# Validation of Seismic Performance of Stainless Press-to-Connect Piping System under Cyclic Loadings
## 1 Introduction  
Piping systems are essential for providing and distributing energy resources, such as water, gas, and oil, in critical facilities. In addition, they are related to system operation and safety. Failure of piping systems in critical structures can cause system shutdown in extreme cases, which leads to a situation where the plant cannot generate power. The failure of piping systems is mostly associated with leakage caused by corrosion, low-cycle fatigue, construction vibration, and seismic ground motions. More specifically, the failure of piping systems can be classified into two groups: (a) failure of pipes, such as elbows and tee joints, and (b) failure of the support system of the piping system, such as hangers and anchors. For example, during the 1994 Northridge earthquake that had a magnitude of 6.8, three transmission piping systems that supplied the city with water were damaged, and leaks of the gas piping system were also reported because of steel pipe corrosion conditions [1]. In addition, the Kobe earthquake in 1995 that had a magnitude of 6.9 resulted in approximately 1600 leakages of water distribution piping systems, and theseleakages mostly occurred at the connections of the piping systems [1]. Pipeline joints can be broadly classified into welding and non-welding connections. The welding joint must be safe against the risk of fires or explosions during construction. However, non-welding connections, such as threaded, grooved, and press-to-connect systems, do not have the same potential risks as welding joints. In addition, many researchers have addressed the seismic performance of threaded and grooved connection systems during and after strong ground motion, considering welding-free conditions. [PERSON] et al. [2] characterized the failure limit state of various sizes of threaded and grooved piping fit joint systems, and a nonlinear finite element (FE) model of the large scale piping system incorporated with the component level piping was validated based on experimental test results. [PERSON] and [PERSON] [3] and [PERSON] et al. [4], using a rotation spring on the OpenSees platform, developed a nonlinear FE model that corresponded to the experimental test data of component levels and then developed seismic fragility as a probabilistic seismic risk assessment of a piping system level, which was identified using twice elastic limit states on a threaded T-joint. Furthermore, the fragility estimation of a system-level piping system with four grooved fit elbows and eight grooved fit T-joint components of a 10-story reinforced concrete building was studied by [PERSON] et al. [5]. [PERSON] et al. [6] investigated the dynamic characteristics of a 2-story building system with nonstructural components, including partition walls, cells, and piping systems, using schedule 40 steel under multiple seismic ground motions based on ICC-AC 156 parameters; in particular, linear and nonlinear frame building systems were subjected to various ground motions on shaking tables. Subsequently, the difference in frequency between the linear and nonlinear systems was observed, and the damage to the nonstructural components related to the experimental tests was reported. In addition, for other joint systems, the numerical and theoretical models of interference joints of circular and oval piping systems were validated by [PERSON] et al. [7] using a strength analysis, and the contact stress corresponding to the equivalent stress in the quantitatively characterized piping prediction model was adequately assessed. Finally, [PERSON] et al. [8] tested the seismic performance of riser piping, press-to-connect, and groove fit joint systems under in-plane cyclic loads, and then image processing corresponding to the deformation angle at the elbow joints was conducted. In summary, over the past decade, there have been only a few studies on the press-to-connect piping component.