To　shorten　the　splicing　time　of　extended　long-connected　bridges,　splicing　method　of　new　and　old　bridges　partially　spliced　in　longitudinal　direction　was　proposed,　according　to　the　characteristic　transversal　displacement　of　extended　long-connected　bridge　which　shows　large　at　both　ends　and　small　at　middle.　The　effects　of　splicing　time　and　non-splicing　length　on　transversal　displacement　were　analyzed　by　finite　element　method.　Checking　calculation　method　for　long-connected　bridge　adopting　the　proposed　partial　splicing　method　was　discussed　according　to　existing　specifications.　Full-scale　experiment　was　conducted　on　steel　plate　splicing　structure　for　non-splicing　parts.　The　results　show　that　transversal　displacements　of　bearings　in　both　new　and　old　bridges　can　be　obviously　reduced,　so　as　to　shorten　the　splicing　time　when　new　and　old　girders　were　symmetrically　spliced　from　mid-span　to　two　ends　by　cast-in-place　wet　joint　and　splicing　isn＇t　carried　out　at　both　end　parts.　Taking　standing　time　of　new　constructed　girders　into　account,　the　length　of　non-splicing　part　at　both　ends　can　be　obtained　according　to　the　principle　that　the　displacement　of　bearings　in　the　old　bridge　should　be　less　than　the　allowable　value　under　the　effect　of　concrete　shrinking　and　creep　in　ten　years　after　extending.　Not　only　bending　and　shearing　bearing　capacity　but　also　torsion　bearing　capacity　should　be　checked　for　new　and　old　constructed　girders.　No　crack　and　crush　appear　at　the　junction　between　steel　plate　and　flange,　deck　pavement,　and　interface　between　deck　pavement　and　flange　when　test　load　is　gradually　increased　to　the　twice　equivalent　vehicular　loads　of　highway-I,　which　verifies　the　method　of　setting　splicing　structure　at　equal　interval　along　the　longitudinal　direction　between　the　flanges　of　the　non-splicing　parts　of　new　and　old　bridge　can　avoid　the　cracks　appearing　in　deck　pavement　and　collision　occurring　between　new　and　old　bridges.　©　2016,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.