Application of Fiber Bragg Grating Sensor on Measurement of Tensile Stress in a Seven-Wire Prestressed Steel Strand

Abstract

An application of fiber Bragg grating(FBG) in the measurement of tensile stress in a prestressed seven-wire steel strand,which is widely used in various prestressed concrete,is carried out.The character of prestressed steel strand is analyzed,and it is used to decide the install techniques of FBG.A series of experiments are carried out and the results show that FBG can represent the overall stress of prestressed steel strand without being affected by specific structure of strand when it is only fixed on one of wires.The fracture test shows that the maximum strain limit of FBG is 5 457 μe,which means the offset of working zero of FBG should at least be 5 000 μe.