U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| REPORT |
| This report is an archived publication and may contain dated technical, contact, and link information |
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| Publication Number: FHWA-HRT-15-074 Date: September 2016 |
Publication Number: FHWA-HRT-15-074 Date: September 2016 |
Sensor installation and field testing activities in support of the project began on Monday, September 16, 2013, and lasted through Friday, September 27, 2013. A significant amount of data resulted from the field testing activities, which when combined with other relevant data (e.g., pavement structure, pavement condition, climate, etc.) necessitated the development of a project database and Web site to facilitate the planned analyses. A summary of the field activities as well as the project database and Web site development activities is provided in this chapter.
The installation of geophones and accelerometers at the MnROAD facility took place during the week of September 16, 2013. This section provides a chronological summary account of the activities that took place.
Monday, September 16, 2013
Activities began on Monday morning with a meeting between project team members and MnROAD staff to coordinate the sensor installation and testing activities. The following people were present at the meeting:
As illustrated in figure 24, 4 geophones and 1 accelerometer were installed at each of MnROAD cells 3, 19, 34, and 72 (for a total of 16 geophones and 4 accelerometers) for accuracy testing. The activities at each cell included the following:
Tuesday, September 17, 2013
Activities on Tuesday were dedicated to verifying the proper installation and performance of the 20 sensors (16 geophones and 4 accelerometers). The performance of each sensor was verified by comparing the deflection from the MnROAD FWD sensor placed directly on top of the embedded sensor with the corresponding deflection reported by the embedded sensor. Based on the successful verification of the performance of all 20 sensors, the embedded sensors were then fully grouted. The feasibility of aligning the tires of the moving deflection devices with the sensors were also verified using the MnROAD truck.
Wednesday, September 18, 2013
On Wednesday morning, members of the project team went to cell 19 to install and test the pressure tubes, which were the second choice for trigger and timing the DAQ for the embedded sensors. Part of this activity involved figuring out the best way to affix the tubes to the surface of the road so that they would be able to withstand the devices that were being tested and yet be easy to move from cell to cell. The project team set up tubes with asphalt tape and drove with a vehicle at different speeds. It was concluded that asphalt tape would not be strong enough, and nailing the tubes to the road would be time consuming. After discussing the situation with MnROAD personnel, they indicated that they had laser triggers that were no longer being used and that those could possibly work for the planned field testing. Once the circuit and power requirements were inspected, permission was requested from MnROAD to wire one of the triggers to the project team's DAQ system.
Thursday, September 19, 2013
The trigger sensors offered by MnROAD were NX5-RM7B from PanasonicTM. They use an infrared LED and a reflector and have a sensing distance of up to 22.96 ft (7 m). The one drawback they have is that they work with 12 Vdc, and the output pulse would have that same amplitude.
Considering that the DAQ system has a limit of ±10 Vdc and the incoming signals from the geophones and accelerometer would have a much lower amplitude, the project team decided to build a small connection box to the MnROAD triggers, which would allow the team to use the signal cables that had been brought to MnROAD and to reduce the pulse amplitude from the trigger. Most of the day was spent building the boxes for the three triggers that were needed. The connection boxes also served to maintain the MnROAD triggers intact; that is, no modification was made to them at all.
The project team had time to set up the triggers at cell 19 and had the MnROAD truck drive at about 40 mi/h (64.4 km/h) to verify their working status.
Friday, September 20, 2013
After analyzing the signals obtained with the MnROAD truck, the project team concluded that the triggering and timing for the field testing could be done with the MnROAD trigger sensors. Two more speeds were performed with the MnROAD truck to ensure everything would work as needed. Markings for the trigger sensor positions were placed on the rest of the cells where accuracy testing was to be done, and some modifications were made to the DAQ system program to include them in the data saving process.
Sunday, September 22, 2013
A list of MnROAD field trials participants includes the following:
Not all people included in this list participated in the meeting. For example, RWD representatives did not arrive until Sunday evening and hence did not participate in the meeting. A photograph of the devices that participated in the MnROAD field testing activities is provided in figure 220; the RWD, Curviametro, and TSD are shown from left to right. While it participated in the field trials, the Curviametro was not part of this project and hence is not addressed in this report.
Figure 220. Photo. MnROAD field testing devices (September 22 to 27, 2013).
The meeting commenced at 9 a.m. and lasted until around 2 p.m. after a tour of the MnROAD facility with special focus on the MnROAD test cells that were going to be used for accuracy testing in the coming days. The general agenda that was followed at the meeting is as follows:
Beyond these items included in the agenda, the most important issue addressed during the meeting was safety, which was covered by MnROAD staff.
Monday, September 23, 2013
Field testing activities on this day focused exclusively on accuracy testing using the ARA RWD and the MnROAD truck. Like the ARA RWD, the Greenwood TSD arrived on Sunday, but it had to be calibrated on Monday prior to testing. Greenwood encountered numerous problems in getting the TSD to the MnROAD facility and hence could not accomplish the calibration in time for the Monday testing. The Euroconsult Curviametro, on the other hand, did not arrive until Monday afternoon due to permit issues encountered when entering Minnesota from Iowa.
From about 7 to 8:30 a.m., members of the project team and ARA RWD staff toured the MnROAD facility, with particular focus on the four accuracy cells (19, 72, 3, and 34). Accuracy testing at cell 19 took place from around 8:30 to 10 a.m. A total of nine passes each were completed by the ARA RWD and MnROAD truck: three passes at ~30 mi/h (48.3 km/h), three passes at ~45 mi/h (72.45 km/h), and three passes at speeds ranging between 50 and 57 mi/h (80.5 and 91.77 km/h). It was not possible to achieve 60 mi/h (96.6 km/h) due to short acceleration distance. The passes were alternated between the two trucks, allowing sufficient time to check results before the next device passed the instrumented cell.
Between 10:30 a.m. and 12 p.m., both the ARA RWD and MnROAD truck completed accuracy testing at cell 72. These two units also completed accuracy testing of cell 3 between 2 and 4 p.m. and of cell 34 between 4 and 5:30 p.m. At cells 72 and 3, a total of nine passes each were completed by the ARA RWD and MnROAD truck: three passes at ~30 mi/h (48.3 km/h), three passes at ~45 mi/h (72.45 km/h), and three passes at 60 mi/h (96.6 km/h). At cell 34, a total of six passes each were completed by the ARA RWD and MnROAD truck: three passes at 30 mi/h (48.3 km/h) and three passes at 45 mi/h (72.45 km/h). It was not possible to complete testing at 60 mi/h (96.6 km/h) on cell 34 due to the short acceleration distance.
During the accuracy testing, data from the geophones and accelerometers installed the week of September 16, 2013, as well as data from the MnROAD working sensors were collected by the combined MnROAD and project team staffs. The MnROAD LVDT rack was also used to collect data at cell 72. Videos were also recorded as each device passed over the embedded geophones/ accelerometer installed at cells where accuracy testing was conducted. All these data were in addition to those data collected by the ARA RWD as well as other ancillary data available at the MnROAD facility (e.g., weather station data).
The weights of the ARA RWD axles as well as overall vehicle were determined at the end of the day using a static scale owned and operated by MnROAD.
It is important to note that the coordination of field testing activities between personnel from the various devices under consideration, MnROAD staff involved in the field testing, and the project team was accomplished using two-way radios provided by MnROAD. The use of these radios proved invaluable during the course of the week.
Tuesday, September 24, 2013
On Tuesday, all three vehicles were ready for testing (the ARA RWD, Greenwood TSD, and Euroconsult Curviametro). Precision testing, accuracy testing, and testing of the 18-mi (29-km) Wright County loop were carried out.
Between 8:30 and 10 a.m., the initial round (colder temperature) of precision testing of the MnROAD LVR was completed by the ARA RWD and Greenwood TSD. Each device completed five passes at 30 mi/h (48.3 km/h) and then five passes at 45 mi/h (72.45 km/h), one following the other with about a half-loop offset. Precision testing by these two devices at 60 mi/h (96.6 km/h) was not attempted for safety reasons due to geometry of the MnROAD LVR.
From 10 to 11:30 a.m., the Euroconsult Curviametro completed the precision testing of the entire MnROAD LVR. As with the other two devices, they completed five passes, but unlike the other two devices, they only performed the testing at close to 11 mi/h (17.71 km/h), the standard data collection speed for the device.
On completion of the precision testing of the MnROAD LVR by the ARA RWD and Greenwood TSD, these two devices were instructed to conduct the 18-mi (29-km) Wright County loop testing. Three passes of the loop were completed by each device between 10 a.m. and 12 p.m. in accordance with the posted speed limits.
Between 12 and 3:30 p.m., accuracy testing of cell 34 was completed by the Euroconsult Curviametro and the Greenwood TSD. A total of three passes at an approximate speed of 10 mi/h (16.1 km/h) were done by the Euroconsult Curviametro. At this cell, preliminary passes by the Euroconsult Curviametro were required to ensure that the device's geophone coincided as close as possible with the geophone/accelerometer assembly installed the week of September 16, 2013, along the middle of the wheel path at this cell. In the case of the Greenwood TSD, six passes were completed at this cell: three passes at ~30 mi/h (48.3 km/h) and three passes at ~45 mi/h (72.45 km/h). It was not possible to perform accuracy testing of cell 34 with the Greenwood TSD at 60 mi/h (96.6 km/h) due to the short acceleration distance.
From 3:30 to 7 p.m., the second round (warmer temperature) of precision testing of the MnROAD LVR was completed by the three devices. The ARA RWD and Greenwood TSD each completed five passes at 30 mi/h (48.3 km/h) and then five passes at 45 mi/h (72.45 km/h), one following the other with about a half-loop offset. As with the morning round, precision testing by these two devices at 60 mi/h (96.6 km/h) was not attempted for safety reasons. Once these two devices were done, the Euroconsult Curviametro completed their precision testing of the LVR and completed five passes at approximately 10 mi/h (16.1 km/h).
During precision testing of the MnROAD LVR and accuracy testing at cell 34, data from the cell 34 geophones and accelerometer installed the week of September 16, 2013, as well as data from the functioning MnROAD sensors at cell 34 were collected. It is noted that MnROAD sensor data were collected with computers whose time were set at Central Standard Time, while most other data were recorded using Central Daylight Time. All these data were in addition to those data collected by the ARA RWD, Greenwood TSD, and Euroconsult Curviametro as well as other ancillary data available at the MnROAD facility (e.g., weather station data).
Wednesday, September 25, 2013
On this day, precision and accuracy testing were carried out. Between 8:30 and 10 a.m., the initial round (colder temperature) of precision testing of the MnROAD mainline (from the start of section 20 to the end of section 1) was completed by the ARA RWD and Greenwood TSD. Due to length of the ARA RWD and hence its turning capabilities (it had to go on Interstate 94 and use the closest exits to a complete turnaround), this device was able to do one pass for every two or three passes of the Greenwood TSD. Consequently, ARA RWD and Greenwood TSD completed three and five passes, respectively, each at 30, 45, and 60 mi/h (48.8, 72.45, and 96.6 km/h).
From about 10 a.m. to 12:00 p.m., the Euroconsult Curviametro completed the precision testing of the MnROAD mainline. As with the other two devices, they completed five passes, but unlike the other two devices, they only performed the testing at close to 10 mi/h (16.1 km/h).
From 1 to 4:30 p.m., the second round (warmer temperature) of precision testing of the MnROAD mainline was completed by the three devices. As with the morning round, the Greenwood TSD performed two or three passes per ARA RWD pass due its ability to turn the device without having to leave the MnROAD facility. ARA RWD and Greenwood TSD completed three and five passes, respectively, each at 30, 45, and 60 mi/h (48.8, 72.45, and 96.6 km/h). Once these two devices were done, the Euroconsult Curviametro completed its precision testing of the MnROAD Mainline, completing five passes at approximately 10 mi/h (16.1 km/h).
From 4:30 to 7:30 p.m., accuracy testing of cells 19 and 72 was completed by the Greenwood TSD and Euroconsult Curviametro. The Euroconsult Curviametro was also able to complete accuracy testing of cell 3; the Greenwood TSD encountered hydraulic problems and hence could not complete accuracy testing of cell 3.
For the accuracy testing of cells 19 and 72, the Greenwood TSD completed nine passes at each cell: three passes at 30 mi/h (48.3 km/h), three passes at 45 mi/h (72.45 km/h), and three passes at 60 mi/h (96.6 km/h). The Euroconsult Curviametro completed three passes at each of these two cells as well as at cell 3 at an approximate speed of 10 mi/h (16.1 km/h). At these three cells, one or more preliminary passes by the Euroconsult Curviametro was required in order to ensure that the device's geophone coincided as close as possible with the geophone/accelerometer assembly installed the week of September 16, 2013, along the middle of the wheel path at these three cells.
During precision testing of the MnROAD mainline, data from the geophones and accelerometers installed the week of September 16, 2013, at cells 19, 72, and 3 were collected. Also, data from functioning MnROAD sensors at cells 19, 20, 72, 4, and 3 were collected. The MnROAD LVDT rack was also used to collect data at cell 72. All these data were in addition to those data collected by the ARA RWD, Greenwood TSD, and Euroconsult Curviametro as well as other ancillary data available at the MnROAD facility (e.g., weather station data).
During accuracy testing of cells 19, 72, and 3 of the MnROAD Mainline, data from the geophones and accelerometers installed the week of September 16, 2013, as well as data from functioning MnROAD sensors were collected. The MnROAD LVDT rack was also used to collect data at cell 72. All these data were in addition to those data collected by the ARA RWD, Greenwood TSD, and Euroconsult Curviametro as well as other ancillary data available at the MnROAD facility (e.g., weather station data).
The weights of the Euroconsult Curviametro axles as well as overall vehicle were determined at the end of the day using a static scale owned and operated by MnROAD.
All required testing activities by the ARA RWD were completed on this day. Prior to their departure from the MnROAD facility, project team staff met with ARA personnel to discuss their data format as well as the data they were going to provide. ARA indicated that the 0.1-mi (0.161-km) ARA RWD data would be provided for the precision testing and 18-mi (29-km) Wright County loop and denser data would be provided for the accuracy testing.
Thursday, September 26, 2013
All required testing activities by the Euroconsult Curviametro were completed on the prior day. Accordingly, prior to their departure from the MnROAD facility, project team personnel met with members of the Euroconsult staff to discuss their data format as well as the data they were going to provide for the precision and accuracy testing at MnROAD. They did not participate in the 18-mi (29-km) Wright County loop testing due to permit and traffic control issues.
Testing on this day was limited to the Greenwood TSD and more specifically to the accuracy testing of cell 3, which Greenwood could not complete the prior day due to problems encountered with the device's hydraulic system. Testing began at around 9 a.m. and was completed by 10:30 a.m. The Greenwood TSD performed nine passes at this cell: three passes at ~30 mi/h (48.8 km/h), three passes at ~45 mi/h (72.45 km/h), and three passes at ~60 mi/h (96.6 km/h).
The weights of the Greenwood TSD RWD axles as well as overall vehicle were determined after completion of the cell 3 accuracy testing day using a static scale owned and operated by MnROAD.
At this point, all required testing activities by the Greenwood TSD were completed. Prior to their departure from the MnROAD facility, project team staff also met with Greenwood staff to discuss their data format as well as the data they were going to provide. Greenwood representatives indicated they would provide 32.8-ft (10-m) data for the accuracy and precision testing as well as for the 18-mi (29-km) Wright County loop. They also indicated they would provide 3.28-ft (1-m) data for the accuracy testing at cells 34, 19, 72, and 3 but would possibly request a signed data non-disclosure form from the project team prior to providing the data.
Once complete, all planned field activities as detailed in the phase 1 work plan were completed and, in some cases, exceeded in terms of what was accomplished (e.g., it was not anticipated that the ARA RWD was going to do the 18-mi (29-km) Wright County loop testing). Much of the credit for this successful field testing effort goes to the MnROAD staff and their support of the project's field testing activities. The installation of geophones and accelerometers the week of September 16, 2013, was successful, and the same goes for the RWD, TSD, and Curviametro field testing activities the week of September 23, 2013.
The field testing plan that the project team put together seemed reasonable for a 4-day period, but the project team was only able to accomplish it because of (1) the MnROAD staff's instrumentation knowledge/expertise, (2) MnROAD staff's willingness to spend long hours helping the project team, and (3) MnROAD's great facility (layout, instrumentation, etc.), which makes carrying out projects such as this one much easier.
Friday, September 27, 2013
No field testing activities took place on this day. However, project team members videographed the 18-mi (29-km) Wright County loop and met with MnROAD staff to gather the MnROAD sensor and other supporting data collected over the past 4 days as well as to better understand those data.
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