What are the methods of design of flat slabs?
Table of Contents
What are the methods of design of flat slabs?
DDM is very simplest and approximate method for analysis of flat slab. In this method total moment (M0) is calculated and then it distributed to total Negative Moment and total Positive moment All the Negative & Positive moments are distributed in the column strips & Middle strips respectively.
How do you design a slab?
The effective depth d of two way slabs can also be assumed using cl. 24.1,IS 456 provided short span is <3.5m and loading class is <3.5KN/m….Or, the following thumb rules can be used:
- One way slab d=(L/22) to (L/28).
- Two way simply supported slab d=(L/20) to (L/30)
- Two way restrained slab d=(L/30) to (L/32)
How are flat slabs constructed?
A flat slab is a two-way reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete columns. The flat plate is a two-way reinforced concrete framing system utilizing a slab of uniform thickness, the simplest of structural shapes.
What is Direct Design Method of flat slab?
2.1 In the direct design method, the total design moment for a span shall be determined for a strip bounded laterally by the centre-line of the panel on each side of the centre-line of the supports. 4 = length of span in the direction of M; and = length of span transverse to l.
What are limitations of direct design method for designing of flat slab?
Limitations of Direct Design Method
- There must be at least three continuous spans in each direction.
- Panels should be rectangular and the ratio of longer/ shorter spans within the panel must not exceed 2 otherwise one-way actions will prevail.
How do you calculate the thickness of a flat slab?
1, then the ratio shall not exceed 0.9 times the value specified above i.e., = 40 ´ 0.9 = 36, if mild steel is used. = 32 ´ 0.9 = 28.8, if HYSD bars are used It is also specified that in no case, the thickness of flat slab shall be less than 125 mm.
How is slab design calculated?
One way slab d = (L/22) to (L/28). Two way simply supported slab d = (L/20) to (L/30) Two way restrained slab d = (L/30) to (L/32)
What is Direct Design Method?
The direct design method is an analytical approach by which the required area of reinforcement for short reinforced concrete columns or shear walls is determined directly without using an interaction diagram. A design diagram shows all possible fitted sections for a particular column or shear wall.
How to design a flat slab floor system?
Design an exterior panel of a flat slab floor system of size 24m x 24m, divided into panels 6m x 6m size. The live load on the slab is 5 kN/m2 and the columns at top and bottom are at diameter 400mm. Height of each storey is 3m. Use M20 concrete and Fe415 steel.
What is the best method for analysis of a flat slab?
Analysis It is normally sufficient to consider only a single load case where all spans are subject to maximum design load, viz: The flat slab can then be analysed using either the Frame Analysis Method or the Simplified Method.
What is the basic design procedure of a two way slab system?
The basic design procedure of a two-way slab system has five steps. 1. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near mid-span. 2. Distribute moments transverse at critical sections to column and middle-strip and if
What is an example of a 2A Flat slab?
Example CEH7422; TOPIC 2A-FLAT SLAB DESIGN 2. MBEYA UNIVERSITY OF SCIENCE & TECHNOLOGY 2 CEH7422; TOPIC 2A-FLAT SLAB DESIGN 1. Definition FLAT SLABS are slabs with or without drops supported generally without beams by columns with or without column heads. The slabs may be solid or have recesses formed on the soffit to give waffle slab.