Civil and Environmental Engineering
First Advisor
Mojdeh Asadollahipajouh
Date of this Version
5-2024
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Civil Engineering
Under the supervision of Professor Mojdeh Asadollahipajouh
Lincoln, Nebraska, May 2024
This project was completed for the Midwest Roadside Safety Facility (MwRSF) Pooled Fund.
Abstract
This document reports the efforts conducted to determine critical parameters and configurations for Manual for Assessing Safety Hardware 2016 (MASH) Test Level 3 (TL-3) compliant breakaway luminaire poles supported by slip bases, including identifying pole configurations with the potential to meet MASH TL-3 as well as recommending critical configurations for full-scale crash testing. A thorough literature review was conducted which included survey results collected from Midwest Pooled Fund state departments of transportation (DOTs), standard plans from state DOT’s, and past luminaire pole testing.
Numerical LS-DYNA models were developed for luminaire poles with 4-bolt slip base utilized by the Utah Department of Transportation (UDOT). The LS-DYNA simulations were validated using the USBLM full-scale crash test series. The validated slip base model was utilized to simulate various pole configurations with 4-bolt slip base under MASH test nos. 3-60, 3 61, and 3-62 at impact angles of 0 and 25 degrees, with vehicle impacting at the center and quarter points. The pole configurations included pole heights ranging from 20 to 50 ft and mast arm length ranging from 4 to 20 ft. The simulations were post-processed and analyzed to identify trends regarding the MASH safety criteria, including occupant compartment deformation, occupant risk measures, and vehicle instability, to identify the critical parameters and configurations for slip base luminaire poles. The following trends were identified from simulation results: (1) none of the simulations exceeded MASH limits for OIV, ORA, roll and pitch values; (2) MASH 3-60 impacts appeared to be more critical in terms of roof crush; (3) Vehicle center impacts were found more critical than quarter point impacts for roof crush; (4) roof crush beyond the 4-in. MASH limit occurred for multiple configurations at each pole height in MASH 3-60 impacts, (5) none of the MASH 3-61 and 3-62 impacts led to intrusion into the occupant compartment; (6) pole configurations with 4-ft long mast arms showed the best potential to pass MASH; and (7) nearly all pole configurations between 450 and 600 lb showed potential to pass MASH. Based on simulations results, critical pole configurations and impact conditions were recommended for full-scale crash testing.
Advisor: Mojdeh Asadollahipajouh
Comments
Copyright 2024, Jacob Conway. Used by permission