Waffle slab plan view reinforcement detail faculdade. Flat slab analysis and design designs beamless concrete slab floors flat slab or waffle slab in accordance with aci 318. One way spanning slabs two way spanning slabs on linear supports coffered slabs from structural 1 at indian institute of technology, roorkee. Flat slab is defined as one sided or twosided support system with sheer load of the slab being concentrated on the supporting columns and a square slab called drop panels.
Coffered vaulted slabs by creagh concrete products ltd. The williams coffer slab system consists of removable plastic coffer blocks suspended between a series of parallel ribs spanned across the area where a concrete slab is required. Simply input the data required within the appropriate box and select update button located of the bottom. Nov 01, 2016 coffers were used in historical buildings even before rcc structures came into being. This form of construction is not very common because of the formwork costs and the low fire rating. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. Waffle slab dwg full project for autocad designs cad. Pdf coffered slabs as a perspective type of the reinforced. Coffered slabs as a perspective type of the reinforced concrete. Here is a detailed article with all the information regarding procedure of. A discreteelement method of analysis for orthogonal slab and. The system is designed for heavy loads uniformly distributed superimposed analysis of waffle slab. Coffered slab beam structure precast concrete scribd. Features of the grid slab they are used on flat sites.
Analyses are for a onebaywide strip using the equivalent frame analysis method of the aci code. One way spanning slabs two way spanning slabs on linear. To validate the results, selected cases are compared with. Late 16th century coffered ceiling of santa maria in aracoeli, rome coffering on. These type of slabs are generally constructed in hotels, universities, function halls, etc. Here is a detailed article with all the information regarding procedure of rcc slab roof laying. A suspended ceiling is not needed as services are contained in the suspended floor. The kwikstrip system produces a coffer grid spacing of 0.
The underside of a waffle slab, showing the grid like structure. Its not like a flat slab which is here and there i. See more ideas about waffle ceiling, architecture and ceiling design. In the case of recessed or coffered slab which is made solid in the region of the columns, the stiffening effect may be ignored provided the solid part of the slab does not extend more than 0. They provide a very good form where slab vibration is an issue, such as laboratories and hospitals. This calculator will estimate the require concrete volume to fill the width, height and depth given. Coffered slabs as a perspective type of the reinforced concrete structures article pdf available in matec web of conferences 86. Coffered slab free download as powerpoint presentation. Each lightweight rigid pvc plastic coffered panel is 24 x 24, available in either deep or shallow styles, and comes in white or black. Determine v max v eff u od where u o is the length of column perimeter check v ma coffered system is quite suitable for medium size floors. A suspended ceiling is not needed as services are contained in the suspended floor above the.
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. The new formscaff coffers can support a slab thickness of 0. The stiffening effect of flared columns heads may be ignored. Check out these 101 handselected coffered ceiling examples for all rooms of a house. So i am glad that you have asked me what a waffle slab system is. Shrinkage of slab is lower than stiffened rafts and footing slabs. Flat slab flat slab are also known as beamless slab, is a type of slab in which the flooring slab is directly supported on columns without the agency of beam or girders. I have used the word flat slab and by that i mean the slab that has leveled surface from both top and soffit.
Introduction analysis and design example xxi chapter 22 elements. Twoway joist concrete slab floor waffle slab system analysis and. This is the compilation of the presentations available for grid slabs on slideshare. 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. Please check out the similar products section for alternatives. Flat slabs may have drop panels at columns and columns may have capitals.
A waffle slab or twoway joist slab is a concrete slab made of reinforced concrete with concrete. The lateral loads are independently resisted by shear walls. Waffle slab or ribbed slab construction procedure and advantages. Because of the ribs and double reinforcement, it is more stable and recommended for larger span slabs or foundations.
Ribbing beams reinforcement, slab top wire mesh, waffles dimensioning, voids width and depth, slab thickness. Inplane axial thrusts, if their distribution is known, are included and coupled with the stiffnesses of the structure. A discreteelement method of analysis for orthogonal slab. The analysis and design follow the equivalent frame analysis method of the aci code, which considers a onebay wide strip of the floor system as a continuous frame.
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. Twoway joist concrete slab floor waffle slab system. The downsides of waffle slabs and cupolex slabs are the same its a slab constructed on top of the ground and its easy for water to get under the slab. Adding corners also adds complexity and expense that is better. Base slab examples xviii chapter 19 rectangular tanks 191. Please practice handwashing and social distancing, and check out our resources for adapting to these times. A coffer or coffering in architecture is a series of sunken panels in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault. What is the maximum possible span between columns to support. Flat slab types of flat slab design and its advantages flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. Although the crosssection is more complex when compared to a solid slab or coffer slab, flexural design poses no significant problem. Dec 01, 2016 features of the grid slab they are used on flat sites. The developed computer program allows for the free variation of stiff nesses, supports, and loads.
At the planning stage, you can make your entire house cost less just by making it a little bit smaller. 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. Introduction coffered slab consists of series of ribs on a small distance from each other and thin plate over them. This difference would cost a significant reduction in overall height of a construction of a multistorey building with appreciable saving in cost. Manual for the design of concrete and reinforced concrete structures of heavy concrete. Some are bare wood beams while other types include crown molding.
Coffered definition of coffered by the free dictionary. Im commercial buildings to save on carpet space the span is kept is 1215m. Now here i need to clarify that this article will not treat waffle slab foundation which is another building element used in high cyclonic and windy areas but that is out of the scope of this article. Concrete slab volume estimator calculator engineers edge. Sound transmission class guidance introduction the noise guidebook, pages 3337, provides an elementary discussion of stc, provides some stc ratings for common building materials and limited exterior and interior wall construction configurations, and describes a method to determine composite stc value of a wall containing a window or door. Flat slab analysis and design free version download for pc. Waffle slabs are preferred for spans greater than 40 feet 12 m, as they are much stronger than flat slabs, flat slabs. The other issue for these slabs in cyclonic regions is the lack of concrete under the big truss reactions. The name waffle comes from the grid pattern created by the reinforcing ribs. Creagh concrete products ltd hasnt formatted technical specifications for coffered vaulted slabs yet. For span from 5 to 9m thin flat slabs are the preferred solution for the.
You have asked this question because waffle slab is not that common throughout the world. We recommend that beginners start with the easiest, simplest design to build, which is a small, square house. Precast was chosen for its energy efficiency the concrete mass provides thermal energy storage and to keep the overall height of the building as low as possible. 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. How to build a log cabin the ultimate guide build log homes. Then rcc waffle slabs were built which resembled coffers and hence it. Coffers are sunken panels attached to a suspended drop grid to create a new ceiling with depth and architectural interest.
The institution of structural engineers the institution of civil engineers march 2000 manual for the design of reinforced concrete building structures to ec2. Analysis and design of waff le slab with different boundary. We would be restricting ourselves to understand the waffle slab used as roof. The crosssection of a cobiax slab has top and bottom flanges which accommodates compressive stresses for either sagging or hogging bending. No beam down drag from clay above ground slab occurs. Analyze and design flat slab or waffle slab floors. The advantage of a coffered slab compared to traditional reinforced concrete slab is a possibility of bridging large spans. Manual for the design of reinforced concrete building. A waffle slab or twoway joist slab is a concrete slab made of reinforced concrete with concrete ribs running in two directions on its underside.
Coffers were used in historical buildings even before rcc structures came into being. May 21, 2017 the slab which has one side fixed and the other side is free is called as projected slab or cantilever slab. To save on beam disruption, pt slabs are widely used instead of regular bed and columns. Nancy debora assistant professor civil karunya university 2. Department of mechanics, materials and structures english. Gilded coffering on a barrel vault of the apsis in nazare, portugal giuliano da sangallos flat caisson ceiling, basilica di santa maria maggiore, rome decorative coffered slabs in historical structures coffering on the arch of septimius severus, rome a series of these sunken panels were used as decoration for a ceiling or a vault, also called. Ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Flat slab types of flat slab design and its advantages. Determine v max v eff u od where u o is the length of column perimeter check v ma free is called as projected slab or cantilever slab. A coffered ceiling is created with coffered panels or coffers. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems.
Coffered slab, concentrated load, winklers model of styrodur, ultimate limit state 1. A series of these sunken panels was often used as decoration for a ceiling or a vault, also called caissons boxes, or lacunaria spaces, openings, so that a coffered ceiling can be called a. Depending on the application, the ribs will be either precast concrete lattice ribs or wooden purlins. Coffered slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extend of foundations. Its a series of geographical shapes created by beams in a square, rectangle or even triangle patterns. Planning your log cabin is the most important stage of the build. Inputs to the program may be retained and used for a series of problems for the con venience of the user. Tips for laying rcc slab roof on 12092014 9091 views 3 comments rcc slab laying is one of major step in any type of construction so it is mandatory to know all the points related to laying rcc slab. Then rcc waffle slabs were built which resembled coffers and hence it is also called coffer slab.
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