To　solve　the　problem　of　unseating　of　bridge　spans　in　small-and-medium-span　simple-supported　girder　bridges　under　strong　earthquakes,a　novel　energy-consuming　and　easy-to-install　integrated　energy-dissipative-unseating-prevention　arc-shaped　plate　device　was　developed.　First,quasi-static　tests　were　used　to　study　the　hysteretic　energy　dissipation　behavior　and　fatigue　failure　mechanism　of　arc-shaped　plate　devices　with　different　cross-sections.　Then,numerical　analysis　was　used　to　explore　the　influence　of　parameters　on　the　skeleton　curve　and　equivalent　damping　ratio　of　the　device,and　the　unseating　prevention　behavior　mode　and　ultimate　capacity　of　the　arc-shaped　plate　device　were　supplemented.　The　results　show　that　the　proposed　new　arc-shaped　plate　device　has　excellent　energy　dissipation　capacity.　T-shaped　arc-shaped　plate　structure　is　more　reasonable,　and　the　equivalent　damping　ratio　can　reach　a　maximum　of　nearly　40%　.　The　device　can　be　designed　by　separating　geometric　parameters　to　design　energy　dissipation　capacity,hysteretic　strength,stiffness　and　displacement　capacity.　Increasing　the　web　height　h2　of　the　middle　section　is　the　most　effective　method　to　improve　the　energy　dissipation　capacity　of　the　arc-shaped　plate.　Increasing　h2　by　50%　can　increase　the　maximum　strength　by　50.　1%　and　the　equivalent　damping　ratio　by　about　4.　7%　.　The　proposed　new　unseating-prevention　device　can　provide　an　integrated　device　solution　for　bridges　with　small-and-medium　earthquake　energy　dissipation　and　strong　earthquake　flexible　unseating-prevention.　©　2024　Southeast　University.　All　rights　reserved.