Reinforced concrete design 1 design of slab examples and. Divide the floor into slabs no more than 110 ft by 110 ft. It is a horizontal structural component, with top and bottom surfaces parallel or near so. Make the slabs square or rectangular, with an aspect ratio not to exceed 1. Aci 360, design of slabsongrade, refers to this as a type b slab. The soil nonlinear behaviour and the loss of contact between slab and soil are accounted for. The design of concrete groundsupported concrete industrial floor slabs.
Stresses from applied loads can be calculated using this or similar models. Special considerations are required for problem soil such as highly expansive or compressive soils. Beams of width and depth are provided on all column lines. These design elements must be enlisted and added in the contract documents by the designer in charge before asking for a bidding. Unlike ground supported floors, the thickness of a piled slab is a function of the proximity of the racking and the aisle spacing. Secondary floor beams are so arranged that they act as simply supported beams and that maximum number of main beams get flanged. Construction of slabs on ground design considerations aci and. A design of a concrete slab on soil using a linear elastic finite element.
The yieldline method for concrete slabs limit state design. Packard portland cement association, 1976 concrete floor slabs on grade subjected to heavy loads army technical manual tm 580912, air force manual afm 883, chapter 15 1987. Construction of slab on ground design elements the construction of slab on ground requires certain basic design elements. The construction and design of concrete slabs on grade. What do the codeapproved design protocols say about foundation performance. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. Floors and screeds design and construction of pile supported. Hence the performance of a slab that is constructed on the ground is dependent on the integrity of the slab and the soil support system. American concrete institute, manual of concrete practice. A comparison with conventional design methods is performed. Aug 23, 2017 model and design slab on ground, end bearing piles and friction piles using the inducta software. A monolithic or thickenededge slab is a ground supported slab on grade with an integral footing i.
Therefore, only ground beams passing through columns are provided as tie beams. Jointed floors with steel fibers in these floors, closelyspaced sawcut joints form the main defense against random cracks. In the context of this guide, slabonground is defined as. Soil conditions the design procedure shown in this report is based on the use of the effective p. Example design of twoway edge supported solid slab. Design of ground supported concrete industrial floor slabs interim technical note 11.
The wire reinforcing institute recommends the use of the subgrade drag theory for slabs up to 150 feet in length. Figure 4a is the illustration of a posttensioned ground supported slab with tendons located below the slab centroid. Two cases are considered, one with the posttensioning tendon below the centroid of the slab and one above it. Grdslab concrete slab on grade analysis spreadsheet. For uniformly distributed loads of w per square foot of the slab, each strip acts approximately like a simple beam uniformly loaded by its share of w. The floor beams are thus absent in the ground floor. Cracking in ground supported posttensioned slabs on expansive soils by ken bondy1 1 introduction posttensioned slabs are widely used as foundations for light residential construction in areas of expansive soils. May 29, 2018 the article handles potential approaches to design and determination of total load capacity of foundation slabs and floors. Most designs space the joints no more than 20 ft apart.
The slab may be unreinforced, reinforced, or posttensioned concrete. Load transfer in a oneway slab, b twoway slab nilson fig. Twoway concrete floor slab with beams design and detailing design the slab system shown in figure 1 for an intermediate floor where the story height 12 ft, column crosssectional dimensions 18 in. The subbase is an optional layer located on top of. Background information on design theories is followed by discussion of the types of slabs, soilsupport systems, loadings, and jointing. Click download or read online button to get the design of ground supported concrete industrial floor slabs book now.
Reinforced concrete design 1 design of slab examples. With a thin slab like this, you have to watch cover, and the effect that has on effective depth. Steel tank institute design conditions designed by. The design of ground supported concrete industrial floor.
Aci 360, guide to design of slabs on ground describes these floors as slabs. Install a polyethylene slipsheet directly beneath the slabs. Covering all aspects of building, engineering, design and construction, it provides its users with a single source for all their technical information needs. The article presents detailed results of the experiment made and advanced numerical modelling based on nonlinear analysis and application of fractureplastic model.
Concrete slabs supported on soil are analysed with the model proposed. Concrete floor slabs on grade are subjected to a varie ty of loads and loading conditions. These slabs generally are modeled as an elastic slab supported by a field of linear springs. The floor is to be designed to carry a service live load. Develops the design methods in technical report 550 design of floors on ground. The depth of a concrete slab floor is very small compared to its span. Punching shear failure of concrete ground supported slab oldrich sucharda1, martina smirakova2, jana vaskova2, pavlina mateckova2, jan kubosek2, and radim cajka2 received october 24, 2017, accepted march 6, 2018 abstract. Design of slabson ground aci 360r06 by american concrete institute slab thickness design for industrial concrete floors on grade is195. The construction and design of concrete slabs on grade 2012 instructor. Figure 42 slab ongrade and perimeter footing transfer loads into soil. After this publication, it was subsequently adopted by the uniform building. In turn, the concrete slab and foundation transfer those forces directly to the ground as shown in figure 42. Flat slab analysis, design and detailing pdf civil.
Cylindrical aboveground storage tank foundation requirements steel tank institute design conditions designed by. This guide presents information on the design of slabson ground, primarily industrial floors. Slabonground foundations refer to ground supported floor slabs used to. The thickness of a floor slab must be determined early in design because the. Aci 360r10 guide to design of slabsonground american. The article handles potential approaches to design and determination of total load capacity of foundation slabs and.
After this publication, it was subsequently adopted by the uniform building code ubc as. To read more about slab thickness evaluation please click here. Punching shear failure of concrete ground supported slab. The primary design issues for stiffened slabs on grade are the sizing of the beams that stiffened the slab and the spacing of the beams. Design guide 11 floors slabsonground for concrete structures. The design procedure set forth in that publication had at that time been in use by the author for about 15 years. Cracking in groundsupported post tensioned slabs on. Tensioning building structures march 12, 2020 2020 educode las vegas. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. Construction of slab on ground design elementsthe construction of slab on. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. Construction of slabs on ground design considerations aci.
These materials are originally located at different websites. Simplified straightline orthogonal moment patterns for a typical rectangular slab plan are shown in figure 2. The subgrade is the ground on which the floor is built. Concrete slab supported di rectly on foundation soil. Select representative 1 m wide design stripstrips to span in the short direction, as shown in figure 8. The design procedure separately incl udes determining thickness of slab under wall load. The research is focused on punching shear failure of reinforced ground supported slab. At ground floor, slabs are not provided and the floor will directly rest on ground. As the floor type name implies, any loads imposed on the concrete floor are carried directly and fairly uniformly by the ground.
Uniform soils that will provide reason able support are. Also m p is the plastic moment of resistance per unit length of the slab, and l is the length of a given yieldline. Pdf fabricreinforced concrete ground slabs and concrete. Flat slab system is an important division of concrete floor system. An early attempt at a rational approach to design was made around 1920, when westergaard proposed the socalled. The design procedure includes determini ng slab thickness based on moving live loads and then checking adequacy of slab thickness for stationary live load. Floors and screeds design and construction of pile. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Stresses in floor slabs on grade resulting from vehicular loads a re a function. It addresses the planning, design, and detailing of slabs. Tm 580912 concrete floor slabs on grade subjected to heavy. For more information on anchorage of braced walls to slab ongrade construction, see chapter 3 of this guide. There is a strong case for specifying the most onerous racking formation and for the provision of saw cuts as the floor may be used for very narrow aisle vna racking at some stage in its life.
Commonly, slabs are supported by beams, columns concrete or steel, walls, or the ground. The slab itself is usually set at a thickness of 0. As the floor type name implies, any loads imposed on the concrete floor are carried directly and fairly uniformly by the ground under the floor. Model slab on ground using either the winkler model or soil structure interaction.
Continuous one way slab figure 1 shows a clear area of 12 m x 8. A concrete slab supported over the soil bed mostly the soils undergo proof rolling. The slab may be of uniform or variable thickness, and it may include stiffening elements such as ribs or beams. Tm 580912 concrete floor slabs on grade subjected to. Pdf in 2003, the third edition of concrete society technical report 34 1 was published. Oneway and twoway slabs university of asia pacific. At the time of the code change before 2005, there was discussion about adding a definition for posttensioned concrete slabs on expansive soils. Common design methods for these slabs assume an uncracked section, where slab. Ground supported floors ground supported concrete floors are used in many types of building, ranging from simple houses through to schools, factories, and very large warehouses. The slab is supported on beams of size 225 x 500 mm spaced at 4.
Slab on ground posttensioned slabson ground provide a costefficient, highperformance solution for problems associated with ground supported residential foundations on shrinkswell soils. Calculation of approximate depth from deflection criteria cl 23. The method of proof rolling well help us to know whether the full layer of soil is able to behave as a supporting system i. Determine slab thickness and concrete strength as if the slab were unreinforced. In the context of this guide, slab on ground is defined as. The construction information service brings together a comprehensive collection of essential technical documents from a wide range of publishers in one online package. Design of groundsupported concrete industrial floor slabs. The slab is of uniform or variable thic kness and it may include stiffening elements such as ribs or beams. The b distance, the b line, the b zone, and the dormant area are shown in figure 1. The compressive stresses resist the anticipated tension stresses induced by the soil movements, enhancing the performance over a nonprestressed foundation.
Design of slab examples and tutorials by sharifah maszura syed mohsin example 2. Flat slab analysis, design and detailing pdf civil engineering. Twoway concrete slab with beams spanning between supports. A posttensioned slab on ground foundation is simply a ground supported concrete slab. Extend horizontally from center line column at least 16 center line span. Calculate aspect ratio aspect ratio 2 longer spanshorter span 2. A civil engineer must know all the aspects regarding the flat floor system. The construction of slab on ground requires certain basic design elements.