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In this paper, a constitutive model is presented to model the behavior of various soils (sand and clay) in different loading conditions and the minimum required parameters are obtained. Although some practical features (concepts) of the bounding surface framework and modified Cam-Clay have been employed in its formulations, the model is developed mainly based on the generalized plasticity framework. Moreover, some concepts such as dilatancy relation and loading history surface are redefined. Finally, the proposed constitutive model is evaluated using the experimental data related to two different sandy soils and three different clays under different loading conditions. Finally, it is concluded that the proposed constitutive model can easily be calibrated for various clayey and sandy soils. It can depict different behavioral aspects of these soils under different monotonic and cyclic loading conditions. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the adequacy of the 100-year discharge along with the Froehlich bridge abutment scour equation adopted by the U.S. Federal Highway Administration (FHwA) in predicting abutment scour for bridge design purposes in South Carolina streams. The analysis utilized bridge properties, stream cross-sectional and hydraulic data, local flood frequency equations, a one-dimensional steady river flow computer model (WSPRO), and procedures recommended by the FHwA for predicting abutment scour. A method was developed to identify the single stream-discharge at each bridge that can cause the abutment scour that was observed at 73 bridge abutments. Analysis of the results revealed that for one-third of the abutments in the sandy soil region of South Carolina, the flow rates required to produce the observed scour depths had return periods greater than 100 years. Although for bridges in the region dominated by clay soil, the return periods were significantly smaller than 100 years. [ABSTRACT FROM AUTHOR]