ASSESSMENT OF CUMMULATIVE TRAFFIC LOADING OVER LIFETIME OF THE ROAD.pptx

Roads are the arteries of our communities, facilitating movement, commerce, and connection. Our comprehensive assessment of cumulative traffic loading is designed to provide invaluable insights into the longevity and performance of roadways, ensuring they remain safe and efficient for years to come.

Why This Assessment Matters: As traffic patterns evolve, so too do the stresses placed on our infrastructure. Understanding cumulative traffic loading allows us to anticipate wear and tear, enabling proactive maintenance and strategic planning that extends the life of our roads.

Our Approach:

In-Depth Analysis: We utilize advanced modeling techniques and real-time data to assess traffic volumes and patterns over time. This thorough analysis helps identify critical stress points and potential failure areas before they become problematic.

Predictive Insights: By evaluating historical data alongside current traffic trends, we offer predictive insights into how roads will perform under projected loads. This foresight empowers decision-makers to allocate resources effectively and prioritize repairs.

Customized Solutions: We believe in tailored strategies that meet the unique needs of each roadway. Our expert recommendations focus on materials, design, and maintenance practices that enhance durability and performance.

The Benefits:

Enhanced Safety: By understanding traffic loading, we can implement timely interventions, reducing the risk of accidents and road failures.
Cost Efficiency: Proactive assessments minimize the need for extensive repairs and costly emergency measures, ensuring better allocation of budgetary resources.
Sustainable Infrastructure: Our commitment to long-term planning supports the development of resilient roadways that withstand the test of time, benefiting both the environment and the economy.

1. ASSESSMENT OF CUMMULATIVE TRAFFIC LOADING OVER LIFETIME OF THE ROAD

2. by Saka Wasiu L aide

3. INTRODUCTION A pavement is designed to last, but it often does not perform as expected and, after a relatively short period of time, needs to be rehabilitated. The main problem that appears in a pavement is surface cracking caused by the pavement bending under traffic loads, thermal shrinkage due to temperature variations, top-down cracking due to stress concentration at the pavement surface, and reflective cracking due to stress concentration near the crack tip of the existing layers of rehabilitated pavement. Other pavement problems are of less importance and are usually overcome during pavement rehabilitation performed because of cracking .

4. The behavior of a pavement depends on the characteristics of its structure (materials and thickness of each pavement layer), the quality of its construction, the climatic conditions (temperature and freeze-thaw cycles), and the subgrade (bearing capacity and presence of water). However , it is the traffic (i.e., load intensity, frequency, and axle and tire configuration) that is primarily responsible for pavement problems due to the loads applied by the axles and tires of vehicles. Heavy traffic causes the most important failures in a pavement producing fatigue cracking and rutting that require pavement rehabilitation.

5. Objectives Facilitate understanding of traffic load characteristics, such as truck distributions and axle load spectra, and provide educational and training opportunities. Analysis of pavement condition using International Roughness Index (IRI ). Establishment of a function that relates maintenance and rehabilitation expenditures to pavement condition. Development of a function that relates pavement condition to load and non-load factors of pavement damage. Development of a function to relate maintenance and rehabilitation expenditures to marginal load-related factors.

6. PROBLEM STATEMENTS OF THE STUDY The analysis of the impact of the overloads in the pavement performance was carried out by studying the following : • Truck factor for overloaded vehicles • Truck factor for legal vehicles • Truck factor for all vehicles (overloaded and legal loads ); and • Influence of asphalt layer thickness and subgrade stiffness modulus on truck factor. relevant for pavement designers, highway agencies, and other professionals concerned with pavement design

7. Cont.. the use of roughness as a measure of pavement performance [ Perera et al., 1995] due to the following reasons: • All states have roughness data for most of their highway sections, over a relatively long period of time • Public perception of pavement performance has been found to be directly related to pavement roughness • There exists relationships between roughness and other common aggregate measures of pavement performance such as PSI • Roughness can be related to the deterioration of pavement structures.

8. for the amount of pavement damage and subsequently on the amount of money expended on maintenance and rehabilitation • Environmental region • Subgrade materials • Pavement usage • Structural capacity of the pavement • Pavement age •

9. Choice of Model Types A model is the representation of a system in which a set of explanatory variables come together to provide a certain response. In the case of statistical experiments, a model is a mathematical relationship that describes the value of an observation in terms of a set of factors and an error component over which there is no control. As indicated by Lytton, there are several ways of measuring pavement performance, and therefore there are many types of performance models and these can be broadly classified into two categories: probabilistic models and deterministic [Lytton, 1988]. Probabilistic models typically yield a range of response variables. Examples include survivor curves, and transition process models such as Markov and semi-Markov models.

10. Use of Econometric Methods General Econometrics may be defined as the field of economics in which the tools of mathematical statistics and statistical inference are applied to the empirical analysis of economic phenomena [Goldberger, 1964]. Economic theory is typically concerned with exact functional relationships among economic variables. the use of econometric modeling techniques explain pavement behavior in response to factors that influence pavement damage [Ben- Akiva , 1992] [ Gopinath et al., 1996] [ Ramaswamy and Ben- Akiva , 1997] [Mohammed et al., 1997]. These techniques have also been used to predict the probability or amounts of maintenance as a function of pavement damage and other explanatory factors.

11. Tire Loads Traffic Data Due to technical, economic, and competitive factors, vehicles have a maximum weight limit that is a function of the number of axles and the axle configuration (i.e., single, tandem and tridem axles). For single axles, the maximum weight limit depends on whether the axle is a steering axle The equation below relates the radius of tire contact to tire inflation pressure and the total tire load : A=Square root of p inverse of p multiply by pie a =radius of tire contact P=total load on tire P=tire inflation pressure

12. Axle and Tire Configurations

13. Axle and Tire Configurations While the tire contact pressure and area is of vital concern in pavement performance, the number of contact points per vehicle and their spacing is also critical. As tire loads get closer together their influence areas on the pavement begin to overlap, at which point the design characteristic of concern is no longer the single isolated tire load but rather the combined effect of all the interacting tire loads.

14. Descriptions Tire-axle combinations are typically described as: Single axle single tire(truck steering axles, etc.) Single axle dual tires Tandem axle single tires Tandem axle dual tires

15. cont. (tandem axle)

16. The Equivalent Single Axle Load The current design practices do not necessarily account for vehicle speed, it does influence pavement loading. In general, slower speeds and stop conditions allow a particular load to be applied to a given pavement area for a longer period of time resulting in greater damage. it becomes quite complicated to determine the number and types of wheel/axle loads that a particular pavement will be subject to over its design life.

17. The Equivalent Single Axle Load

18. Load Equivalency

19. LITERATURE REVIEW Truck weight regulations are used to control the rate of damage to a pavement. Permitting heavier loads can increase the rate at which pavement damage accumulates, thus increasing the cost of maintaining good pavement conditions. High truck loads, load configurations, and number of trucks also lead to pavement deterioration, necessitating load limitations and early replacement ( Zaghloul and White 1994). Using two different data sets, one from an interstate in Illinois and the second from the Federal Highway Administration combining traffic data from seven states, Mohammadi and Shah (1992) observed that the truckload spectra reveal that overloads generally appear with a distinctly different pattern in roads with higher load than in those with lower load levels, mainly among trucks with five or more axles.

20. Cont.… LITERATURE REVIEW In effort to realize the influence of traffic loads on pavement performance, Timm et al. (2005) proposed models to characterize the traffic distribution, based on two or more theoretical distributions, to accurately characterize axle load spectra, which can be used to study the impact of the overload traffic on pavement performance . . Fuentes et al. (2012) evaluated the Truck Equivalency Factors for Colombia and found that for some truck classes (C3—a single unit truck with three axles: a single and a tandem axle; and C3-S3—6 axles tractor semitrailer: a single and a tandem axle in the tractor; a tridem axle in the trailer) the obtained values reveal that these vehicles are circulating excessively overloaded on some roads of the country, causing accelerated deterioration on the pavement structures in terms of fatigue, cracks, and ruts.

21. Methodology The primary data was collected from traffic surveys on the Lokoja -Abuja road. Axle Load Survey is used to examine the axle load of vehicles. In this survey, the axle loads are checked and surveyed with the help of a portable axle weigh pad. Figure 1 is the picture of the Axle weigh pad used for the study and the axle load survey . The secondary data required for the work is the traffic growth rate, pavement life and existing pavement layer, maintenance cost of the roads. These data are collected for determining the deterioration of pavement life.

22. A portable Axle Weigh pad

23. Results and Discussion In this study, the data from Lokoja - Abuja road were collected within a month in April 2021 using weigh-in-motion facilities and automatic traffic counter (ATC) operated by Exosphere Nig. Ltd. The segment considered more the most congested than other section since these segment heading to Abuja. A total of more than 43,514 commercial vehicle data obtained during a week (2nd June, 2021 to 8th June, 2021).

24. Class of vehicle and their standard VDF and overloaded VDF

25. Overloaded Trucks The result indicates that the majority of the truck is overloaded and the traffic control in that area is abysmal. Compared to other countries, this number is exceptionally high. Additional study is developed, the percentage of overloaded vehicles vary from 6% to 16.5%, which is quite low when compared to these results. The percentages of the overloaded truck are estimated by identifying truck axle load that greater than the ECOWAS standard legal limit (10 tons). Each of type truck has a different percentage number of overloaded.

26. The VDF estimated by using the empirical approach through the 4th power formulas derived by Liddle Df =k( qj / qs )^4 DF: Damage Factor, Qi: Actual Load, Qs: standard single axle load 80 kN , k: 1 for single, 0.086 for tandem and 0.053 for tridem axle load

27. Conclusions This study outlines weigh in motion survey data consideration in traffic data analysis at Lokoja -Abuja in Abuja to estimate the impact of overloaded trucks on the pavement structures . The specific result of this study shows that the VDF values form the WIM survey report is hugely more significant than the standard VDF. The overloaded trucks contributed significantly to reducing the service life of the pavement. From the above analyses, we can conclude that the overloaded truck has severe damage to the pavement, especially on service life. The government needs to enforce a restriction regarding axle-load control to achieve the economic life of the road . However, the effect of overloaded vehicles on the pavement performance will be evident for different assumptions.

28. THE END

29. THANKS FOR THE AUDIENCE