Reinforced Concrete Roof Slab Thickness

Lb la 16 12 1 33 2 two way slab minimum depth of two way slab is given by formula hmin perimeter 180 2 16 12 12 180 3 73 in assume h 5.

Reinforced concrete roof slab thickness.

Thickening the structure along the perimeter by another will serve as an integral footing adding strength where the loads are heaviest. Thickness of the slab is decided based on span to depth ratio specified in is456 2000. Typical insulating roof deck form planks manufactured in north america and designed for cast in place reinforced concrete roof decks. For flatwork such as slabs on grade and driveways a minimum thickness of four inches is required but increasing the thickness to five inches can add nearly 50 percent to the load bearing capacity.

Reinforced concrete slabs are heavier and generate higher seismic forces in an event. For example the florida based company hurricane proof systems offers a 7 inch 18 centimeter slab of concrete in three layers. With that in mind i ve seen slabs as thick as 16 18 due to column spacing. For example we build residential in flat plate concrete which will typically have a column spacing of 20 oc and a slab thickness of 8 typ.

A solid slab of concrete capping the top of your house. Cross section of a typical cast in place reinforced concrete roof deck formed with one of the typical icf planks shown in figure above. Assume the thickness of slab take 4 cm per metre run of the span. Commercial is typically steel w a composite deck so you ll have a 5 6 slab sitting on top of steel beams.

The maximum diameter of bar used in slab should not exceed 1 8 of the total thickness of slab. Minimum reinforcement is 0 12 for hysd bars and 0 15 for mild steel bars. If reinforced concrete were to be reused strong connections would have to be made between roof and walls. Such slabs left unconnected to walls caused many deaths in the 2005 quake from school roof collapses.

The diameter of bar generally used in slabs are. Concrete slab design procedure steps to be followed in the design of slab assuming suitable bearings not less than 10cm find the span of the slab between the centers of bearings. Exact specifications vary but most concrete roofs are several inches thick. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less.

A concrete roof is exactly what it sounds like.