Monobox Maintenance Holes

A rectangular monobox MH consists of a true monolithic top and bottom component. In the case of a monobase, the four walls and the base slab are poured together in one continuous concrete pour. Similarly, the monotop consists of the four walls and the top slab. The two halves are stacked to create a complete structure with only one joint. The geometry of these sections allows for much larger hole openings in the four walls to accommodate very large pipe and box units. The standard inside length and width dimensions of these chambers are available in 2400 x 1800mm, 3000 x 2400mm, 3900 x 2400mm and 3900 x 3000mm. Aside from these standard sizes, Concast also has the capability to manufacture specialty sized monobox manholes as well. The height of each monobase and monotop can be varied by 150mm increments. This precast structure is supplied with a shiplap joint that can be filled with a mastic joint treatment.