Design of reinforced concrete structures ii twoway slabs 1 1. Waffle slab or ribbed slab is a structural component which is plain on its top and contains grid like system on its bottom surface. Skydome is a modular formwork system in abs plastic used to build twoway ribbed slabs completely onsite. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Autocad construction details free download, architectural. The prefabricated waffle slab usually costs higher than the other two options. A waffle slab is a type of building material that has twodirectional reinforcement on the outside of the material, giving it the shape of the pockets on a waffle. In this paper, the optimum design of reinforced concrete waffle slabs is so ught using the simple genetic algorithm. Waffle slabs are most suitable for construction of slabs. The ribs are formed due to the pouring of concrete over a set of plastic waffles arranged in series on the ground. The waffle slab has been considered as monolithically connected to band beams.
Sandwich slabs may have the disadvantage of a larger weight compared to the ribbed ones but on the other hand, they have the advantage that their spans and supports behave in the same proper way. Ribbed or waffle slab is a slab system which consists of series of parallel reinforced concrete t beams framing into reinforced concrete girders. Twoway joist concrete slab floor waffle slab system analysis and design design the concrete floor slab system shown below for an intermediate floor with partition weight of 50 psf, and unfactored live load of 100 psf. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3.
Pdf analysis of steel concrete composite waffle slab. Design of reinforced concrete structures ii twoway slabs. A waffle slab formed with skydome virtually eliminates the need for drop beams and column heads. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. Long span structures construction construction technique formwork required reinforcements details modification in grid slab for utility services provided in grid slab benefits.
This pdf file contains a chapter of 23 pages with various aspects of flat slabs including four example of flat slab design. Reinforced concrete effective span centretocentre distance between supports longer dimension of a rectangular panel of slab for yield line calculations modular ratio esec design bending moment per unit width of slab modified to account for axial load moment per unit width about xaxis moment per unit width about yaxis. Optimum design of reinforced concrete waffle slabs alaa c. The slab has to carry a distributed permanent action of 1. Pdf optimum design of reinforced concrete waffle slabs. Manual for design and detailing of reinforced concrete to the september 20 code of practice for structural use of concrete 20 2. The lateral loads are independently resisted by shear walls. Foundation details v1 cad design free cad blocks,drawings,details. Waffle slab or ribbed slab construction procedure and. Cad drawing detail with a plan view of a ribbed waffle slab that can be used as an example for other projects.
Flat slab analysis, design and detailing pdf civil. Download these free autocad files of construction details for your cad projects. This paper deals with the problem of optimum design of reinforced concrete twoway ribbed waffle slabs using genetic algorithms. Waffle slab foundation features and construction details. The slab is the flange of the beam and the extended part is the web. In this paper, the optimum design of reinforced concrete waffle slabs is sought using the simple genetic algorithm. After this publication, it was subsequently adopted by the uniform building. Twoway joist waffle slab design approach and methodology twoway joist slab often called twoway ribbed slab or waffle slab is an economical floor system when the spans are long andor loads are high. The design procedure set forth in that publication had at that time been in use by the author for about 15 years. Contact gilcon to have your waffle slab designed and drafted. Jul 5, 20 cad drawing detail with a plan view of a ribbed waffle slab that can be used as an example for other projects. Twoway joist waffle slab design approach and methodology.
Waffle pod slabs are generally suitable for sites with less reactive soil and use about 30% less concrete and 20% less steel than a raft or ground level slab waffle pod slabs are only suitable. Such stiffened slabs are often called waffle slabs because of the geometric analogy with a waffle. It is usually used where large spans are required e. Design of waffle slab without beams by direct design method 32 32 32 c 1 c 2 c 3 c 4 2 c 5 c 6 c 7 c 8 32 s ss 22 3 7 c 9 c 10 c 11 c 12 32 8 11 b 1210 bb c c 14 c 15 c 16 16. Twoway joist concrete slab floor waffle slab system.
They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. Optimum design of reinforced concrete waffle slabs. Slabs and flat slabs lecture 5 19 th october 2016 contents lecture 5 designing for shear in slabs including punching shear detailing solid slabs flat slab design includes flexure worked example exercise punching shear. Fiberglass waffles slab forms mfg construction and water. Special discounted price for this collection of all librarys reinforced concrete waffle slabs detailed drawings.
The structural modeling used in most commercially available software, where stems are considered as disjointed from the topping slab does not deliver the advantages associated with waffleslab slab construction. Piers and piles a structural member that is driven, screwed, jacked. This makes the soffit completely flat removing all obstacles to the passage of tubes, plumbing and all systems, making their installation easier and more economical. Technical note 5 slab does not adequately represent the mechanical properties of a stemmed floor system for analysis and design. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. A waffle slab foundation, also termed as ribbed slab foundation, is a structure that is plain at the top and has a gridlike system called the ribs at the bottom.
The reinforced concrete waffle slab ribbed slab cross section reinforcement detail comprises ribbing beams reinforcement, slab top wire mesh, waffles dimensioning, voids width and depth, slab thickness. Design of waffle slab without beams by direct design method 32 32 32 c 1 c 2 c 3 c 4 2 c. Waffle slabs are quickly gaining in popularity in construction projects as they can be shipped to site in different modes including. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Feasibility of structural design of members has been ensured under the provision of is. The spacing between the ribs should be in general 2030 inch. The waffle slab system can be called as a two way joist slab system which comprises of ribs constructed in perpendicular direction. A waffle slab is a type of slab with holes underneath, giving an appearance of waffles. See more ideas about waffle ceiling, architecture details and architecture design. Reinforced concrete design 1 design of slab examples.
If you even know what a waffle slab is, youre either building one or having one built. The top of ribbed slab is normally thin and the bottom grid lines are generally ribs which are laid perpendicular to each other with equal depth. This is basically a cad dwg drawing with a typical waffle slab cross section reinforcement detail. Outline of presentation definition where this system can be used features of the grid slab decorative grid slabs in historical structures types of grid slab comparison. Manual for design and detailing of reinforced concrete to. Waffle pod slab a waffle pod slab is constructed entirely above the ground by pouring concrete over a grid of polystyrene blocks known as void forms.
Ill answer these questions and finish up with why, after 20 years of structural engineering, i have never, ever. There are three main types of slab while each main type have their subtypes. The community services department is dedicated to continually improving the level of service we provide to the. This video shows the different types of slab and their subtypes. Waffle slab plan view reinforcement detail faculdade. Bending will take place in the two directions in a dishlike form. This product allow to create a bidirectional slab inspired on the caisson, i. Waffle slab analysis and design is similar to the procedure used with flat plates except that special considerations need. The structural modeling used in most commercially available software, where stems are considered as disjointed from the topping slab does not deliver the advantages associated with waffle slab slab construction.
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