Acces pdf yield line analysis of slabs method part 3 solved examples on yield line theory. Its value is that it accounts for redistribution of forces that take place after the slabs reinforcement yields. All basic aspects for analysis of two way slabs are there. The work method of analysis 36 practical yield line design 2. Two main methods for yield line analysis of slabs valent. Using the dip and strike angles method of representing the geometry of yield line pattern in terms of the dip and strike angles of the deflected slab segments, the yield line analysis of reinforced concrete slabs had been successfully computerized. If, for a given external load, it is possible to find a distribution of moments that satisfies equilibrium requirements, with the moment not exceeding the yield moment at any location, and if the boundary conditions are satisfied, then the given load is a lower bound of the true. The yield line method of analysis for slabs is an upper bound method, and.
Analysis is based on rotation capacity at the yield line, i. Automatic yieldline analysis of slabs using discontinuity layout. Automatic yieldline analysis of slabs using discontinuity. In general, the design of slab become more simpler because compression. If 2way spanning, there are two linear elastic methods of analysis of slabs. This site is like a library, use search box in the widget to get ebook that you want. Types of slabs, design of slabs and yield line theory. Yield line method of slab analysis department of civil engineering, monash university edition. Yeild line theory for steel plates yeild line theory for steel plates chas10. The provisions of aci 31814 are sufficient for the design of flexural reinforcement for factored loads, and they are often sufficient to satisfy equation 3. As mentioned before, the analysis is conducted based on the collapse load of the slab under consideration. Yield line theory for slab design assumptions, methods of analysis.
The yield line method of analysis johansen 1943 is a longestablished and extremely powerful tool for estimating the maximum load sustainable by a reinforced concrete slab. These methods are based essentially upon elastic theory. Using the dip and strike angles method of representing the geometry of. Yield line method is a plastic method of analysis of slabs. Four examples are to be presented in order to determine the efficiency of using yield line theory.
However, the popularity of applicationspecific yield line analysis tools, for example the cobras reinforced concrete bridge assessment tool developed at the university of cambridge, and which involves automatically searching through a library of possible yield line failure mechanisms, indicates that a systematic yield line method would. The purpose of this research project is to examine the analysis methods such as hillerborgs strip, yield line analysis, equivalent frame method, finite element method and etc. Automated yield line analysis and geometric optimisation are used in the analysis and design of a number of practical reinforced concrete slab configurations. I understand what you mean about making the plate too thin will try and check using fe analysis package in the office. This document is highly rated by students and has been viewed 583 times. Excellent complementary reference for johansen theory. Confirming pages 23 yield line analysis for slabs 23. This method is useful in estimating the ultimate load using collapse mechanisms. Pdf yield line analysis of reinforced concrete slabs with. This site is like a library, use search box in the widget to get ebook that. Load paths, one and two way slabs structural concepts and design duration. A comparison is made between the load paths associated with hillerborgs advanced strip method and several alternative formulations.
Numerical examples module 12 yield line analysis for. Yield line solutions for the collapse load of isotropic and nonisotropic slabs supported on three sides were obtained. Yield line analysis is an analysis approach for determining the ultimate load capacity of reinforced concrete slabs and was pioneered by k. Yield line analysis of slabs bending yield engineering scribd. Yield line design is a wellfounded method of designing reinforced concrete slabs. In the case of twoway slab systems, which are statically indeterminate, detailed inelastic analysis yield line analysis is conducted. One way slab supported by steel beam with shear connectors 3. Most concrete slabs are designed for moments found by the methods described in chapter. According to steve yurek, ceo of the air conditioning, heating and refrigeration institute, the hvacr industry is facing change on all fronts. Automated yield line analysis of orthotropic slabs.
This is a classic book for yield line theory teaching. Click download or read online button to get examples of slab design by the yield line theory book now. Yield line design has the advantages of economy, simplicity and versatility, yield line design leads to slabs that are quick and easy to design, and are quick and easy to construct. Structural engineers, before the development of ultimate load analysis, designed reinforced concrete slabs using elastic plate theory. One way slab with cold form steel decking as form and reinforcement 4. The yieldline method of analysis provides a powerful means of identifying the ultimate load carrying capacity of reinforced concrete slabs. I would like to use the yield line theory to check the plate thickness to get a bit more economy.
Yield line analysis method deal with common slab configurations, such as oneway spans of varying support conditions or twoway spans that usually consist of a rectangular slab supported along two or more edges and slabs with openings. The theory focuses attention on the moment capacity of the slab. Yield line analysis for slabs 5 two axes of rotation, which is also common to the two planes. It is closely related to the plastic collapse or limit analysis of steel frames, and is an upper bound or mechanism approach. That account for the actual inelastic behavior of member at the factored load stage. Structural engineers, before the development of ultimate load analysis, designed reinforced concrete slabs. Abstract the yield line technique is the traditional method of determining the flexural collapse load of reinforced concrete flat slabs.
Examples of slabs with openings under various boundary conditions and loading patterns are presented to illustrate the applicability, efficiency. The method can reveal hidden reserves of strength in existing slabs and can lead to highly economic slabs when used in design. It uses yield line theory to investigate failure mechanisms at the ultimate limit state. In this paper two methods are proposed that, without invalidating previous ones. Yield line analysis for slabs most concrete slabs are designed for moments found by the methods based essentially upon elastic theory. Mar 18, 2020 numerical examples module 12 yield line analysis for slabs lesson 33 notes edurev is made by best teachers of.
Benefits of the yieldline method are that it will often identify additional reserves of strength when applied to the analysis of existing slabs, and to highly economic slabs when used in design. Analysis of twoway slabs using yield line theory by. However, the popularity of applicationspecific yieldline analysis tools, for example the cobras reinforced concrete bridge. For two of the chosen configurations comparisons between experimental and. For the overloaded slab, the resisting moment per unit length measured along a yield line is constant as inelastic rotation occurs. The yield line method provides a powerful means of rapidly estimating the ultimate load that can be carried by a reinforced concrete slab. Chapter 1 yield line analysis for slabs lower bound theorem.
Yield line analysis of reinforced concrete slabs with. It is a robust and proven design technique that challenges designers to use judgement. Answers are needed, for example, for round or triangular slabs, slabs with large. To investigate the ultimate load of a rectangular slab supported by four fixed edges. Yield line analysis of slabs supported on three sides. At each region of the yield mechanism of a slab, internal forces acting at yield lines must balance loads and reactions. Automatic yieldline analysis of practical slab configurations via. Yield line analysis of slabs download ebook pdf, epub. Yield line is a crack in a reinforced concrete slab over that the reinforcing bars when it. Design of concrete flat slabs to resist flexureinduced. There is a controversy about whether the classical yield lines analysis methods are in fact different methods or simply different ways to develop basically the same method. Example yieldline pattern for a rectangular slab with simple. Types of slabs, design of slabs and yield line theory different floor and roof slab types.
Click download or read online button to get yield line analysis of slabs book now. To apply the method successfully, traditionally users have had to know something about the rules governing the construction of viable yield line patterns, though these rules can be memorized, and for simple problems a hand. The paper uses yield line theory to derive equations and charts suitable for the limit design of uniformly loaded rectangular reinforced concrete slabs with rectangular openings. Yield line theory for slab design assumptions, methods. Internal forces must be in equilibrium at each side of a yield line.
The introduction to the concept of nodal foces is very good. One way slab supported by monolithic concrete beam 2. This formulation is shown to be both effective and efficient for the yield line analysis of a number of example slabs which include a range of support conditions and boundary geometries. A yield line analysis uses rigid plastic theory to compute the failure loads corresponding to given plastic moment resistance in various parts of the slab. However, because the tool relies on the use of an inbuilt library of predefined yield line. The terms positive yield line and negative yield line. Introduction the yield line method is a simple and efficient method to calculate the plastic collapse load of flat, relatively thin, plates of rigidperfectly plastic material when transversely loaded in bending. The value of vflex is determined by yield line analysis. Pdf yield line analysis of reinforced concrete slabs.
Slab is the only commercially available software to systematically automate the wellknown yield line analysis method for concrete slabs, allowing the ultimate load capacity and critical failure mechanism to be calculated in seconds. This can be done by fol lowing two equilibrium conditions. A yield line method is an upper bound method whereas the strip method is lower bound method. Twoway slab using the work method precise yield pattern reanalyse example 2a using the dimensioned layout of yield lines determined in example 3d by using formulae for this same slab. Chapter 1 9 yield line analysis of slabs 1 nust studocu. What it is the yield line method is a method for the design or assessment of concrete slabs. That is, the yield line or yield line extended must pass through the point of intersection of the axes of rotation of the two adjacent slab segments. On the other hand, reinforcement for slabs is calculated by strength methods that account for the actual inelastic behavior of members at the factored load stage. This paper introduces the yield line method of analysis of twoway slabs. The ratios of the corresponding lengths of the sides of the opening and the slab.
Yield line analysis of slabs the theory presented in this chapter extends the ultimate load analysis of structures, begun in chapter 18 for beams and frames, to reinforced concrete slabs. On the other hand, reinforcement for slabs is calculated by strength methods. Yieldline analysis of two way reinforced concrete slabs. Oral buyukozturk outline 11 limitations on yield line theory. For slabs, the corresponding mechanism is the yield line. The yield line analysis of slab methodology is going to be clarified as flows. This project presents the yield line analysis which can be used to analyze and design different shapes of slabs.
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