the State of Iowa, finite element analysis was used to evaluate the G4(1W) guardrail.[Plaxico00] The only difference between the G4(1W) system and the G4(2W) system is the cross-sectional dimensions of the wood posts (i.e., the posts in the G4(1W) system are 50 mm wider than the posts in the G4(2W) system). Analyses were conducted to simulate NCHRP Report 350 Test 3-11 impact conditions. Crash performance of the G4(1W) was compared to the G4(2W) with respect to guardrail deflection, vehicle redirection and occupant risk factors. Although the larger posts in the G4(1W) provided more lateral stiffness to the system, the dynamic deflections of the posts in the finite element analysis were comparable to the deflections of the posts in the G4(2W) system. The maximum total deflection of the G4(1W) system was only about 4% less than the maximum total deflection of the G4(2W) system. MGS Sicking and other researchers at the Midwest Roadside Safety Facility (MwRSF) developed a new strong-post w-beam guardrail system designed to provide better performance for high center-of-gravity (c.g.) light trucks, allow additional tolerance for low mounting heights, and maintain acceptable safety performance for small automobiles.[Sicking02] Sicking suggested that the existing strong-post w-beam guardrails were at their performance limits in Report 350 Test 3-11 impact conditions and that a reasonable proportion of the passenger vehicle fleet are larger and have higher c.g.âs than the then-current test vehicles. The new design essentially involved modifications to the G4(1S) guardrail system, including: (1) raising the rail height from 27 inches to 31 inches, (2) moving rail splices to the midspan between posts, (3) increasing blockout depth from eight inches to twelve inches, (4) increasing the size of the post- bolt slots, and (5) decreasing embedment depth. A photo of the MGS guardrail is shown in Figure 13. Finite element analysis was used to explore the effects of changes in these barrier attributes. The performance of the new barrier system was verified with full-scale crash testing.[Sicking02] This system has been successfully crash tested to Report 350 and MASH for Test Level 3 (TL-3).[Sicking02; Polivka06c-e]
16 Figure 13. Photo of the MGS guardrail system. [Sicking02] MGS with Round Wood Posts The MGS with round wood posts has also been successfully crash tested at the Midwest Roadside Safety Facility. [Hascal07] Two full-scale crash tests were performed to evaluate system performance according to the testing and evaluation requirements of NCHRP Report 350 Test 3-11. Test MGSDF-1 used guardrail posts made from 7.25-inch diameter Douglas Fir, and Test MGSDF-2 used guardrail posts made from 8-inch diameter Ponderosa Pine. The test results showed that the MGS functioned adequately with posts made from either species. Photographs of the guardrail system with Douglas Fir and Ponderosa Pine are shown in Figure 14. A sequence of snapshots from the test videos are shown in Figure 15 and Figure 16. Figure 14. MGS with (a) 7.25-inch diameter round Douglas Fir posts and (b) 8-inch diameter round Ponderosa Pine posts. (a) 7.25-in. dia. Douglas Fir (b) 8-in. dia. Ponderosa Pine
17 Figure 15. Test MGSDF-1 of the MGS guardrail with 7.25-inch diameter Douglas Fir posts. [Hascal07] Figure 16. Test MGSPP-1 of MGS with 8-inch diameter Ponderosa Pine posts. [Hascal07] G9 Thrie-Beam Guardrail The standard thrie-beam guardrail (G9) is constructed with 6.5-ft long W6x9 steel guardrail posts spaced at 6 feet- 3 inches center-to-center; the 12-gauge w-beam rail is offset 6 inches from the posts using a 21.81 inches long W6x9 steel flanged section. The top of the thrie- beam rail is 31-5/8 inches above grade and the bottom of the rail is 12 inches above grade. The thrie-beam rail is connected to the blockout using two 5/8-inch diameter button-head guardrail bolts (FBB01). The blockout is fastened to the posts using two 5/8-inch diameter hex bolts (FBX16a). Drawings for the system (i.e., AASHTO-AGC-ARTBA designator SGR09a) are shown in Figure 19, drawings of the blockout are shown in Figure 20, drawings of the post are shown in Figure 7 (PWE03), and drawings of the rail-to-blockout fastener are shown in Figure 8 (FBB01). A photo of the G9 guardrail is shown in Figure 17. The G9 system was crash tested at Texas Transportation Institute (TTI Test 471470-31) on April 14, 1995 under NCHRP Report 350 Test 3-11 impact conditions.[Mak99] The system failed to meet the safety requirements of Report 350. A sequence of snapshots from the crash test video is shown in Figure 18. âAfter the vehicle exited the installation, it rolled two and a quarter revolutions and came to rest on its left side 138 feet downstream of the impact point.â
18 Figure 17. Photo of the standard thrie-beam guardrail (G9; SGR09a) Figure 18. Sequential photos of Test 471470-31 on the G9 thrie-beam guardrail. [Mak99]
19 Figure 19. AASHTO-AGC-ARTBA drawings for the SGR09 guardrail systems. [AASHTO04]
20 Figure 20. AASHTO-AGC-ARTBA drawings for the W6x9 steel blockout for the G9 thrie- beam guardrail.[AASHTO04]
21 Thrie-Beam Guardrail with Wood Blockouts The thrie-beam guardrail with wood blockouts is constructed with 6.5-ft long W6x9 steel guardrail posts spaced at 6 feet- 3 inches center-to-center; the 12-gauge w-beam rail is offset 8 inches from the posts using a 22 inches long 6x8-inch routed wood blockout. The top of the thrie-beam rail is 32.5 inches above grade and the bottom of the rail is 12.5 inches above grade. The thrie-beam rail and blockout are connected to the blockout using two 5/8-inch diameter button-head guardrail bolts (FBB03). There currently are no AASHTO-SGC-ARTBA drawings for the assembled guardrail system; however, drawings of the blockout are shown in Figure 6, drawings of the post are shown in Figure 7 (PWE03), and drawings of the rail-to-blockout fastener are shown in Figure 8 (FBB03). The wood blockout component shown in Figure 6 was modified by routing 4 inches wide x 3/8 inches deep on the back-side of the block to fit over the flange of the W6x9 steel posts. A photo of the guardrail system is shown in Figure 21. The system was successfully crash tested at Texas Transportation Institute (TTI Test 476460-1-8) on February 26, 2009 under MASH Test 3-11 impact conditions.[Bullard10] However, the vehicle appeared to be very unstable upon exiting the guardrail, as shown in the sequential photos of the full-scale test in Figure 22. Figure 21. Photo of the thrie-beam guardrail with routed wood blockouts. [Bullard10] Figure 22. Sequential photos for Test 476460-1-8 on the thrie-beam guardrail with routed wood blockouts (MASH Test 3-11).[Bullard10] Modified Thrie-Beam Guardrail The modified thrie-beam guardrail (AASHTO-AGC-ARTBA designator SGR09b) is constructed with 6.75-ft long W6x9 steel guardrail posts spaced at 6 feet- 3 inches center-to- center; the 12-gauge thrie-beam rail is offset 14-inches from the posts using a 21.8 inches long M14x17.2 steel flanged section with a unique cutout at the bottom of the web, as shown in the drawing in Figure 26. The top of the thrie-beam rail is 34 inches above grade and the bottom of the rail is 14 inches above grade. The thrie-beam rail is connected to the blockout using two 5/8-
22 inch diameter button-head guardrail bolts (FBB02). The blockout is fastened to the posts using two 5/8-inch diameter hex bolts (FBX16a). Drawings for the system (i.e., AASHTO-AGC- ARTBA designator SGR09b) are shown in Figure 19, drawings of the blockout are shown in Figure 26, drawings of the post are shown in Figure 7 (PWE04), and drawings of the rail-to- blockout fastener are shown in Figure 8 (FBB02)1. Figure 23. Photo of the modified thrie-beam guardrail (SGR09b). Figure 24. Sequential photos for Test 471470-30 on the modified thrie-beam guardrail (SGR09b) under NCHRP Report 350 Test 3-11 conditions. [Mak99] Figure 25. Sequential photos for Test 404211-5a on the modified thrie-beam guardrail under NCHRP Report 350 Test 4-12 conditions.[Buth99c] The 14-inch depth of the M14x17.2 creates a greater separation between the rail and post (e.g., 8 inches deeper than the SGR09a); while the cutout at the bottom of the web allows the lower section of the rail to deflect inward during impact and helps to keep the face of the rail vertical as the posts rotate back in collisions. A photo of the modified thrie-beam guardrail is shown in Figure 23. The guardrail system was successfully crash tested at Texas Transportation Institute (TTI Test 471470-30) on January 1, 1995 under NCHRP Report 350 Test 3-11 impact conditions.[Mak99] A sequence of 1 See http://www.youtube.com/watch?v=qmNJaBGIETk
23 snapshots from the crash test video is shown in Figure 13. The system was also successfully crash tested on June 12, 1998 at the Texas Transportation Institute with the 18,000-lb single unit truck according to NCHRP Report 350 Test 4-12 test conditions.[Buth99c] A sequence of snapshots from the crash test video is shown in Figure 25. Summary of Full-Scale Tests Conducted on Strong-Post Guardrail Table 3 shows a summary of guardrail systems that have been tested for FHWA eligibility under Report 350 or MASH TL-3 conditions; Table 4 shows a summary of the test results. Many of these systems are composed of essentially the same components and many have very similar designs. The differences in design are primarily limited to post type (e.g., 6x8 inch wood or W6x9 steel), rail type (e.g., w-beam or thrie-beam), blockout type (e.g., steel wide-flange or wood), blockout depth, post embedment depth, and rail height. The similarity in the design of these systems indicates that they may be susceptible to similar damage modes. Typical System Damage in Low-Speed Full-Scale Tests In Report 656, Gabler, Gabauer and Hampton evaluated the performance of the modified G4(1S) guardrail with wood blockouts with pre-existing low- to moderate crash-induced damage.[Gabler10] The evaluation was carried out using full-scale testing and was comprised of two parts: (1) an initial, low-speed impact to induce realistic damage to the guardrail and (2) a subsequent test conducted at NCHRP Report 350 test 3-11 impact conditions. To the authorsâ knowledge, this is the only crash test that has been conducted on a guardrail system with pre- existing crash damage. The low speed test (i.e., Test C08C3-027.1) was conducted by MGA Research Corporation on August 6, 2008.[Fleck08] The test involved a 4,632-lb ¾-ton pickup impacting the undamaged guardrail at 30 mph and 26 degrees. The impact point was 23.27 inches upstream of post 11. The test installation, including end-terminals, was 162.4 ft. long. A sequence of photographs from the crash event is shown in Figure 27. The results of the low-speed test provide information regarding the types and magnitude of damage that can commonly be expected in low-speed collisions with this and similar guardrail types. The deflection of the guardrail was recorded and is shown in Figure 28. Rail and post deflections were the primary damage modes resulting from the impact. There were no torsional deformations of any of the posts, no twisted blocks, nor rail tears, and no significant damage to the splice connection (other than rail bending), as shown in Figure 29.
24 Figure 26. AASHTO-AGC-ARTBA drawings for the M14x17.2 steel blockout for the modified thrie-beam guardrail.[AASHTO04]
25 Table 3. Summary of guardrail systems that have been full-scale crash tested under TL-3 conditions. Height Embed. spacing depth (ft) Type (in) (in) (in) Type (in) Polivka06a 2214WB-1 Modified G4(1S) 175 W 27.8 Steel W6x9 43 75 Wood 8 Polivka06b 2214WB-2 Modified G4(1S) 175 W 27.8 Steel W6x9 43 75 Wood 8 Polivka06c 2214MG-1 MGS 175 W 31 Steel W6x9 40 75 Wood 12 Polivka06d 2214MG-2 MGS 175 W 31 Steel W6x9 40 75 Wood 12 Polivka06e 2214MG-3 MGS 175 W 31 Steel W6x9 40 75 Wood 12 Sicking02 NPG-1 MGS 175 W 32 Steel W6x9 37.2 75 Wood 12 Faller04 NPG-4 MGS 175 W 31 Steel W6x9 40 75 Wood 12 Faller04 NPG-5 MGS w/6-in curb 175 W 31 Steel W6x9 40 75 Wood 12 Faller04 NPG-6 MGS 175 W 31 Steel W6x9 40 37.5 Wood 12 Buth99a 405421-2 G4(1S) 175 W 27.8 Steel W6x8.5 44 75 W6x12 6 Mak99a 471470-27 G4(1S) 225 W 27 Steel W6x8.5 44 75 W6x8.5 6 Bullard96 405421-1 Modified G4(1S) 174 W 27.8 Steel W6x8.5 43 75 Wood 8 Bligh97 439637-1 Modified G4(1S) 175 W 27.8 Steel W6x9 38 75 Routed Wood 6 Bligh97b 400001-MPT1 Modified G4(1S) with recycled blockouts W 27.8 Steel W6x9 43 75 Recycled Plastic 7.9 Bullard09 476460-1-5 G4(2W) W 27 Wood 6x8 inch 44 75 Wood 8 Bligh95 405391-1 G4(2W) round post W 27.8 Wood 7.25-in Dia. 46 75 Wood 5.75 Mak99a 471470-26 G4(2W) 225 W 27 Wood 6x8 inch 36 75 Wood 8 Faller06 MGSDF-1 MGS with Douglas Fir wood posts 175 W 31 Wood 7.25-in Dia. 38 75 Wood 13 Faller06 MGSPP-1 MGS with Ponderosa Pine wood posts 175 W 31 Wood 8-in Dia. 38 75 Wood 13 Buth99b 404211-11 Thrie-Beam 262 Thrie 32 Wood 6x8 inch 48 75 Wood 7.9 Mak99a 471470-30 Modified Thrie-Beam 212 Thrie 34 Steel W6x9 M14x17.2 14 Reference Test System System Length Rail Type cross- section Post Blockout
26 Table 4. Summary of full-scale test results on guardrail systems tested under TL-3 conditions. Mass Speed Angle Deflection (ft) (lb) (mph) (deg) (in) x-dir y-dir x-dir y-dir Polivka06a 2214WB-1 Modified G4(1S) 175 3/4-ton standard-cab 5000 61 25.6 19.8 8.5 17.3 16.2 Fail Rail rupture at splice Override Polivka06b 2214WB-2 Modified G4(1S) 175 1/2-ton quad-cab 2270P 5000 62.4 25.8 47.1 6.9 6.6 17.7 13.1 Pass Rail tear at splice Wheel removed Polivka06c 2214MG-1 MGS 175 3/4-ton standard-cab 5000 62.6 25.2 57 8.8 5.3 17.1 14.8 Pass minor rail-tear at post-bolt resulting from hand- fabricated rail slot Wheel removed Polivka06d 2214MG-2 MGS 175 1/2-ton quad-cab 2270P 5000 62.9 25.5 43.9 8.2 6.9 15.3 15.6 Pass minor rail-tear at post-bolt resulting from hand- fabricated rail slot Wheel removed Polivka06e 2214MG-3 MGS 175 1100C 2425 60.8 25.4 16.1 8.4 14.9 17.1 Pass Sicking02 NPG-1 MGS 175 820C 1956 63.9 18.7 6.1 8 11.5 18.6 Pass Faller04 NPG-4 MGS 175 2000P 4378 61 25.6 43.1 9.5 6.9 18.3 12.8 Pass Faller04 NPG-5 MGS w/6-in curb 175 2000P 4383 60 25.8 40.3 10.5 8.7 17.2 12.9 Pass Faller04 NPG-6 MGS 175 2000P 4411 60.2 25.6 17.6 10.7 9 25 18.4 Pass Buth99a 405421-2 G4(1S) 175 2000P 4572 61.9 25.7 15.8 8.9 30.1 15.2 Fail Rail Rupture Mak99a 471470-27 G4(1S) 225 2000P 4570 63 26.1 7.8 6.2 24.8 16 Fail Severe wheel snag Rollover after redirection Bullard96 405421-1 Modified G4(1S) 174 2000P 4577 63 25.5 39.4 7.9 8.4 23.3 14.4 Pass Bligh97 439637-1 Modified G4(1S) 175 2000P 4409 63.3 24.9 29.5 7.76 6.54 24.2 17.1 Pass improper release of rail caused rail to pull down and vehicle to ramp Bligh97b 400001-MPT1 Modified G4(1S) with recycled blockouts 2000P Pass Bullard09 476460-1-5 G4(2W) 2270P 5009 64.4 26.1 10.2 9.6 21.6 14.1 Fail Rail Rupture Bligh95 405391-1 G4(2W) round post 2000P 4409 63.5 25.4 43.3 10.9 11.8 22.2 14.6 Pass Mak99a 471470-26 G4(2W) 225 2000P 4568 62.6 24.3 32.3 11.6 11.4 24.5 19.3 Pass Faller06 MGSDF-1 MGS with Douglas Fir wood posts 175 2000P 4449 62.1 25.5 60.2 8.76 5.69 13.22 13.22 Pass 7 posts fractured Faller06 MGSPP-1 MGS with Ponderosa Pine wood posts 175 2000P 4464 62.3 25.5 37.6 5.9 4.09 22.5 23.6 Pass 4 posts fractured Buth99b 404211-11 Thrie-Beam 262 2000P 4575 61.9 23.6 8.4 9 20.7 18.4 Pass 2 posts fractured Mak99a 471470-30 Modified Thrie-Beam 212 2000P 4573 62.3 25.1 40.8 9.7 9 25.6 17.1 Pass excessive deflection due to posts twisting Impact Conditions Result CommentORA (G) OIV (ft/s) Result Reference Test System System Length Vehicle Type
27 Figure 27. Low-speed Test C08C3-027.1 on the modified G4(1S) with routed wood blockouts. [Fleck08] Figure 28. Barrier deflections recorded after Test C08C3-027.1. [Fleck08] Figure 29. Guardrail damage in Test C08C3-027.1. [Fleck08]
