Shear　keys　as　sacrificial　members　are　widely　used　in　cap　beams　and　abutments　of　highway　bridges,　to　limit　the　transverse　displacement　of　superstructures　and　control　damage　to　substructures.　An　experimental　program　to＇　study　the　seismic　behavior　of　reinforced　concrete　(RC)　sacrificial　exterior　shear　keys　was　presented.　The　influence　of　reinforcement　ratios　and　construction　joint　types　on　the　mechanical　behavior　of　the　shear　keys　was　investigated,　and　three　failure　modes　of　the　exterior　shear　keys　under　reversed　loads　were　observed　during　testing.　Two　analytical　models　for　predicting　the　force　displacement　backbone　curves　of　the　exterior　shear　keys　With　sliding　shear　failure　and　sliding　friction　failure　were　developed,　respectively.　The　analytical　models　proposed　in　this　paper　were　in　good　agreement　with　the　experimental　data,　indicating　that　they　can　be　used　as　a　reliable　tool　for　predicting　the　response　of　exterior　shear　keys　of　highway　bridges.　(C)\　2017　Elsevier　Ltd.　All　rights　reserved.