Effects of Changes in Legal Load Limits on Pavement Costs. Volume I. Development of Evaluation Procedure

摘要

Program NULOAD evaluates the effect of legal load limit changes on the life cycle costs of flexible, rigid, and/or composite pavements. This final report describes the development of the methodology, program NULOAD, for determining the effects of changes in truck size, weight, and configuration on pavement performance and relating these effects to maintenance and rehabilitation and their related costs. Fifty representative sections can be grouped by system (such as Interstate sections) to reflect the effect of traffic loadings on the different classifications of highway. The procedure permits inclusion of a maximum of ten different truck types along with various axle and tire configurations such as single axles with single tires, tridem axles, single axles, and tandem axle configurations. While truck axle weight and configuration are the major variables considered, new sized trucks such as the triple trailer units can be handled in the procedure. The procedure also includes a computerized gross vehicle and axle load distribution shifting procedure. Volume 1 of the two-volume report describes the development of the evaluation procedure, which culminated in program NULOAD. This volume provides descriptions of the research approach; choice of life cycle, maintenance, traffic and load, overlay, and economic models; state visit findings; and the operation of Program NULOAD.