Local customs among builders, designers, and users should not be overlooked when selecting the slab type. Pdf design of oneway slabs 11 there are two main types of ribbed floors a hollow block floors and b spanning in the short directions supporting a thin topping slab above. Additional reinforced internal ribs are then used in the slab by introducing pontex, the structural cupolex accessory to provide a structure capable of spanning between foundations or piles. This slab type is made up of prestressed beams and hollow blocks and are temporarily propped until set, typically after 21 days. Pdf cost comparison between frames with solid slab and. Pdf assessment of cost variation in solid and hollow. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. Optimum design of reinforced concrete waffle slabs alaa c. Im trying to model a concrete building, and it has hollow block slabs. Description of original building the case of study original building is a reinforced concrete hollow block slab building which can be used as a commercial one, the building is not designed according t o seismic standards. The reinforcement bars are placed in the slab ribs between the blocks. In general, it is seen that in solid slab a portion of concrete below the.
Heavy loads in building s such as warehouses include moving load s, stationary live loads, and wall loads. Hollow blocks are used to fill portions of the slab thickness. The other slab type is a ribbed floor slab consisting of equally spaced ribs, usually supported directly by columns. These types of structural plate systems can minimize. Hello everyone, im trying to model a concrete building, and it has hollow block slabs. Oneway hollow block slab are frequently used in construction, and it is when the ribs are in one direction regardless of the rectangularity lylx. Is it possible to design this type of slabs by using autodesk robot. Theoretical concepts, practi cal applications, basis of. Hordy slab hollow block slab hollow blocks are used to fill portions of the slab thickness. Rib and block concrete slab advantages pro rib and block. Furthermore, precast concrete hollow block slabs exhibit excellent structural integrity, improved sound and heat insulation, and allows for a high quality plastered soft fit finish. Hollow blocks have a minimum crushing strength of 3. Because of this the size of column, footing and other load bearing elements are reduced.
The dead load for the hollow block slab is given by. The cost is managed by supervision of non skilled laborers, following the recommendations in this manual. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. The design aid can be utilized in preliminary or final stages or to verify computer outputs and ensure they conform to bs standard bs81101, 1997.
For those who dont understand what this rib and block means. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. The study was done in ethiopia for the frames with solid slab and ribbed slab in the same seismic zone zone4 and on the same soil class or type soil type a. The main objective of this report is to present different structural flooring that are intended to be considered by the structural designers in the design efforts during the different coming design development stages for the project of thakher city. Our premises occupy some 65000 sqm, and based in kliprivier gauteng, we are well situated to service the gauteng, and other markets. Econo rib and block is a member of the civilworks group of companies, collectively servicing the civils, building, and engineering sectors. The blocks are considered as nonstructural element as they do not contribute to strength of the slab. Introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. This paper deals with the problem of optimum design of reinforced concrete twoway ribbed waffle slabs using genetic algorithms. Mathematical structural analysis of one way ribbed slabs was introduced in this paper.
Each type of floor consists of number of reinforced concrete ribs. In case of ribbed slab the blocks are not permanent. 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. In sap program, the model has been divided to frame elements to represent ribs and beams and shell elements to represent the slab and solid part. Hollow blocks made of lightweight concrete or other. Hollowtile slabs are still built in some places, but only where the cost of both steel and cement is very high relative to labor. The blocks are considered as nonstructural element as they do not contribute to strength of. Jan, 2017 hollow blocks are used to fill portions of the slab thickness. Pdf behavior of one way reinforced concrete slabs with.
Crcm manual 4 crcm means concrete rib construction method, the word method, can create confusion, because the icc ibc uses such word in the section 1701. Econo rib and block has a long history of more than a decade of supply to the building sector. In pre cast solid slab construction t he cost of tr ansportation of units. Advantages of rib clay pot slab over solid concrete slab. A hollow core slab which is precast and installed on site with a crane. Optimization of flexural prediction for ribbed floors in bending. Pdf comparison study for various structural slab systems. 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. Substantial cost savings over conventional rc insitu slabs and speed of erection makes rib and block a more attractive product for modern building techniques. The equivalent thickness of the 200 mm 8 hollow core slab is 125 mm therefore exceeding the 124 mm minimum. For design such this slab i mean detailed reinforcement can be in robot. Twoway joist concrete slab floor waffle slab system analysis and design. Height of hollow block, h mm topping to be placed on top of hollow blocks, t mm 01 0635 as 5102001 design of hollow pot slab ly lx rib plan view of a hollow pot 457 205 h. What is waffle slab and hordy slabhollow block slab.
The main advantage of the ribbed floor is the reduction of the quantity of concrete and hence the considerable savings in the cost. Concrete slab types construction, cost, and applications. Jan 14, 2020 waffle slab end support reinforcement detail. Concrete rib construction method, crcm uses the engineering technology to design the elements structurals to handle the loads originated by climatic and or geographical location of the project.
The ribs are tapered in crosssection in its lower part. Crosssections through a ribbed and hollow block floor slab are shown in ligure 8. The reinforced concrete waffle slab ribbed slab cross section reinforcement detail includes ribbing beams reinforcement, slab top wire mesh, waffles dimensioning, voids width and. Introduction the advantages of ribbed and hollow block slabs are as follows. The ribbed floor is formed using temporary or permanent shuttering while the hollow block floor is generally constructed with blocks made of clay tile or with concrete containing a lightweight aggregate.
Aug 02, 2017 how to build a block wall lay the blocks duration. Reinforced concrete hollow block slab is designed to reduce the dead load of slab and to simplify formwork. Pdf behavior of one way reinforced concrete slabs with styropor. There is a natural human tendency to want to repeat what one has previously done. Waleed abo elwafa mohamed, seismic capacity of rc hollow block slab bu loglqj 2. Ribbed slab article about ribbed slab by the free dictionary. There are two main types of ribbed floors a hollow block floors and b moulded floors as shown in figure 8. This form of construction is not very common because of the formwork costs and the low fire rating. In general, it is seen that in solid slab a portion of concrete below the neutral axis remains ineffective. In case of hollow block slab voided blocks are placed to reduce the total weight of the slab.
Floor slabs which are frightening from underneath, but following. Jul 02, 20 introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. Sketch on hollow pot slab plan slab dimensions hollow pot slab width, b 3. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Apr 24, 2015 ribbed slab hollow block slab hourdi block different sizes 4. May182017 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. Hollow tile slabs are still built in some places, but only where the cost of both steel and cement is very high relative to labor. The saving of materials tends to be offset by some.
Waffle slab end support reinforcement detail in 2020. Structural ribbed concrete slabs the cupolex floor slab can be fully or partially suspended on piles, stem walls or gradeedge beams. The electrical slab boxes, which are the same size as the concrete slab blocks, allow for down lighters anywhere in the slab and the electrical conduits to be positioned correctly. The slab was assumed to be an interior panel in a building with over 3 panels in either direction. But crcm uses concrete a material used more than 3,000. Ribbed slab hollow block slab hourdi block different sizes 4. The slab is thus constrained to act as one way spanning between supports. It is an important type of voided slab and commonly used in long span floor system. Cost comparison between frames with solid slab and ribbed.
Improved sound and heat insulation further enhance this system. Please practice handwashing and social distancing, and check out our resources for adapting to these times. Ribbed and waffle slabs types, advantages, disadvantages. The results of this analysis are compared with the results of the finite element method by sap program. The lateral loads are independently resisted by shear walls. The slab is the flange of the beam and the extended part is the web. Erect suitable temporary propping at not more then. The spacing between the ribs should be in general 2030 inch. A 120mmthick slab with a minimum rib thickness of 125 mm for continuous ribs is required to achieve a 2hour fire rating. Twoway joist concrete slab floor waffle slab system. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Reinforcement detail for a waffle slab support on a reinforced concrete main frame end slab beam. Rib and block concrete slab systems has been designed for easier installation and quicker building times.
Analysis and structural design of a ribbed slab is done using the principles of flanged sections and it is compared with the conventional solid slab floor and observed closely. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Different between solid slab and ribbed hollow slab uae. Beam and block, also referred to as rib and block, is mostly used in residential and industrial applications. This is a very efficient form of slab construction, it is also called a hollow block voided slab or pan joist system. Each type of floor consists of number of reinforced concrete ribs spanning in the short directions supporting a thin topping slab above. Hollow block slabs are ribbed concrete slab formed typically using concrete or sandcrete blocks. Pdf investigating the effect of solid and lightweight hollow block. Bohn type reinforced concrete slab densely ribbed in situ. These types of slabs, widely used throughout the world for many decades, are now becoming more and more popular in nigeria too because of their technical and economic advantages when compared to the. Dec 27, 2016 dec 27, 2016 hordy slab hollow block slab. To conclude, frame with solid slab is the best alternative method in building due to its capability to reduce the cost and have a good overall behavior.
Ribbed slabs oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. The twopart system, consisting of ribs and blocks, forms permanent shuttersholding space for the quick and economical construction of floors in multistory buildings. Investigating the effect of solid and lightweight hollow block slabs on. Hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs.
Nervi, ribbed slabs, isostatics, floor systems, computational tool. Hollow block weight polystyrene weight s120 450mm x 210mm x 120mmh 170mm slab 15kg no polystyrene s150 450mm x 210mm x 150mmh 200mm slab 16kg 11. Ribbed or waffle slab is a slab system which consists of series of parallel reinforced concrete t beams framing into reinforced concrete girders. The hollow block floor is most suitable for small irregularly shaped floors as. Oneway hollow slab oneway hollow block slab are frequently used in construction, and it is when the ribs are in one. Ribbed slabs used herein refer to singly reinforced concrete slabs with hollow blocks or voids in them. Comparative analysis of hollow clay blocks and solid. Pdf in the design of reinforcedconcrete buildings, solid and lightweight hollow block. A panel composed of a thin slab reinforced by ribs in one or two directions, usually at right angles to one an other.
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