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A field program of strain and deflection measurements was conducted. The objective of the program was to evaluate the effect of frozen support, tied-concrete shoulder, and tridem-axle loading on concrete pavement performance. Results of the study on the effect of frozen support are presented in this paper. Field measurements were obtained during October.1982 and February 1983 at five pavement project, sites located on 1-90 in the State of Minnesota. Measurements included edge and corner deflections and edge strains. Loadings applied were 20 kip single-axle, a 34 kip tandem-axle, a 42 kip tandem-axle, and a 42 kip tridem-axle. Theoretical analysis was also conducted using a finite element program. Study results indicate that pavement deflections and strains are greatly reduced during winter months when the support 1s frozen. Based on analysis of these results, it is concluded that the effect of axle loads applied during the winter can be considered to be only 1/7th as damaging as the same loads applied during fall month

A field program of strain and deflection measurements was conducted. The objective of the program was to evaluate the effect of frozen support, tied-concrete shoulder, and tridem-axle loading on concrete pavement performance. Results of the study on the effect of tridem-axle loading are presented in this paper. Field measurements were obtained during October1982 and February 1983 at five pavement project sites located on 1-90 in the State of Minnesota. Measurements included edge and corner deflections and edge strains. Loadings applied were 20 kip single-axle, a 34 kip tandem-axle, a 42 kip tandem-axle, and a 42 kip tridem-axle. Theoretical analysis was also conducted using a finite element program. Study results also indicate that for application to the AASHTO thickness design procedure, a tridem-axle can be considered as equivalent to a single-axle weighing about 50 percent of the tridem-axle and to a tandem-axle weighing about 80 percent of the tridem-axle. Traffic equivalence factors are presented for tridem-axles on concrete pavements.

Field and laboratory pavements were instrumented and load tested to evaluate the effect of lane widening, concrete shoulders, and slab thickness on measured strains and deflections. Eight slabs were tested in the field and two in the laboratory. Pavement slabs were 8- 9-, or 10-in. thick. Other major design variables included the width of lane widening, presence or absence of dowels, presence or absence of a concrete shoulder, joint spacing, and the type of shoulder joint construction. Generally, there was good agreement between measured strains and deflections and values calculated using Westergaard's theoretical equations. Concrete shoulders were effective in reducing the magnitude of measured strains and deflections. A chart is presented to show the reduction in thickness of the outer lane of the mainline pavement that may be permitted with a tied concrete shoulder.

A field program of strain and deflection measurements was conducted by the Construction Technology Laboratories for the Minnesota Department of Transportation. The objective of the measurement program was to evaluate the effect of frozen support, tied concrete shoulder, and tridem-axle loading on concrete pavement performance. Results of the investigation are reported separately for each of the three topics. Results of the tied concrete shoulder and tridem-axle loading studies are given in References 1 and 2, respectively. Minnesota's current concrete pavement design procedure does not consider climatic effects. When the base, subbase, and subgrade are frozen, pavement strains and deflections due to load are smaller. Therefore, traffic induced damage during winter months is greatly reduced. Since concrete pavement design procedures consider repeated application of traffic loading and fatigue damage. It should be possible to take advantage of the frozen support conditions in the design of concrete pavements.