CONCRETE PIPE Vertical Box Section Manholes Box Size Span x Rise 1200 x 600 1200 x 900 1800 x 1200 2400 x 1200 2400 x 1800 2440 x 2440 3000 x 2400 Standard Length 2000 2000 2000 2000 2000 2440 2000 Side Wall Thickness 125 125 175 200 200 200 250 Top Wall Thickness 190 190 200 200 200 200 250 Bottom Wall Thickness 150 150 175 200 200 200 250 Haunch 125 125 175 200 250 200 250 Plug/Top/Base Slab Thickness 300 300 300 300 300 300 300 Approximate Storage Volume (m3) 1.35 2.05 4.15 5.60 8.35 14.30 14.15 Box manholes offer the advantage of increased surface area for pipe connections versus round manhole structures. There are also numerous benefits to the flat faces, including ease of mechanical connections (i.e. steel plates) and mounting of cutting and coring equipment. Top slabs typically transition from the larger diameter to standard 1220 mm diameter manhole material. Alternatively, openings of most any shape and size can be accommodated, including the casting of access grates or hatches if the manhole structure is required to be flush with grade. Vertical Box Manhole Joints Mastic rubber gaskets are available for box manhole joints, but is very dependent on field installation. Additional measures by contractor may be needed if a watertight joint is required. Mastic sealants consist of bitumen and inert mineral fillers. The sealant is applied to the tongue or spigot and inserted into the bell or groove. A sufficient amount of sealant should be used to fill the annular joint space with some squeeze out. PAGE 48 LAFARGE PIPE eMANUAL