This　paper　presents　an　efficient　numerical　framework　for　the　seismic　analysis　of　post-tensioned　concrete　gravity　dams,　which　automatically　inserts　anchors　into　the　structure.　The　proposed　approach　is　implemented　in　the　commercial　finite　element　software　ABAQUS　by　introducing　a　polygonal　user　element　(UEL)　derived　by　the　scaled　boundary　finite　element　method　(SBFEM).　By　inserting　nodes　in　the　polygonal　structural　mesh　along　the　anchor　layouts,　duplicating　the　inserted　nodes　representing　anchors,　and　generating　cohesive　elements　on　the　node　pairs,　post-tensioned　anchors　are　naturally　embedded　into　the　structure,　and　the　bond-slip　interactions　are　considered.　Furthermore,　an　unbounded　UEL　derived　by　the　SBFEM　is　implemented　to　simulate　the　unbounded　foundation　in　the　dam-reservoir-foundation　interaction　systems.　The　unbounded　UEL　only　requires　a　small　truncation　area　around　the　region　of　interest　to　rigorously　capture　the　dynamic　properties　of　the　infinite　foundation　in　terms　of　a　displacement　unit-impulse　response.　This　ABAQUS　implementation　allows　the　use　of　built-in　capabilities　of　ABAQUS　for　nonlinear　dynamic　analysis,　including　contact　modeling　and　cohesive　fracture.　Weak　structural　interfaces　existing　in　a　concrete　gravity　dam　(dam-foundation　interface　and　construction　joints)　are　modeled　by　a　cohesive-frictional　contact　scheme.　In　the　end,　sophisticated　numerical　models　dams　featuring　post-tensioned　gravity　dams　with　weak　interfaces　and　anchors　can　be　generated　in　a　fully　automatic　manner,　requiring　no　special　treatments　for　mesh　generation　such　as　partitioning.　The　accuracy　of　the　proposed　technique　is　verified　through　a　numerical　example　of　the　Manly　dam　strengthened　by　a　vertical　anchor.　The　efficiency　of　this　approach　is　demonstrated　through　a　dam　with　three　construction　joints　anchored　by　multiple　inclined　anchors.　The　input　files　of　the　numerical　examples　are　available　from　the　authors　upon　request.