Field Verification of Moving Load Model for Pavement Response

1996 ◽  
Vol 1540 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Raj Siddharthan ◽  
Jian Yao ◽  
Peter E. Sebaaly
Keyword(s):  
Moving Load ◽  
Field Tests ◽  
Field Testing ◽  
Material Behavior ◽  
Vehicle Speed ◽  
Strain Response ◽  
State University ◽  
Load Model ◽  
Pavement Response ◽  
The Difference

A validation study undertaken to verify the predictive capability of a recently developed moving load model to predict pavement response is described. The full-scale field-measured responses of longitudinal strain at the bottom of the asphalt concrete (AC) layer were used in the verification. The field testing program, in which the strain responses induced by a semitrailer truck were measured as a function of vehicle speed, was carried out at the Pennsylvania State University test track. The material behavior of the AC layer, which was assumed to be viscoelastic, was deduced from the laboratory behavior of the AC and from the backcalculated AC modulus from falling-weight deflectometer data. The unbound material layer properties were assumed to be elastic. The moving load model reproduced many important general observations made from the field tests, such as the existence of a complex interaction in the case of a tandem axle configuration and the strong influence of vehicle speed on the strain response. Good agreement exists between the predictions made by the model for the strain response for single and tandem axle configurations under different loading and vehicle speeds and those measured in the field. The difference is less than 14 percent, thus verifying the applicability of the moving load model to predict pavement response.

scholarly journals The Influence of the Load Model and other Parameters on the Dynamic Behavior of Curved-in-Plane Bridges

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Ioannis G. Raftoyiannis ◽  
George T. Michaltsos
Keyword(s):  
Dynamic Behavior ◽  
Moving Load ◽  
Curvature Radius ◽  
Vehicle Speed ◽  
Continuum Approach ◽  
Theoretical Formulation ◽  
Concentrated Load ◽  
Load Model ◽  
Mass Load ◽  
Real Vehicle

AbstractThis paper deals with the dynamic behavior of curved-in-plane bridges where the effect of the bridge curvature radius, the moving load (vehicle) speed, the truck cant angle, the deck surface conditions and, mainly, the response accuracy depending on the vehicle model used are investigated. Besides the above parameters, the influence of several loading models is studied as well, especially the models of a concentrated load, a damped mass-load, a sequence of two concentrated loads and a real vehicle aswell as a damped vehicle,where its width is taken into account. A 3-DOF model is considered for the analysis of the bridge, while the theoretical formulation is based on a continuum approach, which has been widely used in the literature to analyze such bridges.

scholarly journals Probabilistic bridge weigh-in-motion

2018 ◽  
Vol 45 (8) ◽  
pp. 667-675 ◽  
Author(s):  
Eugene J. OBrien ◽  
Longwei Zhang ◽  
Hua Zhao ◽  
Donya Hajializadeh
Keyword(s):  
Field Tests ◽  
Bending Moment ◽  
Vehicle Speed ◽  
Strain Response ◽  
Simply Supported ◽  
Influence Line ◽  
Weigh In Motion ◽  
Alternative Approach ◽  
Bridge Weigh In Motion ◽  
Good Potential

Conventional bridge weigh-in-motion (BWIM) uses a bridge influence line to find the axle weights of passing vehicles that minimize the sum of squares of differences between theoretical and measured responses. An alternative approach, probabilistic bridge weigh-in-motion (pBWIM), is proposed here. The pBWIM approach uses a probabilistic influence line and seeks to find the most probable axle weights, given the measurements. The inferred axle weights are those with the greatest probability amongst all possible combinations of values. The measurement sensors used in pBWIM are similar to BWIM, containing free-of-axle detector sensors to calculate axle spacings and vehicle speed and weighing sensors to record deformations of the bridge. The pBWIM concept is tested here using a numerical model and a bridge in Slovenia. In a simulation, 200 randomly generated 2-axle trucks pass over a 6 m long simply supported beam. The bending moment at mid-span is used to find the axle weights. In the field tests, 77 pre-weighed trucks traveled over an integral slab bridge and the strain response in the soffit at mid-span was recorded. Results show that pBWIM has good potential to improve the accuracy of BWIM.

Finite-Layer Approach to Pavement Response Evaluation

2000 ◽  
Vol 1709 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Raj V. Siddharthan ◽  
Nadaraja Krishnamenon ◽  
Peter E. Sebaaly
Keyword(s):  
Moving Load ◽  
Vehicle Speed ◽  
Computationally Efficient ◽  
Predictive Capability ◽  
Response Factors ◽  
Load Models ◽  
Concrete Layer ◽  
Ideal Tool ◽  
Pavement Response ◽  
Finite Layer

The following aspects of the proposed continuum-based finite-layer model are presented: (1) theoretical basis, (2) applicability in evaluating pavement response, and (3) verification of predictive capability. The model incorporates important pavement response factors such as noncircular contact area, complex contact stress distributions (normal and shear), vehicle speed, and viscoelastic material characterization. The proposed model is much more computationally efficient than the moving-load models based on the finite-element method. A verification study, undertaken to validate the predictive capability of the proposed approach and its ensuing computer program, is also presented. The validation study includes (1) verification using results from ELSYM5, a widely used pavement response model, and (2) laboratory verification using two foam rubber models. Very good agreement was observed in both cases. Applicability of the proposed approach has also been demonstrated using realistic pavement loading. The proposed finite-layer approach is therefore an ideal tool for modeling the behavior of asphalt concrete layer and for studying the effects of vehicle speed and complex tire-pavement interface stresses on pavement response.

Effect of Off-Road Equipment on Flexible Pavements

2003 ◽  
Vol 1821 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Peter E. Sebaaly ◽  
Raj Siddharthan ◽  
Magdy El-Desouky ◽  
Dan Strand ◽  
David Huft
Keyword(s):  
Flexible Pavements ◽  
Field Tests ◽  
Field Testing ◽  
Load Level ◽  
Agricultural Equipment ◽  
Heavy Equipment ◽  
Load Limit ◽  
Pavement Response ◽  
Pavement Damage ◽  
The Impact

The South Dakota Department of Transportation sponsored a study to evaluate the effect of agricultural equipment on flexible pavements. One thin and one thick flexible pavement were instrumented at two locations and tested under agricultural equipment. Each section was instrumented with pressure cells in the base and subgrade, surface deflection gauges, and strain gauges at the bottom of the asphalt layer. Field tests were carried out during fall 2000, spring 2001, and summer 2001 to evaluate the impact of heavy equipment on flexible pavements under variable environmental conditions. Test vehicles included two types of Terra-Gators, a grain cart, and a tracked tractor. The field-testing program collected the pavement responses under five replicates of each combination of test vehicle and load level and under the 18,000-lb singleaxle truck. Data were examined for repeatability; the average of the most repeatable set of measurements was calculated and used in the analysis. The first part of the research evaluated the relative impact of the equipment defined as the ratio of pavement response under each combination of vehicle-load level over the pavement response under the 18,000-lb single-axle truck. The analysis of the pavement response ratios indicated that ( a) the tracked tractor is not more damaging than the 18,000-lb single-axle truck, ( b) Terra-Gators 8103 and 8144 are more damaging than the 18,000-lb single-axle truck only when fully loaded, and ( c) the grain cart is more damaging than the 18,000-lb single-axle truck only when loaded over the legal load limit. Data from the second part of the research showed that transporting the commodities using tridem-axle trucks caused far less pavement damage than transporting commodities on agricultural equipment.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

Driving in the Dust: Challenges and Lessons Learned from Field Testing in Degraded Visual Environments

2020 ◽  
Vol 64 (1) ◽  
pp. 1916-1920
Author(s):  
Kayla L. Riegner ◽  
Kelly S. Steelman
Keyword(s):  
Research Program ◽  
Field Tests ◽  
Field Testing ◽  
Driving Performance ◽  
Lessons Learned ◽  
Current Paper ◽  
Ground Vehicle ◽  
Significant Safety ◽  
Dust Clouds

Degraded visual environments (DVEs) pose significant safety and efficiency problems in military ground vehicle operations. As part of a larger research program, two field tests were conducted to evaluate driving aids while indirect driving in DVEs. The current paper presents the results of one of these field tests, and focuses on the challenges and lessons learned in designing a challenging test course and producing consistent dust clouds for assessing Soldier driving performance and workload in degraded visual environments.

Railway track irregularity and curvature estimation using doppler LIDAR fiber optics

2016 ◽  
Vol 232 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Masood Taheri Andani ◽  
Andrew Peterson ◽  
Josh Munoz ◽  
Mehdi Ahmadian
Keyword(s):  
Fiber Optics ◽  
Field Testing ◽  
Railway Track ◽  
Vehicle Speed ◽  
Doppler Lidar ◽  
Close Match ◽  
Track Geometry ◽  
Lidar Measurements ◽  
Curvature Estimation ◽  
Geometry Measurement

The application of Doppler-based LIght Detection and Ranging (LIDAR) technology for determining track curvature and lateral irregularities, including alignment and gage variation, are investigated. The proposed method uses track measurements by two low-elevation, slightly tilted LIDAR sensors nominally pointed at the rail gage face on each track. The Doppler LIDAR lenses are installed with a slight forward angle to measure track speed in both longitudinal and lateral directions. The lateral speed measurements are processed for assessing the track gage and alignment variations, using a method that is based on the frequency bandwidth dissimilarities between the vehicle speed and track geometry irregularity. Using the results from an extensive series of tests with a body-mounted Doppler LIDAR system on-board a track geometry measurement railcar, the study indicates a close match between the LIDAR measurements and those made with existing sensors on-board the railcar. The field testing conducted during this study indicates that LIDAR sensors could provide a reliable, non-contact track monitoring instrument for field use in various weather and track conditions, potentially in a semi-autonomous or autonomous manner.

scholarly journals Measurement of Ozone Production Sensor

2010 ◽  
Vol 3 (3) ◽  
pp. 545-555 ◽  
Author(s):  
M. Cazorla ◽  
W. H. Brune
Keyword(s):  
Production Rate ◽  
High Efficiency ◽  
Ambient Air ◽  
Ozone Production ◽  
State University ◽  
Photostationary State ◽  
Sample Chamber ◽  
Efficiency Conversion ◽  
The Difference ◽  
Teflon Film

Abstract. A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS), measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

scholarly journals State-of-the-Art-Review of Collapsible Soils

2000 ◽  
Vol 5 ◽  
pp. 115 ◽  
Author(s):  
A. A. AL-Rawas
Keyword(s):  
Field Tests ◽  
Clay Content ◽  
Field Testing ◽  
Dry Density ◽  
Foundation Design ◽  
Treatment Methods ◽  
Collapse Potential ◽  
Collapsible Soils ◽  
Different Types ◽  
Compaction Control

Collapsible soils are encountered in arid and semi-arid regions. Such soils cause potential construction problems due to their collapse upon wetting. The collapse phenomenon is primarily related to the open structure of the soil. Several soil collapse classifications based on parameters such as moisture content, dry density, Atterberg limits and clay content have been proposed in the literature as indicators of the soil collapse potential. Direct measurement of the magnitude of collapse, using laboratory and/or field tests, is essential once a soil showed indications of collapse potential. Treatment methods such as soil replacement, compaction control and chemical stabilization showed significant reduction in the settlement of collapsible soils. The design of foundations on collapsible soils depends on the depth of the soil, magnitude of collapse and economics of the design. Strip foundations are commonly used when collapsing soil extends to a shallow depth while piles and drilled piers are recommended in cases where the soil extends to several meters. This paper provides a comprehensive review of collapsible soils. These include the different types of collapsible soils, mechanisms of collapse, identification and classification methods, laboratory and field testing, treatment methods and guidelines for foundation design.

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