Grade of concrete construction is selected based on structural design requirements. Floor slabs can range from a simple residential basement slab to a heavyduty industrial floor. Subgrade the subgrade must be properly compacted and drained in order to give the bearing support assumed in design. Different grades of concrete, their strength and selection. This paper documents changes to technical manual tm 580912, concrete floor slabs on grade subjected to heavy loads. Cracking and concrete spalling of topping slab plaza deck system. It is a horizontal structural component, with top and bottom surfaces parallel or near so.
A concrete mixture ratio of 1 part cement, 3 parts sand, and 3 parts aggregate will produce a concrete mix of approximately 3000 psi. Concrete slab, a very common and important structural element, are constructed to provide flat, useful surfaces. It was concluded that designing plain concrete slabs without reinforcement on grade according to pca and the wri methods leads to slab fatigue, even though. Concrete slab on grade analysis calculator for post or wheel.
Tm 580912 concrete floor slabs on grade subjected to. The thickness necessary to prothe desired loadcarrying capacity of a rigid slab is a function of five principal variables. The construction and design of concrete slabs on grade. Ufc 332006a 1 march 2005 unified facilities criteria ufc concrete floor slabs on grade subjected to heavy loads approved for public release. Slabs on grade identifying the problem slabonground is a wellused building solution in north america and other parts of the world, and they are very well known to not provide healthy interior environments.
Causes of cracks over reinforcement in slabs on ground. Chapter 5 addresses the design of concrete floors as it relates to their constructibility. The slab has to carry a distributed permanent action of 1. Mixing water with the cement, sand, and stone will form a paste that will bind the materials together until the m. Specific design requirements for concrete floor construction are found in aci 360r for slabsonground, aci 223r for shrinkagecompensating concrete floors, and aci 421. This manual prescribes the criteria for the design of concrete floor slabs on grade in buildings for heavy loads and is applicable to all elements. Nov 12, 2018 before casting slab on grade, the earth is excavated up to the required depth and compacted to expel air voids. Pdf a new method for designing floor slabs on grade due to the. The alternative to using this guide is to go to title 210 national engineering manual, section. However, no matter how basic or complex the floor is, the construction. Tm 580912 concrete floor slabs on grade subjected to heavy.
Concrete is weak in tension and, therefore, if its natural tendency to shrink is restrained, tensile stresses that exceed its tensile strength can develop, resulting in cracking. Concrete slab on grade analysis the engineering community. A good tool for thickness design with various nonuniform loads is concrete floors on ground, published by portland cement association farny. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Guide for concrete floor and slab construction aci 302. Changes to design criteria for thickness determination concerned impact factor, percent standard thickness versus coverage relationship, thickness reduction for highstrength subgrades, and design life. Without support, the slab has little chance of supporting. Residential foundation guideline johnson county kansas. Develop and report on criteria for design of slabs on grade, except highway and airport pavements 1.
Supply vibrating screeder, rider trowel and other equipment for the works provide lifting equipment to unload, shift and place the equipment onto area near to casting floor. Most aci standards and committee reports are gathered together in the annually revised aci manual of. Design of slabs on grade aci committee was specifically charged to cover design. Production of a quality concrete slab requires proper techniques and adequate planning. Review of rigid pavement design for concrete floor slabs on. Introduction concrete slabs on grade are a very common type of concrete construction. This study prepared a design manual for concrete slabs on grade subjected to moderate tu heavy loads. And then, soil investigation is done to design the thickness of the slab. Aci 360r10 guide to design of slabsonground american. Equivalent tensile stress design appendix 5examples using shrinkagecompensating concrete, p. Stresses in floor slabs on grade resulting from vehicular loads are a function of. Concrete mixes for interior floors shall have a slump of 120 30 mm at the point of discharge.
Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. For slabs with light loads, as those for homes, include wire mesh midway up the thickness of the slab to reduce cracking. Asce, secb course content slab on grades construction. Moisture moves to the slab surface by capillary action or wicking. Shear strength of beamless slabs usually a controlling factor. Concrete slab on grade concrete building engineering. Aci 360, design of slabs on grade, refers to this as a type b slab. Reinforced concrete design 1 design of slab examples and. The floor slab design procedure presented the maximum allowable stationary live load is lim herein is based on limiting the critical tensile stresses ited by both the positive bending moment stress produced within the slab by the vehicle loading, as under the load and the negative bending moment. Mass concrete thermal control planning with new annex t. The attached excerpted resource materials have been made. Stresses in floor slabs on grade resulting from vehicular loads a re a function. Stepbystep procedures, sample solutions, and commentary ringo, boyd c.
Manual for design and detailing of reinforced concrete to the september 20 code of practice for structural use of concrete 20 2. Slab on grade or grade slab types construction procedure. The objective of the analysis was to study the effect of the link properties that is, stiffness fig. The major structural components of a slabongrade foundation are the floor slab itself and either grade beams or foundation walls with footings at the perimeter of the slab see figures 42 and 43. Design guide 11 floors slabsonground for concrete structures. Feb 23, 2019 concrete slab design monolithic slab foundation design more recent slab on grade design information recommends and even calls for monolithic slab foundation design concrete floor slab design nz. Concrete slab on grade design ksdphilippines structural 3 jun 08 02.
Minimum allowable footing concrete cure time prior to wall placement is 24 hours. Twoway concrete slab with beams spanning between supports. Nominal mix concrete are those which are generally used for small scale construction and small residential buildings where concrete consumption is not high. Slab on grade design calls for a slab thickness a minimum of 4 thickening to a minimum of 6 within about 16 of the perimeter for additional reinforcing steel to support exterior wall loads. Slab thickness design for industrial concrete floors on grade is195.
The construction and design of concrete slabs on grade d. The minimum thickness can be determined by many factors. Powered by the equivalent frame method of analysis and design per latest american aci 31814 and canadian csa a23. Development of a design manual for concrete floor slabs on grade. The most common reinforcement associated with slabsongrade is welded wire fabric. The thickness of a floor slab must be determined early in design because the weight of the slab is an important part of the dead load of the structure. For slab subjected to interior concentrated post or wheel loading. Often the water movement is so aggressive that standing water will be on the floor surface, creating hazardous slippery conditions. Concrete slab design monolithic slab foundation design more. Remove of all existing vegetation of new on grade concrete slab construction area. 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. Concrete slab on grade design structural engineering. Design of slabs on grade aci 360r92 by american concrete institute from aci. Euclid chemical concrete floor systems design guide.
The scope of this article is limited to the design of industrial concrete floor slabs on grade for concentrated loads caused by the columns of freestanding. Manual for design and detailing of reinforced concrete to the. Mar, 2019 slab on grade concrete slab on grade analysis for concentrated post or wheel loading. Cracks in concrete cannot be prevented entirely, but they can be controlled and minimized by properly designed joints.
Design of slabs on ground aci 360r06 by american concrete institute 2006 4. The wire reinforcing institute recommends the use of the subgrade drag theory for slabs up to 150 feet in length. Ground water sources and when the floor slab is in contact with saturated ground, or if drainage is poor. Ufc 332006a concrete floor slabs on grade subjected to. Consequently, aci 360 was formed with this mission. There are two types of concrete mixes, nominal mix and design mix. These boards act as a concrete mould, which helps in identifying slab corners. Concrete slab supported di rectly on foundation soil. Stresses in concrete slabs come from volume changes in the concrete from shrinkage and temperature changes or from imposed loads. The depth of a concrete slab floor is very small compared to its span. Slabs may be supported on two sides only or have beams on all four sides. Batters are marked and placed in position as per plan before concrete pour. Reported by committee 302 american concrete institute. The slab on ground is in direct contact with the typical draining layer such as a gravel, sand or a compacted subbase and under complicated hydrothermal conditions.
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