Analysis and design of slabs two way civil engineers pk. Determine the allowable unform live load that a one way slab can sustain 3. Ce 433, fall 2006 slab design example 1 6 design a one way slab for an exterior bay of a multistory office building using the information specified below. Fundamentals of posttensioned concrete design for buildings part one. This will appear at the top of the first page of the output. One way slabs are those supported continuously on the two opposite sides so that the load sare carried along one direction only. Slab design is comparatively easy when compared with the design of other elements. The critical sections shall be located with respect to. Reinforced concrete design 1 design of slab examples. Designing of slabs depends upon whether it is a one way or a two way slab, the end conditions and the.
Pdf shear in oneway slabs under concentrated load close. Design of reinforced concrete structures ii two way slabs 1 1. Two way slab design based on aci 31811 using finite element method. For two way joist slab, it is necessary to check shear at multiple sections as defined in the aci 31814. One way slab one way slabs are those slabs with an aspect ratio in plan of 2. We believe that the quickest way to learn is by actual application of the information. The output of the program for the slab in the example is shown in the following pages. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. Rectangular beams and oneway slabs page 5 of 9 maximum permissible steel ratio, max an overreinforced beam will fail in a brittle manner while an underreinforced beam will. Other bridges in mo superstructure steel concrete bridge number 061 140 149 152 710 avg 028 057 069 520 avg year built 2008 2008 2008 2009 2010 avg 2009 2010 2011 2006 avg span length 50 50 40 62 64 53.
Twoway concrete slab on beams floor analysis and design. Chapter 3 design of rectangular beams and oneway slabs. Analysis of twoway slabs using direct design method shms. The pca computer program pcaslab can be used to expedite the design of different slab systems. One way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. Oneway slab design procedures and design example civil. Shear strength of beamless slabs usually a controlling factor. Free version of rcsolver concrete design with ec2, ec8, and aci 318. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. Primarily slabs are classified into two types one way slab and two way slab to know more about the differences refer here. Posttensioned oneway slab pennsylvania state university. The requirements for two of them are described in detail in aci 31814 chapter 8 8. In this example, the latter option will be used to achieve better understanding for the design of two way joist slab often called two way ribbed slab or waffle slab. Examples c1 through c5 are a set of examples that illustrate the elevation of a singlestory home with a crawlspace.
Design procedure steps for one way slab slab design steps. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in plane loads, if any, per unit width of slab. Rectangular beams and one way slabs page 3 of 9 design of rectangular beams and one way slabs continued a. Design criteria there are three criteria which must be considered for the design of a conventional one way slab system. If slab is supported on all four sides and r shorter side longer side one way slab. Here are the steps for the design procedure for one way slab in steps. One way simply supported slab analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. A reinforced concrete slab is built integrally with its. In one way slab, the ratio of longer span l to shorter span b is equal or greater than 2, i. One way concrete slab metric canada one way concrete slab metric canada miguelpenawse structural op 5 jun 14 18. The construction and design of concrete slabs on grade d.
Twoway concrete floor slab with beams design and detailing. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Types of one way slab one way slab may be solid hollow ribbed 6. Analysis of two way ribbed and waffle slabs with hidden beams. A slab strip of unit width is analysed using simple beam theory. Oneway and two way slabs one way slabs transfer the imposed loads in one direction only. One way and two way slabs one way slabs transfer the imposed loads in one direction only. Continuous oneway solid slab concrete structures eurocode. Whatever may be the width of the slabs it should always be designed for a width of equal to one metre and the same design should be adopted for the rest of the slab. Or if someone hasknows of a one way slab design example pdf or url metric units, and hopefully one that follows the canadian code it would be great. Continuous one way slab figure 1 shows a clear area of 12 m x 8. For the love of physics walter lewin may 16, 2011 duration. The slab is 150 mm thick, the beams are 400 mm wide and 600 mm deep and the joists are 300 mm wide and 500 mm deep. The trial depth is selected based on spandepth ratio of 7, as in is.
The service live load is 100 psf and 4000 psi concrete is specified for use with steel with a yield stress equal to 60000 psi. Aci 360, design of slabsongrade, refers to this as a type b slab. These are the direct design method presented in chap. Summary and comparison of twoway slab design results. Get full capabiltiies with our free version of rcsolver once you signup for our newsletter. Explain the range in x, y and z directions and group. Fundamentals of posttensioned concrete design for buildings part one a suncam online continuing.
Accordingly, main reinforcement is required in the two directions. All about structural analysis and design 4,029 views 55. For consistency, many of the numerical examples are based on a fictitious sevenstory reinforced concrete building. Analysis and design of slabs one way civil engineers pk. Download code one way slab design procedures and design. A six storey building for a commercial complex has plan dimensions as shown in figure 1. For example the name lsacposx can be interpreted as left slab acute corner. Load the abaqus solver to read the input file and carry out a linear analysis. Two way slab design by direct design method as per aci 31811, step by step procedure and limitations of direct design method for two way slab is presented. With the free version you will have to wait 30 seconds for advertisements. The basic design procedure of a two way slab system has five steps. Assume partitions cannot be damaged by deflections. Oneway and twoway slabs university of asia pacific.
The slab is part of an office building and the slab is supporting masonry wallspartitions that are sensitive to excessive deflections. Quantity of reinforcement steel required for slab or bar bending schedule for slab. For those who do not know what are the des ign requirements of a slab. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Comparison of concrete two way slab analysis and design methods a slab system can be analyzed and designed by any procedure satisfying equilibrium and geometric compatibility. Jul 18, 2016 there are some basic steps which we generally do while designing theoretically some steps are rcc slab design guidelines. In this example deflection will be calculated and checked to satisfy project deflection limits. Flat slab haunched slab a longitudinal slab is one of the least complex types of bridge superstructures.
Chajjas and verandahs are an practical example of one way slab. The design procedure for a uniformly loaded one way reinforced slab can be divided in the following steps. Design of one way slabs ce a433 ce a433 rc desginrc design t. One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. In any span, the max cable sag, zd depends on the concrete cover requirements and the tendon dimensions. A single slab with oneway reinforcement rebars will be analyzed with rcsolver. The first stage of the design is finding the bending moment of the slab panels. Twoway joist waffle slab design approach and methodology. Verandah slab is a type of one way slab, where the slab is spanning in the shorter direction.
The program covers wide range of two way slab systems and can be used for more complex slab layouts. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Design a simply supported one way slab subjected to dead and live loads 4. The following example illustrates the example building. Ribbed slab design spreadsheet civil engineering community. Beams and one way slabs how to design concrete structures using eurocode 2 design procedure a procedure for carrying out the det ailed desi gn of slabs assumes that the slab thickness has previously been determined during conceptual design. Can be used for larger spans with relatively higher cost and higher deflections one way joist system suitable span 6 to 9m with ll 46knm2. Depending on the boundary condition and the properties of the slabs, methods of finding bending moment is expressed in the bs 8110 part 01 as follows.
Before going to this topic, please read it there are two types of slab classification based on the direction of bending occurs in these slabs. When zd is determined, the prestressing force required to balance an. The design shear force v d is below the maximum punching strength v rd,max. Next, select the structural system as one way slab. Beams of width and depth are provided on all column lines. Design of slab examples and tutorials by sharifah maszura syed mohsin example 2. The direction in which the load is carried in one way slab is called the span. Design of reinforced concrete structures ii twoway slabs. One way beam action and two way punching shear considerations. In both of them, the shear resistance has to be determined by means of slab tests, however the total number of test can be considerably reduced, because once the longitudinal strength. He defined a critical perimeter based on the punching provisions in the draft version of. Two way slabs have two way bending unlike one way slab. Master of science and hereby certify that, in their opinion, it is worthy of acceptance. Slabs having supports on less than four sides can be designed as one way.
Designing of slabs depends upon whether it is a oneway or a two way slab, the end conditions and the loading. Aug 15, 2016 download code ribbed slab design spreadsheet. Example design of two way edgesupported solid slab. Learn to design reinforced concrete one way slabs through.
Assign the loads on a structure and compare the results with the manual calculation. Mar 12, 2017 the direct design method is an approximate method used to analyze two way slabs. The two classifications are oneway slab and two way slab. Generally all the cantilever slabs are one way slab. Civilax is the knowledge base covering all disciplines in civil engineering. In this post, i am finding out the estimation of steel reinforcement required for a slab to work on this i considered a plan as shown below.
Twoway joist concrete slab floor waffle slab system. The reinforced concrete design handbook now provides dozens of design examples of various reinforced concrete members, such as one and two way slabs, beams, columns, walls, diaphragms, footings, and retaining walls. The dimensions of an interior bay are shown in figure 1. Effective span of slab shall be lesser of the two 1. Slab with reinforcement with yield stress, f y, exceeds 60,000 psi measured at a yield strain of 0. However, i have no idea if and how that property can be set via pdf. Generally, there are two types of slab which are one way and two way slabs. Slab is a common term used to describe the structural elements such as floors and roofs where the thickness of the element is very small compared to the length and. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. The construction and design of concrete slabs on grade. Design of cantilever slab spreadsheet engineering books.
Pdf experimental study of shear in reinforced concrete one. Bridge approach slab analysis and design incorporating elastic soil support presented by. For 1m slab width, moment, shear force, one way continuous slab for continuous slab, moment and shear force can be obtained from table 3. Download code oneway slab design procedures and design.
How to disable highlighting in browser pdf viewer firefox. This will appear at the top of the each subsequent page of the output. This earlier handbook format was a collection of design aids and illustrative examples, generated in the precalculator era. Distribute moments transverse at critical sections to column and middlestrip and if. 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. Two way slab design by direct design method as per aci 31811.
Introcduction slab in which the deflected surface is predominantly cylindrical termed as one way slabs spanning in the direction of curvature. Reinforced concrete design 1 design of slab examples and. Oneway and twoway slabs oneway slabs transfer the imposed. Although the major reinforcement in one way slab span is in the short direction, yet at the corner, the moment is actual supported by beams at both directions. The ratio of the total costs was found to be within the range 1. Difference between one way slab and two way slab daily civil. One way slabs normally design as a beam with cables running in the direction of the span at uniform centres. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4. However, the section can neither take an axial load. Comparison of one way and two way slab behavior economic choices one way slab on beams suitable span 3 to 6m with ll 35knm2. A slab is supported only one direction that is one way slab now tha loads are transferred only this two supports. They may be supported on two opposite sides only fig. The codes governing the design of the one way slab will be aci 31802 and ibc 2003.
Ce 433, summer 20 slab design example 1 5 design a one. The building is located in seismic zone iii on a site with medium soil. Many of these earlier design aids intended to carry out relatively simple design calculations were eliminated in the sp1709 edition. For the purpose of this tutorial, enter the general title as sixspan, one way slab. How to design two way slab simply supported corners free to lift limit state method is 4562000 duration. The proposed slab system must meet the current code. The wire reinforcing institute recommends the use of the subgrade drag theory for slabs up to 150 feet in length. Twoway flat plate concrete slab floor analysis and design. Fundamentals of posttensioned concrete design for buildings. Pdf design calculation design of one way slab slab s1. Introduction concrete slabs on grade are a very common type of concrete construction. Pdf reinforced concrete oneway slabs subjected to concentrated loads.
They are projections from wall face of lintel beams or floor slabs. Deep ribs, the concrete and steel quantities are relative low expensive formwork expected. Firstly, one has to check if the design shear force v d is smaller than the maximum punching strength v rd,max. This appendix presents design examples of the retrofitting techniques for elevation, dry floodproofing, wet. Time saving design aids two way slabs page 6 of 14 the pca computer program pcaslab can be used to expedite the design of different slab systems. This calculation is intended to show in detail the provisions of designing a slab to eurocode 2 using essentially the same slab as used in example 3. Asc steel deck is leading the way in innovation with ongoing testing of. In two way slabs shorter direction strip carry greater %age of load.
D mm d 105 mm loads on slab self weight of slab 3. Reference 5 focused on analysis of two way ribbed slabs with. The pdf format offers a possibility to disallow copying text, as you can see when you look at the document properties of a pdf in acrobat reader. Chapter 18 concrete slab structures january 2019 183 18. Also the slab is supported four sides but the length breadth lylxration is greater than or equal to two, the slab is designed as one way slab. A 175 mm thick continuous slab is required to support screed, finishes, an office variable action of 2. This example is to be used for educational purposes only. A reinforced concrete slab is built integrally with its supports and consists of equal span of 15 ft. Two way slab is a slab supported by beams on all the four sides and the loads are carried by the supports along both directions, it is known as two way slab. Calculate the design moment strength of a one way slab 2. Asce, secb course content slab on grades construction.
Floor slabs can range from a simple residential basement slab to a heavyduty industrial floor. Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. The minimum thickness can be determined by many factors. The proposed slab system must be able to be constructed at a reasonable cost. Chapter 3 design of rectangular beams and oneway slabs 12. The slab is supported on beams of size 225 x 500 mm spaced at 4.
Even while designing they are considered as one slabs with cantilever fixed or continuous at supports. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3. More detailed advice on determining design li fe,actions, material properties, methods of analysi s. Plan view of floor system assume partitions will not be damaged by deflections. Bending will take place in the two directions in a dishlike form.