Design and study on behaviour of skew slab bridges with. High crack width in solid slab indicated lower shear strength. Yieldline plasticity and tensile membrane action in. The theory focuses attention on the moment capacity of the slab.
As mentioned before, the analysis is conducted based on the collapse load of the slab under consideration. Feb 19, 2017 what it is the yield line method is a method for the design or assessment of concrete slabs. The application of yield line theory to the ultimate load design of reinforced concrete skew slabs is considered in some detail. An introduction to the practical use of yield line theory in the design of economic reinforced concrete slabs, including examples of design of flat slabs. In this paper two methods are proposed that, without invalidating previous ones, really correspond to the two different ways of performing yield line analysis and therefore facilitate a better comprehension of the general. Evaluating the collapse load of the slab using the yield line method 3. Design criteria for right and skew slabandgirder bridges. Jul 01, 20 chapter 1 yield line analysis for slabs. Generalised collapse analysis of concrete bridges university of. 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.
With the advent of ultimate load methods, yield line analysis of slabs gained popularity and was considered as. Yield line method applied to slabs with different supports. With the advent of ultimate load methods, yield line analysis of slabs gained popularity and was considered as an accepted method for predicting the ultimate load. In this paper two methods are proposed that, without invalidating previous ones. One way slab supported by monolithic concrete beam 2. Yield line analysis of reinforced concrete skew slab. Abatraeta numerical method based on the virtual work approach of the yield line theory is presented. Pdf reinforced concrete skew slabs with different boundary conditions have been analysed using yield line theory. To investigate the ultimate load of a rectangular slab supported by four fixed edges. Following methods could be adopted for analysis of skew slab, as they are. The method presented here, yield line theory, was developed in the early 1960s by the danish engineer, k. Structural concrete discusses the design and analysis of reinforced and prestressed concrete structural components and structures. Elastic and ultimate behaviour of skew composite slabon.
Yield line design is a wellfounded method of designing reinforced concrete slabs. A detailed study on variation of bending moments in simply supported skew slab bridges with various skew angles is given in this project using structural analysis software staad pro, and analysis is as per provisions of indian codes irc 6. Yield line design demands familiarity with failure patterns, i. Bridge slabs with parallel and nonparallel abutments are investigated and the theoretical development is accompanied by the results of a series of experiments on model.
The same goes for yield lines in the xdirection opposed by the y m capacity of the slab. Ebook the analysis of slabs by the yield line theory as. A literature study indicates that there is no information available that tells a designer exactly how to. Yield line analysis of reinforced concrete skew slabs under. The design based on elastic theory could not indicate a true margin of safety against failure and hence necessity of predicting the ultimate load was felt. Gamble research on skew slab andgirder bridges has had limited impact on practical bridge design. Moreover, the analysis through yield line theory was utilized to yield different general formulae to predict the failure load of skew composite bridges. Skew slabs are the requirement of the present situation to satisfy the architectural need, optimum utilisation of.
October 2010, italy elias yusuf ali politecnico di milano. The yield line theory for the determination of the ultimate load for slab structures is a well documented method of analysis. Oral buyukozturk outline 11 limitations on yield line theory. A comparative study of shear design methods for straight. Practical yield line design 4 yield line design is a robust and proven design technique. Furthermore, rather than initially considering the yield line analysis problem directly, as most others have done with only limited success, the procedure described in this paper was developed following a conjecture that there existed a direct analogy between the layout of bars in optimum trusses and the layout of yield lines in slabs, since. Two main methods for yield line analysis of slabs valentn quintas1 abstract. The variables among the specimens were the direction and. This crack formation is seen in under reinforced concrete slabs and the yield line theory considers only under reinforced concrete slabs. Loaddeflection behaviour of simply supported rc skew slabs upto cracking load the load deflection behaviour of the reinforced concrete slab can be calculated using elastic skew plate theory.
The method can reveal hidden reserves of strength in existing slabs and can lead to highly economic slabs when used in design. Load deflection behaviour of restrained rc skew slabs using. 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. Two main methods for yield line analysis of slabs valent. Yield line analysis slabs yield line analysis slabs the following are the assumptions of the yield line analysis of reinforced concrete slabs. For the love of physics walter lewin may 16, 2011 duration. The results obtained by using fem technique software tool ansys are compared with experimental and theoretical results.
Cope 4 used this approach to examine a skew reinforced concrete bridge. A skew angle of 15o, 30o and 45o are used to study the behavior of slabs. Reinforced concrete skew slabs are widely used in bridge construction when the. It uses yield line theory to investigate failure mechanisms at the ultimate limit state. Column grids on skew but parallel lines can be regarded as a first step away from rectangular layouts towards truly irregular layouts. Load deflection behaviour of restrained rc skew slabs. In the design of the models, the average shear stress direct design of reinforced concrete skew slabs table 1. Yieldline theory and limit analysis of plates and slabs. Only shortspan bridges are consid ered for the reason discussed later. It may be applied to many types of slab, both with and without beams.
The yield line method provides a powerful means of rapidly estimating the ultimate load that can be carried by a reinforced concrete slab. In fact, work has been carried out athe cement and concrete association on this problem with particular reference to slab bridges. Theory of plasticity and limit design of plates, volume 18. These methods are the nearly abandoned normal moment method and a new skew moment method. Automatic yieldline analysis of slabs using discontinuity. Pdf using yield line theory for interior panels of slabs. It is also possible to use the yield line analysis for slabs with nonuniform reinforcement distribution, though it may be more difficult 3. The slab thicknesses and girder properties used cover the practical ranges for this type of bridge. A simplified method for designing rc slabs under concentrated.
Pdf a study on reinforced concrete skew slab behavior ahsanul. Redwood department of civil engineering and applied mechanics, mcgill university, montreal, quebec, canada h3a 2k6 received 11 august 1986 abatraeta numerical method based on the virtual work approach of the yield line theory is presented. At the collapse stage, the steel reinforcement will be fully yielded along the yield lines. Oral buyukozturk outline 11 oneway slabs twoway slabs l1 1 2 2 l l l2 yield line analysis. And also for all eighteen simply supported reinforced concrete skew slabs a theoretical yield line analysis has done. Yield line theory principle mechanism characteristics assumptions here we provide you all theory related part of yield line theory with diagram. Experimental investigation of simply supported skew slabs. Yield line theory, rankine grashoff theory, waffle slabs, crack width. This site is like a library, use search box in the widget to get ebook that you want. This site is like a library, use search box in the widget to get ebook that. The yieldline method of analysis provides a powerful means of identifying the ultimate load.
A comparative study of shear design methods for straight and. Studies in the yield line theory of concrete slabs which have largely avoided the question of the distribution of the support reaction were addressed by johnarry 1. Correspondence on yield line analysis of reinforced concrete. Using yield line theory, determine the collapse load q. It is closely related to the plastic collapse or limit analysis of steel frames, and is an upper bound or mechanism approach. A yield line method is an upper bound method whereas the strip method is lower bound. Detailed descriptions are given on the plastic behaviour of homogeneous, reinforced and sandwich plates, and on the rise of various yield line patterns. A great deal of researchers 2,3,4,5and 6 has worked extensively on johansen discovery with the aim of tying the yield line theory with more classical. Types of slabs, design of slabs and yield line theory. Limitanalysis of rc slabs exposed to standard fires. Slab is the only commercially available software to systematically automate the wellknown yieldline analysis method for concrete slabs, allowing the ultimate load capacity and critical failure mechanism to be calculated in seconds.
It is a versatile tool that challenges designers to use judgement. The yield line and rankine grashoff theories have facilitated the accurate analysis of precast waffle slabs by separating the slab and rib portions. There are rules to be observed when postulating a yield line pattern. There are two approaches to the calculation of the ultimate loadcarrying capacity of a reinforced con crete slab involving yield line theory. The yield line theory for concrete slabs by peikao hsueh b. This generalization of yield line analysis allows defining new equilibrium conditions not included in classical yield lines theory and permits obtaining more accurate solutions. Pdf yield line analysis of reinforced concrete skew slab.
Yield line analysis of reinforced concrete skew slabs. Modified tjs method for yield line analysis and design of slabs. The ultimate load of the slab system is estimated by postulating a collapse mechanism which is compatible with the. With a view to application in highway bridge design, the ha and hb load systems are considered.
Yield line theory is used effectively in the design and assessment of slabs in bridges. One way slab with cold form steel decking as form and reinforcement 4. 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. In models l and 2, point loads on the slab were achieved by using a system of simply supported spreader beams to dis tribute a single concentrated load. Analysis is based on rotation capacity at the yield line, i. Yield line design has the advantages of economy, simplicity and versatility. To encourage the use of yield line theory, this paper provides experimental evidence on yield line patterns for flat slabs supported on a parallelogram layout. Each of the eight chapters of the book tackles a specific area of concern in structural concrete.
The text first deals with the serviceability and safety, and then proceeds to the properties of materials and mix. Clark correspondence on yield line analysis of reinforced concrete skew slabs under highway bridge loading. Skewed yield lines generally slab reinforcement is placed orthogonally, that is. Click download or read online button to get examples of slab design by the yield line theory book now. Direct design of reinforced concrete skew slabs 481 was negligible and therefore in the rest of the models, the corners were not held down.
Several established methods are available to analyse the flexural behaviour of slabs, traditionally applying either the upper or lower bound analysis from the theory of plasticity, such as those based on the yield line theory, or the strip method. Yield line analysis of slabs download ebook pdf, epub. Yield line theory can also be applied to slabs resting on soil, i. In this process, the original pdf page is inserted into a new blank pdf page. Yield line method is a plastic method of analysis of slabs. With increment in the skew edge, the stresses in the. In the case of skew slabs there is the possibility of shear failure at the obtuse comer because of the concentration of vertical reaction in that region. This project presents the yield line analysis which can be used to analyze and design different shapes of slabs.
Types of slabs, design of slabs and yield line theory different floor and roof slab types. The yield line theory is found useful for slab with. Direct design of reinforced concrete skew slabs sciencedirect. The common yield surfaces of metal plates are compared with the upper yield surface, and the yield surface of the arbitrarily reinforced concrete slab is derived. Reinforced concrete skew slabs with different boundary conditions have been analysed using yield line theory. Yield liens divide the slab into rigid regions which remain plane through the collapse. Design criteria for right and skew slab andgirder bridges hendrik j. In the section of the paper headed serviceability limitstate the authors state that further attention should be given to the problem of cracking in skew slabs where the cracks do not necessarily form perpendicular to the reinforcement. Yield line theory for slab design assumptions, methods. Yield line design is a wellfounded method of designing reinforced concrete slabs, and similar types of elements. One way slab supported by steel beam with shear connectors 3. Finally, the relationship between yield line theory and limit analysis is discussed, and it is concluded that the two theories are consistent in their foundation.
Axes of rotation generally lie along lines of support and pass over any columns. Yield line pattern for concentrated load in the case of existence of a concentrated load, the schem a. Pdfill pdf deskew provides a quick way to correct the skew in the scanned images from acrobat pdf documents. Yield line theory for slab design assumptions, methods of. Once grasped yield line design is an exceedingly powerful design tool. However, because the tool relies on the use of an inbuilt library of predefined yield line. During the collapse, the slab is deformed plastically and they gets separated into segments. Click download or read online button to get yield line analysis of slabs book now. The investigation and configuration of skew slab is very confounded than those for a right slab.
In this paper, it is tried to show the application of the yield line method how powerful and easy for design and analysis, by considering the different fire conditions on the slab. Yield linestypical crack patterns generated when ultimate moment is reached characteristics of yield lines are, i yield lines are straight. It is a robust and proven design technique that challenges designers to use judgement. The yield line method of analysis for slabs is an upper bound method, and. Chapter 1 9 yield line analysis of slabs 1 nust studocu. In the case of twoway slab systems, which are statically indeterminate, detailed inelastic analysis yield line analysis is conducted. In order to simplify yield analysis johansen, by means of his. Correspondence on yield line analysis of reinforced. The method consists of computing the yield load of a plate based on the geometry of an assumed collapse. Using yield line theory for interior panels of slabs. Pdf two main methods for yield line analysis of slabs.
The analysis of slabs by the yield line theory top results of your surfing the analysis of slabs by the yield line theory start download portable document format pdf and ebooks electronic books free online rating news 20162017 is books that can provide inspiration, insight, knowledge to the reader. The yieldline method of analysis provides a powerful means of identifying the ultimate load carrying capacity of reinforced concrete slabs. The nonlinear finite element analysis was also used to conduct a parametric study and to evaluate the ultimateload capacity of skew bridges. The theory can be used to analyse slabs with beams.