Twoway slabs have two way bending unlike oneway slab. Preliminary design of slab thickness thickness design depends on boundary conditions supports. If none of the values satisfies, you need to change d. Chapter 3 design of rectangular beams and oneway slabs. The two classifications are oneway slab and twoway slab. Two way slabs are normally supported from four sides. 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. Here are the steps for the design procedure for one way slab in steps. Using udls simplifies the analysis and remains popular. The ratio of the total costs was found to be within the range 1.
Twoway concrete floor slab with beams design and detailing design the slab system shown in figure 1 for an intermediate floor where the story height 12 ft, column crosssectional dimensions 18 in. Beams of width and depth are provided on all column lines. Teaching twoway ribbed slab analysis and design using the. Load transfer in a oneway slab, b twoway slab nilson fig. For those who do not know what are the des ign requirements of a slab. Design procedure steps for one way slab slab design steps. There are various established methods for analysing ribbed slabs and dealing with the solid areas. Two way slab design by direct design method as per aci 31811.
Analysis and design of slabs one way civil engineers pk. If slab is supported on all four sides and r shorter side longer side procedure for a uniformly loaded oneway reinforced slab can be divided in the following steps. The pca computer program pcaslab can be used to expedite the design of different slab systems. Oneway slab twoway slab flat plate flat slab grid or waffle slab 7. The ratio lb which is less than 2 is known as two way slab. 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. 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. Rectangular and circular columns, and also columns with any general shape. Design of an oneway reinforced concrete slab with rcsolver software program according to eurocode 2 specifications. Oneway spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement.
Panak and hudson matlock, includes a procedure for analysis of twoway bridge floor slabs continuous over many supports. Bending will take place in the two directions in a dishlike form. Accordingly, main reinforcement is required in the two directions. 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. An optimal plan geometry with all same supports is a square, based on load distribution into both directions. The use of this method was restricted to structures with dimensions similar to those from which it was developed. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. 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. Design of beam and slab sections for flexure, shear and torsion. Is there a design procedure for compression reinforcement. Aci design factors for calculating shear and moment in slab limitation. 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. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. A one way slab is simply a very wide beam that spans between supports.
Difference between one way slab and two way slab simple. Chapter 3 design of rectangular beams and oneway slabs 12 h a 12 strip in a simply supported one way sl ab. In twoway slabs shorter direction strip carry greater %age of load. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan.
Technical note 2 parabolic stressstrain curve with the maximum stress at fc and maximum strain at 0. Design of reinforced concrete structures ii twoway slabs 1 1. A six storey building for a commercial complex has plan dimensions as shown in figure 1. Oneway slab design spreadsheet civil engineering downloads. Analysis and design of slabs two way civil engineers pk. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in. Distribute moments transverse at critical sections to. Oneway slab design spreadsheet civil engineering community. Civilax is the knowledge base covering all disciplines in civil engineering. When slab is supported at all sides and lengthwidth 2 of a slab panel. More detailed advice on determining design li fe,actions, material properties, methods of analysi s.
Twoway flat plate concrete floor system analysis and design. Download code oneway slab design procedures and design. Design of reinforced concrete structures ii twoway slabs. Continuous ribbed slabs concrete structures eurocode. These are the direct design method presented in chap. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. Types of one way slab one way slab may be solid hollow ribbed 6. One way slab is normally designed for gravity load only.
A discreteelement method of multipleloading analysis for. When slab is supported on two opposite sides only, total load is carried along the perpendicular direction of supporting beams. 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. Distinction of twosystems from oneway systems is given by aci 31814 r8. The program covers wide range of twoway slab systems and can be used for more complex slab layouts. The prokon suite includes a series of modules for designing concrete elements. After a large number of reinforced concrete slab structures had been built and loadtested, an empirical method of determining moments was developed.
One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. Thanks for a2a the slabs having ratio of longer length to its shorter length lylx greater than 2 is called one way slab otherwise as two way slab. The output of the program for the slab in the example is shown in the following pages. Oneway and twoway slabs university of asia pacific. The building is located in seismic zone iii on a site with medium soil. Master of science and hereby certify that, in their opinion, it is worthy of acceptance. Design procedure the basic design procedure of a twoway slab system has five steps. Model and analysis files 8 about us civilax based to server in civil engineering provides etabs and sap2000 tutorials, civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads.
The following example illustrates the example building. Flexural analysis of oneway concrete slabs r einforced with t. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. In one way slab main reinforcement is parallel to shorter direction and the reinforcement paralle. Reference 5 focused on analysis of twoway ribbed slabs with. Analysis of two way ribbed and waffle slabs with hidden beams. Use it as you see fit, but please note that there is no technical support available to answer any questions about. I have developed a microssoft excel software for design of a two way rcc slab.
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. Bridge approach slab analysis and design incorporating elastic soil support presented by. This student guide is intended as just that a guide for students of civil engineering. Generally, there are two types of slab which are one way and two way slabs. User is given the option to override the code value. In the table 1 sb is the tested slab identification, d is the effective depth of the sections. Design of a two way rcc slab structural engineering. Modulus of elasticity of concrete is automatically calculated and displayed by the program using fc, wc, and the following relationship 3 of the code.