BACKGROUND: The size, geometry, weight, and other features of farm equipment, known as implements of husbandry (IoH), have increased and changed significantly to meet the needs of the modern agricultural industry. While intended primarily for use on the farm or in the field, frequently IoH travel on roads and bridges. Highway pavements are generally designed for traffic loadings and configurations defined by 13 vehicle classes using FHWA classifications. However, the configurations, weight and size, and other features of IoH differ substantially from the FHWA 13 vehicle classes and, therefore, may result in different forms of pavement distress and damage than those caused by truck traffic. Although a great deal of research has been performed on the effects of truck traffic on pavement performance, limited research has dealt with the procedures of quantifying the influence of IoH on pavement performance and there are no nationally accepted procedures to estimate these effects. There is a need to identify the procedures currently available for quantifying the effects of IoH on pavement performance and develop procedures that can be used for the different IoH configurations, pavement types, and applications. Also, there is a need to develop a tool to facilitate the implementation of these procedures. These procedures and accompanying tool should help highway agencies in making decisions regarding the movement of IoH on highway pavements.
OBJECTIVES: The objectives of this research are to (1) propose procedures for quantifying the effects of implements of husbandry (IoH) on pavement performance and (2) develop a tool to facilitate implementation of these procedures.
Accomplishment of the project objectives will require at least the following tasks.
Phase I: (1) Collect and review relevant domestic and foreign literature; research findings; agency practices; and other information relative to the effects of IoH on pavement performance. This information may be obtained from published and unpublished reports, contacts with transportation agencies and industry organizations, and other sources. (2) Identify and evaluate the factors that influence the effects of IoH on pavement performance (e.g., IoH configuration, weight and size; pavement structure; and speed and location on pavement), and recommend the factors that merit consideration in the process of quantifying the effects of IoH on pavement performance. (3) Identify and evaluate available procedures for quantifying the effects of IoH that consider the factors recommended in Task 2, and recommend potential and/or new procedures for further development in Phase II. (4) Develop a research plan for work to be executed in Phase II to (a) further develop and validate the procedures recommended in Task 3 and (b) prepare other material to facilitate implementation of these procedures. (5.) Prepare an interim report that documents the research performed in Phase I and includes an updated work plan for Phase II. Following review of the interim report by the NCHRP, the research team will be required to make a presentation to the project panel. Work on Phase II of the project will not begin until the interim report is approved and the Phase II work plan is authorized by the NCHRP. The decision on proceeding with Phase II will be based on the contractor’s documented justification of the updated work plan.
Phase II: (6) Execute the plan approved in Task 5. Based on the results of this work, develop and validate procedures for quantifying the influence of IoH on pavement performance for use by state DOTs and other highway agencies. (7) Using the developed procedures, prepare (a) a tool to facilitate implementation and use of the procedures, (b) a step-by-step guide for applying the procedures, and (c) examples to illustrate use of the procedures for different applications/scenarios. (8) Prepare presentation material in a PowerPoint or other format to facilitate implementation and use of the developed procedures. (9) Prepare a final deliverable that documents the entire research effort. The procedures and tool shall be prepared in a format suitable for consideration and adoption by AASHTO.
STATUS: Research in progress.