Steel-ultra-high　performance　concrete　(UHPC)　composite　walls　can　use　high-strength　tie　bars　(HBs)　as　shear　connectors　to　satisfy　the　increased　requirement　of　interfacial　shear　resistance.　However,　there　is　a　lack　of　research　on　the　shear　behavior　of　HBs　embedded　in　UHPC.　To　address　it,　this　paper　conducts　33　push-out　tests,　considering　the　effects　of　the　following　six　parameters:　yield　stress　and　thickness　of　steel　plates,　yield　stress　and　diameter　of　tie　bars,　and　compressive　strength　and　fiber　content　of　concrete.　Test　results　demonstrate　that:　(i)　the　failure　modes　include　shear　failure　of　tie　bars　(for　specimens　using　UHPC　with　steel　fibers)　and　splitting　failure　of　concrete　(for　the　other　specimens),　these　are　different　from　the　traditional　failure　modes　of　shear　studs　embedded　in　conventional-strength　concrete　and　should　be　considered　in　design;　and　(ii)　using　UHPC　or　using　tie　bars　with　higher　yield　stress　or　larger　diameters　can　remarkably　improve　the　shear　strength.　The　applicability　of　current　design　equations　to　estimate　the　shear　strength　of　HBs　embedded　in　concrete　is　also　evaluated.　It　is　shown　that　the　accuracy　of　current　design　equations　depends　on　the　governing　failure　mode.　When　tie　bar　shear　failure　governs,　AASHTO　LRFD　(AASHTO　2012)　can　accurately　estimate　the　strength,　while　the　other　equations　are　quite　conservative;　when　concrete　splitting　failure　governs,　all　equations　seem　unconservative　as　they　are　based　on　concrete　compression　failure.　©　2025　Institution　of　Structural　Engineers