An　experimental　study　and　numerical　analysis　on　eleven　reinforced　concrete　(RC)　beams　and　four　partially　prestressed　concrete　(PPC)　beams　strengthened　with　U-shaped　steel　strips　were　carried　out　under　static　loading.　The　influences　of　damage　degree,　ratio　of　shear　span　and　effective　depth　of　section,　stirrup　ratio,　spacing　of　the　steel　strips,　level　of　effective　prestressing,　and　thickness　of　steel　strips　on　the　shear　performance　of　these　strengthened　beams　were　investigated.　Some　conclusions　are　drawn　from　the　testing　and　numerical　analysis　results　as　follows:　(1)　The　development　of　inclined　cracks　can　be　effectively　restrained　using　the　proposed　strengthening　method　with　U-shaped　steel　strips,　and　the　shear　load-carrying　capacity　and　ductility　of　the　strengthened　RC/PPC　beams　can　be　effectively　improved.　(2)　Both　strengthened　with　the　same　amount　of　U-shape　steel　strips,　the　increase　of　shear　carrying-capacity　of　a　PPC　beam　is　less　than　that　of　a　RC　beam.　(3)　For　damaged　beams,　the　loads　causing　the　yielding　of　stirrups　and　steel　strips　are　decreased　after　strengthening.　The　shear　strengthening　effects　are　more　obvious　for　beams　with　higher　shear　span　ratios.　(4)　The　proposed　nonlinear　finite　element　(FE)　model　can　better　predict　the　shear　performance　of　strengthened　RC/PPC　beams.　The　results　from　FE　model　agree　very　well　with　those　from　testing.　(5)　The　usable　strength　of　steel　strips　should　be　effectively　reduced　for　the　shear　strengthening　design　of　the　practical　engineering　cases.