Slabs may be supported on monolithic concrete beam, steel beams, walls or directly over the columns. Solid slabs can be designed and produced with mild reinforcing or by adding prestressing strands. In case of hollow block slab voided blocks are placed to reduce the total weight of the slab. In case of ribbed slab the blocks are not permanent. This paper presents an experimental and computational study on ribbed slabs with widebeam, two oneway slabs and two twoway slabs. The reason why, concrete and steel are used together to construct rcc slab, is in their individual properties as separate building materials and their individual limitation. Ribbed and waffle slabs types, advantages, disadvantages. Reinforced concrete design to bs8110 structural design 1. Jan, 2017 advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. Pdf comparison between ribbed slab structure using. Jul 15, 2017 ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Oneway and twoway slabs university of asia pacific. Ribbed slab article about ribbed slab by the free dictionary. This is basically a cad dwg drawing with a typical waffle slab cross section reinforcement detail.
Advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. Ribbed slabs types and its advantages in construction. 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. The ribbed slab was analyzed exactly by finite element theory through sap 2000 program. The load transfer mechanism between the reinforced concrete. Jul 02, 20 introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. In this section, two types will be discussed, oneway solid slabs and oneway ribbed slabs. Twoway joist concrete slab floor waffle slab system analysis and design.
Oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. This practical design and detailing manual intends to outline practice of. Ifon and ifthe opening in the slab cutsalso the ribsofthe ribbed plate,then new openingsare. 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. At the face of all supports for slabs with spans not exceeding. Optimum design of reinforced concrete waffle slabs integrated. Ribbed slabs are made up of wide band beams running between columns with equal depth narrow ribs spanning the orthogonal direction. Apr 19, 2017 animation showing the construction process of a reinforced concrete ribbed slab.
Unlike other 2d diaphragmbased slab design programs, adaptfloor pros true 3d fem analysis provides the most accurate results even for the most complex transfer and waffle slabs. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. 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. Solid slabs are fully customizable concrete slabs of varying width, length and thickness. Manual for design and detailing of reinforced concrete to the code. The floor system of a structure can take many forms of slabs such as in situ solid slab, ribbed slab or precast units. If flat slab construction is employed, the columns can be provided without soffit beams and at the corners of the floor system. British system of units conversion, 594 defined, 591.
This form of construction is not very common because of the formwork costs and the low fire rating. They may be supported on two opposite sides only fig. This paper focuses on analysis of twoway ribbed and waffle slabs with hidden beams. 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. Pdf optimum design of reinforced concrete waffle slabs. 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. Bringing together experience, integrity and design excellence, precast concrete products offered by bianco precast are of the highest quality, durability and flexibility. Rib and block slabs installation by royal concrete slabs duration. My graduation project with my mate ghassan faris, a two way ribbed slab of clear span of 18 x 25 m was designed by safe 2014, the building is 3storey concrete. Ribbed slab design spreadsheet civil engineering downloads.
For the purpose of this document, rrms is defined as a system of stiffening beams and slab. Longitudinal steel should be detailed in a 2bar alternating pattern, with one of the bars continuous through the slab. Optimum design of reinforced concrete waffle slabs alaa c. Devoran metals guide to reinforcing steel if a customer is unsure which mesh or rebar they need, check the. Slab thickness of ribbed or waffle slabs is less than other slab systems. The historical discussion includes the evolution of the floor slab from a nonstructural element to an inspired structural. You can find out the dead load per unit area since the density of the concrete is known. In general, the beam slab flexural stiffness ratio is about 0. Twoway joist waffle slab design approach and methodology. All the electrical appliances can be installed easily in the gap of the ribs which can be architecturally aesthetic. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. Reinforcing bar rebar is a ribbed, hightensile bar used to reinforce concrete, and it can be cut and.
Ribbed slab design spreadsheets to eurocode 2 en 19921. Ribbed slabs are made up of wide band beams running between columns with narrow ribs. Civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads. Ribbed slab design spreadsheets to eurocode engineering. Mathematical structural analysis of one way ribbed slabs was introduced in this paper. A panel composed of a thin slab reinforced by ribs in one or two directions, usually at right angles to one an other. 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. Conversion of general components to structural members. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. The slab column structure began to emerge in the structural design since early nineteen century. This is attributed to the rapid shattering, ease of construction, and the reduction in the time of erection. The slab is the flange of the beam and the extended part is the web. The slab has to carry a distributed permanent action of 1.
There are many methods that are used to analyze twoway slabs and the precision of these methods vary depending. The minimum spacing of reinforcing bars should preferably be 6 in. Slab cast integrally with a series of closely spaced joist which in turn are supported by a set of beams. Different between solid slab and ribbed hollow slab uae. Slabs are usually used in floor and roof construction. When one says ribbed slab it is actually a one way spanning system with ribs where as in waffle slab. Flat slab analysis, design and detailing pdf flat slab system is an important division of concrete floor system. The saving of materials tends to be offset by some. Waffle slab construction consists of rows of concrete joists at right angles to. Ribbed slabs oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning. Additional reinforced internal ribs are then used in the slab.
Reinforced concrete design 1 design of slab examples. Though the code has provisions for converting the biaxial bending problem. Dec 06, 2017 basic of ribbed slab with aci 31802 code requirements. Structural design versus cost comparison of solid and ribbed slab constructed building. In analysis, ratio of deepest to shallowest rib depth cannot exceed. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. 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. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Design of the composite flooring slab with profiled sheets t153 ruukki for a residential building, 35 pages, 1 appendix saimaa university of applied sciences, lappeenranta technology, civil and construction engineering civil and construction engineering bachelouv theviv 201.
Reinforced and posttensioned concrete slab design software. Since then extensive research had been made to understand the punching behaviour of flat slab column structure. Bending will take place in the two directions in a dishlike fo. Jul 22, 2015 design of two way ribbed slab 18 x 25 m clear span 1. Design of reinforced concrete structures ii twoway slabs 1 1. Analysis of two way ribbed and waffle slabs with hidden beams. Reinforced concrete ribbed slabs with widebeam lajes. The model provides the actual behavior for ribbed slab by analyzing the structure as oneunite in two dimensions. Aug 15, 2016 download code ribbed slab design spreadsheet. The results of this analysis are compared with the results of the finite element method by sap program.
Some of them are outdated and many of them are frequently used everywhere. Waffle slabs tend to be deeper than the equivalent ribbed slab. A civil engineer must know all the aspects regarding the flat floor system. Reinforced concrete design to bs8110 structural design 1 lesson 5 1 lesson 5. Pdf structural design versus cost comparison of solid. Design of continuous one way slabs checks, detailing included. Comparison of oneway and twoway slab behavior economic choices oneway slab on beams suitable span 3 to 6m with ll 35knm2. Ribbed or waffle slabs are an easy solution for this purpose. A wide variety of ribbed slab options are available to you, there are 263 suppliers who sells ribbed slab on, mainly located in asia. Sep 03, 2011 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. Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete. Their function is the same as any slab, to support loads coming from the roof and ultimately to the ground and to also act as a floor. This paper deals with the problem of optimum design of reinforced concrete twoway ribbed waffle slabs using genetic algorithms.
Design of reinforced concrete structures ii twoway slabs. Filler slab technology is a simple and a very innovative technology for a slab construction. Pdf this paper deals with the problem of optimum design of reinforced. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. Ribbed slab design spreadsheet civil engineering community. This strip can then be analyzed by the methods that were used for rectangular beams, the bending moment being computed for the strip of unit width. This paper presents an historical and analytical evaluation of the ribbed floor slab systems developed by. Twoway joist concrete slab floor waffle slab system. 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. Analysis of two way ribbed and waffle slabs with hidden beams ibrahim mohammad arman international journal of civil and structural engineering volume 4 issue 3 2014 345 length and l2 is the transverse distance or frame width.
Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. In sap program, the model has been divided to frame elements to represent ribs and beams and shell elements to represent the slab. As simple as i can answer, a rib slab or ribbed slab is similar to flat slabs. Continuous ribbed slabs concrete structures eurocode. The code allows idealization of the ribbed slab or waffled slab as. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. A slightly deeper section is required but these stiffer floors. Designed as a series of parallel tbeams and economical for medium spans with light to medium live loads. Advantages of rib clay pot slab over solid concrete slab. This 300 mm deep ribbed slab is required for an office to support a variable action of 5 kn m2 it is supported on wide beams that are the same depth as the slab, as shown in figure 3. Civilax is the knowledge base covering all disciplines in civil engineering. Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete article pdf available march 2010 with 4,944 reads how we measure reads. This document provides guidance for the design and construction of conventionally reinforced ribbed mat slab rrms foundation systems.
The historical discussion includes the evolution of the floor slab from a nonstructural element to an inspired structural system, culminating in nervis patented ribbed floor systems. Structural ribbed concrete slabs the cupolex floor slab can be fully or partially suspended on piles, stem walls or gradeedge beams. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. This type of slabs or flooring system consists of series of small closed spaced reinforced concrete tbeams.
Their function is the same as any slab, to support loads coming from the roof and ultimately to the ground and to. The cost is managed by supervision of non skilled laborers, following the recommendations in this manual. 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 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. Ribbed slabs have been widely used in buildings due to their many advantages, especially the decrease of concrete below the neutral line. Bianco precast precast concrete in south australia. Flat slab analysis, design and detailing pdf civil engineering. The load per unit area on the slab becomes the load per unit length on the slab strip. The blocks are considered as nonstructural element as they do not contribute to strength of. There are 16 different types of slabs in construction.
They can be used in a variety of applications such as bridges, piers, building floors, roof systems, detention vault lids and boat launches. The model provides the actual behavior for ribbed slab. Sandwich slabs may have the disadvantage of a larger weight compared to the ribbed ones but on the. The waffle slab is also sometimes termed as ribbed slab system but you would find it interesting to know that ribbed and waffle slab are somehow two different things. A proudly south australian business, blending historical success and a bold vision. In this article, ill give a detailed explanation of each slab where to use particular slab. Reinforcement detail of waffle slab cross section this is basically a cad dwg drawing with a typical waffle slab cross section reinforcement detail. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab.
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