Bhutani, Srishti (2021-12). Development of the Preliminary Guidelines for the Evaluation and Repair of Portable Concrete Barriers. Master's Thesis.
Thesis
Portable concrete barriers (PCBs) are roadway safety hardware designed to contain and redirect vehicles during accidents and prevent vehicles from entering the construction zone, while protecting drivers. The Texas Department of Transportation (TxDOT) requires a set of formal guidelines governing the evaluation and repair of PCBs. Arriving at the guidelines is a multi-task research procedure. Objectives of this project are: (i) to conduct a non-destructive evaluation (NDE) of selected PCBs (ii) to develop preliminary evaluation guidance for the classification of PCBs and to propose repair procedures for minor damages, (iii) to develop calibrated finite element models of PCB in LS-DYNA (an advanced general-purpose multi-physics simulation software package) and study the behavior of damaged and undamaged PCB assembly when subjected to impact by MASH vehicles, (iv) to identify the most critical pre-existing damage or a combination of damages and further evaluate its effect on the crashworthiness of the PCB by carrying out predictive finite element analysis (FEA) simulations. NDE was conducted to analyze the internal structure of selected damaged PCBs and see whether a correlation existed between the NDE results and the damages observed in the component crash test with the surrogate test vehicle. Based on the findings of the latest literature review and observations from the component crash test, a preliminary evaluation and repair guidance was drafted for PCBs. Finite element model of the PCB assembly was developed in LS-DYNA, it was validated by running a crash simulation with surrogate vehicle, which replicated the results of the component crash test previously conducted. Predictive simulations were carried out to impact the undamaged and pre-damaged models of 210-foot-long PCB assembly with MASH vehicle models under the Test Level-3 (TL-3) impact conditions. Crash data obtained was further processed in TRAP (Test Risk Assessment Program) and compared with the corresponding prescribed limits given in MASH. The location and extent of pre-existing damages in the PCB were decided based on the provisions outlined in the preliminary guidance. The researcher recommends verifying the FEA results of this research study by carrying out full-scale crash testing under MASH TL-3 impact conditions.
