Finite　element　analysis,　based　on　various　construction　and　service　stages,　of　a　genetic　bridge　was　carried　out　to　find　the　potential　reasons　causing　longitudinal　reflection　cracking　on　top　of　bridge　deck　as　well　as　the　cures　for　solving　this　problem.　Meanwhile,　the　effect　of　applied　transverse　posttensioning　magnitude　and　tendon　location　as　well　as　bearing　pads＇　supporting　restraint　was　modeled　in　the　FEA　to　investigate　their　effect　on　the　distribution　of　transverse　posttensioning　force　along　the　joints　between　adjacent　box-girders.　Results　show　that　(1)　transverse　posttensioning　and　diaphragms　reduce　efficiently　the　tensile　stress　on　top　of　deck;　but　this　efficiency　slows　down　significantly　in　bridge　corner　area,　where　exists　still　relatively　higher　tensile　stress　than　other　locations;　(2)　In　some　cases　of　loading　combination,　most　locations　on　top　of　deck　along　the　joints　exist　transverse　tensile　stresses,　but　the　magnitude　is　less　than　0.7Mpa,　which　could　not　cause　the　cracking　if　the　decking　concrete　cover　and　keyway　grout　are　properly　selected　and　cast　to　the　designated　specifications;　(3)Two　patterns　of　transverse　posttensioning　output　almost　same　result　in　the　clamping　stress　along　the　joints　for　this　proposed　particular　bridge　model;　(4)The　vertical　spacing　between　two　tendon　locations　(upper　and　low　level)　should　be　farther　spaced　than　the　currently　specified　1/3　girder　depth　so　that　less　tensile　stress　or　compressive　stress　is　expected　on　top　of　deck;　(5)　The　restrain　from　bearing　pads　modeled　in　this　FEA　has　little　effect　on　the　stress　distribution　along　joints　between　box　girders.