Truncated base mechanically stabilized earth walls are the MSE walls with narrow base excavation length and steep excavation slope designed to save construction cost while pushing the technological envelope of geosynthetic reinforcement development. A wall with truncated geometry of a narrow base length and steep excavation slope can significantly increase its base bearing pressure.
The Twin Tunnels project will add an additional lane of highway capacity and improve roadway geometry for about 3 miles of eastbound I-70 from the East Idaho Springs Interchange (milepost 241) to the base of Floyd Hill (milepost 244) where the project ties into an existing three-lane section. The eastbound bore of the Twin Tunnels will be expanded to accommodate the widened roadway section.
An adequate longitudinal joint tie bar system is essential in the overall performance of concrete pavement. Excessive longitudinal joint openings are believed to be caused by either inadequate tie bar size or spacing or improper tie bar installation. If designed and installed properly, tie bars prevent the joints from opening and consequently improve load transfer efficiency between slabs and between slabs and shoulders, resulting in increased load carrying capacity. CDOT should adopt the mechanistic-empirical tie bar design procedure developed in this study.
Proper structural design of pavement systems requires knowing the resilient modulus of the soil as this parameter is a proven predictor of the stress-dependent elastic modulus of soil materials under traffic loading. In addition, the R-value test is conducted using a device called a stabilometer, where the material's resistance to deformation is expressed as a function of the ratio of the transmitted lateral pressure to that of the applied vertical pressure. Both tests are expensive and time consuming; however, establishing accurate and reliable correlations between the test results and the soil's physical properties, in lieu of laboratory testing, can save a considerable amount of time and money in the analysis and quality control process. For these reasons, correlations are typically used for estimating the resilient modulus and R-value for soils. The variability of a given soil type in different regions and states requires developing modified and specific correlations for each state based on statistical analysis of the statewide soil data collected. The main goal of this research study was to develop correlations among R-value, Resilient modulus, and soil's basic properties for available AASHTO soil types in databases in Colorado.
The objective of this study is to determine if the development of a standardized subset of bridge plans s feasible and cost effective. The past 30 years of successful Colorado Department of Transportation bridge design can be used as a starting point to create a standardized subset of bridge plans.
