Abstract: A non-linear theory is presented for stability of an arch with central curvc of symmetrically variable curvature under uniform lateral load.By use of the variational principle of total potential energy,governing equations are obtained respectively for symmetrical and antisymmctrical deformations of the arch.Analytical solutions are given for deflection and inner forces and moments of the arch under symmetrical defonnation. Critical eigen conditions are also obtained analytically for the arch under antisymmetrical deformation. The total behavior of the areh under loading is,therefore,revealed,including deflection,bucklinng and postbuckl-ing.The example calculations made for a real structure show that the current analysis has rather good accuracy and convenience for engineering purposes.

Key words: arches, nonlinear, lateral stability