In　high-rise　buildings　with　high-strength　concrete　column　and　normal-strength　concrete　floor,　the　beams　and　slabs　are　usually　cast　in　a　continuous　fashion　through　the　beam-column　joint　to　simplify　construction,　and　this　results　in　the　lower　strength　concrete　at　the　beam-column　joint　core　(sandwich　joint).　It　will　influence　the　capacity　of　the　joint.　In　this　article,　three　groups　of　three-dimensional　specimens　consisting　of　sandwich　joint　specimens　and　corresponding　traditional　joint　specimens　were　tested　under　bidirectional　reversed　cyclic　loads　to　investigate　seismic　performance,　including　the　failure　mode,　ductility,　energy　dissipation,　and　deformation.　The　test　results　show　that　the　beam-column　joint　core　can　be　cast　with　normal-strength　concrete　when　the　column　concrete　strength　is　less　than　1.5　times　that　of　the　beam.　However,　when　the　ratio　exceeds　1.5,　the　failure　mode　of　the　joint　may　change　from　beams　flexural　failure　to　joint　shear　failure　and　additional　strengthening　measures　should　be　taken.　Finally,　the　formula　for　calculating　shear　capacity　of　the　three-dimensional　sandwich　joints　is　presented,　and　the　predictions　are　compared　to　the　experimental　results.