The present invention is a general structural member assembly. A basic structural unit of the present invention has two adjacent shafts, both further having a cross sectionally triangular shape with a longitudinal side completely or substantially mostly removed to form legs. The leg ends are formed or machined such that they present two outward surfaces generally parallel to the open face of a first adjacent shaft. The outward surfaces of the leg ends are then positionally fixed, albeit with some flexible movement in some embodiments, to generally have a parallel and longitudinal interface with the longitudinal outside edges of a solid side of a second shaft. A stacked assembly may be formed from the structural members capable of sediment retention or accumulation.