Demountable modular structure for the construction of one-deck raised parking lots, preferably without foundations, designed to be employed for parking vehicles in angled arrangement, or herringbone pattern, including two or more parallel structure strips, each one defined by two rows of pillars offset from each other in the longitudinal direction of the structure strip so as to form, between two adjacent couples of pillars, parallelogram-shaped portions of ground surface, wherein the upper level is made of an orthogonal network of main beams resting on each one of the rows of pillars and secondary beams resting on the pillars or fixed in orthogonal position to the main beams, and of rectangular or square floor slabs. The structure allows easier parking and maneuvering of larger vehicles as compared with structures with 90-degree parking stalls, with no detectable losses of efficiency in terms of parking places obtainable from a given available surface.