Actual Axle Load Research Articles

Multifactorial Analysis of the Axle Load of Truck Sets during the Transport of Sawmill By-Products

The aim of the study was to investigate the actual axle loads of vehicles used for the transport of sawmill by-products, resulting from the total weight of the transport set (GVW) at different times of the year and depending on the type of sets and transported assortment. Sawmill by-product loads were divided into groups: wood chips, sawdust, slabs and recycled wood. The research was carried out at the recipient of the sawmill by-products as well as at the producer. The GVW was determined on the basis of weighing the entire set on a stationary scale at the premises of the companies. The load on the individual axles of high tonnage truck units was measured using Model DINI ARGEO WWSD portable truck scales with a 3590M309 weighing terminal. Almost 230 transports were analyzed. It was shown that the average GVW is 39.25 t for transport sets with a load of 22.44 t of sawmill by-products with the usage of the semi-trailer capacity of 0.85. For all transport sets, the average load on the individual axles range from 6.72 t (axle 5 in a six-axle truck and trailer-TT) to 10.29 t for axle 2 in a truck and semi-trailer (TST), where the highest occurs on axle 2 of the truck (drive axle). The influence of the type of transport set (TST or TT) and the type of the assortments on the axle load is shown, and the existing correlations are at the level of 0.604–0.669 for axles 3–5 in the TST set. The static axle loads of the transport sets for the sawmill by-products and the distribution of the total weight of the set among the axles are different from those for roundwood transport.

PENGARUH BEBAN KENDARAAN TERHADAP UMUR DESAIN PERKERASAN (STUDI KASUS JALAN NASIONAL LAMBARO – BATAS PIDIE PROVINSI ACEH)

Better capabilities of a vehicle (higher speeds, larger payloads) allows freight operators to perform "transport efficiency" (carrying goods as much as possible in one way that will provide benefits). This problem affects the cumulative equivalent standard axle (CESA) plan, which will experience a shift (Plans of CESA are reached before the service Period of the construction ends). The study is located on the eastern route of Aceh Province, especially on Lambaro-Pidie border. The purpose of this research was to know the relation of vehicle load with time, how to design pavement age and residual CESA value, in the service lifespan (time) of construction (10 years). The data used in this study was secondary data obtained from relevant agencies. The method used in this research was descriptive by doing comparison analysis to the relationship that happened. The data analysis and simulation were conducted in 3 scenarios, where Scenario 1 refers to the design data, Scenario 2 refers to the actual average daily traffic and the standard axle, and Scenario 3 refers to the actual LHR and actual axle load (Weigh in measurement results Motion-WIM). From the results of this study, it is known to simulate vehicle loads with time, Scenario 1 is y = 1,0794x - 2171,3, Scenario 2 y = 0,4935x2 - 1987,9x + 2E+06, and Scenario 3 y = 0,8605x2 - 3466,3x + 3E+06. The result of simulation lifespan of pavement design and CESA value, it is known that pavement design lifespan has decreased on average by 3.5 years, and CESA residual value is 42,138,92 thousand ESA.

Dynamic response assessment in compliance with the Eurocodes for the elevated viaducts of the Doha Metro Green Line

The double track elevated viaducts of Doha metro green line, currently under construction, is of 2.7 kilometers long and consist of cast-in-situ and precast segmental simply supported spans ranging from 20 to 35 m and continuous cast-in-situ two and three spans (39.5–57 m), (50–51–44 m) and (37–68–37 m) U-trough decks. The non-typical configuration of the continuous span was imposed due to utilities and infrastructures requirements. All viaduct decks (cast-in-situ and precast) are posttensioned to minimize any concrete cracking. To ensure passenger comfort and traffic safety during train operation, performing a dynamic analysis was vital. The dynamic analysis focuses on the vertical accelerations and vertical displacements. The actual train of the project composed of 6 vehicles with a total length of 120m and with actual axle loads (maximum axle load of 160 kN with 4 axles per vehicle) is adopted in the dynamic analysis. The analysis is carried out using both direct time integration of the equation of motion and modal time history analysis for different train speeds ranging from 60 km/hr to the maximum permissible speed along the metro line (160 km/hr). For each train speed the maximum vertical accelerations and the maximum vertical deflections are monitored using the CSI bridge software applied in the current project and are compared to the allowable values given in EN 1991-2 and EN 1990-Annex 2. According to relevant Eurocodes requirements, the vertical accelerations and the vertical deflections were found acceptable.

Dynamic analysis of elevated viaducts of Doha metro green line

The 2.7 kilometers double track elevated viaducts of Doha metro green line, currently under construction, consist of cast-in-situ and precast segmental simply supported spans ranging from 20 to 35 m and continuous cast-insitu two and three spans (30-57 m), (50-51-44 m) and (37-68-37 m) U-trough decks. The non-typical configuration of the continuous span arrangements was imposed to the designer by existing underneath utilities and infrastructures. In order to ensure the passenger comfort and traffic safety by preventing track instability during train operation for this special landmark project, performing a dynamic analysis was vital. The dynamic analysis focuses on the vertical accelerations and vertical displacements as well as lateral frequencies of vibration. All simply supported spans as well as the continuous spans of the project are considered. The real train of the project composed of 6 vehicles with a total length of 120m and with actual axle loads (maximum axle load of 160 kN with 4 axles per vehicle) is adopted in the dynamic analysis. The analysis is carried out using both direct time integration of the equation of motion and modal time history analysis for different train speeds ranging from 60 km/hr to the maximum permissible speed along the metro line (160 km/hr) with the maximum operating speed ranging from 100 to 130 km/hr. For each train speed the maximum vertical acceleration and the maximum vertical deflection are monitored using the CSI bridge software and are compared to the allowable values given in EN 1991-2 and EN 1990-Annex 2. According to relevant Euronorm requirements, the vertical accelerations and the vertical deflections were found acceptable for all segments of the elevated viaduct.

The Influence of Different Subbase Materials on the Crack of Cement Stabilized Macadam Base during Construction

According to actual axle load data and the measured mechanical parameters of cement stabilized macadam material with different cement dosages, the bottom tensile stresses of different subbase structures are calculated and the results show that: to graded gravel subbase, the weight of construction vehicle is inadvisable to be more than 35t and the cement dosage of base course shall be more than 3.0%; and, the maximum bottom tensile stress of graded gravel subbase shall be much more than that of lime-flyash soil subbase. According to the measured dry shrinkage strain and dry shrinkage coefficient, the dry shrinkage crack space of base course is analyzed and the results show that: under the same cement dosage, the crack space of the base course with graded gravel subbase is smaller than that of lime-flyash soil subbase; with the increase of cement dosage, the crack space of base course increase first and then decrease, and when the cement dosage is 3.5%, the dry shrinkage strain and dry shrinkage coefficient is minimum and the crack space of base course is maximum.

Toward Monte Carlo Simulation-Based Mechanistic-Empirical Prediction of Asphalt Pavement Performance

The mechanistic-empirical study of pavement performance requires that immediate pavement responses due to tire loading be mechanistically computed for pavement structures, and the long-term pavement performance be related to the computed pavement responses. The problem becomes very complicated when variability is considered for loading, pavement and environmental conditions. A Monte Carlo simulation-based mechanistic-empirical pavement design/analysis procedure was verified in this study. The complex tire-pavement interaction was more realistically handled and computed using finite element models and measured tire-pavement contact stress data. The computation time problem involved in pavement response computations was resolved by using a computationally efficient method that relates critical pavement responses to tire loading and pavement structural conditions. In the Monte Carlo simulation, different truck classes were drawn from the truck population empirically based on actual traffic volume data. Axle load spectra were characterized by actual axle load data collected at a weigh-in-motion site. Results from a survey of truck configurations were used to describe the distribution of truck tire pressure. Pavement structural parameters and relationships between material moduli and environmental conditions were obtained from the Long-Term Pavement Performance data. The distress models developed in National Cooperative Highway Research Program Project 1–37A were employed to predict pavement performance. The simulation study estimates the effects of increased tire pressure and steering axle load on a typical pavement structure for 2 million truck passes. The Monte Carlo simulation method and models used in this study can provide useful experience for the development of future flexible pavement design and analysis procedures.

Condition assessment of multispan masonry arch bridges

A reliability-based condition assessment procedure of multispan masonry arch bridges is presented in this paper. Safety margins (limit state functions) are introduced for each arch of the bridge, with the authors considering axle load as assessment criterion. Two variables constitute the introduced safety margins: provisional axle load (PAL) which is estimated using MEXE methods, and actual axle load (AAL), which is estimated using weigh-in-motion measurements of the bridge. That both variables follow log normal distribution is assumed. Failure probabilities of each arch (estimated from statistical parameters of variables) then are combined to get the failure probability of the bridge using reliability bounds. The bridge reliability index is estimated from the failure probability. Bridge condition prediction is performed through comparison of the reliability index with its acceptable reliability index. Further, corresponding reliability index changes are discussed when the statistical parameters behave as interval numbers. The introduced assessment procedure is illustrated by a Sri Lankan four span brick masonry arch bridge.

Mechanistic-Based Model for Predicting Reflective Cracking in Asphalt Concrete–Overlaid Pavements

One of the most common types of pavement on the national highway system is composite asphalt concrete (AC) over portland cement concrete (PCC). With a large percentage of PCC pavements either approaching or at the end of their design lives, AC overlay of PCC pavements has become one of the most common methods of rehabilitation. This has resulted in several thousand kilometers of composite AC/PCC pavements. As the level of heavy truck traffic loading continues to increase on a majority of pavements, it is likely that the total length of composite pavements in the nation will continue to increase considerably in the coming years. A common type of distress that occurs on these composite pavements is reflective cracking. This occurs when the joints or cracks in the underlying PCC pavement reflect through the AC overlay. A performance model that can be used to predict accurately the amount of reflective cracks in composite AC/PCC pavements has enormous potential uses. The development of a mechanistic-based performance model for predicting the amount of reflective cracks in composite AC/PCC pavements is described. Data from the Long-Term Pavement Performance database were used to develop the model. Using the principles of fracture mechanics, it is illustrated that a mechanistic-based model can be developed that closely models the real-life behavior of composite pavements and predicts the amount of reflective cracks. Because of the mechanistic nature of the model, it is particularly effective for performance prediction for design checks and pavement management. Also, since the model can take into account the relative damaging effect of the actual axle loads in any traffic distribution, it has great potential for application in cost allocation.

Calibration of Mechanistic-Empirical Rutting Model for In-Service Pavements

Rutting is a major failure mode for flexible pavements. Pavement engineers have been trying to control and arrest the development of rutting for years. Many models are available to relate pavement rutting to design features, traffic loading, and climatic conditions. These models range from purely empirical to mechanistic models. Mechanistic-empirical models (the Asphalt Institute and Shell) were used to predict the development of rutting for 61 Long-Term Pavement Performance (LTPP) test sections. The rutting damage, calculated using these models, did not appear to be a good predictor of the observed rutting depth. A new rutting model was developed and calibrated using the data from the 61 LTPP sections. The model accounts for the plastic deformation in all pavement layers and allows the use of actual axle load and type, rather than the equivalent single axle load, in characterizing traffic.