Jeongho Oh

Impact of Repeat Overweight Truck Traffic on Buried Utility Facilities

Increasing overweight truck traffic, as evident by a rapid increase of permits issued for such traffic in Texas, tends to accelerate the deterioration of pavement structural integrity. However, it is less known to what degree buried utility facilities along and across the right-of-way are affected by these overweight loads, especially if these facilities are aged or placed under an exception to the Texas Utility Accommodation Rules (UAR). In this study, researchers evaluated the damage potential of buried pipe subjected to repeat overweight traffic loads. Based on a review of technical design and engineering requirements for utility accommodation in Texas, a large-scale laboratory test was conducted to investigate fatigue behavior of polyvinyl chloride (PVC) and concrete pipe. The result of both static and fatigue load tests indicated that pipe deformation in terms of vertical diameter reduction was less than 5% of pipe diameter, the maximum allowable value. However, fatigue damage was observed for the concrete pipe even though the deformation level was very minimal. A sensitivity analysis based on the finite-element method was conducted to validate the findings of the laboratory test. The study concludes that the current UAR appear adequate with respect to the likelihood of fatigue damage to buried pipes attributable to repeat overweight loads.

Part 4: Pavement Subsurface Drainage: Estimation of Expected Moisture Contents for Pavements by Environmental and Soil Characteristics

Expected moisture contents were evaluated for pavements on the basis of climatic and soil characteristics with the use of the Enhanced Integrated Climatic Model (EICM). Subgrade moisture content varies with environmental and soil conditions and has significant influence on pavement performance. Thus, it is important to establish realistic estimates of expected subgrade moisture contents to account for the effects of this variable on predicted pavement performance during the design stage properly. To predict expected moisture contents, researchers examined regional variations in climatic and soil-water characteristic curves in Texas. Through cluster analysis, seven climatic and nine soil regions were established that captured the variations in climatic and soil characteristics across the state. Typical pavement structures and groundwater table data in different regions were used to reflect regional characteristics and to estimate the initial boundary soil suction profile for a given pavement, which is a cr...