Crashworthy Foundations for Soil-Embedded Roadside Safety Hardware

University

University of Nebraska-Lincoln

Principal Investigator

Joshua Steelman (joshua.steelman@unl.edu)

Total Project Cost

$351,791

Funding Type

2016 USDOT

Start Date

09/01/2020

End Date

6/30/2024

Agency ID or Contract Number

69A3551747107

Abstract

Luminaire pole foundations in weak, soft soils are typically installed with deep foundations because the soils are believed to be too weak to resist vehicle impact forces. However, designing the foundation as though the crash load is constant for an indeterminate amount of time ignores the potentially beneficial reality of a short term impulse load. A foundation may be pushed into surrounding soil for a fraction of a second during an impact, and then recover to its original position after the luminaire pole has broken away. This research seeks to provide improved understanding of these types of crash phenomena and the response of soil-embedded elements, particularly those surrounded by weak, wet soils. Ultimately, this improved knowledge will translate into crashworthy foundations that are cheaper and easier to install, benefiting workers installing them and the traveling public.

Description

The objective of this MATC-funded research effort is to develop reliable computational soil modeling, enabling cost-effective crashworthy foundation design for soil-embedded roadside safety hardware. The project is particularly focused on weak, loose, and saturated soils or site conditions. Optimized foundations for luminaire poles in soft, saturated soils should provide reliable breakaway behavior for the luminaire pole with only minor permanent movement of the foundation.

Impacts/Benefits

This project will allow luminaire pole foundations to be more cost-effectively designed, thereby freeing resources for redistribution to improve safety elsewhere in state agencies’ transportation networks. Additionally, the findings from this research will be applicable to other similar soil-embedded roadside safety hardware.

Deliverables

Download the Final Report