Based　on　the　research　of　trial　designs,　tests　of　an　arch　model　having　steel　truss　web　and　concrete　flange　(STW-RC)　under　unsymmetrical　in-plane　loads　were　carried　out.　The　arch　model　failed　in　a　punching　shear　failure　mode　similar　to　those　of　most　truss　structures.　All　the　test　results　demonstrate　that　the　node　section　under　the　concentrated　force　causing　the　stress　concentration　was　the　key　factor　for　the　failure　of　the　STW-RC　arch.　The　mechanical　behaviours　of　such　node　sections　should　be　paid　more　attention　in　the　design　of　this　type　of　arch　bridges.