Pendulum impact testing of an impact-breakaway, windresistant base connection for multi-post ground signs.

Final report; Feb. 2011-May 2012.PDFTech Report2012/92174BDK75 977-40SignsStructural supportsImpactImpact testsAccidentsBreakaway supportsFinite element methodDynamic structural analysisStatic structural analysisFrictionFloridaUniversity of Florida. Dept. of Civil and Coastal EngineeringConsolazio, Gary R.Bui, Long H.Walters, Robert A.University of Florida. Dept. of Civil and Coastal EngineeringFlorida. Dept. of Transportation. Research Management CenterNTL-OPERATIONS AND TRAFFIC CONTROLS-OPERATIONS AND TRAFFIC CONTROLSNTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Control DevicesNTL-SAFETY AND SECURITY-Highway SafetyNTL-SAFETY AND SECURITY-AccidentsUS Transportation CollectionRoadside signs play an important role in traffic control systems and must be placed adjacent to roadways. If they are not designed,fabricated, and installed properly, ground signs may pose potential hazards to vehicle passengers in the event of a vehicular collision with asign structure. Ground signs must be strong enough to resist hurricane wind loading and self-weight, and yet sufficiently frangible to avoidextreme vehicular deceleration on impact. Such deceleration can cause abrupt occupant deceleration or excessive vehicle compartmentdeformation, either of which can cause serious or fatal occupant injuries. Consequently, sign structures located adjacent to roadways aregenerally designed to break away or yield under vehicle impact loading. Presently, a breakaway slip-base connection system is used inFlorida. The breakaway mechanism of this system, however, depends on specific pretension levels in the bolts of the connection.Therefore, the performance of this system is undesirably sensitive to the level of bolt-torque that is imposed during installation andmaintenance.In this study, a new breakaway sign post base connection, the \ue2\u20ac\u2dcshear-controlled moment collar\ue2\u20ac\u2122, was developed and subjected tostatic and dynamic testing. The new connection system is capable of resisting code-specified equivalent static hurricane wind loads, butalso breaks away under low energy impact (vehicular) loads. Development of the connection involved several phases: conceptualdevelopment using nonlinear dynamic finite element analysis; structural design; validation of wind load capacity using static experimentaltesting; and validation of breakaway performance using pendulum impact testing. Experimental determination of friction coefficients forTeflon sheets, used in conjunction with structural steel, was also carried out. In addition, a permanent high-energy impact pendulum testfacility was designed and constructed as part of this research and used to conduct dynamic impact tests on the newly developed breakawayconnection