A　new　type　of　integral　bridge　with　flexible　abutments　is　proposed,　which　can　better　accommodate　the　thermal　expansion　and　contraction　deformation　of　main　girder,　reduce　soil　pressure　behind　the　thin-walled　integral　abutments　and　mitigate　the　restraint　of　backfill　to　the　overall　bridge.　In　this　type　of　the　bridge,　part　of　backfill　behind　the　wing　walls　is　replaced　by　expanded　polystyrene　(EPS)　geofoam　and　lightweight　foam　concrete.　The　Maluanshan　Bridge　in　Shenzhen　is　taken　as　the　prototype　bridge　to　study　the　mechanical　property　of　the　flexible　abutment　integral　bridge,　and　based　on　which　a　trial-design　bridge　was　designed.　The　finite　element　models　of　the　prototype　and　trial　bridges　were　built　up　to　verify　the　design　calculation　and　bridge　structures,　and　compare　the　mechanical　properties　and　natural　vibration　characteristics　of　the　prototype　and　trial　bridges　under　loads.　It　is　shown　that　due　to　the　weakening　of　the　boundary　constraints　of　the　overall　bridge　structures,　in　the　trial-design　bridge,　the　absolute　values　of　hogging　moments　at　the　two　girder　ends　under　dead　loads　are　reduced　by　21.　94%　and　26.　28%,　respectively,　while　the　absolute　values　of　hogging　moments　at　the　two　girder　ends　under　live　loads　arc　reduced　by　16.54%　and　17.26%,　respectively,　on　the　basis　of　the　original　bridge,　which　means　the　bridge　is　more　capable　of　addressing　the　concrete　cracking　induced　by　girder-end　hogging　moments.　Under　the　action　of　overall　temperature　rise　and　fall,　the　longitudinal　displacement　of　the　main　girder　at　the　abutments　of　the　trial　bridge　is　intensified　by　59.　85%　to　63.　12%,　and　the　bending　moment　and　stress　have　been　reduced　by　66.　18%　to　66.　73%　and　31.　18%　to　32.　11%,　respectively.　Under　both　live　and　dead　loads,　no　significant　variation　of　midspan　and　pier-top　bending　moments　was　observed,　with　a　fluctuation　less　than　6%.　The　natural　vibration　frequencies　of　first　10　modes　of　the　trial　bridge　are　smaller　than　those　of　the　original　bridge,　which　is　favorable　to　accommodate　the　internal　forces　imposed　on　the　bridge　under　seismic　and　other　loads.　©　2023　Wuhan　Bridge　Research　Institute.　All　rights　reserved.