A　reciprocating　low-cycle　pseudo-static　loading　test　on　three　reinforced　concrete　(RC)　piles　was　performed　in　the　Structural　Laboratory　of　Fuzhou　University　to　study　their　failure　modes　and　seismic　behaviors.　The　modified　calculations　of　lateral　deformation　and　soil　pressure　along　the　piles　were　further　verified　based　on　the　test　results.　In　this　article,　a　displacement-based　simplified　calculation　for　pile-soil　interaction　of　piles　was　proposed　based　on　the　shear　equilibrium　and　test　results,　and　then　it　was　compared　with　the　traditional　m　method　and　p-y　curve　method.　The　test　results　show　that　m　method　overestimated　the　bearing　capacity　of　piles,　leading　to　a　lower　safety　factor　for　the　piles.　Therefore,　it　was　not　suitable　to　calculate　the　internal　force　and　lateral　displacement　under　large　displacement.　Moreover,　the　ductility　of　prestress　high-strength　concrete　pipe　piles　or　RC　piles　would　be　overestimated　by　the　p-y　curve　method.　Although　the　p-y　curve　method　took　into　account　the　nonlinearity　of　soil,　the　calculated　force-lateral　displacement　curve　still　showed　a　significant　difference　with　the　test　results　under　large　deformation.　The　test　results　further　show　that　the　modified　calculation　of　lateral　displacement　and　soil　pressure　can　be　preferably　validated　by　test　results,　which　indicates　that　the　displacement　law　of　laterally　loaded　pile　can　be　accurately　assessed.　Furthermore,　the　proposed　displacement-based　simplified　calculation　showed　a　good　agreement　with　the　test　values　in　terms　of　internal　forces　and　force-lateral　displacement　curve.　Therefore,　it　was　recommended　for　analyzing　the　cyclic　behavior　of　laterally　loaded　pile　foundations　considering　soil-pile　interaction　in　integral　abutments　jointless　bridges　(IAJBs).　Copyright　©　2019　by　ASTM　International.