An analytical model and corresponding closed-form equations capable of determining the internal forces, moments, and deflections about the weak and strong axes, as well as the angle of twist along the span and the rigid body rotation of a prismatic long-span beam with overhangs at both ends and with an initial horizontal curvature are presented. The beam was supported on two nonlinear elastic bearings, each with an initial slope, and temporarily held by a crane at the middle point of its total span. The beam cross section was assumed to be doubly symmetrical and made of a continuous, homogeneous, and linear elastic material. The effects of cross-sectional distortion, shear deformations, initial vertical curvature, and residual stresses and prestressing were not included in the analysis. An example is presented and discussed in detail showing the effectiveness and accuracy of the proposed method.