Abstract: A nonlinear finite element formulation is given for a staticallyindeterminate elasticviscoplastic structure in the present paper. The nonlinear behavior of material is characterized by a coupling of power law with exponential function. Variations of stresses, strains and strain rates in a coplanar truss are studied in the case of constant loading rate. Meanwhile, the creep is also investigated when the structure is subjected to a constant external force.