In　order　to　estimate　seismic　performance　of　RC　(reinforced　concrete)　bridge　piers　with　hollow　sections　under　composite　earthquake　loads,　quasi-static　testing　was　carried　out　on　three　RC　rectangular　hollow　bridge　piers　under　bidirectional　cyclic　load　with　a　spiral　shape　loading　protocol.　Using　finite　element　numerical　analysis,　the　lateral　displacement-force　curves　and　curvature-moment　curves　of　specimens　were　studied.　The　parameters　considered　were　axial-compression　ratio,　wall　thickness,　and　bi-axial　bending　strength　ratio.　By　analyzing　the　effect　of　these　parameters　on　the　hysteretic　behaviors　of　specimens,　failure　characteristics,　and　section　performance,　a　new　lateral　displacement-force　hysteretic　curve　model　under　bidirectional　cyclic　load　with　a　spiral　shape　loading　protocol　was　proposed.　In　the　new　hysteretic　model,　the　coupling　effect　on　strength,　stiffness,　and　displacement　under　lateral　bidirectional　load　was　referenced.　Then　the　proposed　model　was　further　used　to　obtain　calculated　lateral　displacement-force　curves,　which　agree　well　with　experimental　results.　©　2016,　Engineering　Mechanics　Press.　All　right　reserved.