The slab on grade can be installed on the virgin ground, a layer of stone or porous material, etc. Why are there different f factors for the same horizontal insulation distance and the same rvalue. Slab on grade definition what does slab on grade mean in. If there are concerns regarding the ability of the earth to support the slab on grade, the. Reinforced concrete solid slabs can be either oneway spanning or two way. Why are there different ffactors for the same horizontal insulation. The report addresses the planning, design, and detailing of slabs. Design of slabs onground reported by aci committee 360 aci 360r06 this document presents information on the design of slabs onground, primarily industrial floors.
Calculate the maximum length of steel reinforced slabongrade floors. An interior load condition is assumed for flexural analysis. The steady state heat transfer through the floor is calculated as, q area u eff t air,out t air,in t air,out t air,in p exp ffactor where, q is the steady state heat transfer through the floor in watt. Online concrete slab on grade analysis calculator for slab subjected to interior concentrated post or wheel loading assuming slab is reinforced for shrinkage and temperature only.
Specifying and achieving a level composite steel floor. In some cases additional footings often a thickened slab are necessary under bearing walls. New floor design book this article is based on sections from the book designing floor slabs on grade by boyd ringo and robert anderson. Utilizing a concrete strength of 4000 psi and a factor of safety of 2, im coming up with a slab in the 11 to 12 thickness range.
A heated slab is a type of construction that has a slabongrade concrete floor with a heating system embedded in or beneath the slab floor. Designing floor slabs on grade civil engineering community. Background information on design theories is followed. Floor slabs can range from a simple residential basement slab to a heavyduty industrial floor. Fully enclosed attic floor system the ceiling insulation is enclosed on all six sides by an air barrier system, such as taped drywall below, solid framing joists on the sides. As per the above figure floor slab 2 is a one way slab. Concrete slab on grade analysis the engineering community. Analysis of concrete slabs on grade spreadsheet grdslab is a spreadsheet program written in msexcel for the purpose of analysis of concrete slabs on grade. As crosssectional area in square inches of steel per lineal foot of slab width f friction factor l distance in feet between joints the distance between the free ends of the slab that can move due to shrinkage contraction or thermal expansion. It includes a significant percentage of single family houses as well as a large percentage of commercial buildings. For example, an f l number of 20 and an f f number of 25 would be adequate for a carpeted office space. 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. How the construction is described will depend on the energy simulation model.
Fnumbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab. They are calculated using the standards set forth in astm e1155, which is the standard test method for determining f f floor flatness. That is, the concentrated post or wheel load is assumed to be well away from a free slab edge or corner. The length of slab is limited to ensure the deflection is within the limit however the above values can be modified with percentage of steel, because when we add steel. A new method for designing floor slabs on grade due to the. The example below that is highlighted is that if i have a slab with 12 inches of r5 horizontal insulation is the f factor 0. Slabongrade heat loss estimation hvacr engineering. The construction and design of concrete slabs on grade d. Matching these slabongrade construction layersinsulation will mean youre achieving the target ffactor for your perimeter zones. Where heated slabs are below grade, belowgrade walls shall comply with the f factor requirements for heated slabs. Contain stepbystep procedures and all the charts, tables, and equations needed to apply them. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1.
Ground heat transfer calculations using c and f factor. Concrete slab on grade thickness analysis for slab. Very good reference for designing concrete slabs on grade. It addresses the planning, design, and detailing of slabs. Building additions that include a slabongrade construction also are subject to the slab edge requirements listed in the ieccirc. Per pca slab thickness design for industrial concrete floors on grade figure 3, page 5 job name. I could not find a better reference that covered the subject matter like this book does. In this kind of slab mains bars cranked bars are provided in shorter direction hence there is no need of calculating the crank bar length in ydirection from fig. Preparation and installation slab on grade footing. This article presents a methodology for designing slabs on grade for industrial floors where there is an eccentricity between the slab centroid and the gravity centre loads of the loaded axle of forklift trucks travelling over the floor. The number of buildings with this type of floor construction is huge. Search for abbreviation meaning, word to abbreviate, or lists of abbreviations. Concrete slab on grade analysis calculator for post or.
Slabongrade and underground floors defined with ffactors. Introduction concrete slabs on grade are a very common type of concrete construction. Following are the rcc slab design and detailing guidelines. Empirical method a method of design and analysis based on a nationally approved or equivalent standard may be used to design slabson. Unit weight, wc 150 pcf topslab reinforcing yield, fy 60000 psi subgrade modulus, k 200 pci concentrated load, p 0. The slab on grade worksheet assumes a structurally unreinforced slab, aci360type b, reinforced only for shrinkage and temperature. Ffactors are provided for both heated and unheated slabs. The example below that is highlighted is that if i have a slab with 12 inches of r5 horizontal insulation is the ffactor 0. Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for oneway and twoway slabs as per is 456. For slab subjected to concentrated post loading for k 100 pci per pca slab thickness design for industrial concrete floors on grade figure 7b, page 10. Stepbystep procedures, sample solutions, and commentary ringo, boyd c. The construction and design of concrete slabs on grade. Analysis of concrete slabs on grade spreadsheetdownload free. Steelreinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner.
Ffactors scientifically proven approach allows you to achieve results without hunger, deprivation, or denial. Unheated slabongrade floors are all other floors in contact with ground. Asce, secb course content slab on grades construction. Grdslab concrete slab on grade analysis spreadsheet. Clean the area of any loose materials prior to start any work make sure that the compacted fill to received concrete is approved by the consultant engineer. Calculators for structural engineers, construction professionals and. Does anyone know what the two different columns for unheated and heated slabs represent in table a6. In contrast to the ufactor for floors, the ffactor for slabongrade floors is expressed per linear foot of building perimeter. So you could try using an edge r of zero and a floor u based on 6inch thick concrete and see what result you get. The higher the number, the flatter or more level the slab. A shallow foundation is a type of building foundation that transfers building loads to the earth very near to the surface, rather than to a subsurface layer or a range of depths as does a deep foundation. Floor levelness and flatness are specified by f l and f f numbers, respectively. The configuration of insulation and the ffactors for the baseline building are shown in bookref idbaselinebuildingffactorcriteriaforslabongradefloors.
Why are there different ffactors for the same horizontal insulation distance and the same rvalue. Title 24 require the underground wall constructions and slabsongrade or underground floors not to exceed certain maximum values of cfactor and f factor. The ffactor diet book discover the secret to permanent weight. Reinforced concrete design 1 design of slab examples. Specifically, a concrete slab on grade may be subjected to concentrated post or.
Title 24 require the underground wall constructions and slabsongrade or underground floors not to exceed certain maximum values of cfactor and ffactor. Concrete floor slabs on grade subjected to heavy loads army technical manual tm 580912, air force manual afm 883, chapter 15 1987 streses and stains in rigid pavements lecture notes 3 by. What is the need for modification factor check during slab. Calculate the required floor thickness for a concrete slabongrade floor supported by a stabilizedmodified soil subgrade. Shallow foundations include spread footing foundations, mat. Limiting factors on the width of the slab edge insulation in this situation are determined by attachment of floor finishes and width of foundation. Applying ffactor constructions to ground floor perimeter. A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Heated slabongrade floors include all floors that are heated directly in order to provide heating to the space. Where heated slabs are below grade, belowgrade walls shall comply with the ffactor requirements for heated slabs. Based upon my inexperience with this application and the fact that the adjacent warehouse only has a 7 thick slab, i am concerned that ive overlooked something that is making my design overly conservative. As the past has demonstrated, concrete slabongrade floors are ideal for radiant floor heating.
Reinforced concrete slab design and detailing guide is456. The magnitude of these stresses depends on factors. The best way to do this is create the first one and edit the ffactor field to what all the other ones should be, and put in a place holder for area and perimeter such as 1. Guide to design of slabsonground reported by aci committee 360 aci 360r10 this guide presents information on the design of slabsonground, primarily industrial floors. The 2nd edition includes new chapters on the hybrid posttensioned slab and troubleshooting, plus expanded commentaries and details. Reinforced concrete slab is the most popular floor slab system used in residential building construction in sri lanka. The ffactor could be related to the configuration of. Many of the simplifications and enhancements developed for comcheck have provided the technical basis for code changes submitted to the international code council icc. Design and construction of concrete slabs on grade, aci scm1186, american concrete institute, detroit, 1986. A slab on grade does not have any voids below it and can be as thin as 4 inches. Published by the aberdeen group, the book gives stepbystep procedures, sample solutions, and commentary for design of floor slabs. The design of the slab on grade is engineered by the structural engineer. Stresses in floor slabs on grade resulting from vehicular loads are a function of.
Department of energy doe and pacific northwest national laboratory pnnl intend to refine and enhance the comcheck materials over time in response to needs expressed by users. Slab on grade ffactor for a large building leeduser. Concrete strength, f c 4000 psi instructions for use of figure 3. C 5 is the slope correction coefficient co is the consolidation correction coefficient as an example. Ive just input floor areas through the wizard and selected the type of foundation insulation i have from the dropdown lists. Simple models may include just an ffactor, representing an instantaneous heat lossgain to outside air. Background information on design theories is followed by discussion. Note that c factor doesnt include soil or air films.
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