In order to study the full-range failure process of bar-wrapped cylinder concrete pressure pipe (BCCP) under internal water pressure

tests on three prototype BCCPs with different diameters were designed. Annular strain gauges were arranged on the cylinder

steel bar

and concrete protective cover of the BCCP with a diameter of 1 800 mm

and the force response of each part under the action of internal water pressure was obtained by increasing the applied internal water pressure to 2.5 MPa step by step. It was found that the load-bearing process of BCCP from prestressing to ultimate failure could be divided into 5 stages. First

the concrete core was subjected to the force of the prestressed steel bar without protective cover. After being wrapped

the core formed by cylinder and concrete was subjected to an initial pre-compression stress. Second

the whole pipe was in the elastic stage before the protective cover cracked. It corresponded to the stage when the internal water pressure in the test was less than 1.5 MPa

and the core was still under pressure

while the prestressed steel bar and the outer concrete protective cover were under tension. Third

the concrete core was in the elastic stage after the protective cover cracked. When the internal water pressure arrived at 1.6 MPa

the cover reached the tensile strength and began to crack

and the concrete core also transformed from the initial compression to tension slowly and remained in elastic state. Fourth

the cylinder and the steel bar were in the elastic stage of tension after the concrete core cracked. As the water pressure arrived at 2.2 MPa

the concrete core cracked radially

but the stress of cylinder and bars still increased steadily with the internal water pressure. Fifth

the pipe was completely destroyed. The cylinder and the steel bars reached the ultimate yield strength

and the whole pipe lost its bearing capacity. The research results could provide basis for the popularization and application of BCCP in water transfer engineering and the formulation of relevant standards.