Abstract: An arch structure for use in forming an overfilled structure includes at least one footing and at least one precast concrete bridge element forming an open bottom arch structure that is supported on the at least one footing. The arch structure has an upper portion, that may be formed by a first half-ellipse shape, and a lower portion, that may be formed by part of a second half-ellipse shape. The upper portion and lower portion meet at an elevation along the rise of the arch structure, and such elevation defines the largest span of the arch structure. The arch structure includes lower ends that come back inward toward each other, such that the span at the bottom of the arch structure is less than the largest span.