To　investigate　the　seismic　performance　of　grouting　metal　corrugated　pipe　(GCP)-assembled　concrete　double-column　piers　under　biaxial　loads,　three　test　specimens,　including　the　cast-in-place　(CIP),　GCP　and　prestressed　GCP　(PGCP)　piers,　were　designed　and　fabricated.　Bi-axial　quasi-static　tests　were　conducted　to　study　the　failure　modes,　hysteretic　characteristics,　skeleton　curves,　stiffness　degradation,　residual　displacement,　and　joint　opening　rules　for　the　GCP　and　PGCP　piers,　and　compared　with　those　of　the　CIP　pier.　The　analysis　on　the　displacement　ductility　and　deformation　capacity　of　the　PGCP　pier　was　emphasized.　The　results　show　that　the　bending　failure　fails　to　dominate　the　CIP　and　GCP　specimens,　and　the　prestressed　force　increases　the　axial　load　and　damage　degree,　thereby　increasing　the　crashed　concrete　height　of　the　PGCP　pier　to　15　cm　in　contrast　to　that　of　the　GCP　pier　(10　cm).　Under　the　bidirectional　load,　the　energy　dissipation　and　ultimate　bearing　capacities　and　stiffness　of　the　CIP　pier　are　higher　than　those　of　the　GCP　pier.　After　adding　prestressed　tendons,　the　bearing　capacity,　stiffness,　and　deformation　capacity　of　the　PGCP　pier　in　the　strong　axis　direction　are　approximately　equal　to　those　of　the　CIP　pier.　The　bearing　capacity　of　the　PGCP　pier　reaches　97.9%　of　that　of　the　CIP　pier.　The　displacement　ductility　coefficient　(4.79)　of　the　PGCP　is　higher　than　that　of　the　CIP　pier　(3.23).　The　residual　displacement　of　the　PGCP　pier　decreases　to　70%　of　that　of　the　CIP　pier.　Furthermore,　the　displacement　ductility　and　ultimate　deformation　capacity　of　the　PGCP　pier　in　two　directions　are　almost　similar,　indicating　that　the　full　plastic　hinge　mechanism　in　two　directions　can　be　formed　to　avoid　early　failure　in　one　direction,　and　the　overall　seismic　performance　of　the　PGCP　pier　is　significantly　improved.　The　results　can　provide　an　experimental　basis　for　the　design　and　application　of　the　PGCP　pier.　Keywords:　©　2021,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.