Experimental study on the behavior of a prestressed nineteen parallel wire strand (PWS) in suspension bridges under hydrocarbon pool fires

Abstract

Modern suspension bridges are constructed by increasing use of high perfor mance tension members in which parallel wire strand (PWS) type, has been used as a suspender (hanger) cable for long-span suspension bridges. The main cables of a suspension bridge system support the total bridge deck load through these suspender cables. This study focuses on the special effects of open-air hydrocarbon type pool fires which may possibly outcome of a freighter truck crash or sabotage ever since the quan tity and flammability of its contents poses one of the worst-case threats to a nearby abovementioned suspender cables. Most of the research on bridge fires is based on the theoretical finite element models whose validity has not been checked experimentally. In this thesis, experimental testing was built to have a full understanding in the behav ior with regard to tensile strength and ductility of PWS system which was subjected to in-service stresses and fire loading. Each specimen contains 19 galvanized wires with 1860 Mpa grade of 5.1 mm diameter and 4 meter length in between socket ends. The program includes static loading tests at ambient temperature and transient elevated temperature tests while specimens held at constant load level at 45% of ultimate load capacity. The specimens exposed to UL-1709 standard fire and a realistic gasoline pool fire scenario until the rupture. Thus, for the insulated specimen static test after cooling was conducted. It is shown through these test results that the high-strength bridge wires are very susceptible and critical tension components when exposed to a pool fire load and these results can be used as an actual data for developing relevant design strategies for mitigating fire hazard in suspension bridges.