Papers by Ronald K Faller
Transportation Research Record, Jun 30, 2020
A new, side-mounted, steel beam-and-post bridge rail was designed, crash tested, and evaluated ac... more A new, side-mounted, steel beam-and-post bridge rail was designed, crash tested, and evaluated according to safety performance guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). The new bridge rail system was designed to be compatible with multiple bridge decks, including cast-in-place concrete slabs and prestressed box beams. Additionally, the bridge rail was designed to remain crashworthy after roadway overlays up to 3 in. thick. The bridge rail was designed and optimized based on strength, installation cost, weight per foot, and constructability. The new bridge rail consisted of three rectangular steel tube rails supported by standard steel cross section, W6 Â 15 steel posts spaced at 8 ft on-center. The upper rail was a 12 Â 4 Â 1 = 4 in. hollow structural section (HSS) steel tube, and the lower two rails were 8 Â 6 Â 1 = 4 in. HSS steel tubes. The top mounting heights for the upper, middle, and lower rails were 39 in., 32 in., and 20 in. above the surface of the deck, respectively. A new, side-mounted, post-to-deck connection was also developed that incorporated HSS steel spacer tubes that offset the posts 6 in. from the bridge deck and aligned the face of the bridge rail with the edge of the deck. Thus, the traversable width of the bridge was maximized. Three full-scale crash tests corresponding to the MASH TL-4 testing matrix were performed on the new bridge rail. All three crash tests successfully contained and redirected the vehicles and satisfied all MASH evaluation criteria.
Transportation Research Record, May 29, 2023
The Midwest Pooled Fund Program has been developing a prototype design for a non-proprietary, hig... more The Midwest Pooled Fund Program has been developing a prototype design for a non-proprietary, high-tension, cable median barrier for use in a 6H:1V median V-ditch. This system incorporates four evenly spaced cables, Midwest Weak Posts (MWPs) spaced at 8 to 16 ft (2.4 to 4.9 m) intervals, and a bolted, tabbed bracket to attach the cables to each post. Full-scale crash testing was needed to evaluate the barrier's safety performance. According to the Manual for Assessing Safety Hardware 2016 (MASH) testing matrix for cable barriers installed within a 6H:1V median V-ditch, a series of eight full-scale crash tests are required to evaluate the safety performance of a system. Several previous tests have failed due to the posts penetrating into the occupant compartment. In order to mitigate the floor pan tearing, a modified MWP was designed. Test no. MWP-9 was conducted on the modified barrier system, consisting of MWPs with ¾-in. (19-mm) diameter weakening holes at the ground line. Additionally, a two-part cap with a single retainer bolt was added to the top of the posts. The cap shielded the free edges of the MWPs during the post-to-vehicle contact. This test was conducted according to MASH 2016 test designation no. 3-10 and utilized an 1100C small car impacting the barrier on level terrain. The vehicle was contained by the system. The two-piece cap mitigated the floor pan tearing. However, one cable (cable no. 3) snagged on the cap retainer bolt and caused two cables (cable nos. 3 and 4) to become interlocked with the left-side A-pillar on the impact side of the vehicle, which resulted in excessive A-pillar crush. Therefore, test no. MWP-9 was deemed unacceptable. However, the two-part cap demonstrated that a closed-section post should be capable of mitigating floor pan tearing.
Several types of elastomeric energy absorbers were evaluated for use in a Manual for Assessing Sa... more Several types of elastomeric energy absorbers were evaluated for use in a Manual for Assessing Safety Hardware (MASH) Test Level 4 (TL-4) energy-absorbing, urban roadside/median barrier. Twelve dynamic bogie tests were conducted on 60- and 80-durometer Ethylene Propylene Diene Monomer (EPDM) rubber cylinders. Five dynamic bogie tests were conducted on marine shear fenders. One dynamic test was conducted on a 27-ft (8.2-m) long installation of 2-in. (51-mm) thick EPDM rubber cylinders spaced at 8 ft (2.4 m) on center and attached to the front face of a 32-in. (813-mm) tall, concrete New Jersey-shaped barrier with a continuous 6-in. x 12-in. (152-mm x 305-mm) steel tubular front rail. One dynamic test was conducted on a 28-ft (8.5-m) long installation of 11⅝-in. (295-mm) tall marine shear fender posts spaced at 8 ft (2.4 m) on center with a 6¾-in. (171-mm) tall, upper timber rail. Both barrier concepts showed promising results. Several static tests were conducted on the marine shear fenders at hot, cold, and room temperatures to evaluate its effect on energy-absorber behavior.
Engineering Structures, May 1, 2021
Abstract Experimental and numerical investigations were conducted on impact performance and defle... more Abstract Experimental and numerical investigations were conducted on impact performance and deflection of precast, portable concrete construction barrier, referred to as a portable concrete barrier (PCB), with a free-standing and a box-beam stiffened configuration. A 61-m long PCB system, consisting of ten 6.1-m long PCBs, was initially evaluated with two full-scale crash tests in a free-standing configuration and a box-beam stiffened configuration according to safety performance guidelines in Manual for Assessing Safety Hardware (MASH) 2016 for Test Level 3 (TL-3). Finite element models were developed using LS-DYNA and validated with these crash tests to ensure their feasibility to estimate barrier deflections and evaluate safety performance. The validated numerical models were used to conduct numerical simulations and investigate effects of concrete constitutive models and barrier length on the performance of PCB system with a box–beam stiffened configuration. Numerical results provided information on the selection and use of concrete constitutive models for evaluation of reinforced concrete barrier impact performance. Furthermore, the reduced-length analysis demonstrated that a reduction in the total system length resulted in decreased dynamic barrier deflection during impact events, as the ends of each system were pinned. This reduced-length analysis provided useful guideline on PCB system design and application for traffic control plan.
Transportation Research Record, Jun 22, 2023
A W-beam to thrie beam stiffness transition with a 4-in. (102-mm) tall concrete curb was develope... more A W-beam to thrie beam stiffness transition with a 4-in. (102-mm) tall concrete curb was developed to connect the 31-in. (787-mm) Midwest Guardrail System (MGS) to a previously-approved thrie beam approach guardrail bridge transition system. This stiffness transition was configured with standard steel posts that are commonly used by several State Departments of Transportation. The toe of a 4-in. (102-mm) tall sloped concrete curb was placed flush with the backside face of the guardrail and extended the length of the transition region. Three full-scale crash tests were conducted according to the Test Level 3 (TL-3) safety standards provided in American Association of State Highway and Transportation Officials' (AASHTO’s) Manual for Assessing Safety Hardware (MASH). During the first test, MASH test no. 3-20, the 1100C small car extended and wedged under the rail and contacted posts while traversing the curb. Subsequently, the W-beam rail ruptured at a splice location. A repeat of MASH test no. 3-20 was performed on an updated design which used a 12-ft 6-in. (3.81-m) long, nested W-beam rail segment upstream from the W-beam to thrie beam transition element. The 1100C small car was successfully contained and redirected. During MASH test no. 3-21, a 2270P pickup truck was successfully contained and redirected. Following the crash testing program, the system was deemed acceptable according to the Test Level 3 (TL-3) safety performance criteria specified in MASH.
Temporary concrete barrier (TCB) systems that are not pinned into the pavement can be displaced d... more Temporary concrete barrier (TCB) systems that are not pinned into the pavement can be displaced during an impact and can result in workers being crushed between the barrier and objects within the workspace. Alternatively, the barrier could be moved far enough to fall off of the paved surface and onto workers in an excavation, below a bridge, or onto traffic under the bridge. The process for drilling holes in a bridge deck to anchor temporary concrete barriers is time-consuming, costly, and may ultimately result in damage to the bridge. Thus, a means for reducing the deflection of the barrier system is necessary and without the use of anchoring the barrier sections to the underlying pavements with pins, rods, or bolts. The primary objective of this study was to evaluate the potential for reducing barrier deflections through the use of box beam stiffening on New York State's TCBs. The secondary objective of the study was to evaluate stiffened and unstiffened versions of New York State's temporary concrete barrier system according to the Test Level 3 (TL-3) criteria set forth in the currently proposed Update to NCHRP Report No. 350. The research study included three full-scale vehicle crash tests with Dodge Quad Cab pickup trucks. The first system utilized 152-mm x 152-mm x 4.8-mm (6-in. x 6-in. x 0.1875-in.) box beam sections placed across three joints. The second system consisted of an unstiffened version of the temporary concrete barrier system. The final system utilized 152-mm x 203-mm x 6.4-mm (6-in. x 8-in. x 0.25-in.) box beam sections placed across six joints with the back side of the barriers placed 305 mm (12 in.) away from the bridge deck edge. Following the successful redirection of all three pickup trucks, the safety performance of the unstiffened and the two stiffened designs were determined to be acceptable according the TL-3 evaluation criteria specified in the currently proposed Update to NCHRP Report No. 350. Furthermore, the stiffened versions of the temporary concrete barrier system can be safely installed with a 305 mm (12 in.) gap between the bridge deck edge and the back side of the barriers.
Numerous roadside safety systems are configured with reinforced concrete materials, such as bridg... more Numerous roadside safety systems are configured with reinforced concrete materials, such as bridge railings, median barriers, and roadside parapets. The analysis and design of these structures may involve impact simulation with finite element software, like LS-DYNA, which includes multiple concrete material models. This Phase I study investigated the viability and performance of existing concrete material models to simulate unreinforced components subjected to common loading conditions, such as compression, tension, shear, and bending. For this study, five material models were evaluated – CSCM, K&C, RHT, Winfrith, and CDPM. Initially, single-element simulations were conducted in order to gain a basic understanding of material model performance. Next, small components with multiple elements were simulated to evaluate different loading conditions. Physical test data was obtained from several external experimental testing programs with unreinforced concrete in three basic load cases - compression, tension, and shear. The CSCM and K&C concrete material models provided adequate simulation results when compared to the experimental test results. Experimental tests with unreinforced concrete were conducted to obtain more results to compare with simulations. Concrete cylinder compression tests, dog-bone specimen tension tests, and four-point bend tests which created either flexure or shear failures were conducted. The CSCM and K&C material models showed promise in predicting peak forces and damage patterns in simulations of the experimental tests. Further investigation is recommended for the five selected concrete material models when used in combination with steel reinforcement.
The objective of this research study was to review and analyze the system failure observed during... more The objective of this research study was to review and analyze the system failure observed during crash testing of an increased span length for the MGS long-span guardrail system in test no. MGSLS-2. Test no. MGSLS-2 was a full-scale crash test conducted on the MGS long-span guardrail with a span length of 31¼ ft (9.5 m). This test utilized universal breakaway steel posts (UBSPs) adjacent to the long span in lieu of the controlled release terminal (CRT) wood posts used in previous long span systems. An engineering analysis was undertaken to review the downstream end anchorage failure observed in test no. MGSLS-2. The analysis also compared critical aspects of the barrier performance with previous full-scale crash tests that had similar features or increased anchor loading. The results of this analysis and conclusions regarding potential causes of the anchor failure suggested that there was no identifiable root cause for anchor failure, but the pocketing and deflection suggest that the barrier system may have been pushed near its limits. It was noted that certain factors may have contributed to the anchor failure, including increased span length, location of the impact point, differences in the breakaway post behavior adjacent to the unsupported span, and natural variation in wood strength. Following the analysis, several potential design modifications were noted for improving the barrier system and reducing the potential for end anchorage failure. However, it was noted that further analysis of these potential improvements, selection of a preferred design, and evaluation of the revised barrier system through full-scale crash tests will be required to fully evaluate the system to MASH TL-3 criteria.
... Due to vehicle snag and subsequent vehicle rollover, the first test was unsuccessful. Followi... more ... Due to vehicle snag and subsequent vehicle rollover, the first test was unsuccessful. Followingminor design modifications, the barrier system was retested. ... Pagination: 126 p. Authors: Polivka,KA. Bielenberg, RW. Faller, RK. Sicking, DL. University of Nebraska, Lincoln. Rohde, JR ...
Transportation Research Record: Journal of the Transportation Research Board
Portable concrete barriers (PCBs) are commonly used to protect work-zone personnel and to shield ... more Portable concrete barriers (PCBs) are commonly used to protect work-zone personnel and to shield motorists from hazards in construction areas. It is not uncommon to encounter longitudinal gaps within PCB installations resulting from the practice of constructing and connecting the barriers from different ends during setup or contractor operations. Longitudinal gaps can also be created by tensioning issues following an impact event. These gaps can range from 6 in. to a full barrier segment length of 12.5 ft. Longitudinal gaps between adjacent installations of PCB systems pose a serious safety concern for the errant motorist. Therefore, a need existed to develop a treatment capable of shielding the longitudinal gaps that occur between adjacent installations of PCB systems. In this research, design concepts for the gap-spanning hardware were conceived, and two design concepts were selected for further investigation and refinement through LS-DYNA computer simulation. Based on simulation ...
Transportation Research Record: Journal of the Transportation Research Board
New top-mounted sockets for use with the weak-post, Midwest Guardrail System (MGS) on low-fill cu... more New top-mounted sockets for use with the weak-post, Midwest Guardrail System (MGS) on low-fill culverts were developed and evaluated. The system was adapted from the MGS bridge railing for attachment to the top slab of a concrete box culvert. Three design concepts were developed and evaluated through dynamic component testing. Both lateral and longitudinal impact tests were conducted on the design concepts while mounted to simulated concrete culverts. Two concepts, a cylindrical concrete foundation and a steel tube socket assembly, proved strong enough to withstand the impact loads transferred from the posts without sustaining significant damage or displacements. However, the third concept, a concrete slab, fractured and allowed the sockets to rotate back without developing the post bending strength. Thus, only the cylindrical concrete foundation and the steel tube socket assembly in combination with the weak-post, MGS were determined to be crashworthy according to the Manual for As...
The objective of this study was to evaluate and compare the energy absorption characteristics of ... more The objective of this study was to evaluate and compare the energy absorption characteristics of W6x8.5 (W152x12.6) posts at a reduced embedment depth of 36 in. (914 mm) to that of the standard 40-in. (1,016-mm) embedded W6x8.5 (W152x12.6) posts used in the original Midwest Guardrail System (MGS). A total of eight dynamic component tests were performed – two tests with the 40-in. (1,016-mm) embedment depth and six with a 36-in. (914-mm) embedment depth. For two of the six 36-in. (914-mm) embedment tests, the load height was increased from 24⅞ in. (632 mm) to 28⅞ in. (733 mm). The posts were embedded in a highly compacted, coarse, crushed limestone material. For each test, acceleration data was used to determine the force vs. deflection and energy vs. deflection characteristics of the various post installations. Post-soil interaction forces and energy dissipation characteristics of the steel posts with a 36-in. (914-mm) embedment depth were compared to those for the steel post used i...
Geotechnical Earthquake Engineering and Soil Dynamics V, 2018
An accident reconstruction technique was developed for estimating the energy absorbed during an i... more An accident reconstruction technique was developed for estimating the energy absorbed during an impact with a cable barrier system as well as the initial impact velocity. The kinetic energy absorbed during a cable barrier system impact is comprised of several components: (1) plastic deformation/rotation of posts in a rigid foundation or soil foundation; (2) vehicle-ground interaction; (3) internal cable energy; and (4) frictional losses during vehicle-barrier interaction. The energy absorbed by deforming the J-bolt clips was analyzed and determined to be negligible for this study. Charts were developed that estimate the energy absorbed by deforming S3x5.7 (S76x8.5) cable line posts based on the soil condition, deformed post orientation, and deformed post height above the ground. Charts were also developed relating the cable tension to the cable energy absorbed versus the lateral deflection of the vehicle and the frictional energy versus the vehicle’s distance traveled for both a str...
The Iowa Department of Transportation (IaDOT) was interested in investigating the use of epoxy ad... more The Iowa Department of Transportation (IaDOT) was interested in investigating the use of epoxy adhesive anchorages for the attachment of posts used in the BR27C combination bridge rail system. Alternative anchorage concepts were developed using a modified version of the ACI 318-11 procedures for embedded anchor design. Four design concepts were developed for review by IaDOT, including: (1) a four-bolt square anchorage, (2) a four-bolt spread anchorage, (3) a twobolt centered anchorage, and (4) a two-bolt offset anchorage. IaDOT representatives selected the four-bolt spread anchorage and the two-bolt offset anchorage as the preferred designs for evaluation. In addition to these two proposed configurations, IaDOT also requested that the researchers evaluate a third option that had been previously installed on the US-20 bridge near Hardin, IA. The proposed alternative anchorages and the original cast-in-place anchorage for the BR27C combination bridge rail were evaluated through dynamic component testing. The test of the original cast-in-place anchorage was used a baseline for comparison with the alternative designs. Test no. IBP-1 of the original cast-in-place anchorage developed a peak load of 22.9 kips (101.9 kN) at a deflection of 1.5 in. (38 mm). All three of the tested alternative anchorages provided greater load capacity than the original cast-in-place design and were deemed acceptable surrogates. Of the three alternative designs, the two-bolt offset design was deemed the best option.
During the last decade, the use of cable median barriers has risen dramatically. Cable barriers a... more During the last decade, the use of cable median barriers has risen dramatically. Cable barriers are often utilized in depressed medians with widths ranging from 30 to 50 ft (9.1 to 15.2 m) and with fill slopes as steep as 4H:1V. A careful review of accident records has indicated that passenger vehicles occasionally penetrate through the standard three-cable median barrier and enter opposing traffic lanes. As a result, the Midwest States Regional Pooled Fund Program sponsored a research and development project to improve the safety performance of existing, non-proprietary, cable median barriers. These safety improvements included increased cable spacing, increased cable height, the use of four cables, increased cable tension, and optimized keyway bolts. For this study, one Test Level 3 (TL-3) full-scale crash test was performed on the improved high-tension, four-cable median barrier according to the Manual for Assessing Safety Hardware (MASH). The cable barrier system was configured ...
Transportation Research Record: Journal of the Transportation Research Board, 2020
Concrete box culverts are usually installed under roadways to allow water drainage without affect... more Concrete box culverts are usually installed under roadways to allow water drainage without affecting the motoring public. Culvert openings can represent a hazard on the roadside when they do not extend outside of the clear zone, and often require safety treatments in the form of roadside barriers. In this study, a modified design of Midwest Guardrail System (MGS) was evaluated for installation on a low-fill culvert with the strong-post attachment using through-bolts and epoxy anchorage through full-scale crash testing. The test installation consisted of MGS with a 31 in. top rail height, supported by W6 × 9 posts, spaced at 37½ in., attached to a low-fill culvert’s top slab with a 12 in. offset from the back of the post to the culvert headwall. Two crash tests were conducted according to the American Association of State Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety Hardware (MASH) 2016 Test Level 3 impact safety criteria. In test number CMGS-1, a 2,428-...
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Papers by Ronald K Faller