Load transfer in a oneway slab, b twoway slab nilson fig. The program covers wide range of twoway slab systems and can be used for more complex slab layouts. Analysis and design of slabs two way civil engineers pk. All available load test results indicated that the flat plate or flat slab was a most efficient design with an adequate safety factor. 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. Slabs are primarily categorized as either one way or two ways. If slab is supported on all four sides and r shorter side longer side pdf available april 2009 with 10,441 reads how we measure reads. Cornell university, david darwin university of kansas, charles dolan university of wyoming 3.
One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. Coefficients, for a variety of load types, with a variety of boundary conditions are tabulated and you also have the theory and derivations with a l. Dissatisfaction with results of previously required procedures of analysis and design for twoway slabbeam systems was the original reason for the massive research upon twoway slab systems begun about 1955. Generally, there are two types of slab which are one way and two way slabs. The most common method is the aci direct design method. Twoway slab analysis and design using equivalent frame method efm aci 318 states that a slab system shall be designed by any procedure satisfying equilibrium and geometric. In this video deisgn of two way slabs has been covered using is 456. Previous article one way slab design spreadsheets to eurocode 2 en 19921. Analysis of slabs spanning in two directions under.
The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Oneway and twoway slabs oneway slabs transfer the imposed. Difference between one way slab and two way slab simple. Coefficient method journal of the civil engineering division, the institution of engineers, ba ngladesh, vol. Design of twoway slab by coefficient method the constructor. This method depends on determining the moments in the frames using coefficients.
Following are the rcc slab design and detailing guidelines. Chapter 3 design of rectangular beams and oneway slabs. Reinforced concrete slab design and detailing guide is456. The accuracy of these methods depends on the assumptions that are stated in the method procedure. The following example illustrates the example building. Strength design or ultimatestrength design usd strength design or ultimatestrength design usd with strength design method, the working dead load dl and live load ll are. The coefficient method is a method of designing twoway slabs that are supported by edge beams. Okay, i know it is based on upper bound thorem and the solution might be unsafe. Twoway slab design using the coefficient method free download as pdf file. Civilax is the knowledge base covering all disciplines in civil engineering. Recommendations use method 2 or method 3 generally. Twoway flat plate concrete floor system analysis and design the concrete floor slab system shown below is for an intermediate floor to be designed considering partition weight 20 psf, and unfactored live load 40 psf.
In which code book are the bending moment coefficients for. However, plastic method can be the best method for designing such cases of twoway slabs. Click to share on twitter opens in new window click to share on facebook opens in new window related posts. Two way slabs are normally supported from four sides. Twoway slab design coefficient method tables architectural. In the sixties and seventies, i used the the text book theory of plates and shells by timoshenko. Allowable stress design or working stress design wsd 2. Direct design method alias ddm as well as coefficient method are used to design the slabs. The pca computer program pcaslab can be used to expedite the design of different slab systems. Two way reinforced concrete slab design spreadsheet. A discreteelement method of multipleloading analysis for twoway bridge floor slabs by john j. Introduction concrete slabs on grade are a very common type of concrete construction. Then, the frame moments are distributed to the beam and the slab using tables.
Shear strength of beamless slabs usually a controlling factor. Please read the lauses mentioned in the video while solving the problem. Two way slab design by direct design method as per aci 31811. 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.
Twoway slab design using the coefficient method beam. Twoway slab analysis and design using elastic frame method. Design of two way slabs is 456 limit state method youtube. Direct design method ddm for slab systems with or without beams loaded only. Oneway and twoway slabs university of asia pacific. Design of concrete structures 14th edition, 2009, by arthur h. Two way slab design spreadsheet working stress design.
No certain method can be found in the design codes or references for designing twoway slabs subjected to concentrated loads. The construction and design of concrete slabs on grade d. Oneway slab design spreadsheet civil engineering community. But, with proper application and enough safety factor yield line method. 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. Flat plate concrete floor system does not use beams between columns or. A discreteelement method of multipleloading analysis for. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3.
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. Accordingly, main reinforcement is required in the two directions. Panak hudson matlock research report number 56 development of methods for computer simulation of beamcolumns and gridbeam and slab systems research project 356356 conducted for the texas highway department. Bending will take place in the two directions in a dishlike form. Pdf deflection estimation of twoway edgesupported slabs. Method 2 gives a better rep resentation of internal forces in a slab panel than method i.
Design of two way slab moment coefficient method bnbc 1993. Mention the parameters governing slab moment coefficients and explain their effects on moment. 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. The ratio lb which is less than 2 is known as two way slab. Two way slab design spreadsheet working stress design coefficient method. Best is subjective, so i will give my opinion here. Floor slabs can range from a simple residential basement slab to a heavyduty industrial floor. In twoway slabs shorter direction strip carry greater %age of load. If the proportion of longer dimension of the slab panel to the shorter dimension is more than or equivalent to 2 then it is defined as one way slab. Asce, secb course content slab on grades construction. The procedure of the design of twoway slabs will have all the six steps mentioned in sec. Two way reinforced concrete slab design spreadsheet working stress design coefficient method download spreadsheet.
Design of reinforced concrete structures ii twoway slabs 1 1. The effective beam and slab sections for the computation of stiffness ratio. Rectangular beams and oneway slabs page 2 of 9 two methods. Method 2 yieldlines may be successfully used for uniformly loaded slab panels with different boundary conditions. This method requires various formulas for different conditions of rc slab. As presented by egyptian code for design and construction of concrete structures eccs 2032007, the analysis of this problem can be.
These are the direct design method presented in chap. Types of one way slab one way slab may be solid hollow ribbed 6. Analysis and design of slabs one way civil engineers pk. The analysis of rectangular twoway slabs subjected to concentrated load uniformly distributed over defined area after dispersion down in the two directions to the reinforcement is a practically important case. Plan view of floor system assume partitions will not be damaged by deflections. Twoway slab design coefficient method tables free download as pdf file. Twoway slabs have two way bending unlike oneway slab. Two way slab design spreadsheets to eurocode 2 en 19921. However, it should be known that the coefficient method is still applied for two way slabs. Design of two way slab by usd method and wsd method slab 1 case 2 slab dimension short span,a 20 long span,b 22 m ab 0. Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter.
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