Development of New Kinds of Mobile Safety Barriers.

摘要

This document reports on two studies supported under the noted task order. The first part of the report discusses the status of intrusion alarms for work zones. An intrusion alarm detects when a vehicle breaches the work zone and alerts people in the proximate area. The main selling point is to capitalize on being rapidly deployed, while providing advance warning to the workers when a vehicle penetrates the work zone. These devices have an audible alarm (typically 130-120 db) to notify workers and the general public when a work zone breach has occurred. While the concept of an intrusion alarm seems promising, there are many limitations to these systems which make them generally impractical. Additionally, based on the fact that many companies have looked into intrusion alarms and that only one company has an active product line suggests that current systems have significant limitations both from their technical implementation as well as worker acceptance. Additionally, this report covers the finite element crash test simulations on the low-profile barrier to determine the geometry that had the least permanent deflections and best met construction feasibility. The simulations were completed under the guidelines of test level 2 of the National Cooperative Highway Research Program (NCHRP) Report 350. Prior to the crash test simulations, a foundation had to be designed. A 2-dimensional finite element parametric study of various cross-sections for the foundation was studied and one as selected because of its simpler constructability and ability to resist impacts. There were two crash test case studies. The first case tested the maximum permanent deflections (installed in weak soil) whereas the second case tested the barrier structure (installed in rigid soil). The study concluded that both the weak and rigid soil simulations were within acceptable limits.