In twoway slabs shorter direction strip carry greater %age of load. The following example illustrates the design methods presented in aci 31805 and ibc 2003. Accordingly, main reinforcement is required in the two directions. In accordance with as28702011 residential slabs and footings construction a site classification of class p is applicable to this site due to fill. The slab is propped at the centre during construction stage. Sorry i was wrong, the contract says mclass waffle pod slab and the promotion list says upgrade to hclass slab if required, sorry for the mistake. Framing dead load selfweight superrimposed dead load 25 psf partitions, me, misc. Usually the soil test has further clues that describe the problem with the soil. The attached excerpted resource materials have been made. Manual for the design of reinforced concrete building. Following are the rcc slab design and detailing guidelines. There is a nominal strength that is reduced by a factor which must exceed the factored design stress.
When approaching a class p site, engineers at intrax consider various elements, as discussed below, to find the. The slab is positioned on steel tbeams which can be rolled or compound. Laboratory trial mix for class p concrete must produce an average 28 day flexural strength of at least 650 psi. There are various established methods for analysing ribbed slabs and dealing with the solid areas.
If slab supported by four side of beams or walls, the slab is considered oneway if ratio of long span ly to short span lx greater than 2. Fundamentals of posttensioned concrete design for buildings part one. Site class e, depth 30 ft site class c, depth 10 ft site class c, depth 30 ft 0. Fundamentals of posttensioned concrete design for buildings. The codes governing the design of the oneway slab will be aci 31802 and ibc 2003. Lecture series on design of reinforced concrete structures by prof. This manual p rescribes the criteria for the design of concrete floor slabs on grade in buildings for heavy loads and is applicable to all elements responsible for military construction. Analysis of two way ribbed and waffle slabs with hidden beams. Introduction concrete slabs on grade are a very common type of concrete construction. Continuous ribbed slabs concrete structures eurocode.
Slabs may be supported on two sides only or have beams on all four sides. Bending will take place in the two directions in a dishlike form. C 5 is the slope correction coefficient co is the consolidation correction coefficient as an example. Hvac systems design fundamentals karachi, pakistan, february 22, 2011 wei sun, p. This report is intended to serve as a manual of good practice for the design of prestressed concrete flat slabs in addition to the recommended procedures, other methods are described for the sake of completeness and to compare different methods of design. This manual supersedes tm 580912afm 883, chapter 15, dated 1 april 1977. The p classification acts as a warning bell to the footingslab designer that particular site features need to be considered when designing the footings. Instructional materials complementing fema p751, design examples.
Ongrade concrete floor slabs shall be placed on a 4inch fill of coarse aggregate or on a. The slab has to carry a distributed permanent action of 1. Design criteria there are three criteria which must be considered for the design of a conventional one way slab system. Steel rods aiiia400 and steel wires bpi are used as reinforcement. Class p sites class p sites are those sites that may contain some of the features described in the table below. Blended portland cement type sf, may be used in class dp or hp concrete. What is a soil test and how is it used to design house. Extra soil that has been placed on your block that. Reinforced concrete slab design and detailing guide is456. The construction and design of concrete slabs on grade. Twoway slabs have two way bending unlike oneway slab.
Structural steel composite slab 1 of 7 rev design project. One of the most significant characteristics of this type of valves is its. Design and construction of concrete slabs on grade, aci. When approaching a class p or difficult site, engineers must find innovative, collaborative design solutions that mitigate risks to residential projects. Flat slab system is an important division of concrete floor system. Design of reinforced concrete 10th edition pdf free download. Analysis and design of slabs two way civil engineers pk. It is a horizontal structural component, with top and bottom surfaces parallel or near so. In such a design, a wedge slides cross a general passageway in order to control fluid flow like a sliding gate hence, the name.
Australian standard residential slabs and footings materialstandard. A mat foundation is a large concrete slab that supports column or line loads that. On the otherhand there could be some real problems that are costly. Thus p is an extra given to your site because it has extra problems. Construction requirements the minimal thickness of the concrete layer above the profiled sheet should be. Basic design criteria concentrically loaded d2 all sides c critical section for twoway shear b critical section for oneway shear a critical section for flexure outside face of concrete column or line midway between face of steel column. The proposed slab system must be able to be constructed at a reasonable cost. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. Youll need an engineer to design your footings to solve these problems. A civil engineer must know all the aspects regarding the flat floor system. Sto 00472005 coiled steel is used for profiled sheets. Reinforced cast on site concrete, 3 different floor solutions.
Features of the geometry and details of loads applicable to the floor slab covered by this report are included herein. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. P just means there is a problem with the soil and an engineer will need to design your slab. Class p concrete shall contain 70 percent to 80 percent portland cement and 20. Instructional materials complementing fema p 751, design examples reinforced concrete footings. Having poor or uncertified fill could result in a p class soil but an engineer could just design a modified m slab which might be a standard inclusion anyway which was us. As 28701996 residential slabs and footingsconstruction. The wire reinforcing institute recommends the use of the subgrade drag theory for slabs up to 150 feet in length. This standard does not include design details for class p sites. Whoever is building your house will be the one to speak to because it varies between builders.
Concrete slab, a very common and important structural element, are constructed to provide flat, useful surfaces. Some advisory material is included in the commentary. The construction and design of concrete slabs on grade d. In the absence of the fill material, the designing engineer should recognise that the natural soils encountered on this site. Sum fatigue and erosion damage factors over all of the. A simple way to think of it, which is like how the buidler explained, a h2 slab will be used, but due to the extra problems of the site p class, the slab needs extra support. Using udls simplifies the analysis and remains popular. Flat slab analysis, design and detailing pdf civil.
There are several factors that may greatly affect the design of slab footings on these sites. Part two is an example intensive course, with key concepts introduced along. The ratio of the total costs was found to be within the range 1. In the current research, a parametric study was carried out to investigate the structural response of industrial slab. The example presented here is for twoway posttensioned design. Posttensioned oneway slab pennsylvania state university. The proposed slab system must meet the current code. The analysis and design of posttensioned, twoway slabs incorporate the full tributary slab width without the distribution of forces and reinforcement between column strips and middle strips, synonymous with mild reinforced two. Besides being a medic, he loves blogging, and he always strives hard to share the highquality content with others.
The pt slab analysis and design is a most complicated process because it involves primary moments from basic frame analysis and secondary moments from pt forces. Building systems designed and constructed in accordance with this standard on a normal. Data is taken from manufacturers tables yield strength of steel, f yp 280 nmm 2 design thickness, allowing for zinc, t p 0. Department of mechanics, materials and structures english. Reinforced concrete design 1 design of slab examples and.
Tm 580912 concrete floor slabs on grade subjected to. These materials are originally located at different websites. One method is to ignore the weight of the solid part of the slab in the analysis of the ribbed slab and the weight of the solid area added to the supporting beam. Design of reinforced concrete structures ii twoway slabs. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Asce, secb course content slab on grades construction. Dhang, department of civil engineering, iit kharagpur. Furthermore, assume that the top of the footing is 2 feet below grade the overlying soil. For class p sites, the classification report shall include the reason for the p. Design of reinforced concrete structures ii twoway slabs 1 1. Floor slabs can range from a simple residential basement slab to a heavyduty industrial floor. Design of reinforced concrete 10th edition pdf free.
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