Autonomous Vehicles

2017 ◽  
Vol 2640 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Hossein Noorvand ◽  
Guru Karnati ◽  
B. Shane Underwood
Keyword(s):  
Autonomous Vehicles ◽  
Fatigue Cracking ◽  
Transportation Infrastructure ◽  
Transportation Sector ◽  
Potential Benefits ◽  
Pavement Structures ◽  
Technological Improvements ◽  
Long Term Performance ◽  
Pavement Thickness ◽  
Term Performance

With ongoing technological improvements and research in the field of autonomous vehicles, it is becoming evident that the technology has the potential to substantially affect the transportation sector. Although the potential benefits with respect to productivity increases, cost decreases, and safety are evident, the potential for these vehicles to negatively or positively affect the transportation infrastructure is unclear. In this study, the influence of truck loadings positioning on the long-term performance of transportation infrastructure was estimated by carrying out performance simulations of pavement structures. Scenarios considering both full and partial use by autonomous trucks were considered. In all cases, performance was estimated with respect to rutting, fatigue cracking, and overall pavement smoothness, and the results were compiled in terms of reduced pavement thickness. It was found that if controlled appropriately, autonomous trucks could be highly beneficial for the pavement infrastructure design, and they would be most effective when they represented more than 50% of the total truck traffic. It was also found that in the absence of appropriate control, specifically by repeatedly positioning trucks in the same location, the amount of damage could be highly detrimental, and noticeable influences may occur at autonomous truck volumes as low as 10%.

Effects of construction cracks on the design of asphalt pavements

1994 ◽  
Vol 21 (3) ◽  
pp. 410-418 ◽  
Author(s):  
A. O. Abd El Halim ◽  
A. G. Razaqpur ◽  
A. H. El Kashef
Keyword(s):  
Finite Element ◽  
Field Tests ◽  
Fatigue Tests ◽  
Asphalt Pavements ◽  
Steel Wheel ◽  
Asphalt Mix ◽  
Pavement Structures ◽  
Stress Fatigue ◽  
Long Term Performance ◽  
Term Performance

Compaction of asphalt mix has been recognized as one of the most important factors that affect the long-term performance of the pavement. Problems experienced in compacting asphalt mixes have generally been ascribed to the mix. Roller "checking," the result of compaction with steel rollers, has been disregarded or considered as irrelevant. Compaction based on a new concept, using a soft plate, avoids roller checking, as demonstrated by a series of side-by-side field tests with steel and pneumatic rollers. The surface cracks initiated by the steel wheel roller may provide an explanation for the often reported phenomenon of early deterioration of asphalt pavements. Finite element analyses of pavement structures with roller-induced cracks have shown significantly higher tensile stresses than the corresponding stresses in otherwise identical uncracked pavements. The analytical findings are supported by indirect tensile and stress fatigue tests results obtained in the laboratory from asphalt samples compacted in the field. The test samples were recovered from pavements compacted either by existing compaction equipment and technique or by the new soft plate method. Key words: asphalt, crack, compaction, fatigue, finite element, tensile strength testing, pavement.

scholarly journals Agricultural Water Management Using Two-Stage Channels: Performance and Policy Recommendations Based on Northern European Experiences

2021 ◽  
Vol 13 (16) ◽  
pp. 9349
Author(s):  
Kaisa Västilä ◽  
Sari Väisänen ◽  
Jari Koskiaho ◽  
Virpi Lehtoranta ◽  
Krister Karttunen ◽  
...  
Keyword(s):  
Environmental Benefits ◽  
The European Union ◽  
Two Stage ◽  
Subsidy Scheme ◽  
Northern European ◽  
Potential Benefits ◽  
Additional Costs ◽  
Additional Value ◽  
Long Term Performance ◽  
Term Performance

Conventional dredging of ditches and streams to ensure agricultural drainage and flood mitigation can have severe environmental impacts. The aim of this paper is to investigate the potential benefits of an alternative, nature-based two-stage channel (TSC) design with floodplains excavated along the main channel. Through a literature survey, investigations at Finnish field sites and expert interviews, we assessed the performance, costs, and monetary environmental benefits of TSCs in comparison to conventional dredging, as well as the bottlenecks in their financing and governance. We found evidence supporting the expected longer-term functioning of drainage as well as larger plant and fish biodiversity in TSCs compared to conventional dredging. The TSC design likely improves water quality since the floodplains retain suspended sediment and phosphorus and remove nitrogen. In the investigated case, the additional value of phosphorus retention and conservation of protected species through the TSC design was 2.4 times higher than the total costs. We demonstrate how TSCs can be made eligible for the obligatory vegetated riparian buffer of the European Union agri-environmental subsidy scheme (CAP-AES) by optimising their spatial application with respect to other buffer measures, and recommend to publicly finance their additional costs compared to conventional dredging at priority sites. Further studies on biodiversity impacts and long-term performance of two-stage channels are required.

Pavement Evaluation for ERS Steel Deck Pavement Using Accelerated Loading Test

2017 ◽  
Vol 744 ◽  
pp. 97-104
Author(s):  
Fei Chen ◽  
Ke Zhong ◽  
Xiao Hao Wei
Keyword(s):  
Steel Bridge ◽  
Loading Test ◽  
Pavement Evaluation ◽  
Loading System ◽  
Loading Tests ◽  
Pavement Structures ◽  
Long Term Performance ◽  
Term Performance ◽  
Steel Deck

In order to verify the practical application of ERS steel deck pavement system, based on the project of Jia Shao bridge, the pavement accelerated loading system is used to test the long-term performance of the steel bridge deck pavement. Tests find that the absolute value of the average rut growth depth of ERS and ERN is less than 5mm when the number of axle loads is 2.05 million times. After more than 1.3 million loading tests, the two deck pavement structures are almost impermeable to water and their anti-skid properties also tend to be stable. The results show that ERS and ERN are not cracked under natural conditions and have excellent anti-rutting performance.

Sustainability Considerations for PCC Pavement Design and Construction

2013 ◽  
Vol 857 ◽  
pp. 147-159
Author(s):  
Liang Liang Chen ◽  
Dan G. Zollinger ◽  
Bo Tian
Keyword(s):  
Field Testing ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Factors Affecting ◽  
Key Issues ◽  
Pavement Structures ◽  
Long Term Performance ◽  
Term Performance ◽  
Relevant Material

This paper addresses key issues regarding important factors affecting the sustainability and long-term performance of Portland cement concrete (PCC) pavement structures. Key distress types and their associated features are discussed in terms of their effect on performance and sustainability in terms of specific pavement components. Relevant material properties are also identified and discussed as to how they are represented in laboratory and field testing. A process to manage inspection resources is described and illustrated with the aid of a sustainability worksheet. This paper does not represent a guide or a standard for design or analysis.

Lessons Learned from the Long Duration Exposure Facility

1993 ◽  
Vol 36 (5) ◽  
pp. 38-42
Author(s):  
Wayne Stuckey
Keyword(s):  
Space Shuttle ◽  
Lessons Learned ◽  
Space Environment ◽  
Special Investigation ◽  
Long Duration ◽  
Potential Benefits ◽  
Long Term Performance ◽  
Term Performance

The Long Duration Exposure Facility (LDEF) was launched by the space shuttle in April, 1984, and recovered in January, 1990. There were 57 experiments containing over 10,000 specimens to test the effects of the space environment on materials, components, and systems. Originally planned for 1 yr, the exposure actually lasted almost 6 yr. While many LDEF investigations are continuing, results to date have provided valuable information on long-term performance in orbit. Results from the LDEF investigators and the special investigation groups are briefly summarized along with potential benefits from LDEF for future missions.

Fine Particle Mass Monitoring with Low-Cost Sensors: Corrections and Long-Term Performance Evaluation

2019 ◽  
Author(s):  
Carl Malings ◽  
Rebecca Tanzer ◽  
Aliaksei Hauryliuk ◽  
Provat K. Saha ◽  
Allen L. Robinson ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Fine Particle ◽  
Low Cost ◽  
Particle Mass ◽  
Long Term Performance ◽  
Term Performance

Long-term performance of the Hancock bioprosthetic conduit for aortic root replacement

2008 ◽  
Vol 56 (S 1) ◽  
Author(s):  
CC Badiu ◽  
W Eichinger ◽  
D Ruzicka ◽  
I Hettich ◽  
S Bleiziffer ◽  
...  
Keyword(s):  
Aortic Root ◽  
Aortic Root Replacement ◽  
Long Term Performance ◽  
Term Performance
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