The aim of this study is to evaluate the behavior of a discharge manifold that has space restrictions. These restrictions do not allow a suitable design by the usual practice. Thus, for its evaluation an upgraded methodology was necessary for structural analysis and revision. The upgrade includes the soil-thrust blocks-pipeline interaction and the influence of fittings outside the blocks using a simplified model. The manifold was assumed as a whole structure. The pipeline was modelled with frame elements. The behavior of the thrust blocks was simulated by means of a Winkler-like model with torsional and horizontal springs. Additionally, the influence of reducers and valves lying outside the blocks was included. Two analyses were performed. The first one, the interaction between soil, thrust blocks and pipeline is neglected; the second one includes the interaction among the elements. It is concluded that the overall capacity of the structural system increases when the interaction among elements is considered. The effects due to the interaction and the fittings lying outside the blocks can be estimated with the proposed model. Finally, it is shown that the reducers not embedded in the blocks produce a significant increment (up to 47%) in the pipeline longitudinal stresses. Nevertheless, the manifold resulted suitable for its operation. Thus, to evaluate a manifold that has space restrictions the enhanced methodology described in this paper can be used.