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 historical discussion includes the evolution of the floor slab from a nonstructural element to an inspired structural. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. This type of slabs or flooring system consists of series of small closed spaced reinforced concrete tbeams. Manual for design and detailing of reinforced concrete to the code. Pdf structural design versus cost comparison of solid. A proudly south australian business, blending historical success and a bold vision. A wide variety of ribbed slab options are available to you, there are 263 suppliers who sells ribbed slab on, mainly located in asia. Solid slabs are fully customizable concrete slabs of varying width, length and thickness. Advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments.
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. Ribbed slabs are made up of wide band beams running between columns with equal depth narrow ribs spanning the orthogonal direction. Twoway joist concrete slab floor waffle slab system analysis and design. Twoway joist concrete slab floor waffle slab system. Structural ribbed concrete slabs the cupolex floor slab can be fully or partially suspended on piles, stem walls or gradeedge beams. This form of construction is not very common because of the formwork costs and the low fire rating. 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 are made up of wide band beams running between columns with narrow ribs spanning. Reinforced concrete ribbed slabs with widebeam lajes. 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.
The ribbed slab was analyzed exactly by finite element theory through sap 2000 program. 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. Apr 19, 2017 animation showing the construction process of a reinforced concrete ribbed slab. Civilax is the knowledge base covering all disciplines in civil engineering.
Sandwich slabs may have the disadvantage of a larger weight compared to the ribbed ones but on the. The floor system of a structure can take many forms of slabs such as in situ solid slab, ribbed slab or precast units. Reinforced concrete design 1 design of slab examples. Continuous ribbed slabs concrete structures eurocode. A civil engineer must know all the aspects regarding the flat floor system. Design of reinforced concrete structures ii twoway slabs 1 1. Designed as a series of parallel tbeams and economical for medium spans with light to medium live loads. There are many methods that are used to analyze twoway slabs and the precision of these methods vary depending. 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. The cost is managed by supervision of non skilled laborers, following the recommendations in this manual.
In case of hollow block slab voided blocks are placed to reduce the total weight of the slab. 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. Reinforced concrete design to bs8110 structural design 1. Their function is the same as any slab, to support loads coming from the roof and ultimately to the ground and to. The slab has to carry a distributed permanent action of 1. Jan, 2017 advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. They can be used in a variety of applications such as bridges, piers, building floors, roof systems, detention vault lids and boat launches. Devoran metals guide to reinforcing steel if a customer is unsure which mesh or rebar they need, check the. You can find out the dead load per unit area since the density of the concrete is known. This document provides guidance for the design and construction of conventionally reinforced ribbed mat slab rrms foundation systems. Some of them are outdated and many of them are frequently used everywhere. Reinforced and posttensioned concrete slab design software.
In case of ribbed slab the blocks are not permanent. A panel composed of a thin slab reinforced by ribs in one or two directions, usually at right angles to one an other. British system of units conversion, 594 defined, 591. Ribbed or waffle slabs are an easy solution for this purpose. Ribbed slab article about ribbed slab by the free dictionary. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. The load per unit area on the slab becomes the load per unit length on the slab strip. Ribbed slab design spreadsheets to eurocode 2 en 19921. Flat slab analysis, design and detailing pdf flat slab system is an important division of concrete floor system. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete. Structural design versus cost comparison of solid and ribbed slab constructed building. 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. All the electrical appliances can be installed easily in the gap of the ribs which can be architecturally aesthetic.
The model provides the actual behavior for ribbed slab. Optimum design of reinforced concrete waffle slabs integrated. Ribbed slab design spreadsheets to eurocode engineering. 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. Waffle slabs tend to be deeper than the equivalent ribbed slab.
Ifon and ifthe opening in the slab cutsalso the ribsofthe ribbed plate,then new openingsare. Ribbed and waffle slabs types, advantages, disadvantages. Ribbed slab design spreadsheet civil engineering community. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the orthogonal direction. Bending will take place in the two directions in a dishlike fo. Twoway joist waffle slab design approach and methodology. Reinforcing bar rebar is a ribbed, hightensile bar used to reinforce concrete, and it can be cut and. Aug 15, 2016 download code ribbed slab design spreadsheet. 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. Conversion of general components to structural members. Rib and block slabs installation by royal concrete slabs duration. Design of reinforced concrete structures ii twoway slabs.
Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. They may be supported on two opposite sides only fig. Comparison of oneway and twoway slab behavior economic choices oneway slab on beams suitable span 3 to 6m with ll 35knm2. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. Design of continuous one way slabs checks, detailing included. This is attributed to the rapid shattering, ease of construction, and the reduction in the time of erection.
Bianco precast precast concrete in south australia. Longitudinal steel should be detailed in a 2bar alternating pattern, with one of the bars continuous through the slab. Bringing together experience, integrity and design excellence, precast concrete products offered by bianco precast are of the highest quality, durability and flexibility. 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 is basically a cad dwg drawing with a typical waffle slab cross section reinforcement detail.
In this section, two types will be discussed, oneway solid slabs and oneway ribbed slabs. Ribbed slabs are made up of wide band beams running between columns with narrow ribs. This paper presents an historical and analytical evaluation of the ribbed floor slab systems developed by. 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. Jul 02, 20 introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. Pdf comparison between ribbed slab structure using. 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.
However no research had been made to aid the understanding of the load transfer mechanism between the reinforced concrete ribbed. This paper focuses on analysis of twoway ribbed and waffle slabs with hidden 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. Analysis of two way ribbed and waffle slabs with hidden beams.
Can be used for larger spans with relatively higher cost and higher. The minimum spacing of reinforcing bars should preferably be 6 in. A slightly deeper section is required but these stiffer floors. If flat slab construction is employed, the columns can be provided without soffit beams and at the corners of the floor system. 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. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Slab thickness of ribbed or waffle slabs is less than other slab systems.
The slab is the flange of the beam and the extended part is the web. Optimum design of reinforced concrete waffle slabs alaa c. Ribbed or waffle slab is a slab system which consists of series of parallel reinforced concrete t beams framing into reinforced concrete girders. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. Additional reinforced internal ribs are then used in the slab. Waffle slab construction consists of rows of concrete joists at right angles to. 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. Slabs may be supported on monolithic concrete beam, steel beams, walls or directly over the columns. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. This practical design and detailing manual intends to outline practice of. 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. 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. Oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. Slab cast integrally with a series of closely spaced joist which in turn are supported by a set of beams.
The model provides the actual behavior for ribbed slab by analyzing the structure as oneunite in two dimensions. Though the code has provisions for converting the biaxial bending problem. Flat slab analysis, design and detailing pdf civil engineering. 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. The blocks are considered as nonstructural element as they do not contribute to strength of. Slabs are usually used in floor and roof construction. Ribbed slab design spreadsheet civil engineering downloads. As simple as i can answer, a rib slab or ribbed slab is similar to flat slabs. Reinforced concrete design to bs8110 structural design 1 lesson 5 1 lesson 5. 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. Ribbed slabs types and its advantages in construction. 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. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Dec 06, 2017 basic of ribbed slab with aci 31802 code requirements.
Jul 15, 2017 ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads. Reinforcement detail of waffle slab cross section 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. The saving of materials tends to be offset by some. Pdf optimum design of reinforced concrete waffle slabs. Oneway and twoway slabs university of asia pacific. The load transfer mechanism between the reinforced concrete. Ribbed slabs have been widely used in buildings due to their many advantages, especially the decrease of concrete below the neutral line. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only.
Jul 22, 2015 design of two way ribbed slab 18 x 25 m clear span 1. In sap program, the model has been divided to frame elements to represent ribs and beams and shell elements to represent the slab. This paper presents an experimental and computational study on ribbed slabs with widebeam, two oneway slabs and two twoway slabs. In general, the beam slab flexural stiffness ratio is about 0. The code allows idealization of the ribbed slab or waffled slab as. The slab column structure began to emerge in the structural design since early nineteen century. 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. At the face of all supports for slabs with spans not exceeding. Solid slabs can be designed and produced with mild reinforcing or by adding prestressing strands. In analysis, ratio of deepest to shallowest rib depth cannot exceed.
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