Design and Full-Scale Crash Testing of an Anchored Temporary Concrete Barrier and its Transition System for Use on Asphalt Pavement

Transcription

1 Design and Full-Scale Crash Testing of an Anchored Temporary Concrete Barrier and its Transition System for Use on Asphalt Pavement By Chiara Silvestri Dobrovolny *, Nauman M. Sheikh, Paul B. Fossier, Kurt Brauner, and Chris Guidry * Corresponding Author. Authors:. Chiara Silvestri Dobrovolny, Ph.D. Associate Research Scientist Texas A&M Transportation Institute, College Station, Texas, - Phone: --- Fax: c-silvestri@ttimail.tamu.edu. Nauman M. Sheikh, P.E. Associate Research Engineer Texas A&M Transportation Institute, College Station, Texas, - Phone: --- Fax: nauman@tamu.edu. Paul B. Fossier, P.E. Bridge Design Engineer Administrator Louisiana Department of Transportation & Development, Baton Rouge, Louisiana, 00 Phone: paul.fossier@la.gov. Kurt Brauner, P.E. Bridge Engineer Manager Louisiana Department of Transportation & Development, Baton Rouge, Louisiana, 00 Phone: kurt.brauner@la.gov. Chris Guidry, P.E. Assistant Bridge Design Administrator Louisiana Department of Transportation & Development, Baton Rouge, Louisiana, 00 Phone: chris.guidry@la.gov Submission date: July 0, 0 Word Count:,0 (only words) Number of Tables/Figures: =,0

2 Silvestri Dobrovolny, et al 0 0 Design and Full-Scale Crash Testing of an Anchored Temporary Concrete Barrier and its Transition System for Use on Asphalt Pavement Keywords: Anchored, Pinned, Temporary, Safety, Crashworthiness, Finite Element Analysis, Crash Testing ABSTRACT In 00, Texas A&M Transportation Institute developed a pinned down anchored temporary concrete barrier system for use on concrete pavements. This F-shape barrier with pin-and-loop connections was anchored using steel pins that passed through inclined holes cast in the toe of the barrier, and continued a short distance into the underlying concrete pavement. The objective of the presented research was to extend the use of this existing anchored barrier design for placement on asphalt with minimum design modifications. By performing a series of dynamic subcomponent tests and full-scale impact simulation analyses, the researchers developed an appropriate anchoring design for pinning the barrier on asphalt. This design involves placing the barrier on a inch thick asphalt pad and pinning it to the ground using three steel pins per barrier segment. The design was developed to perform in accordance with MASH test level criteria (000-lb vehicle, mi/h, degrees) at the critical impact point. MASH test - was performed on an installation of pinned down barrier segments placed adjacent to a.h:v slope with a -foot lateral offset. The pinned down anchored barrier design performed successfully according to MASH TL- criteria. A transition system between non-anchored free-standing barrier segment and anchored section was also designed to allow smooth vehicle transition from the free-standing to the pinned-down anchored barrier system installed on asphalt. The transition design was crash tested and performed acceptably in accordance with MASH test - criteria.

3 Silvestri Dobrovolny, et al INTRODUCTION AND BACKGROUND In 00, Texas A&M Transportation Institute (TTI) developed a restrained F-shaped temporary concrete barrier design that was easy to install and minimized damage to the bridge deck or concrete pavement (). This restraint mechanism was developed for use on concrete bridge decks and pavements. It used.- inch diameter steel pins dropped into inclined holes cast in the toe of the barrier segments. The pins passed through the holes in the barrier and continued a short distance into the underlying concrete pavement, thus locking the barrier in place. The pinned-down barrier successfully passed the National Cooperative Research Program (NCHRP) Report 0 Test Level (TL-) requirements (). The maximum permanent and dynamic barrier deflections were. inches and. inches, respectively. There was no significant damage to the underlying concrete pavement. A desired was raised to develop a transition for using the pinned down barrier with the rigid concrete barrier. In 0, TTI conducted a study to develop a transition design that could be used to transition from a free-standing F-shape temporary concrete barrier system to the pinned down F shape barrier placed on concrete pavement or bridge deck (). One of the desired objectives was to keep the transition design relatively simply but not attaching external members to the barrier segments (such as bolting thrie beam rail elements to the face of the barriers, attaching other brackets or straps, etc ). The transition concept consisted in one standard F-shape barrier segment in the transition region that connected the free standing and the anchored barrier segment. Only one pin was used in the transition segment to pin it to the underlying concrete, near the anchored barrier end of the installation. The drop-pin used in the transition segment was the same ½ inch diameter pin used to anchor the existing pinned-down barrier. The design was crash tested in accordance with the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) test - criteria (000-lb vehicle, mi/h, and degrees) at the critical impact point (). The transition design from the free-standing to anchored F-shape barrier placed on concrete performed acceptably for MASH TL-. Among other anchored concrete barrier designs, Midwest Roadside Safety Facility (MwRSF) has developed a design for the F shape temporary concrete barrier along with various transition details. In 00, MwRSF developed a concrete bridge deck tie-down system for. ft long, F-shaped Kansas temporary barriers (). Three anchor bolts were passed through the holes in the barrier and fastened to the bridge deck on the traffic side of the barrier. The maximum static and dynamic deflections were. inches and. inches, respectively. Later on in 00, MwRSF developed an NCHRP Report 0 compliant tie down design for. ft long temporary concrete barriers with pin-and-loop type connection for use on asphalt pavements that are at least two inches thick (). The barrier was installed at a inch lateral offset from the edge of a ditch. This tie-down system used three.-inch diameter steel pins that were driven down vertically through holes cast in each barrier segment. The pins were -ft long and pinned the barrier to the underlying asphalt ground. The maximum static and dynamic deflections in the test were. inches and. inches, respectively. In the same study, MwRSF developed a transition from the free-standing.-ft long temporary concrete barrier to the anchored temporary concrete barrier design developed earlier in 00. The transition section was comprised of four.-ft long barrier segments in which steel pins were driven in through the holes in the barrier. The number of pins in the transition barrier segments was gradually reduced to transition from the anchored to the free standing barrier. Barrier segments in the transition section of this design were placed on a -inch thick asphalt layer. The barrier was installed at a -inch lateral offset from the edge of a ditch. The maximum static and dynamic deflections in the test were. inches and. inches, respectively. In 00, MwRSF developed a transition design for attaching free-standing F-shape barrier to the rigid concrete barrier (). This design employs the anchored barrier segment developed by MwRSF earlier in 00 and an intermediate section to transition from the free-standing to the rigid barriers. At one end the anchored barrier segments connect to the free-standing barrier, and at the other end they connect to a rigid concrete barrier. A -inch tall single slope barrier was used as the rigid barrier system. The number of pins in the anchored barrier segments was varied to gradually increase the lateral restraint of the barrier over four.-ft long segments. The anchored barrier segments were place on a -inch

4 Silvestri Dobrovolny, et al thick asphalt pad. To reduce snagging of the vehicle while transitioning from anchored barrier to the rigid barrier, a nested -gauge thrie beam section was used. The rail segment was attached to the traffic side face of the rigid and the anchored barrier segments. In, California Department of Transportation (Caltrans) developed a pinning/staking configuration for its 0-ft long, NJ profile concrete barriers, connected with a pin-and-loop type connection (). The configuration met NCHRP Report 0 evaluation criteria and consisted of four - inch diameter pins that were driven. inches vertically into the underlying asphalt pavement. Each barrier segment was pinned at its four corners. The barrier was tested in a median configuration and there was no ditch or slope behind the barrier. The maximum static and dynamic deflections of the system were. inches and 0 inches, respectively. OBJECTIVES The objectives of this research effort were: ) Modify the anchoring design of the previously developed F-shape pinned-down concrete barrier and extend its use for asphalt pavement; and ) Develop a transition design for use to transition from pinned-down F-shape barriers placed on asphalt to free-standing F-shape barriers. Both designs were to be developed to perform in accordance with AASHTO MASH TL- criteria, using the existing pinned F-shape temporary concrete barrier design to the extent possible. DESIGN OF ANCHORED TEMPORARY CONCRETE BARRIER FOR USE IN ASPHALT The researchers performed several subcomponent level pull tests followed by finite element (FE) analyses to determine the appropriate pinning design for anchoring the temporary concrete barrier on asphalt. Pin Pullout Tests To determine the appropriate pinning scheme, the researchers evaluated the response of a single anchoring pin when installed in soil and asphalt. A series of dynamic pull tests were performed to determine the lateral resistance and deflection response of a single anchoring pin when installed in soil and in different thicknesses of asphalt pad laid over soil base. These tests revealed that pinning the barrier directly on soil is not likely to yield enough lateral restraint to sufficiently anchor the barrier with two to three pins per barrier segment. The researchers conducted further dynamic pull-tests with pins installed in different thickness of asphalt (). Three -ft long and -ft wide asphalt pads with,, and -inch thickness were constructed. The pads were constructed over a -inch wide and -inch deep soil bucket that contained compacted crushed limestone road base. The pins were installed using a purposely designed metal frame (Figures (a) and (b)). A tractor was used to apply the load on the pins by pulling on a cable that was attached to the frame (Figure (c)). A load cell was used to measure the dynamic tensile force in the cable. The first test was performed with a -inch long pin installed in the -inch thick asphalt pad. The pin started to deform once the cable was taught and the pull vehicle was travelling at a speed of approximately mi/h. After significant bending of the anchoring pin, the asphalt pad started to delaminate from the soil base and was pulled forward (Figure (d)). A peak load of kips was achieved from the -inch pad. This restraint level was considered sufficient to anchor the barrier in the final design. However, the researchers performed another test with the -inch thick pad to determine if the thinner pad could also achieve acceptable lateral restraint. The pull test with the -inch pad however resulted in significant tearing of the pad (approximately 0 inches) as the inclined anchor pin moved laterally (Figure (e)). The large lateral movement of the pin in the -inch pad implied a potential for large overall barrier deflection, which would be an unacceptable outcome. The peak restraint force achieved with the -inch thick pad was. kips. Thus, due to the high lateral deflection and lower lateral restrain force, the -inch pad was considered undesirable for the final anchoring design. Based on the findings of the dynamic pull tests, the pinned down anchored barrier design was developed for placement on a -inch thick asphalt pad.

5 Silvestri Dobrovolny, et al (a) Anchoring Pin Details (b) Anchoring pin installed in asphalt pad (c) Test set up (d) Tear in asphalt pad due to pin pullout on - inch pad (e) Tear in asphalt pad due to pin pullout on -inch pad FIGURE Test Set Up and Results for Dynamic Pull Testing of Pins Installed in Asphalt (). FULL-SCALE CRASH TEST OF ANCHORED TEMPORARY CONCRETE BARRIER FOR USE IN ASPHALT Test Installation The precast concrete segments used in this crash test were. ft long and had a standard F profile. The barriers were inches tall, inches wide at the base, and. inches wide at the top. Horizontal

6 Silvestri Dobrovolny, et al barrier reinforcement consisted of eight # bars spaced along the height of the barrier within the vertical reinforcement. Vertical barrier reinforcement consisted of rebar stirrups of # bars spaced inches on centers. These vertical bars were bent to conform to the F-shape barrier profile and to provide sufficient concrete cover for the faces of the barrier and the drainage scupper at the base of the barrier. For the last two vertical stirrup bars adjacent to the ends of the barrier segments, the spacing was reduced to. inches and. inches, respectively. All rebar reinforcement was grade 0 steel material. Adjacent barrier segments were connected using a pin and loop type connection. The loops were made of /-inch diameter round stock steel. The outer diameter of the loops was. inches and they extended inches outside the end of the barrier segment. The barrier connection was comprised of two sets of three loops. When installed, the distance between adjacent barrier segments was 0. inches. A - inch diameter, 0-inch long connecting pin was inserted between the loops to establish the connection. A -inch diameter and / inch thick washer was welded / inch from the top of the connecting pin. The pin was held in place by resting the washer on insets built into the faces of adjacent barriers. Three.-inch wide and -inch long slotted holes, inclined 0 degrees from the ground, were cast into the toe of each barrier segment. These slotted holes started from the traffic face of the barrier and exited near its bottom centerline. Two of the slotted holes were positioned inches away from each face of the barrier. The third slotted hole was positioned in the middle of the barrier segment. The barriers were placed adjacent to a.h:v slope with a -inch offset from the slope break point. The underlying ground was comprised of -inch thick, -feet long, and -feet wide asphalt pad constructed on top of a inch thick layer of crushed limestone road base (Type A, Grade ), which was compacted to % of standard proctor density. A layer of asphalt binder (CSS-H tack coat binder) was sprayed at the interface between the asphalt and soil surfaces. The asphalt used was hot mixed Type D with reclaimed asphalt pavement (RAP). Once the barriers were positioned in place, the slotted holes in the barrier segments were used as a guide to drill pilot holes in the underlying asphalt and soil base. The pilot holes were drilled using a.-inch diameter drill bit. After each pilot hole was drilled, a.-inch diameter, -inch long anchoring pin was passed through the slotted hole in the barrier and driven into the asphalt-soil base. Thus, each barrier segment was anchored to the ground with three pins. The anchoring pin was fabricated with a - inch tip. The top of each anchoring pin had a ½-inch thick, -inch -inch A plate cover welded to it. The plate covers were welded at a -degree angle from the vertical so that they matched the profile of the barrier s toe when installed. Inside the barrier segments, a -inch long U-shaped # bar was diagonally placed at the location of each slotted hole. The U-shaped bar circumvented the slot to reinforce the concrete around it and to resist pullout of the anchoring pin in the event of concrete failure in the vicinity of the slotted hole. The completed test installation consisted of barrier segments connected together for a total length of approximately 0 ft and inches. The end barrier segments on each side of the installation were placed directly on native soil and were not anchored. The remaining 0 barrier segments were placed on the asphalt pad and were anchored as described above. Barrier segments used in the test installation were donated by WASKEY. Details of the barrier and the pin down restraint are shown in Figure.

7 Silvestri Dobrovolny, et al (a) End View Drawing Details 0 0 (b) Impact Side Installation View (c) Field Side Installation View FIGURE Anchored Temporary Concrete Barrier Drawing and Installation Details (). Pickup Truck Test 00-- A 00 Dodge Ram 00 pickup truck was used for the crash test. Test inertia weight of the vehicle was 0 lb, and its gross static weight was 0 lb. The height to the vehicle s center of gravity was. inches. The 00 Dodge Ram 00 pickup, traveling at an impact speed of. mi/h, impacted the temporary concrete barrier system pinned on asphalt. ft upstream of the joint between segments and at an impact angle of. degrees. At approximately 0.0 s, the vehicle began to redirect, and at 0.0 s, the left front tire blew out. The vehicle became airborne at 0. s. Maximum deflection of. inches occurred at 0. s. At 0. s, the vehicle began traveling parallel with the barrier at a speed of. mi/h. At 0. s, the vehicle lost contact with the barrier and was traveling at an exit speed and angle of 0. mi/h and. degrees, respectively. The vehicle touched ground at 0. s, and the brakes on the vehicle were applied at. s. The vehicle came to rest ft downstream of impact and ft toward traffic lanes from barrier traffic face. Damage to the barrier installation is shown in Figure (a). The anchor pins on segments, and pulled upward, and the pin on the upstream end of segment was deformed. The downstream end of segment moved 0. inch toward the traffic side. The concrete around the anchoring pin in the toe area of segment failed and spalled off due to the impact. The upstream end of segment moved.0 inches toward the field side, and the downstream end moved. inches toward traffic lanes. The upstream end of segment moved 0. inch toward traffic lanes. Working width was. inches, maximum dynamic deflection during the test was. inches, and maximum permanent deformation was.0 inches.

8 Silvestri Dobrovolny, et al 0 0 Figure (b) shows damage to the 0P vehicle. The left front upper and lower A-arms, left tie rod end, left frame rail, left rear U-bolts, and drive shaft were damaged. Also damaged were the front bumper, left front fender, left front tire and wheel rim, left front and rear doors, left rear cab corner, left rear exterior bed, left rear tire and wheel rims, and rear bumper. Maximum exterior crush to the vehicle was.0 inches in the side plane at the left front corner at bumper height. Maximum occupant compartment deformation was 0. inch in the lateral area across the cab at driver s hip height. Data from the accelerometer, located at the vehicle s center of gravity, were digitized for evaluation of occupant risk. In the longitudinal direction, the occupant impact velocity was. ft/s at 0.0 s, the highest 0.00-s occupant ridedown acceleration was. Gs from 0. to 0.0 s, and the maximum 0.00-s average acceleration was -. Gs between 0.0 and 0.0 s. In the lateral direction, the occupant impact velocity was. ft/s at 0.0 s, the highest 0.00-s occupant ridedown acceleration was. Gs from 0. to 0. s, and the maximum 0.00-s average was 0. Gs between 0.0 and 0.0 s. These data and other pertinent information from the test are summarized in Figure. The F-shape temporary concrete barrier pinned on asphalt contained and redirected the 0P vehicle. The vehicle did not penetrate, underride, or override the installation. Maximum dynamic deflection of the barrier during the test was. inches. No detached elements, fragments, or other debris were present to penetrate or to show potential for penetrating the occupant compartment, or to present hazard to others in the area. Maximum occupant compartment deformation was 0. inch in the lateral area across the cab at passenger hip height. The 0P vehicle remained upright during and after the collision event. Maximum roll and pitch angles were and 0 degrees, respectively. The occupant risk factors were below the preferred values specified in MASH. According to the MASH criteria required for test -, the anchored temporary concrete barrier placed on asphalt pavement performed acceptably. (a) Test Article Damage (b) Vehicle Damage FIGURE Test Article and Vehicle Damage for Full Crash Test 00-- ().

9 Silvestri Dobrovolny, et al s 0.0 s 0.0 s 0.00 s General Information Test Agency... Test Standard Test No.... TTI Test No.... Date... Test Article Type... Name... Installation Length... Texas Transportation Institute (TTI) MASH Test November, 0 Portable Concrete Median Barrier (pinned) Temporary CMB pinned to asphalt 0. ft Soil Type and Condition... Asphalt and Soil, Dry Test Vehicle Type/Designation... 0P Make and Model Dodge Ram 00 Pickup Curb... lb Test Inertial... 0 lb Dummy... No dummy Gross Static... 0 lb Impact Conditions Speed.... mph Angle.... degrees Occupant Risk Values Impact Velocity Longitudinal.... ft/s Lateral.... ft/s Ridedown Accelerations Longitudinal.... G Lateral.... G THIV....0 km/h PHD.... G ASI.... Max s Average Longitudinal...-. G Lateral G Vertical...-. G Post-Impact Trajectory Stopping Distance... 0 ft dwnstrm ft twd traffic Vehicle Stability Maximum Yaw Angle... degrees Maximum Pitch Angle... 0 degrees Maximum Roll Angle... degrees Test Article Deflections Dynamic.... inches Permanent....0 inches Working Width.... inches Vehicle Damage VDS... LFQ CDC... FLEW Max. Exterior Deformation....0 inches OCDI... LF Max. Occupant Compartment Deformation inch FIGURE Summary of Results for MASH test - on Temporary Concrete Barrier Pinned on Asphalt (Test 00--) ().

10 Silvestri Dobrovolny, et al DESIGN OF A TRANSITION FOR ANCHORED TEMPORARY CONCRETE BARRIER FOR USE IN ASPHALT Transition Concept Design The developed transition concept was a single standard F-shape barrier segment in the transition region that connected the free-standing and the anchored barrier segments (Figure (a)). Only one pin was used in the transition segment to pin it to the underlying asphalt pavement, near the anchored barrier end of the installation. The anchor pin used in the transition segment was the same ½-inch diameter pin used to anchor the existing pinned-down barrier. Finite Element Analyses MASH recommends using FE analysis to determine the Critical Impact Point (CIP) for a transition design. The researchers developed a full-scale FE model of the barrier system to perform MASH Test - impact simulations. The barrier system was comprised of the.-ft long F-shape free-standing barrier segments, one transition segment with one anchor pin, and the standard anchored barrier system with three anchor pins per segment (0). Using this barrier system model, the researchers performed MASH test - vehicle impact simulations at four impact locations. The first impact point was selected just upstream of the anchoring pin in the transition segment. The second, third, and fourth impact points were spaced. ft apart. The objective of these simulations was to determine the critical impact point at which the vehicle would have the greatest instability due to pocketing of the barrier system. Simulation results for impacts closer to the standard anchored barrier indicated that the barriers do not deflect significantly. Vehicle impacts closer to the standard anchored barrier do not allow enough interaction with the vehicle for the barrier segments in the free standing and the transition region to deflect laterally. Thus, vehicle pocketing cannot be evaluated with these impact points. For this reason, it was concluded that impact points and are not the critical impact points. Simulation results for impact points and, which are farther upstream from the start of the standard anchored barrier segments, showed greater lateral barrier deflection than impact points and. For impact point, the vehicle had significant chance of pocketing due to the lateral deflection of the barriers. Even though the lateral deflection increased for impact point, the performance at this point resembled that of a free standing barrier as opposed to a transition. For this reason, the vehicle resulted being more stable for impact point compared to impact point (0). Since impact point offers greatest chance of vehicle instability and pocketing, it was selected as the CIP for the transition design. This impact point was. ft upstream from the joint between the transition barrier segment and the anchored barrier segment. A crash test was subsequently performed at this impact point. FULL-SCALE CRASH TEST OF THE TRANSITION FOR ANCHORED TEMPORARY CONCRETE BARRIER FOR USE IN ASPHALT Test Installation The overall length of the test installation was ft- inches. The installation was comprised of thirteen ft- inch long precast concrete barrier segments that were inches tall and had the standard F profile. The first seven barrier segments ( to ) were free-standing and were not anchored to the underlying asphalt pavement. Barrier segment was pinned to the underlying asphalt pavement using a single ½ inch diameter, -inch long steel pin that passed through the inclined slotted hole near the downstream end of the segment. Segments through were pinned using three ½ inch diameter, - inch long steel pins per barrier segment. These pins were passed through the inclined slotted holes in the barrier and driven into the asphalt-soil base. The anchoring pin was fabricated with a -inch long tapered tip. The top of each anchoring pin had a ½ inch thick, -inch -inch A plate cover welded to it. The plate covers were welded at a degree angle from the vertical so that they matched the profile of the barrier s toe when installed.

11 Silvestri Dobrovolny, et al Precast concrete barrier segments used in the test installation were donated by WASKEY and details regarding their geometry, reinforcement, pin and loop connection have been reported above in the description of the test article for the first full-scale crash test reported in this paper. The barriers were placed on flat level ground. The underlying ground was comprised of 0-ft long, and -ft wide asphalt pad constructed on top of a layer of crushed limestone road base (Type A, Grade ), which was compacted to percent of standard proctor density. The anchored barriers were pinned to a -inch thick asphalt layer (whose total length was 0 ft) on top of a -inch thick layer of crushed limestone road base, while the free standing barriers were positioned on a -inch thick asphalt layer (whose total length was 0 ft) on top of a -inch thick layer of crushed limestone road base. A layer of asphalt binder (CSS-H tack coat binder) was sprayed at the interface between the asphalt and soil surfaces. The asphalt used was hot mixed Type D with reclaimed asphalt pavement (RAP). Once the barriers were positioned in place, the slotted holes in the barrier segments that required anchors were used as a guide to drill pilot holes in the underlying asphalt and soil base. The pilot holes were drilled using a ¾-inch diameter bit. After each pilot hole was drilled, a ½-inch diameter, -inch long anchoring pin was passed through the slotted hole in the barrier and driven into the asphalt-soil base. Thus, barrier segments through were anchored to the ground with three pins. Barrier segments used in the test installation were donated by WASKEY. Details of the barrier and the pin down restraint are shown in Figure (b) and (c). Pickup Truck Test 00-- A 00 Dodge Ram 00 pickup truck was used for the crash test. Test inertia weight of the vehicle was 0 lb, and its gross static weight was 0 lb. The height to the vehicle s center of gravity was. inches. The 00 Dodge Ram 00 pickup, traveling at an impact speed of. mi/h, impacted the temporary concrete barrier system pinned on asphalt ft inches upstream from the joint between the transition barrier segment and the first anchored barrier segment at an impact angle of.0 degrees. At approximately at 0.00 s, the barrier began to deflect towards the field side at the joint between segments and, and at 0.00 s, the downstream end of segment began to deflect towards the traffic side and the upstream end of segment began to deflect towards the traffic side. The upstream end of segment began to deflect toward the field side at 0.0 s, and then began to rotate clockwise at 0. s. At 0. s, the vehicle began traveling parallel to the barrier, and at 0. s, the rear of the vehicle contacted the barrier. The vehicle became airborne at 0.0 and began to roll clockwise. At 0. s, the vehicle lost contact with the barrier and was traveling at an exit speed and angle of. mi/h and. degrees, respectively. The right front tire touched ground at 0. s, and as the vehicle continued forward, it continued to roll clockwise. The vehicle came to rest upright. ft downstream of impact point and ft toward traffic lanes from barrier traffic face. Damage to the barrier installation is shown in Figure (a). The downstream anchor pin on segment pulled upward.0 inches, and the pin on the upstream end of segment pulled upward.0 inches. Minimal spalling of the concrete segments occurred at the joint between segments and. Working width was. inches, and vehicle intrusion was. inches. Maximum dynamic deflection during the test was. inches, and maximum permanent deformation was.0 inches. Figure (b) shows damage to the 0P vehicle. The front bumper, right front fender, right front tire and wheel rim, right front and rear doors, right rear cab corner, right rear exterior bed, right rear tire and wheel rim, rear bumper, and tailgate were damaged. The windshield sustained stress cracks in the lower left corner. Maximum exterior crush to the vehicle was.0 inches in the side plane at the right front corner at bumper height. Maximum occupant compartment deformation was. inches in the lateral area across the cab in the kick panel area.

12 Silvestri Dobrovolny, et al (a) Transition Design Concept (b) End View Drawing Details (c) Impact Side Installation View (d) Field Side Installation View FIGURE Transition for Anchored Temporary Concrete Barrier Drawing and Installation Details (0). Data from the accelerometer, located at the vehicle s center of gravity, were digitized for evaluation of occupant risk. In the longitudinal direction, the occupant impact velocity was. ft/s at 0.0 s, the highest 0.00-s occupant ridedown acceleration was. Gs from 0. to 0. s, and the maximum 0.00-s average acceleration was -. Gs between 0.0 and 0.0 s. In the lateral direction, the occupant impact velocity was. ft/s at 0.0 s, the highest 0.00-s occupant ridedown acceleration

13 Silvestri Dobrovolny, et al 0 was. Gs from 0. to 0. s, and the maximum 0.00-s average was. Gs between 0.0 and 0.0 s. These data and other pertinent information from the test are summarized in Figure. The transition from the free-standing F-shape barrier to pinned F-shape barrier placed on asphalt pavement contained and redirected the 0P vehicle. The vehicle did not penetrate, underride, or override the installation. Maximum dynamic deflection of the barrier during the test was. ft. No detached elements, fragments, or other debris were present to penetrate or to show potential for penetrating the occupant compartment, or to present hazard to others in the area. Maximum occupant compartment deformation was. inches in the lateral area across the cab at hip height. The 0P vehicle remained upright during and after the collision event. Maximum roll and pitch angles were 0 degrees and degrees, respectively. Occupant risk factors were within preferred limits specified in MASH. According to the MASH criteria required for test -, the transition from the free-standing to anchored F-shape barrier placed on asphalt pavement performed acceptably. (a) Test Article Damage (b) Vehicle Damage FIGURE Test Article and Vehicle Damage for Full Crash Test 0- (0).

14 Silvestri Dobrovolny, et al s 0. s 0. s 0.00 s General Information Test Agency... Test Standard Test No.... TTI Test No.... Date... Test Article Type... Name... Installation Length... Material or Key Elements... Texas A&M Transportation Institute (TTI) MASH Test - 0- March, 0 Transition Transition from free-standing F-shape barrier to pinned F-shape barrier on asphalt and soil. ft Asphalt pavement, CMB, Transition Soil Type and Condition... Asphalt and Soil, Dry Test Vehicle Type/Designation... 0P Make and Model Dodge Ram 00 Pickup Curb... lb Test Inertial... 0 lb Dummy... No dummy Gross Static... 0 lb Impact Conditions Speed.... mph Angle....0 degrees Location/Orientation... Occupant Risk Values Impact Velocity Longitudinal.... ft/s Lateral.... ft/s Ridedown Accelerations Longitudinal.... G Lateral.... G THIV.... km/h PHD.... G ASI.... Max s Average Longitudinal...-. G Lateral...-. G Vertical...-. G Post-Impact Trajectory Stopping Distance.... ft dwnstrm ft twd traffic Vehicle Stability Maximum Yaw Angle... degrees Maximum Pitch Angle... degrees Maximum Roll Angle... 0 degrees Test Article Deflections Dynamic.... inches Permanent....0 inches Working Width.... inches Vehicle Intrusion.... inches Vehicle Damage VDS... 0RFQ CDC... 0FREW Max. Exterior Deformation....0 inches OCDI... LF Max. Occupant Compartment Deformation.... inch FIGURE Summary of Results for MASH test - on Transition for Temporary Concrete Barrier Pinned on Asphalt (Test 0-) (0).

15 Silvestri Dobrovolny, et al SUMMARY AND CONCLUSIONS Previously, TTI had developed a pinned down anchored temporary concrete barrier system for use on concrete pavements (). The first objective of this research was to extend the use of the previously developed pinned down barrier design for placement on asphalt or soil base. The researchers were required to keep the existing design features to the extent possible. The second objective of the study was to develop a transition design that can be used to transition from free-standing F-shape barrier to the pinned-down F-shape barrier placed on asphalt. To determine the appropriate pinning scheme of the anchored system, the researchers developed a series of dynamic pull tests and finite element computer analyses. Pull tests were used to determine the appropriate thickness for the asphalt pad for placement of the pinned down anchored barrier design was determined. Finite element analyses were needed to evaluate the performance of the pinned barrier system under MASH test - conditions, when different pinned scheme were considered. Results of the computer analyses showed slightly better performance when three pins per segment were used to anchor the barrier. The anchorage design with three pins per barrier segment was then evaluated through fullscale crash testing and it performed acceptably according to MASH test - standards and evaluation criteria Next, the researchers designed a transition for the temporary concrete barrier pinned for use in asphalt pavement. The transition was to be developed for MASH test level criteria, using the existing pinned F-shape temporary concrete barrier design to the extent possible. The final design of the transition segment included use of only one pin located near the anchored barrier end of the installation. The researchers performed finite element analyses to determine the CIP of the transition system to be then evaluated through full-0scale crash testing under MASH test - conditions. The system performed acceptably according to MASH test - standards and evaluation criteria. IMPLEMENTATION As described for both crash tests reported, the test installations was comprised of a -inch thick asphalt pavement over a -inch thick Type-A Grade- crushed limestone road base for anchorage of pinned and transition barrier segments. This road base was primarily used to meet MASH requirements for the type of soil that should be used for testing, and to be able to compact the -inch thick asphalt pavement on top. In a field installation, it may not always be feasible to have a -inch thick road base for the anchored barriers. Furthermore, native soil conditions may vary from one site to another. It should be noted that the primary resistance to the deflection of the barrier comes from the asphalt pavement. While differences in soil properties underneath the asphalt layer can have some influence on the lateral deflection of the barrier, their effect is expected to be minimal as long as the sub-base is stable enough to roll and compact the asphalt pavement on top of it. Thus smaller thickness of road base may also be used in combination with native soil if the sub-base can be stabilized to achieve proper compaction of the minimum inch thick asphalt pavement on top. Based on previous research, the anchored barrier segments can be placed adjacent to a.h:v or flatter slope with a minimum -inch offset from the slope break point (). The free standing barrier segments, however, should not be placed adjacent to a slope. Free-standing segments should have at least ft offset from a slope break point or other objects to allow for barrier deflection during the impact event. The length of the barrier segments used in the test installation was ft inches. This is the minimum segment length of the portable concrete barriers used among the participating Pooled Fund states. While the design was developed using the smallest barrier segment length, it can also be extended for use with longer barrier segments by adding additional anchoring pins if needed. The connections between adjacent barrier segments are the weakest points in the system. Due to this, the distance of the anchoring pins adjacent to the connections should not be increased with respect to the connection. Doing so can alter the restraint characteristics of the barrier. Additional pins should therefore only be added to the mid span of the barrier segment without altering the location of the pins adjacent to the barrier connections.

16 Silvestri Dobrovolny, et al ACKNOWLEDGMENT This research project was performed under TPF-() Roadside Safety Research Program Pooled Fund Study. The authors acknowledge and appreciate their assistance and guidance. REFERENCES () Sheikh N. M., Bligh R. P., and Menges W. L., "Crash Testing and Evaluation of the ft Pinned F- Shape Temporary Barrier," Texas Transportation Institute, College Station, Texas, 00. () Ross, Jr., H.E., Sicking, D.L., Zimmer, R.A. and Michie, J.D., Recommended Procedures for the Safety Performance Evaluation of Highway Features, National Cooperative Highway Research Program Report 0, Transportation Research Board, National Research Council, Washington, D.C.,. () Sheikh, N.M. and Menges, W.L., Development and Testing of a Transition from Free-Standing to Pinned Temporary Concrete Barrier, Test Report No. 00- Texas A&M Transportation Institute, College Station, Texas, 0. () AASHTO, Manual for Assessing Safety Hardware, American Association of State Highway and Transportation Officials, Washington, D.C., 00. () Polivka, K.A., Faller, R.K., Rohde, J.R., Holloway, J.C., Bielenberg, B.W., and Sicking, D.L., Development and Evaluation of a Tie-Down System for the Redesigned F-Shape Concrete Temporary Barrier, Midwest Roadside Safety Facility, Nebraska, 00. () Bielenberg, B.W., Reid, J.D., Faller, R.K., Rohde, J.R., and Sicking, D.L., Tie-downs and Transitions for Temporary Concrete Barriers, Transportation Research Record, TRR, 00. () Wiebelhaus, M.J., Terpsma, R.J., Lechtenberg, K.A., Reid, J.D., Faller, R.K., Bielenberg, R.B., Rohde, J.R., and Sicking, D.L., Development of Temporary Concrete Barrier to Permanent Concrete Median Barrier Approach Transition, Draft Report to the Midwest State s Regional Pooled Fund Program, Transportation Research Report No. TRP 0-0-0,00. () Jewel, J., Weldon, G., and Peter, R., Compliance Crash Testing of K-Rail Used in Semi-Permanent Installations, Report No. -0, Division of Materials Engineering and Testing Services, CALTRANS, Sacramento, CA,. () Sheikh N. M., and Menges W. L., "Development and Testing of Anchored Temporary Concrete Barrier for Use on Asphalt", Report No. 00--, Texas A&M Transportation Institute, College Station, Texas, 0. (0) Silvestri Dobrovolny C., Sheikh N. M., and Menges W. L., "Transition for Anchored Temporary Concrete Barrier System in Asphalt Pavement Phase II", Report No. 0-, Texas A&M Transportation Institute, College Station, Texas, 0.