Contact gilcon engineering for waffle slab construction in sydney. Also, consideration of the reactive soil proves to be a significant factor in the construction of waffle slab. Waffle slab is a reinforced concrete roof or floor containing square grids with deep sides. Waffle slab analysis and design is similar to the procedure used with flat plates except that special considerations need. The speed of construction for such slab is faster compared to conventional slab. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. Calculations for waffle pod slabs need download adobe reader for pdf file. Waffle slab or ribbed slab construction procedure and advantages. Definition a grid or waffle slab is a type of building material which has two directional reinforcement on the outside. Pdf optimum design of reinforced concrete waffle slabs. Pdf this paper deals with the problem of optimum design of. Slab thickness of ribbed or waffle slabs is less than other slab systems.
Waffle slab or ribbed slab construction procedure and. This paper deals with the problem of optimum design of reinforced concrete twoway ribbed waffle slabs using genetic algorithms. In this 3d animation, youll see six simple steps to build a wafflemat foundation, from clearing the pad to setting the individual waffleboxes, to pouring the concrete and removing the form boards. Optimum design of reinforced concrete waffle slabs alaa c. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Each was examined through different slab aspect rations r of 1, 1. Design of waffle slab without beams by direct design method. More economy can be achieved if we make use of standard size for formation. It has been kept as 65 mm for all the floors studied herein. The overall tendency is to shrink and this can cause cracking at an early age. Aci 318 minimum slab thickness for twoway construction. The waffle pod slab system is a better way of building concrete slabs for new homes, extensions or commercial industrial buildings. 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.
Promotors of waffle slabs put forward a case that this type of slab is cheaper, there are less site works required, hence less labour and contracting costs, and that there is better insulative properties through the ground to the floor of the house. Ribbed and waffle slabs types, advantages, disadvantages. Waffle pod slabs vs raft slabs simon anderson consultants. Waffle slab is a popular option for commercial construction. 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.
Cip 6 joints in concrete slabs on grade what are joints. 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. A waffle slab can be made in different ways but generic forms are needed to give. The shape of ribs is considered as rectangular during analysis, although in actual practice it may be slightly tapered. Reducing the extent of foundations by reducing the ultimate load. The spacing between the ribs should be in general 2030 inch. Waffle slabs home builders in melbourne supa group. The simplest and most economical floor system is the flat plate, where a plain floor slab about 20 centimetres.
Concrete slab types construction, cost, and applications. Mar 01, 2018 waffle slab laid out and ready for the concrete to be poured. A wide variety of waffle slab construction options are available to you, there are 9 suppliers who sells waffle slab construction on, mainly located in asia. Waffle slab purpose, uses, advantages and disadvantages. Lighter and stiffer slab than an equivalent flat slab. Analysis of steel concrete composite waffle slab with opening irjet. A waffle slab or twoway joist slab is a concrete slab made of reinforced concrete with concrete. The shear strength of the joint must enable the transfer of moment and shear through it. Waffle slabs are composed by intricate formwork, and may be more expensive than other types of slabs, but depending on the project and the quantity of concrete needed it may be cheaper to build. The waffle pod slab systems allows more accurate specification of concrete quantities, reduces waste and provides a substantial boost to building site efficiency. I am checking a waffle slab building built in 1956, in particular the shear strength of the waffle ribs. Traditional construction technique of waffle slab system includes the storage of materials, establishment of supports and formwork assembly in situ for worker. Dec 01, 2016 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.
There are two common ways to build a slab for a house. The assembling process is quite similar to that of any twoway voided waffle slab, with a. Waffle slab laid out and ready for the concrete to be poured. Waffle pod slabs are generally suitable for sites with less. This form of construction is not very common because of the formwork costs and the low fire rating. It has equally spaced ribs parallel to the side having a waffle appearance from below. One hundred and thirty real models were tested for the sake of comparing the traditional oneway composite slab and waffle composite slab in both construction and composite stages. 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. They come in four thicknesses for use on different sites. 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.
Waffle slab construction allows a considerable reduction in dead load as compared to conventional flat slab construction since the slab thickness can be. Ribbed and waffle slabs are lighter and stiffer as compared to flat slab. Waffle pod slab construction and reinforcement details. Waffle pods are used in residential concrete slabs. A waffle slab gives a substance significantly more structural stability without using a lot of additional material. They provide good structural stability along with aesthetic appearance. Design of waffle slab without beams by direct design method 32 32 32 c 1 c 2 c 3 c 4 2 c.
Direct design method is used for the structural analysi s and design of slabs. Where concrete is relatively expensive, spans are generous, and it is not critical to select the smallest floor thickness, a posttensioned waffle slab construction is. This type of reinforcement is common on concrete, wood and metal construction. Traditional construction technique of waffle slab system includes the storage of materials, establishment of supports and formwork assembly in situ for worker convenience. The load carrying capacity of waffle slab is greater than the other types of slabs. Apr 22, 2012 this reinforced concrete waffle slab ribbed slab cross section reinforcement cad drawing detail includes ribbing beams reinforcement, slab top wire mesh, waffles dimensioning, voids width and depth, slab thickness. Waffle pod slab construction has a number of benefits including speed of production and huge cost savings. The ribs are categorized as ribbed slab and waffle slab. The concrete waffle slab is often used for industrial and commercial buildings while wood and metal waffle slabs are used in many other construction sites. Structural behavior analysis of twoways waffle composite slabs. Waffle pods 175, 225, 300, 375 mm waffle pod are made from polystyrene and are 1090mm square. Twoway joist concrete slab floor waffle slab system. Step 1 level the site using laser tools to suite the slab and house construction and set the datum. Due to the high formwork cost and degraded fire rating, this type of construction generally is not recommended.
The prefabricated waffle slab usually costs higher than the other two options. This video shows the different types of slab and their subtypes. Because of the ribs and double reinforcement, it is more stable and recommended for larger span slabs or foundations. Mar 19, 2020 this type of reinforcement is common on concrete, wood and metal construction. This makes a waffle slab perfect for large flat areas like foundations or floors. 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. Slab is a horizontal flexural member like the member. See more ideas about waffle ceiling, architecture details and architecture design. Can you tell me if the files are regular pdf files, that you can cut and paste, or are they. The slab is the flange of the beam and the extended part is the web. Formwork construction and pouring of concrete occur on site, then the slab is. The waffle slab is a monolithicpoured concrete slab with a flat top surface and an undersurface made of a rectangular grid of deep concrete beams running at right angles.
Technical note 5 slab does not adequately represent the mechanical properties of a stemmed floor system for analysis and design. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. According to tradeline, waffle slab construction is defined as a building system using concrete waffle slab floors supported by columns. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Long span structures construction construction technique formwork required reinforcements details modification in grid slab for utility services provided in grid slab benefits. Waffle slabs provide stiffer and lighter slabs than an equivalent flat slab.
Upon completion of the waffle slab house, the ground around the slab is built up by the builder to reduce the height of the slab above the surrounding ground. Hollowcore ribbed slabs derive their name from the. Waffle slabs are quickly gaining in popularity in construction projects as they can be shipped to site in different modes including. They can be cut to fit within the dimensions of the plan. A waffle slab has a holes underneath, giving an appearance of waffles.
The lateral loads are independently resisted by shear walls. Design, construction and when waffle slabs are used. The top countries of suppliers are china, hong kong s. Its typically used when stiffness is important or if there are abnormally heavy loads. For instance, the design and construction of floor slabs are usually solid, adequately reinforced in 2direc tion and concreted. This saving of weight can change in structural characteristic. Waffle pod slabs are less affected by rain delay than conventional slabs waffle pod slabs provide better insulation from the ground, allowing minimal heat and cold. Fiberglass waffles slab forms mfg construction and water. The most common material for a waffle slab is concrete. Waffle slabs are used for larger span slabs or floors and used when there is limited requirement for number of columns.
It uses 30% less concrete and 20% less steel than a raft slab. Twoway joist concrete slab floor waffle slab system analysis and design. Width of the ribs has been taken as 100 mm figure 3. Irregular cracks are unsightly and difficult to maintain but generally do not affect the integrity of concrete.
Dec 25, 2014 waffle slab is a reinforced concrete roof or floor containing square grids with deep sides. Waffle slabs are the preferred method of construction for many project builders and prestige home builders alike. Top slab of the waffle slab floors may be kept at its minimum thickness from construction point of view. 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. In ribbed slab, there is oneway spanning and in a waffle slab, there is twoway ribbed system. Waffle slab twoway pan joist twoway joist slab, also called a waffle slab. In fact, a lot of builders refer to this type of slab as a floating slab. Optimum design of reinforced concrete waffle slabs researchgate. Defination according to engineer florentino regalado1, the waffle slab belongs to the family of reinforced concrete slabs that are nonhomogeneous, lightened, and reinforced in two orthogonal directions, forming a ribbed plate.
Because the waffle slab is constructed on the ground, when the waffle slab is finished it sits about 400mm higher than the surrounding ground. Feb 15, 2012 in this 3d animation, youll see six simple steps to build a wafflemat foundation, from clearing the pad to setting the individual waffleboxes, to pouring the concrete and removing the form boards. Holedeck waffle slab construction system saves 20 per. These offer a very good form to resist the slab vibration that occurs in. The economy in waffle slab construction is attained by having maximum repetition of the forms and sizes used in construction. Twoway joist waffle slab design approach and methodology.
The waffle pods are lightweight, yet strong enough to support the weight of workers and wet concrete during site preparation and concrete pour. Waffle slab is a popular option for commercial construction work such as industrial building projects, bridges and others needing extra stability. With an interesting name, it can make you think that the slab floats like a raft. Optimum design of reinforced concrete waffle slabs integrated. 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. Because there are joists in both directions, this floor system is the strongest and will have the least deflection.
This type of slab is used in construction projects needing intense strength to weight ratios. Holedeck waffle slab construction system saves 20 per floor. If bars can transfer moment, they can also transfer shear as far as monolithic construction is concerned. Any change in the size can bring economy by bringing small changes in depths, spacings, and thickness. There are three main types of slab while each main type have their subtypes. Waffle slab structural engineering general discussion. Waffle slab construction consists of rows of concrete joists at right.
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