The most widely used model to perform piles analysis under static and dynamic lateralrnloads consists of modeling the pile as beam elements and representing the soil as a grouprnof unconnected, concentrated springs perpendicular to the pile (Discrete Winkler Model).rnThe absence of interaction between the individual springs in the Discrete Winkler Modelrnproduces an unrealistic response.rnThis study aims to perform an analytical and numerical study of the static and dynamicrnresponse of the pile-soil system under lateral loads (considering homogeneous soil profile)rnusing a two-parameter subgrade model. In order to develop a rational method that includesrnshear interaction between the concentrated springs, a two-parameter model proposed byrnWorku (2014) was used.rnA simplified expression for the adopted model parameters was obtained by performing arnseries of numerical and parametric investigation. The proposed model was calibrated usingrnoutputs from PLAXIS 3D, and from the result, it was observed that the proposed modelrncould predict pile-head stiffness within a maximum error of 3% when compared to FErnoutput. A new approach for determining the critical pile length is also introduced. Usingrnthis new approach, critical pile lengths for different boundary conditions are introduced.rnBased on the variation of pile-head stiffness, a new classification, other than "short" andrn"long" piles, was introduced, namely "transitional" piles. Simplified expressions for pilernhead stiffness for piles in a "transitional" state are provided.rnThe dynamic stiffness (or impedance) and the kinematic response are investigated.rnEquivalent spring and dashpot coefficients at the pile-head are computed to provide arnsimplified procedure to replace the entire soil-pile system with a spring and a dashpot atrnthe top that will produce the same effect on the overlying structure.rnEquivalent spring coefficients at the top of the pile are obtained from the beam on elasticrnfoundation techniques. Equivalent damping coefficients are obtained following arnsimplified approach that uses the concept of conservation of energy. Results are comparedrnwith those given by a dynamic finite element (DFE) analysis over a range of frequenciesrnfor piles in a homogeneous soil layer, and from the result, it is evident that the model is inrngood agreement with the DFE results.