Flat Slab Punching Shear Design


















































they require more steel compared to two-way slabs. The use of. I need to apply stricter deflection limits on the Live loads as they can damage my cladding and façade but I also. The critical element of this system is the slab to column connection because of the concentration of the punching shear stress. Punching shear checks are critical. 2 Flexural Design of Flat Slab 2. Without Beams, Flat Plates and Flat Slabs Tests of flat plate structures indicate that in most practical cases, the capacity is governed by shear. 3-14, Design of Concrete Structures, and recommendations of ACI 421. Fracture Analysis of Punching Shear in Flat Slab with Conventional Punching Shear Reinforcement and Steel Fiber using FEA Software - written by Mahesh Bariya , Krishna Nair published on 2019/09/18 download full article with reference data and citations. This paper describes an experimental study of the punching resistance of unbonded post-tensioned slabs with shear reinforcement. The floor system consists of six panels in each direction. punching shear. Flat slab, Punching shear. The design values of the punching shear for the slabs with openings were obtained according to EC 2. Punching shear reinforcement system such as truss, studs and stirrups are used for the analysis. A major difference between the shear stud behavior in the proposed system and in composite beams is that in the proposed system, the amount of concrete available to resist punching shear is limited due to the small depth of the flat concrete slab. • Punching shear is a type of two-way shear, often found in flat slabs or pad footings. 1 - Punching failure surfaces of flat slab Fig. Prof, CEN, SUB DESIGN OF THE FLAT PLATE SLAB BY DDM DESIGN OF PUNCHING SHEAR REINFORCEMENT Le. Punching stresses generally arises when a concentrated load is applied to a small area of slab. Although generally preceded by flexural failure, punching shear is a brittle failure mode and the risk of progressive collapse requires a higher safety class in structural design. usually slabs • When shear reinforcement isrequired e. 2 Proposed equations for punching shear strength of slabs without shear reinforcement 38 4. Punching shear failure of the slab is usually sudden and leads to a progressive collapse of the flat plate structures. Column tends to penetrate through the RCFP, flat slabs and footings because of the high shear stresses, around the columns perimeter. Concrete flat slabs and footings: Design method for punching and detailing for ductility Broms, Carl Erik KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges. 1 A typical flat slab (without drop and column head) The column head is some times widened so as to reduce the punching shear in the slab. Punching shear failure of slabs is usually sudden and leads to progressive failure of flat plate structures; therefore, caution is needed in the design of slabs and attention should be given to avoid the sudden failure conditions. Punching Shear Design - The following design guidelines should be maintained for punching shear: 1. In flat slab structures this occurs at column support points. Punching and Shear Reinforcement Systems DELTABEAM ® is the best alternative to post-tension flat slab. 15 to account for Mt. generally when you define the slab using a rectangle or contour to define the outline perimeter boundary of the slab you smap to the centreline of the column, however is there a way to make the slab edge allign with the. The flat plate concrete slab format is normally faster and more cost effective, and is a preferred method for constructing. Column heads:. with a panel size of 6. The deficiencies of CP114 in shear became a cause célèbre in structural. Flat slab, Punching shear. several aspects of punching shear previously observed in testing as size effect (decreasing nominal shear strength with increasing size of the member). The aim of this master thesis was to compare the punching shear resistance obtained in accordance with both design codes. on the safety of existing flat slabs and, in many cases, how they should be strengthen ed against punching shear. advantages, flat-slabs, depending on their design (i. Study Design: Parametric study is carried out by varying the repair and strengthening number of stirrups rows and the stirrups materials. Apart from its usefulness in evaluating punching shear and the necessary shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial. punching shear capacity in the test specimen with shear stud reinforcement. The purpose of this example is to verify slab punching shear design in SAFE. The LinkStudPSR System comprises short lengths of carbon steel deformed bar. Design procedure is that for punching shear. Shear reinforcement is usually not required in slabs supported on beams or walls because the depth is small and the span therefore fairly slender so bending and deflection will nearly always govern the design. A model many years for design of flat slab joints to punching under symmetric loading was proposed by – Kinnunen [1]. The shear design procedures for waffle slabs subjected to punching have not been considered in current. KEYWORDS –ANSYS, Drop Panel, Flat Slab, Punching. The minimum thickness requirements for flat plates are given in Section 9. Flat slab, Punching shear. Nirma Design Associates January 2006 – April 2008 2 years 4 months. Tests have established that punching shear in slabs can be effectively resisted by reinforcement consisting of vertical rods mechanically an chored at top and bottom of slabs. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. Generalnsideration Co s for use of Flat slab Floor System The following are the main factors to be considered before adopting the use of the concrete flat plate with steel/concrete column system. Punching Shear Design in Eurocode 2 "Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings" (from now on referred to as EC2) defines rules for design for shear punching. of reinforcing slabs again st shear failure h ave bee n developed. In flat slab structures this occurs at column support points. often limited due to punching shear action around columns, and consequently they are used for light loads and relatively small spans. HOME; PRODUCTS. 4 A 3 2 1 B C D X Y 0. I would not expect beam shear to be a problem in most slabs (especially two-way slabs) unless you have penetrations or heavily a loaded/reinforced slabs, in these situations it can be of significance. It was of interest to compare the proposal with the current punching shear design provisions. 1 PUNCHING SHEAR RESISTANCE OF STEEL FIBER REINFORCED CONCRETE FLAT SLABS L. 53 CE 317: Design of Concrete Structures II, Md. The flat plate concrete slab format is normally faster and more cost effective, and is a preferred method for constructing. to minimize the effect of punching shear, the slab thickness at the near column zone is increased which is normally known as Drop-cap. HOME; PRODUCTS. There are two shear failure mechanisms that can be encounter in a flat slab system. higher punching shear capacity of shear rails when compared to stirrups. The provision of these swimmer bars would eliminate the need of drop panels in flat slabs and raft foundation in the vicinity of columns, leading to savings and ease of construction. Punching shear may result from a concentrated load or reaction acting on a relatively small area. Beams, see Lecture 3 • Punching shear requirements e. Mahbub-ul-Alam, Asst. In flat slab structures, this occurs at column support points. Punching shear is caused by the transfer of shear forces from the slab to the column connections. The minimum length of perimeter around a slab support no closer than d/2 to the face of support times the slab. Although generally preceded by flexural failure, punching shear is a brittle failure mode and the risk of progressive collapse requires a higher safety class in structura. Keywords: Flat slabs, punching shear, unbalanced moment. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. If the design shear vEd exceeds the shear capacity vRd,c the program computes the necessary shear (links) reinforcement. The study was part of a larger national and multidisciplinary project about fire safety of car parks, from which. Accounting for the proposed failure criterion and load-rotation relationship of the slab, the punching shear strength of a flat slab is shown to depend on the span of the slab, rather. 4 A 3 2 1 B C D X Y 0. This transferred moment increases the shear forces at the face of the column. flat slabs The maximum shear strength in the UK should not exceed. PDF | RC Flat slabs are being adopted increasingly in several parts of the world due to their aesthetic appearance, as well as economic advantages. The design of reinforced concrete flat slabs requires special care for punching shear, especially with the presence of holes near the column. Punching shear failure is one of the typical concrete slab collapses. In flat slab structures this occurs at column support points. the accurate prediction of punching shear strength of simply supported interior slab-column connection. Punching shear failure of flat concrete slabs is a complex phenomenon with brittle failure mode, meaning sudden structural failure and rapid decrease of load carrying capacity. Why does my flat slab (or flat plate) model have one-way shear reinforcement or fail the shear check? When engineers design flat slabs by hand, they often ignore the one-way shear checks. Account for the moment redistribution that would occur in a full structure, a reduced bending moment due to moment redistribution can improve the punching shear strength at a column. usually slabs • When shear reinforcement isrequired e. 3 of ACI 318-05 and in Table 9. The analysis and design follow the equivalent frame analysis method of the ACI code, which considers a one-bay wide strip of the floor system as a continuous frame. The flat plate concrete slab format is normally faster and more cost effective, and is a preferred method for constructing. For overwidth vehicles, the effective width of the slab may be taken as the width of the vehicle under consideration. • Punching shear is a type of two-way shear, often found in flat slabs or pad footings. Flat plates are commonly used in parking garages due to their functional and economic advantages. Here is some information on those calculations. Perimeter of flat slabs 8. Two ways how to determine maximum punching resistance of flat slabs with shear reinforcement are currently used. The benefits of using flat slab construction are becoming increasingly recognized. These slabs which are directly supported by columns are called Flat Slabs. Struc-tural failures of flat slab buildings due to punching have been reported in the past in America, Asia and Europe; some examples. There are two main failure modes of flat slabs: Flexural Failure. - preparation of floor formworks, punching shear reinforcement, guidelines, hand sketches for reinforcing the floor's elements: beams, slabs, - coordination of drawings revisions based on changes in architecture, instalations, construction, demands of the general contactor on site. However, the system is also prone to brittle shear failures at slab-column connections. They may be supported on two opposite sides only [Fig. In order to. NUMERICAL SIMULATION OF THE PUNCHING SHEAR BEHAVIOUR OF SELF-COMPACTING FIBRE REINFORCED FLAT SLABS Marcos D. 2 Flexural Design of Flat Slab 2. Post-Punching Response of Flat Plate Slab-Column Connections i Abstract The post-punching failure response of reinforced concrete flat plate slab-column connections is investigated. Punching Shear Reinforcement Insulated Balcony Connectors Refractory Fixings 3 Used within a slab to provide additional reinforcement around columns, Ancon Shearfix is the ideal solution to the design and construction problems associated with punching shear. Two Way (Punching) Shear - Concept Explained and Flat Plate Example - CSA A23. Punching failure arises when a slab fails locally in shear around a column. Punching shear verification is a program that checks the Failure Limit State of concrete for punching shear in flat and waffle slabs exposed to concentrated loads from rectangular or circular supports. Different types of shear reinforcement used at column heads. Two Way (Punching) Shear - Concept Explained and Flat Plate Example - CSA A23. If as the engineer you feel punching shear is a potential failure mechanism then it should be checked. Empirical. In the past punching shear has been relieved by adding further concrete to the building such as the use. The use of flat slab construction is popular because of the advantages it offers in speeding up the construction process. on the safety of existing flat slabs and, in many cases, how they should be strengthen ed against punching shear. HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Compressive cylinder strength ƒc,cyl [N/mm²] V Test / V R,c, EC 2 [-] Punching shear of the column head through the concrete slab Uneconomical Enlargement of the slab at the column head or the whole concrete slab. PUNCHING SHEAR • always a critical consideration in flat plate design around the columns • instead of using thicker section, shear reinforcement in the form of shear heads, shear studs or stirrup cages may be embedded in the slab to enhance shear capacity at the edges of walls and columns. Ancon Punching Shear Reinforcement system – Shearfix The system consists of double-headed studs welded to flat rails The weight of a slab supported on a column induces shear stresses in the slab, which may result in the column ‘punching’ through the slab and destruction due to the punching and not bending. Take care of punching shear i. Punching shear is caused by the transfer of shear forces from the slab to the column connections. Direct design method. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that "punches" through. Components of flat slabs: Drops: To resist the punching shear which is predominant at the contact of slab and column Support, the drop dimension should not be less than one -third of panel length in that Direction. The punching shear design according to EN 1992-1-1 checks that the acting shear force vEd does not exceed the resistance vRd. All panels are supported by 0. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. Carried out checks on the design including punching shear and verification of pile loads. However, despite an increasing popularity of waffle slabs a significant research has been carried out. A new method to increase the punching shear strength and ductility of the footing-to-column connection was proposed. Punching shear reinforcement system such as truss, studs and stirrups are used for the analysis. The shear resistance at a column after punching can be very low unless. flat slabs and pad foundations Shear There are three approaches to designing for shear: • When shear reinforcement is notrequired e. of Sheffield) Professor Peter Waldron Professor (Univ. Punching shear of flat slabs is a local, brittle failure that may occur before the more favourable ductile flexural failure. The first way is verification of the concrete strut capacity at the column periphery defined as VRd,max. method of providing Punching Shear Reinforcement around columns, and piles with-in flat slabs and post-tensioned slabs, at slab to shearwall junctions, beam to col-umn junctions and within footings and foundation slabs. The design of flat slabs at ultimate is mainly governed by the detailing of the slab-column 5 connection in order to provide sufficient punching shear and deformation capacity. Punching Shear Design. 3 Prestressed Flat Slabs and Plates Prestressed flat slabs and plates have been developed mainly in Australia and the USA over the last 30 years. The study was part of a larger national and multidisciplinary project about fire safety of car parks, from which. (2008) presented a nonlinear analysis of flat slab model with layered shell element, and identify the influence of the distribution of transverse shear strain on the punching shear failure. Two Way (Punching) Shear - Concept Explained and Flat Plate Example - CSA A23. Two methods of design are available for flat slabs: 1. One of the main concerns related to flat slabs is its punching shear capacity at slab column connection. Fracture Analysis of Punching Shear in Flat Slab with Conventional Punching Shear Reinforcement and Steel Fiber using FEA Software - written by Mahesh Bariya , Krishna Nair published on 2019/09/18 download full article with reference data and citations. Henrik Stang and Mikael Braestrup, 1–13. The analytical basis of previous work by other researchers was used to propose a formula to calculate the punching shear strength of flat plates with good accuracy for a wide range of slab thicknesses, tensile reinforcement ratios, and concrete compressive strengths. The main variable parameter was slab longitudinal reinforcement ratio. • Optimized design of flat plate system for deflection as well as punching shear and provided detail reinforcement for the above system. Moreover, the design and construction details of this parking garage are used to illustrate code requirements, flat-slab analysis, design details, and the construction of GFRP-RC flat slabs. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. Punching Shear for Flat Slab Bridges. e use more steel or thickness of concrete where there is chance of punching shear in the concrete slab. i was wondering if someone could help me. punching shear reinforcement system in order to study their effects on the flat slab behavior. This paper is concerned with the design method for providing resistance against punching shear for flat slabs where the slab extends substantially up to the surrounding supports - e. Loading scheemes 9. Therefore, the slab can be reinforced with shear reinforcement complying with.  Two-way shear (punching shear) If the flat slab is gradually subjected to increase the loading, the first crack will appear at the top of the slab around the column due to negative moment near the column. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. Barros b, Vítor M. A major difference between the shear stud behavior in the proposed system and in composite beams is that in the proposed system, the amount of concrete available to resist punching shear is limited due to the small depth of the flat concrete slab. Keywords: Flat slabs, punching shear, unbalanced moment. 10 Limit States and other Methods of Analysis for Slabs 2-22 2. They comprise enlargements of the support region (by the addition of column capitals or. Punching Shear Basics. - preparation of floor formworks, punching shear reinforcement, guidelines, hand sketches for reinforcing the floor's elements: beams, slabs, - coordination of drawings revisions based on changes in architecture, instalations, construction, demands of the general contactor on site. However, the punching shear failure at the slab. Column inclination. Several equations to predict the punching shear strength of the slab are available. In addition to this, the shear capacity can also be reduced in particular around the column head where large shear forces can develop. The scope of work will be as below. Flat Slab Analysis and Design designs beamless concrete slab floors (flat slab or waffle slab) in accordance with ACI 318. from the column face, providing a shear perimeter b o = 24 × 4 = 96 in. Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the bearing capacity of slab-column connections. The ultimate load at these columns supporting flat slabs may be distinctly below the flexural capacity and with a brittle failure. 1 A typical flat slab (without drop and column head) The column head is some times widened so as to reduce the punching shear in the slab. generally when you define the slab using a rectangle or contour to define the outline perimeter boundary of the slab you smap to the centreline of the column, however is there a way to make the slab edge allign with the. This the responsibility of the engineer. The LinkStudPSR System comprises short lengths of carbon steel deformed bar. Cunha c, Bernardo N. A flat slab may come in the form of solid slab or contain recesses developed on the soffit in order that the soffit contains a series of ribs in two directions. CADS RC Slab Designer can accept area, uniform, distributed, point, line, triangular and trapezoidal load types. Flat Slab Analysis and Design PDF Flat Slab Design PDF 1. Nowadays is possible to account in. The punching shear resistance can thus be increased by. Ancon Shearfix Punching Shear Reinforcement System - Used within a slab to provide additional reinforcement around columns, Ancon Shearfix provides an ideal solution to the design and construction problems associated with punching shear. Based on the tributary area of loaded floor, the factored shear is. PSB ® Punching and Shear Rails offer simple and reliable solutions against punching shear failure and shear failure of slabs, foundations, walls and beams by increasing their resistance. ), can be susceptible to punching shear failure around the slab-column connections. So for effective control of punching shear the design is necessary. The critical element of this system is the slab to column connection because of the concentration of the punching shear stress. Tests have established that punching shear in slabs can be effectively resisted by reinforcement consisting of vertical rods mechanically anchored at the top and bottom of slabs. EXAMPLE ACI 318-08 RC-PN-001. Punching shear verification checks the Failure Limit State of concrete for punching shear in flat slabs, waffle slabs and mat foundations using two methods: Point tangential stress check and Check in accordance with the design standards. A model many years for design of flat slab joints to punching under symmetric loading was proposed by - Kinnunen [1]. Punching shear in slabs is analogous to shear in beams. Normal design practice is to always control for punching shear in cases where the structure functions as a flat slab. 3-14, Design of Concrete Structures, and recommendations of ACI 421. Cunha c, Bernardo N. Download Code Flat Slab Design, Strip Design and Punching Shear check in. Design Considerations. You should design for shear in the slab, be it punching or beam. If the design shear vEd exceeds the shear capacity vRd,c the program computes the necessary shear (links) reinforcement. Punching shear is caused by the transfer of shear forces from the slab to the column connections. 2 Proposed equations for punching shear strength of slabs without shear reinforcement 38 4. Barros b, Vítor M. This type of failure is one of the most critical considerations when determining the thickness of flat slab at the slab-column intersection. Although generally preceded by flexural failure, punching shear is a brittle failure mode and the risk of progressive collapse requires a higher safety class in structural design. 1, IS456-2000). Design by the direct design method a typical interior flat slab with drop panels to carry a dead load of 7. Later on, Hong. The flat plate concrete slab format is normally faster and more cost effective, and is a preferred method for constructing. The weight of a concrete slab, supported directly onto a column, can result in concentrated localised shear stresses, causing the slab to ‘punch’ through the column below. Investigations on the topic of punching shear strength have shown that the presence of prestress in flat slabs has a number of potential beneficial effects, namely the vertical component (force) carried by inclined tendons, the in-plane compression stresses and the bending moments developed near the supported region. ) Dr Kypros Pilakoutas Reader (Univ. NGUYEN-KIM4 1, 3, 4 Division of Structural Design, Faculty of Civil Engineering, HCMUT, Vietnam. scope: In seismic design, the displacement-induced unbalanced moment and the accompanying shear forces at flat platecolumn connections should be accounted for. I have a real passion for my profession, and so far I've accumulated some experience in the domains of building maintenance, design of building structures, teaching, and research. i was wondering if someone could help me. HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Compressive cylinder strength ƒc,cyl [N/mm²] V Test / V R,c, EC 2 [-] Punching shear of the column head through the concrete slab Uneconomical Enlargement of the slab at the column head or the whole concrete slab. The aim of investigation was the experimental verification of efficiency of double-headed studs as punching shear reinforcement. higher punching shear capacity of shear rails when compared to stirrups. A civil engineer should study these lectures and materials for structural engineering acumen. Appropriate design and detailing of the slab–column joints are essential to prevent such failure. The LinkStudPSR System comprises short lengths of carbon steel deformed bar. A primary concern in the design of reinforced concrete flat slab structures is that of punching shear at the slab-column connections. Several equations to predict the punching shear strength of the slab are available. the punching shear strength reduces with an increase in slab inclination, and it has been incorporated in the Model Code 2010. A new method to increase the punching shear strength and ductility of the footing-to-column connection was proposed. In the past punching shear has been relieved by adding further concrete to the building such as the use. 1 Design without transverse reinforcement according to EC2 9 2. Therefore, the punching shear failure belongs to one of the most critical aspects in the design of concrete buildings. His research interests include the area of Deep beams, Corbels, fiber concrete, shear of high and ultra high performance concrete beams and slabs, punching shear strength of flat plate. Account for the moment redistribution that would occur in a full structure, a reduced bending moment due to moment redistribution can improve the punching shear strength at a column. One of the main problems of flat slabs is its punching shear capacity at slab-column connection, which is subjected to a very complex triaxial stress state. The punching shear strength is an extremely significant parameter for the design of flat slabs, i. Although generally preceded by flexural failure, punching shear is a brittle failure mode and the risk of progressive collapse requires a higher safety class in structural design. If it is less, no further checks are. Finite element analysis of reinforced concrete slabs subjected to punching load is evaluated and results are compared with. the FE modeling technique in simulating the punching shear behaviour of flat slabs and thus such modeling can be further applied to numerically study the behaviour of multi panel flat plate systems as an alternative to experiments. However, despite an increasing popularity of waffle slabs a significant research has been carried out. Barros b, Vítor M. "Punching shear design of earthquake resistant slab column connections" by Sami Megally and Amin Ghali, ACI Structural Journal, Title No. irregular slab geometry. In addition, Wenyuan Wang et al. Flexural and Punching Shear Design of FRP RC Flat Slabs Flexural and Punching Shear Design of FRP RC Flat Slabs Dr Abdel Wahab El-Ghandour Lecturer (Ain Shams Univ. Apart from its usefulness in evaluating punching shear and the necessary shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial. Flat plates are commonly used in parking garages due to their functional and economic advantages. thickness or using drop panels or column capitals is often not an economical and/or practical option. advantages, flat-slabs, depending on their design (i. The aim of investigation was the experimental verification of efficiency of double-headed studs as punching shear reinforcement. 5(c) for slabs without interior beams. The punching shear resistance can thus be increased by. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. The thickened portion ie the projection below the slab is called drop or drop panel. The story height is 3. A variety of factors can reduce the punching shear design capacity, including openings and construction tolerances. COMPARISON OF SLAB DESIGN BETWEEN BS 8110 AND EUROCODE 2 BY Way Slab 2. The slab-column connections in flat plate slabs are uniquely sensitive to the combined effects of unbalanced moment and direct shear loading. In the concrete column with flat plate design, the connection is more simplified without the need for base plate connection. they require more steel compared to two-way slabs. This article presents an alternative method for designing concrete flat slabs subjected to flexure-induced punching. punching shear resistance in flat slabs in the vicinity of columns. Punching is a brittle type of 6 failure with almost no warning signs. While DIN EN 1992-1-1 and the national annex of Germany treat punching shear design for in-situ concrete slabs and centrically loaded footings in great detail [1, 2], joints between semi precast slabs and columns, concrete core activation in areas endangered by punching shear, or eccentrically loaded footings are treated in quite different ways. The first way is verification of the concrete strut capacity at the column periphery defined as VRd,max. The expanded parts are known as column heads. Many alternative reinforcement systems had been introduced in literature; e. In this sequence, SAFE traces the punching perimeters required for calculation. punching shear can be checked and reinforcement designed at columns below slabs and at transfer columns on floors and mats/rafts. t: +44 (0) 1442 402770 | e: [email protected] Punching, which may be suffered by two-dimensional (2D) reinforced-concrete (RC) structural elements (such as flat slabs, plates, footings, etc. Column heads:. Studs of a predetermined length and diameter, according to design specifi ‐. Chittagong, Bangladesh. 32,Part (A), No. Design Considerations. The problem of punching shear failure of flat concrete slabs exposed to fire has been studied extensively at Magnel Laboratory for Concrete Research of Ghent University in 2010-2012. These slabs which are directly supported by columns are called Flat Slabs. Flat-slab construction has been widely used in construction today because of many advantages that it offers. Teixeira a, Joaquim A. 3 Shear in concrete slabs 12 2. For the flat slab, funnel-shaped punching shear preventer shown in Figure 1(a) is sometimes used to increase the punching shear strength of flat slab-to-column connection. NUMERICAL SIMULATION OF THE PUNCHING SHEAR BEHAVIOUR OF SELF-COMPACTING FIBRE REINFORCED FLAT SLABS Marcos D. 1 A typical flat slab (without drop and column head) The column head is some times widened so as to reduce the punching shear in the slab. • Analyzed and designed the slabs, beams and girder for. Punching shear verification checks the Failure Limit State of concrete for punching shear in flat slabs, waffle slabs and mat foundations using two methods: Point tangential stress check and Check in accordance with the design standards. Punching in slabs is usually associated with the application of concentrated loads or the presence of columns. The LinkStudPSR System comprises short lengths of carbon steel deformed bar. Beams, see Lecture 3 • Punching shear requirements e. Hence it is necessary to re-examine the applicability of the present punching shear design methods for HSC slabs, using the published data. This article presents an alternative method for designing concrete flat slabs subjected to flexure-induced punching. Finite element analysis of reinforced concrete slabs subjected to punching load is evaluated and results are compared with. If we have a drop panel, what is the use of the extra drop assuming it is less or larger than the slab thickness? Is it to only find the required shear? How would the drop panel "d" be used for finding Vc?. The basic philosophy in the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments at the slab column junction which is critical. The main objective of this sheet is to evaluate the effect of design tje RC slab for punching shear strength. One way shear. The critical element of this system is the slab to column connection because of the concentration of the punching shear stress. (This is often decided without much consideration – it just “seems right”). Sway moments derived from a full frame analysis can be entered with the resulting shear forces automatically considered in the design. Tests have established that punching shear in slabs can be effectively resisted by reinforcement consisting of vertical rods mechanically an chored at top and bottom of slabs. British Cement Association documents within the Construction Information Service. The increase in column diameter at the head flaring of column head takes care of punching shear developed at a distance of d/2 all around the junction between the slab and column head. 1 - Punching failure surfaces of flat slab Fig. Both beam (one way) and punching (two way. Punching Shear Behavior of UHPC Flat Slabs Dissertation for the acquisition of the academic degree Doktor der Ingenieurwissenschaften (Dr. These stresses produce concrete cracking and may lead to the slab failure. ACI 318 sets out the principles of design for slab shear reinforcement and makes specific reference to stirrups, headed studs, and shearheads. The flat plate concrete slab format is normally faster and more cost effective, and is a preferred method for constructing. Here is some information on those calculations. Punching shear is a phenomenon in flat slabs caused by concentrated support reactions inducing a cone shaped perforation starting from the top surface of the slab. Punching shear failure would occur at a load well below the flexural capacity due to the concentration of shear forces and the unbalanced. Punching shear is a localized slab to column reinforced concrete connection failure. Punching stresses generally arises when a concentrated load is applied to a small area of slab. The use of flat plate system will be checked. Design by the direct design method a typical interior flat slab with drop panels to carry a dead load of 7. • Optimized design of flat plate system for deflection as well as punching shear and provided detail reinforcement for the above system. Lastly, a study of the bond stress development in the slab shear reinforcement was carried out to investigate whether this anchorage-driven failure can be captured using different provisions currently available for the assessment of reinforced concrete flat slabs. The punching shear design of flat slabs and footings was revised with the introduction of Eurocode 2 in Germany (EC2+NA(D)) in 2012. advantages, flat-slabs, depending on their design (i. provisions for design against punching shear. Parameters of slab thickness and reinforcement ratio were also varied to investigate their respective impacts on punching shear behaviour at elevated temperature. I need to apply stricter deflection limits on the Live loads as they can damage my cladding and façade but I also. Direct design method: (Cl. Why does my flat slab (or flat plate) model have one-way shear reinforcement or fail the shear check? When engineers design flat slabs by hand, they often ignore the one-way shear checks. For ease of reference, the following description of the task solution is based on the punching failure verification model presented in EC2 —see Fig. Finite element analysis of reinforced concrete slabs subjected to punching load is evaluated and results are compared with. The benefits of using flat slab construction are becoming increasingly recognized. collapse resistance of a flat-slab structure following the explosion of a column, in which the collapse was arrested in part due to the proper modeling of the slab post punching response. flat slabs and pad foundations Shear There are three approaches to designing for shear: • When shear reinforcement is notrequired e. In the design of concrete flat plates, the punching shear strength around the column-slab connections always poses a critical analysis problem. Good correlation is observed between the results of the proposed model and other experimental one, resulting in its capability of capturing the fracture of flat slab under punching shear behavior to an acceptable accuracy. The study was part of a larger national and multidisciplinary project about fire safety of car parks, from which. Cunha c, Bernardo N. The shear bolt consists of a headed vertical rod threaded at the other end for anchoring using a washer and nut system. You can design slabs at internal, edge and corner columns by specifying the distance from the support to the slab edge; the program automatically determines the shear perimeters. i was wondering if someone could help me. The term punching shear denotes slab failure in the zone where the concentrated load is applied, or in the support zone (column) due to shear stress. Annerel, Emmanuel, and Luc Taerwe. Whereas in many former codes the punching shear resistance was determined regardless of the type of member, in EC2+NA(D) two different design equations for flat slabs and footings were introduced. Punching shear verification is a program that checks the Failure Limit State of concrete for punching shear in flat and waffle slabs exposed to concentrated loads from rectangular or circular supports. Apart from its usefulness in evaluating punching shear and the necessary shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial.