Experimental Study on Cross Arms Inserted in Concrete-Filled Circular GFRP Tubular Columns

In recent years, development of new structural systems based on fibre-reinforced polymer (FRP) materials attracted much attention. Concrete-filled FRP tubes taking advantages of both FRP and concrete show great promise for the potential application in piling, poles, highways overhead sign structures and bridge components. The hybrid member also provides an alternative solution for traditional transmission structures. However, the connection between concrete-filled FRP tubes and cross arms has not been fully investigated. This paper conducted an experimental study on steel cross arms inserted in concrete-filled circular glass FRP (GFRP) tubular columns. The structural responses of the system when the cross arms were subjected to concentrated loads were carefully recorded. It was found that the concrete-filled GFRP tubes could offer a sufficient restraint to the cross arm, leading to a limited deformation. Although stress and strain concentrated on the GFRP tube at the corner of the cross arm, no visible cracks were observed.