Please practice handwashing and social distancing, and check out our. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. 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. Ribbed and waffle slabs types, advantages, disadvantages. In general, the beam slab flexural stiffness ratio is about 0. This answer will be easy if i make you understand with a building structure. The spacing between the ribs should be in general 2030 inch. Ribbed or waffle slab is a slab system which consists of series of parallel reinforced concrete t beams framing into reinforced concrete girders. Analysis of two way ribbed and waffle slabs with hidden beams. The floor system of a structure can take many forms of slabs such as in situ solid slab, ribbed slab or precast units. This paper presents an historical and analytical evaluation of the ribbed floor slab systems developed by. Structural ribbed concrete slabs the cupolex floor slab can be fully or partially suspended on piles, stem walls or gradeedge beams. Jul 22, 2015 design of two way ribbed slab 18 x 25 m clear span 1.
This paper deals with the problem of optimum design of reinforced concrete twoway ribbed waffle slabs using genetic algorithms. Waffle slab or ribbed slab is a structural component which is plain on its top and contains grid like system on its bottom surface. Ribbed slabs are made up of wide band beams running between columns with equal depth narrow ribs spanning the orthogonal direction. Introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. This guide specification serves as a guideline for slabs supported by pedestals for pedestrian roof plaza decks.
In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. In this article, the author presents a parallel approach to the traditional teaching method of twoway ribbed slabs. Ribbed slabs oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. Analysis and parametric study of reinforced concrete. Continuous ribbed slabs concrete structures eurocode. In the analysis of ribbed slab as solid slab traditional, the structural system of the ribs is considered as beams supported on main cross beams which are considered as rigid. In case of ribbed slab the blocks are not permanent. Ribbed slabs have been widely used in buildings due to their many advantages, especially the decrease of concrete below the neutral line. Yasser workwebsitepdf07 slabs01 solid slabs model 1.
Nov 27, 2014 as simple as i can answer, a rib slab or ribbed slab is similar to flat slabs. The historical discussion includes the evolution of the floor slab from a nonstructural element to an inspired structural. Slab software free download slab top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. In comparison to the solid slab, the span limits of ribbed slabs are. 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. A ribbed slab gives considerable extra strength in one direction while a waffle slab gives added strength in both directions. Ribbed slab article about ribbed slab by the free dictionary. Ribbed slabs of dimensions 610, 810 and 1010 were analyzed to indicate the effect of connection between ribs and supported beams on b. T beams are known as joists which are formed by setting steel pan at a constant spacing. Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete. Reference 1 tested three models of reinforced concrete waffle slab to study the effect of rib orientation on the. The load per unit area on the slab becomes the load per unit length on the slab strip. Right know im doing it with slab and beam elements.
Pdf comparison between ribbed slab structure using. Solid slabs can be designed and produced with mild reinforcing or by adding prestressing strands. Because of this the size of column, footing and other load bearing elements are reduced. 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. Analysis of an ultrahigh performance concrete twoway.
Ribbed slabs are suitable for medium to heavy loads, can span reasonable distances, are very stiff and particularly suitable where the soffit is exposed. Cost comparison between frames with solid slab and ribbed. Ribbed slab design spreadsheet civil engineering community. Which slab is better ribbed slab or solid slab one way or two way. Ribbed slab system which consists of a series of parallel reinforced concrete t beams framing into reinforced concrete girders. As simple as i can answer, a rib slab or ribbed slab is similar to flat slabs. For the purposes of analysis and design, the ribbed slab will be replaced with a solid slab of equivalent moment of inertia, weight, punching shear capacity, and oneway shear capacity. The ribbed floor slab systems of pier luigi nervi form finding lab. The depth of all slabs is based on deflection control ec2 7. Optimum design of reinforced concrete waffle slabs alaa c. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning. Rib and block concrete slabs installation tutorial duration. The design and construction of floor slabs are usually solid, adequately reinforced in.
Slabs may be supported on monolithic concrete beam, steel beams, walls or directly over the columns. This form of construction is not very common because of the formwork costs and the low fire rating. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the. 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 5,039 reads how we measure reads. Jan, 2017 advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. Jun 27, 2017 does anyone know how to design a waffle ribbed slab in staad. 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 slabs had solid parts in two directions with width 0. Design of reinforced concrete structures ii twoway slabs. Slabs are structural members forming floors and roofs in buildings.
Solid slabs are fully customizable concrete slabs of varying width, length and thickness. This is attributed to the rapid shattering, ease of construction, and the reduction in the time of erection. A panel composed of a thin slab reinforced by ribs in one or two directions, usually at right angles to one an other. The blocks are considered as nonstructural element as they do not contribute to strength of the slab. This document is a technical summary of the unpublished federal highway administration report, analysis of an ultrahigh performance concrete twoway ribbed bridge deck slab, available only through the national technical information service. What is the difference between a flat slab and a ribbed. Twoway joist concrete slab floor waffle slab system analysis and design. Twoway joist waffle slab design approach and methodology. This pdf file contains a chapter of 23 pages with various aspects of flat slabs including four example of flat slab design. The results of this analysis are compared with the results of the finite element method by sap program. Waffle slab plan view reinforcement detail faculdade. Nervi, ribbed slabs, isostatics, floor systems, computational tool.
Bending will take place in the two directions in a dishlike form. Structural design versus cost comparison of solid and ribbed slab constructed building. Guide specifications for construction of hydrapressed slab roof pavers section 32 14. Civilax is the knowledge base covering all disciplines in civil engineering. Some of them are outdated and many of them are frequently used everywhere. Mar, 2017 how to form, pour, and stamp a concrete patio slab duration. Waffle slabs have a thin topping slab and narrow ribs spanning in both directions between column heads or band. The cost is managed by supervision of non skilled laborers, following the recommendations in. Twoway joist concrete slab floor waffle slab system. 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. Mathematical structural analysis of one way ribbed slabs was introduced in this paper. Waffle slab or ribbed slab construction procedure and. Wall street business magnate stephen chu, winner of the strathmores whos who registry honoring the most successful business tycoons in the world, says the demolisher betting system lived up exactly to its billing.
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. Ribbed slabs as shown below are common in engineering practice. Considering a building structure structurally we generally found the following components 1. There are many methods that are used to analyze twoway slabs and the precision of these methods vary depending. 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. Slabs and beams the design of the geometry of slabs and beams has to fulfill both ultimate uls and serviceability limit states sls requrements. Ribbed slab design beam structure building engineering scribd. In this article, ill give a detailed explanation of each slab where to use particular slab.
Jul 02, 20 introduction hollow block and ribbed slabs are formed by placing blocks on the slab and concrete ribs. They can be used in a variety of applications such as bridges, piers, building floors, roof systems, detention vault lids and boat launches. This paper focuses on analysis of twoway ribbed and waffle slabs with hidden beams. These slabs were one way and the ribs were supported directly on the beams without solid part. Mike day everything about concrete recommended for you. The result of this study shows that oneway ribbed slab with beam used in residential building is more preferable from the economical point of view since it is. A wide variety of ribbed slab options are available to you, there are 301 suppliers who sells ribbed slab on, mainly located in asia.
Ribbed slab design spreadsheets to eurocode 2 en 19921. 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. Design of reinforced concrete structures ii twoway slabs 1 1. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Gsa how to simulate ribbed slab using orthotropic material. Which slab is better ribbed slab or solid slab one way. Ribbed slab design spreadsheet civil engineering downloads. Designed as a series of parallel tbeams and economical for medium spans with light to medium live loads.
The text must be edited to suit specific project requirements. Teaching twoway ribbed slab analysis and design using the mathcad program mohammed s. Reinforced concrete ribbed slabs with widebeam lajes. I havent heard of anyone creating a family to generate a ribbed slab. To model the ribbed slab in details in finite element analysis when doing whole model analysis may create a huge model that may take too long to analyze or the model size is just too large to be analyzed using available computers. Gsa how to simulate ribbed slab using orthotropic material 2d elements. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Ribbed slab design spreadsheets to eurocode engineering. Teaching twoway ribbed slab analysis and design using the. Using modified material properties or modified slab behavior properties is a possible way to simulate such a voided slab, but the program only analyzes and designs solid slabs. Jul 12, 2010 if you are talking about a thin top slab and a thin bottom slab with air between them, thats beyond the scope of the program. The saving of materials tends to be offset by some.
In this section, two types will be discussed, oneway solid slabs and oneway ribbed slabs. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Waffle slab construction slab depths typically vary from 75 to 125 mm and rib widths from 125 to 200 mm. Xaxis a unit width of slab is then designed for the moment per unit width found from the computer analysis. Pdf ribbed slabs have been widely used in buildings due to their many. Waffle slabs tend to be deeper than the equivalent ribbed slab. Rib and block slabs installation by royal concrete slabs duration. Oneway ribbed slab system a oneway joist floor slab consists of a series of small, reinforced concrete t beams that are connected with girders that in turn carried by the building column. Oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section.
Civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads. Economy of construction is obviously an important consideration, but this is a qualitative argument until specific cases are discussed, and is a geographical variable. And this is possible only in monolithically cast concrete which is the twoway grid of beams. Till now i dont know how to export a panel design to dxf with the panel thickness shown and the reinforcement also shown on cross section of panel. Aug 15, 2016 download code ribbed slab design spreadsheet. They may be solid of uniform thickness or ribbed with ribs running in one direction or two directions waffles. First of all, it depends on the use of the structure. Ribbed and waffle slabs in ram concept bentley communities. The blocks are considered as nonstructural element as they do not contribute to strength of. The two methods ive seen the most to perform this has either been. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. 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. 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.
Advantages of rib clay pot slab over solid concrete slab. Animation showing the construction process of a reinforced concrete ribbed slab. Pdf structural design versus cost comparison of solid. Find, read and cite all the research you need on researchgate. Waffle slab analysis and design is similar to the procedure used with flat plates except that special considerations need. Ribbed definition, one of a series of curved bones that are articulated with the vertebrae and occur in pairs, 12 in humans, on each side of the vertebrate body, certain pairs being connected with the sternum and forming the thoracic wall. 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 thickness of solid parts was the same depth of the ribs. Ribbed slab design spreadsheets to eurocode ribbed slabs are widely used in many countries. Ribbed slabs types and its advantages in construction. Flat slab analysis, design and detailing pdf civil engineering.
There are 16 different types of slabs in construction. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Yasser workwebsitepdf07 slabs01 solid slabs model 1 author. Advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. 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. The slab is the flange of the beam and the extended part is the web.
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