| Abstract: | The objective of this project was to develop structurally independent foundations for TxDOT’s 36-inch tall single slope traffic rail (SSTR). The barrier and foundation systems were required to meet AASHTO MASH Test Level 4 (TL-4) criteria, and require minimal maintenance after a design impact. Foundation designs were needed for two common field installation scenarios; a foundation that has a shallow depth but can have a wider footprint, and a foundation that has a narrow footprint, but can have greater depth. Researchers developed preliminary design concepts for the barrier and foundation systems. This was followed by developing finite element models of these designs and performing full-scale impact simulations with MASH Test 4-12 impact conditions. Results of the simulations were used to modify and improve the foundation designs and select final configurations for developing reinforcement details. Two foundation systems were developed under this project. One was a moment slab foundation, and another was a concrete beam foundation. Of these, the moment slab foundation was evaluated further by performing MASH Test 4-12, which involves a 10000S vehicle impacting the barrier at a target impact speed and impact angle of 56 mi/h and 15 degrees. The SSTR on the moment slab foundation performed acceptably for MASH Test 4-12 for longitudinal barriers. This report provides details of the preliminary foundation designs, modeling and simulation of the various designs, and reinforcement details of the selected designs. Also included is a detailed documentation of the crash test and results, and an assessment of the performance of SSTR with moment slab foundation for MASH Test 4-12 evaluation criteria for longitudinal barriers |
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