Design of CFRP-steel hybrid structure pipeline for concrete pumping under ultrahigh pressure

Abstract

The pipeline is the main channel for concrete pumping in construction, and lightweight, safe, long service life pipeline is very important for concrete pump trucks. This paper presents the design and experimental study on hybrid structure of carbon fiber reinforced polymer (CFRP) filament-winded strengthened circular long steel pipe. The filament-winded CFRP contains three layers: the inner layer for stress sharing of brittle steel tube, the middle layer for connecting to ductile steel flanges and the outer layer for explosion-proof and protection. With calculation of the hybrid structure stress, the design guideline of inner and outer layer CFRP is presented. Based on the design and test of the connection structure between pipe flange and CFRP, this paper conducted an optimization on the filament winding patterns of the middle layer. The experiment result shows the new hybrid structure pipeline can bear the pressure of 17 MPa and the axial loading of 210 kN, and the working requirements of concrete pumping can be satisfied. The test result indicates that the hybrid structure pipeline reduces 43% mass compared with the traditional double-layer steel pipe, and also the service life is 50% increased so as to the explosion-proof safety performance of concrete pump trucks is obviously improved.