Behavior of Jointed Ductile Iron Pipelines

Abstract

Experimental data on the axial, bending and torsional behavior of ductile cast iron pipes with rubber gasket joints is presented. Analytical expressions are provided which predict the resistance mechanisms and behavior of the joints. The bending mechanism is found to be quite different from the axial and torsional mechanism. By repeating the tests in a specially designed soil box, the effects of burial depths are determined. A joint stiffness matrix including axial, bending and torsional effects is provided. The slip behavior of the joint changes the stiffness values, however this occurence may be dealt with by using an appropriate flag system. To minimize axial compressional stresses and interlocking bending stresses at the joint, a minor geometrical change in the joint needs to be made. Joints with larger lip lengths provide more flexibility when subjected to axial compression or joint bending rotations.