00743631

Component

https://doi.org/10.3141/1599-07

http://scholar.google.com...nges&publication_year=1997

Researchers at Texas Transportation Institute designed a Slip Safe connection for use with steel U-channel sign-support structures within the highway right-of-way. The Slip Safe connection has two design configurations: a small Slip Safe design for single U-channel posts and a larger Slip Safe for back-to-back U-channel posts. Both configurations utilize Rib-Bak U-channel posts weighing up to 5.9 kg/m manufactured from 552-MPa yield billet steel. The Slip Safe is designed for use in a range of soil types with up to three supports per installation. There are two advantages of this Slip Safe design. First, the Slip Safe eliminated the dependency on material properties to achieve acceptable breakaway performance. In the past, all direct-driven and the majority of current breakaway designs for steel U-channel, square tube, wood, and round pipe sign supports have depended upon this. Second, the Slip Safe is omnidirectional and both hardware and supports are highly reusable due to the low energy required to activate the system. The Slip Safe designs are unlike most types of highway safety appurtenances in which performance is critically dependent on the failure of a bolt or bolts, the support material properties, or a combination of both. The Slip Safe has two advantages over the other current U-channel connections. First, activation of the Slip Safe occurs with approximately one-third of the force needed to activate fracture-type connections. Second, the only disposable component in the Slip Safe connection is the keeper plate. All casting, bolts, and U-channel supports were undamaged, yielding economic advantages in high-frequency impact locations.

This paper appears in Transportation Research Record No. 1599, Roadside Safety Features and Other General Design Issues.

English

p. 57-63

1997

Transportation Research Record

0309061709

Figures (3) ; Photos; References (2) ; Tables (2)

Activation (Chemistry); Breakaway supports; Cost effectiveness; Design; Performance

Design; Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure

TRIS, TRB, ATRI

Dec 11 1997 12:00AM

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• STATUS REPORT OF COLORADO SCENIC AND HISTORIC BYWAYS PROGRAM, 1989 TO 1996
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