In this study, a nonlinear analysis procedure is developed to reproduce the full response of concrete deep beams reinforced with GFRP bars using matrix truss formulation. The load-deflection curve of the beam is described by extracting several main key points represented by the cracking and ultimate capacity levels and four more intermediate points. The strut-and-tie method (STM) is followed when defining the type of truss elements and analyzing the nodal displacements under a unit load while estimating the actual load based on attaining the key points in the different types of critical truss elements. Once the cracking and ultimate level loads are estimated, the four intermediate loads are defined and the elongation, strain, and stress in each element in the truss are iteratively recovered by matrix analysis for all six load levels, thus, avoiding the need to approximate or establish the nonlinear strain profile across the depth and along the span. Also, the solution strategy using the secant stiffness is formulated, and its results are compared to the experimental findings. An attempt is made to analytically define the failure mode using the critical truss element at the ultimate loading stage compared with the experimental results. This study shows an excellent agreement between the present nonlinear analysis approach and the experimental response curves for the entire range of shear span-to-depth ratios.