Analysis and design of slabs one way civil engineers pk. That is, the load factor at which the uls moment equals the moment capacity. 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. In case of slabs thin members, no need of even minimum shear reinforcement. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Reinforced concrete design 1 design of slab examples and. The width of a oneway slab does not influence the shear capacity of the slab sherwood et al. 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. If slab is supported on all four sides and r shorter side longer side problems pdc tr0803 september 2008 1 1. Oneway concrete slab design problem hi, can somebody please explain why is in area 497 mm2 shown 12 120 cc its 942 mm2 total thanks for answers.
Design of reinforced concrete structures ii two way slabs 1 1. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. Following are the rcc slab design and detailing guidelines. Bending will take place in the two directions in a dishlike form. Design of one way and two way slabs, design of staircases. Assume partitions cannot be damaged by deflections. 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. Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for one way and two way slabs as per is 456. Design of concrete structures 14th edition, 2009, by arthur h. Design of one way slabs the structural action of a one way slab may be visualized in terms of the deformed shape of the loaded surface. One way slab here i solve a probleam based on the one way slab, the diamentions are provided in the probleam 1st determine the aspect ration and with respect to the aspect ratio the type of slab. The program is divided into three separate screens, which correspond to the three major areas of concern in the design of a posttensioned member. It was actually the widespread use of the posttensioned slabonground which induced this interest in design procedure and in many studies of reported slab failures.
Design of reinforced concrete structures ii twoway slabs. If slab is supported on all four sides and r shorter side longer side one way slab. The slab has to carry a distributed permanent action of 1. The distribution of floor loads on floor beams is based on the geometric configuration of the beams forming the grid. In any span, the max cable sag, zd depends on the concrete cover requirements and the tendon dimensions. Reinforced concrete design 1 design of slab examples. One way slab is supported on two opposite side only thus structural action is only at one direction. The bottom of the footing is ft below finished grade. Example design of two way edgesupported solid slab. Posttensioned concrete design spreadsheet program a pdh.
The dimensions of an interior bay are shown in figure 1. Oneway and two way slabs one way slabs transfer the imposed loads in one direction only. Design of slab examples and tutorials by sharifah maszura syed mohsin. The two classifications are oneway slab and twoway slab.
Accordingly, main reinforcement is required in the two directions. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Flat slab analysis, design and detailing pdf civil engineering. Oneway concrete slab design problem autodesk community. In two way slabs shorter direction strip carry greater %age of load. Sep 04, 2014 10 design of oneway solid slabs reinforcement, 2. The ratio of longer span l to shorter span b is equal or greater than 2, considered as one way slab because this slab will bend in one direction i. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. The basic design procedure of a two way slab system has five steps.
Explain one way distribution and compare the results with area load. Footings example 1design 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. Moduleiii design of short and long columns with axial and eccentric loading, design of isolated column footing. Slab is checked for deflection shear and development length. A slab strip of unit width is analysed using simple beam theory. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3. Analysis and design of slabs two way civil engineers pk. Chapter 3 design of rectangular beams and oneway slabs 12. 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. 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.
Pdf slabs are the flooring systems of most structures including office. Here are the steps for the design procedure for one way slab in steps. Tributary areas many floor systems consist of a reinforced concrete slab supported on a rectangular grid of beams. Beams of width and depth are provided on all column lines. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Numerical problem of design of singly reinforced beam. Once design compressive strength of concrete and yield stress of reinforcement are specified, the next steps are. Load transfer in a one way slab, b two way slab nilson fig. Ce 433, summer 20 slab design example 1 5 design a one. Minimum thickness of oneway ribbed slabs summary of oneway ribbed slab design procedure. Distribute moments transverse at critical sections to column and middlestrip and if. Types of one way slab one way slab may be solid hollow ribbed 6.
Oneway and twoway slabs oneway slabs transfer the imposed. Oneway slabs normally design as a beam with cables running in the direction of the span at uniform centres. Shear due to loads always must be less than the shear strength of concrete. Example problems for sbeds singledegreeoffreedom blast. 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. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown.
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. These values are applicable for normal loading conditions and for slabs not supporting or attached to partitions or other construction likely to be. Slabs are usually used in floor and roof construction. Designing of slabs depends upon whether it is a oneway or a two way. Total load is carried in the direction perpendicular to the supporting beam. Load transfer in a oneway slab, b twoway slab nilson fig. Figure 1 shows a rectangular slab, simply supported along its two opposite long edges and free of any support along the two opposite short edges. Cornell university, david darwin university of kansas, charles dolan university of wyoming 3. They may be supported on two opposite sides only fig. Pdf reinforced concrete form principal construction material in the. Footings example 1 design of a square spread footing of a. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. To see their result for this slab we will find the load factor. The two classifications are oneway slab and two way slab.
D mm d 105 mm loads on slab self weight of slab 3. Design of one way slabs as per is 456 worked step by step. The program covers wide range of two way slab systems and can be used for more complex slab layouts. Twoway slabs for ml l l s concrete slab structures january 2019 183 18. The following example illustrates the example building. Slabs having supports on less than four sides can be designed as one way. Assign the loads on a structure and compare the results with the manual calculation. One way slab being supported on two opposite sides only leads to the structural action in single direction. Pdf design calculation design of one way slab slab s1. A combination of these values will determine the slab stresses at the time of stressing and at service loads.
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. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4. You should look at the bar diameter and spacing in the table displayed next to the graphical viewer or at fi16 400 mm on the description of the reinforcement bar in this zone instead as this is the actual area of the provided reinforcement. The output of the program for the slab in the example is shown in the following pages. Pdf design calculation design of one way slab slab s1 span. The design procedure for a uniformly loaded one way reinforced slab can be divided in the following steps. If a slab is supported on all the four sides but the ratio of longer span l to shorten span b is greater than 2, then the slab will be considered as one way slab. Explain the range in x, y and z directions and group. Rectangular beams and one way slabs page 3 of 9 design of rectangular beams and one way slabs continued a. One way slabs are such slabs in which the loads are shared only by the shorter direction of the slab.
The recommendations derived from these and other studies vary from extremely light to extremely heavy. Two way slab design by direct design method as per aci 31811. Here ratio of longer span of slab to the shorter span of slab is greater than 2. A reinforced concrete slab is built integrally with its supports and consists of equal span of 15 ft. Flat slab haunched slab a longitudinal slab is one of the least complex types of bridge superstructures. Oneway simply supported slab analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. Chapter 3 design of rectangular beams and oneway slabs. Rectangular beams and oneway slabs page 3 of 9 design of rectangular beams and oneway slabs continued a. 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. Nov 15, 2014 one way slab here i solve a probleam based on the one way slab, the diamentions are provided in the probleam 1st determine the aspect ration and with respect to the aspect ratio the type of slab. For those who do not know what are the des ign requirements of a slab.
Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. This spreadsheet program provides for the design and analysis of posttensioned concrete one way beam and slab systems and two way flat plate slab systems. Both vertical and horizontal loads may be transferred from one member to another properly if the beams and slabs are designed succesfully. Pdf oneway shear strength of thick slabs and wide beams. One way slab here i solve a probleam based on the one way slab, the diamentions are provided in the probleam 1st determine the aspect. Introduction sbeds single degree of freedom blast effects design spreadsheet is an excel workbook. May 02, 2017 one way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. Plan view of floor system assume partitions will not be damaged by deflections. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types.
Two way slabs have two way bending unlike one way slab. Pdf numerical analysis of oneway rc slabs subjected to air. Apr 27, 2017 2 even when a rectangular slab is supported on all the four edges, the slab may be considered as a one way slab if the lengthtobreadth lb ratio of the slab is equal to or greater than two. Design procedure steps for one way slab slab design steps. Nov 01, 2018 sbeds example problems pdc tr0803 september 2008 1 1. Ultimate behavior of oneway spanning slab linear elastic analysis methods such as moment distribution are linear elastic methods. This pdf file contains a chapter of 23 pages with various aspects of flat slabs including four example of flat slab design. Reinforced concrete slab design and detailing guide is456.
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