Experimental study and numerical simulations of mechanical properties of anti-seismic joints for ductile iron pipes

Abstract:

Effective seismic measures for pipeline joints are the key to optimizing the seismic performance and post-earthquake functional recovery capability of urban water supply pipeline networks. In this paper, a new type of self-anchored anti-seismic joint for ductile iron pipes is proposed based on the thoughts of mechanical self-anchoring design and self-deformation compensation. This article conducted axial tensile quasi-static tests and refined three-dimensional finite element numerical simulations of anti-seismic joint, and studied the mechanical characteristics of the anti-seismic joint, including tensile bearing capacity, initial tensile stiffness, deformation resistance, and ultimate damage state. The research results show that the water pressure variation within 0.2 MPa has little effect on the axial mechanical properties and damage mode of the common push-on joint, and the transition deformation from the initial leakage to the functional failure state of the joint is about 2.5 mm; the new self-anchored anti-seismic joint has good tensile bearing capacity and resistance to large deformation, and its tension resistance curve is divided into three stages: the gasket bearing stage, the snap ring bearing stage and failure damage. When the deformation of the snap ring is about 9 mm, it reaches a peak bearing capacity of about 330 kN.