Finite Element Analysis Of Prestressed Concrete Cylinder Pipe

At home, there is nothing about numerical modeling of Prestressed Concrete Cylinder Pipe (PCCP), and aboard, it is at the phase of starting. In this dissertation, for the first time, the whole course which is from manufacture, installation to running is modeled. The superiority of PCCP is discoursed upon from different aspect, such as the onset of crack, the character of stress, and so on. That how the creep of core affect the pipe is analyzed, which makes up the deficiency about the study aboard.(1) Load steps and what is analyzed. The loads are applied in the following order: prestress, pipe weight, earth load, fluid weight, and internal pressure. Those including displacement, stress, crack, the change of stress after cracking and creep are analyzed.(2) The Displacement of PCCP. Firstly, the pipe shrinks as the function of the prestressed steel wires. Then, it ovalizes before the internal pressure applied. And then, it tends to re-round and expands as the internal pressure increases.(3) Crack developing. The mortar cracks prior at springline, and the crack expands towards both sides along with increasing of the internal pressure. The outer core cracks at the springline earlier than at other parts, and the crack expands towards both sides and extends deeply as the internal pressure increasing. The inner core cracks at crown and angle at one blow.(4) Stress changing. The hoop stress in the inner core changes similarly with that in the inside of outer core, and it in the outside of outer core is tally with that in the mortar. The prestressed steel wires make the core and the cylinder hoop compressed, and makes the wires pulled axially. During the earth load functions, the axial tensile stress in the steel wires increases at crown and invert, whereas it decreases at springline. At the same time, the compressive stress in the inner core and the inside of outer core decreases at crown and invert, but it increases at springline, and in the outside of outer core and mortar, the hoop stress changes reversely. As the internal pressure increasing, the tensile stress increases, and the compressive stress decreases in the pipe.(5) Stress changing suddenly after cracking. After the core cracking, the stress around the crack redistributes. The core in the zone of crack releases the tensile stress, and the core nearby the crack takes a sudden change from being compressed to being pulled, and the compressive stress increases suddenly apart from the crack. In...