Experimental Investigation on Isolated Strut Behavior of High Strength Steel Fiber Reinforced Concrete Panels [高強度鋼纖維混凝土版之壓桿行為實驗研究]

High strength reinforced concrete have been promoted and developed in recent years. Due to brittle nature of high strength concrete, higher amounts of transverse reinforcement are required to ensure the ductility of members. By adding steel fiber into high strength concrete, which is so-called steel fiber reinforced concrete (SFRC), shear strength and deformation capacity can be significantly improved and damage tolerance is also enhanced because cracks can be restrained effectively. Moreover, SFRC is expected to replace certain amount of transverse reinforcement for better construction workability. In this study, uniaxial compression tests of 24 SFRC panels were conducted to verify strut mechanism and behavior of SFRC in the isolated strut. The result results show that the addition of steel fiber not only changes the failure mode from brittle splitting failure to ductile strut crushing, but also increases both strengths at the first-cracking and ultimate stages. Furthermore, by analyzing different shapes of strut, an index named effective tie area is proposed to verify tensile force contributed from steel fiber in the bottle-shaped strut. The results indicate that in the specimen with 0.75% and 1.5% volume fraction of steel fiber, effective tie area can raise up to 40% and 50%, respectively. ? 2020, Chinese Institute of Civil and Hydraulic Engineering. All right reserved.