Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. For 1m slab width, moment, shear force, one way continuous slab for continuous slab, moment and shear force can be obtained from table 3. Slab shear strength two way shear check the adequacy of slab thickness for punching shear two way shear at an interior column figure 4. Check the applicable joist dimensional limitations as follows. The design shear force can be reduced to account for the loads applied inside the outer perimeter. They may be supported on two opposite sides only fig. 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. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. In twoway slabs shorter direction strip carry greater %age of load.
Twoway flat plate concrete floor system analysis and design. Design of reinforced concrete structures ii two way slabs 1 1. The thickness of equivalent flat slab is taken from table 9. In case of slabs thin members, no need of even minimum shear reinforcement. One way slab being supported on two opposite sides. Oneway concrete slab design part 1 concept explained and. A single slab with twoway reinforcement rebars will be analyzed with rcsolver. Load transfer in a oneway slab, b twoway slab nilson fig. Continuous one way slab figure 1 shows a clear area of 12 m x 8. A single slab with oneway reinforcement rebars will be analyzed with rcsolver. 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. Oneway simply supported slab, span length, l 10 ft normal weight concrete unit weight 145 pcf, 60 grade steel, fy 60,000. 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.
Bending will take place in the two directions in a dishlike form. Reinforced concrete design 1 design of slab examples and. Twoway concrete slab on beams floor analysis and design. Examples of the portion of slab to be included with the beam under. A detailed explanation will be given of the checksto be carried out, the aspects to be considered in the design and the construction procedures and sequences of a posttensioned slab. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. Footings example 1 design of a square spread footing of a sevenstory building design and detail a typical square spread footing of a six bay by five bay sevenstory building, founded on stiff soil, supporting a 24 in. 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. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. If you continue browsing the site, you agree to the use of cookies on this website. In two way slabs shorter direction strip carry greater %age of load. Task is to derive a split factor c x for twoway slab with supports in direction x as simplesimple ss and in direction y o as simplefixed sf. Sep 04, 2014 10 design of one way solid slabs reinforcement, 2.
The building is located in seismic zone iii on a site with medium soil. Nov 04, 2017 in the first part of this series, we explain the concept of one way load transfer in concrete slabs and how to determine the minimum slab thickness based on deflection criteria. Ce 433, fall 2006 slab design example 1 6 design a oneway slab for an exterior bay of a multistory office building using the information specified below. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in.
One way and two way slabs one way slabs transfer the imposed loads in one direction only. A six storey building for a commercial complex has plan dimensions as shown in figure 1. The ratio of the total costs was found to be within the range 1. In lieu of detailed calculation for deflections, aci 318 code gives minimum thickness for twoway slab with beams spanning between supports.
The first reinforced concrete design manual formerly titled aci design handbook was developed in accordance with the design provisions of 1963 aci 318 building code by aci committee 340, design. This will appear at the top of the first page of the output. Plan view of floor system assume partitions will not be damaged by deflections. Beams, see lecture 3 punching shear requirements e.
Sachpazis date 18012014 chkd by date appd by 1 flat slab design to bs8110. The execution of the design will be explained with reference to an example. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4. Two way reinforced concrete slab design spreadsheet working stress design coefficient method download spreadsheet. The 2012 edition of the reinforced concrete design manual sp1711 was developed in accordance with the design provisions of aci 31811, and is consistent with the format of sp1709. Determine moments at critical sections in each direction, normally the negative. Analysis and design of slabs one way civil engineers pk. Mathematical structural analysis of one way ribbed slabs was introduced in this paper. Design of reinforced concrete structures ii twoway slabs 1 1. Ce 403, fall 20 oneway slab design 3 4 aci 31811 referenced pp 2 4 rating. Department of mechanics, materials and structures english. These are the direct design method presented in chap. Two way slab design by direct design method as per aci 31811.
Twoway slabs have two way bending unlike oneway slab. Slab is checked for deflection shear and development length. Fanella, which appeared in the october 2001 edition of structural engineer magazine. The design procedure for a uniformly loaded oneway reinforced slab can be divided in the following steps. The slab is supported on beams of size 225 x 500 mm spaced at 4.
Shear due to loads always must be less than the shear strength of concrete. We assume that the verandah slab is a two way slab instead of one way slab in order to calculate mb,neg now, using moment coefficient method for analysis. In lieu of detailed calculation for deflections, csa a23. One way slab vs two way slab civil engineering community. The design moment and reaction for monolithic support should generally be taken as the greater of the elastic and redistributed values critical design moment usually at face of support. Finally, since shear reinforcement is not used in oneway slabs, the concrete. This will appear at the top of the each subsequent page of the output. Analysis and design of slabs two way civil engineers pk.
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. Ce 433, summer 20 slab design example 1 5 design a one. Chapter 3 design of rectangular beams and oneway slabs. D mm d 105 mm loads on slab self weight of slab 3. A continuous 3span haunched slab structure is used for the design example. One way slab one way slabs are such slabs in which the loads are shared only by the shorter direction of the slab. Twoway slab analysis and design aci 318 states that a slab system shall be designed by any procedure satisfying equilibrium and geometric compatibility, provided that strength and serviceability criteria are satisfied. Design of reinforced concrete structures ii twoway slabs.
Two way slab being supported on four sides the load will be carried in both the directions. Design procedure steps for one way slab slab design steps. This example is to be used for educational purposes only. The dimensions of an interior bay are shown in figure 1. Analysis of two way ribbed and waffle slabs with hidden beams ibrahim mohammad arman international journal of civil and structural engineering volume 4 issue 3 2014 344 2. Fundamentals of posttensioned concrete design for buildings. Analysis of two way ribbed and waffle slabs with hidden beams. Rectangular beams and oneway slabs page 3 of 9 design of rectangular beams and oneway slabs continued a. For the purpose of this tutorial, enter the general title as sixspan, oneway slab. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Teaching twoway ribbed slab analysis and design using the. 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.
Accordingly, main reinforcement is required in the two directions. Advanced slab design mode enables concrete slabs defined with or without holes to be designed using the ramconcept or adaptbuilder software. The results of this analysis are compared with the results of the finite element method by sap program. One way slab design how to design one way slab daily civil. Design of slab examples and tutorials by sharifah maszura syed mohsin example 2.
Oneway and twoway slabs oneway slabs transfer the imposed. In case of two way slabs, the moment coefficient tables are applicable to two way slab system where a two way slab is continuous with a two way slab. Hollow blocks made of lightweight concrete or other materials are arranged between the ribs or the voids between ribs. Time saving design aids two way slabs page 1 of 14 the following example illustrates the design methods presented in the article timesaving design aids for reinforced concrete, part 2. One way slabs are those supported continuously on the two opposite sides so that the load sare carried along one direction only. The thickness of slab and depth of rib of waffle slab can be then computed by equalizing the moment of inertia of equivalent flat slab to that of waffle slab. Design of isolated square and rectangular footings aci. Two way slabs have two way bending unlike one way slab. The tensile strength of concrete is neglected in flexural strength calculations aci sec. Distinction of twosystems from oneway systems is given by aci 31814 r8. This course is intended to be an introductory course for structural engineers new to posttensioned. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Here ratio of longer span of slab to the shorter span of slab is greater than 2.
Equivalent frame method most commonly used method the flat slab structure is divided longitudinally and transversely into frames consisting of columns and strips of slabs with. What is the design of a one way slab and a two way slab. The following example illustrates the example building. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Design of rcc rectangular slab s as per is 4562000 1. Chapter 3 design of rectangular beams and oneway slabs 12. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. The direction in which the load is carried in one way slab is called the span. Design of a two way rcc slab structural engineering.
Oneway and twoway slabs university of asia pacific. The nominal shear resistance, vn, for twoway action, shall be determined as. Two way reinforced concrete slab design spreadsheet. Use i wsd, ii usd to design the twoway slab shown below, carrying floor finish 30 psf, random wall 50 psf and live load 60 psf given. Dec 12, 2007 rc slab design ec2 worked example bending reinforcement duration. Slab design reading assignment chapter 9 of text and, chapter of aci31802. Concrete slabs are commonly divided into the following types. In this example, the calculating value of the effective depth d v is equal to the effective depth d minus the concrete cover c on the bottom surface of the slab. The effect of fixing the corners of the slab against lifting 5. Twoway joist concrete slab floor waffle slab system. Analysis and design of one way and two way slab in staad. Sometimes the minimum depth is adequate as per flexure design, but if deflection criteria arent fulfilled such slabs will face vibration even under small loads like walking, jumping, etc. Footings example 1 design of a square spread footing of a.
Oneway ribbed slabs since resistance of concrete in tension is too small compared with that in compression, concrete in the tension zone may be gathered in regularly spaced ribs cast monolithically with topping slab on top of these ribs. Design of one way slabs ce a433 ce a433 rc desginrc design t. 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. This method has been used extensively since 1963 for slabs supported at the. Minimum depth of the one way concrete slab, most of the times is governed by deflection criteria.
One way slab design criteria with design example according to aci code slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Direct design method ddm for slab systems with or without beams loaded only. In the strength design method, the service loads are increased sufficiently by factors in order to obtain the load at which teaching twoway ribbed slab analysis and design using the mathcad program mohammed s. Application of the yield line theory for more complex situations 8. Pdf design calculation design of one way slab slab s1 span. Rectangular beams and one way slabs page 3 of 9 design of rectangular beams and one way slabs continued a. Here the ratio of longer span of slab to the shorter span of slab is less or equals to 2. In this article, i will discuss how to design one way slab with example. For example, the minimum slab thickness for a twohour fire rating is 4. Spring 2007 updated spring 2009 definition a one way slab is simply a very wide bthtbeam that spans between supports design for a 12 width when you solve for a s, you are soli flving for a sft width.
However main reinforcement bar and distribution bar. One way slab being supported on two opposite sides only leads to the structural action in single direction. Assume partitions cannot be damaged by deflections. This 300 mm deep ribbed slab is required for an office to support a variable action of 5 kn m2 it is supported on wide beams that are the same depth as the slab, as shown in figure 3. In sap program, the model has been divided to frame elements to represent ribs and beams and shell elements to represent the slab and solid part. If slab is supported on all four sides and r shorter side longer side london job ref. In case of one ways slabs, the aci approximate analysis is applicable to one way slab system where a one way slab is continuous with a one way slab. Click to share on twitter opens in new window click to share on facebook opens in new window related posts.
Continuous ribbed slabs concrete structures eurocode. When a slab is supported on all four sides and the ratio of long span to short span is equal or greater than two, it will be considered as one way slab. Following are the rcc slab design and detailing guidelines. The load on the slab is carried by the short span in one direction. Slab with reinforcement with yield stress, f y, exceeds 60,000 psi measured at a yield strain of 0.
Calculation reference reinforced concrete design bs8110 concrete slab design created on 17 september 2012 97. 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. For joist depth determination, waffle slabs are considered as flat slab aci. I have developed a microssoft excel software for design of a two way rcc slab. Nov 27, 20 one way slab design criteria with design example according to aci code slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Two way concrete slabs with openings the static system and the design of reinforcement. Generally, there are two types of slab which are one way and two way slabs. Reinforced concrete slab design and detailing guide is456. Beamless slabs beamless slabs are supported only on columns and are applied mostly in large industrial and public buildings. The bottom of the footing is ft below finished grade. One way slabs are such slabs in which the loads are shared only by the shorter direction of the slab. The basic design procedure of a two way slab system has five steps.
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