This writing i defines the different conditions for punching shear calculation, ii presents the relationships used for code check of each condition using aci318, iii presents a numerical example for each condition, and iv demonstrates that the program adaptbuilder. Design step 7 design of substructure prestressed concrete bridge design example task order dtfh6102t63032 741 shear capacity or flexural capacity and, hence, can be neglected. Punching force kn perimeter mm plate thickness mm shear strength kn mm 2 converted into metric tons. This writing i defines the different conditions for punching shear calculation, ii presents the relationships used for code check of each condition using aci318, iii presents a numerical example for each condition, and iv demonstrates that the program adaptpt correctly. Feb 06, 2019 in this video, we investigate how to analyze a slab for punching shear, how to design rebar and stud rails, and some theory, tips and tricks. Punching shear design according to eurocode 2 in rfem.
Introduction to punching shear reinforcement 4 advantages of the jordahl punching shear reinforcement jda 5 design according to eta6 6 9 summary of proofs 6 round cut guide 6 design load 7 punching shear resistance without punching shear reinforcement 7 punching shear resistance with doubleheaded anchors 8. On the other hand, the punching shear strength depends of the column location on the footing, either interior, edge or corner, per the expression. Example a mat foundation is to be design by the conventional method. Punching strength of flat slabs with and without shear. Punching shear resistance is, as the article states, a planar phenomenon rather than a point stress phenomenon. Design codes, however, are generally also applicable to thick slabs and footings 0. Pdf simplified punching shear design method for slabcolumn. Punching shear stress check and reinforcement design based on.
Punching shear safe 2016 tutorial example and practical. Pdf the aims of this study is to present a new simple accurate equation to determine the punching shear strength of normal and high strength. Effectiveness of punching shear reinforcement to en 199211. Sep 03, 2011 design of reinforced concrete slabs 103 calculated punching shear stress at perimeter ui shear force per unit width for bending about xaxis shear force per unit width for bending about yaxis maximum crack width mm depth of neutral axis from compression face distance from edge in ldirection to start of a yield line. Design of foundations universiti teknologi malaysia. The bottom of the footing is ft below finished grade. Aci design handbook in accordance with aci 31805 circular critical section properties for twoway shear stress calculations for circular column are shown below. Punching strength with shear reinforcement firstly, one has to check if the design shear force v d is smaller than the maximum punching strength v rd,max. Punchingshear formulation safe computers and structures.
Pdf design of acitype punching shear reinforcement to. Punching shear at the loaded area a perimeter of the loaded area b design value of the shear stress at the loaded area c design value of the maximum punching shear resistance at the loaded area 14 7. Punching shear reinforcement will be required but there will only be 1 or 2 perimeters. Basic principles 9 14 pointload supported slabs 9 design concept 10combination of system elements 15 combinations of hdb.
This design example provides stepbystep handcalculations and compares various aci methodologies to determine the critical shear perimeter of circular. Punching shear check at wall ends and wall corners. If the concrete s shear capacity is smaller then the actual shear force. Effective punching shear and moment capacity of flat plate. Punching shear capacity of fibre reinforced concrete slabs. According to muttoni and schwartz,12 the width of the critical crack can. Punching strength with shear reinforcement firstly, one has to check if the design shear force v d is smaller than the maximum punching. The basic perimeter, u 1 is at 2d eff from the column. Based on the geometry of the floor slab at the vicinity of a column, each column is categorized into to one of the following options. For the flat slab with the general arrangement as shown below, let us design the punching shear for column b1 given the following design information. The punch area is calculated at an average distance of d2 from column face on all sides fig. The punching shear strength of the concrete is not sufficient.
Design example of punching shear in slabs eurocode 2. Calculation of shear reinforcement nominal shear strength provided by concrete according to eq. Footings example 1design of a square spread footing of a seven. 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. Punching shear arises when a concentrated load is applied to a small area of a slab or, most commonly, the reaction of a column against a slab. Punching shear check at wall ends and wall corners trenno structural 19 jul 18 09. An example is the calculation of the load increment factor. Taking an internal column from the load takedown example refer to page. Punching shear is a phenomenon where a concentrated force on a slab causes a.
Design the pile cap shown in the following figure with 12 in. Department of mechanics, materials and structures english. To check if shear reinforcement and which system can be used, one can calculate the minimal needed value of factor ksys. The critical section of punching shear stress is at a distance, d2, from edge of pile, d is the effective depth of pile cap. The home is located on little bay in harrison county, mississippi, approximately. As discussed in chapter 4, the critical section for punching shear is located at distance d 2 from column faces and usually takes the shape of the column. Example calculation external corner condition a circular pattern square corner 36 36 17. Some special types of reinforcement are also available in the market for this purpose.
Shear reinforcement is also provided around the column to reduce the effect of the punching shear. Footing thickness is adequate for resisting punching shear once vu vc. This verification example provides stepbystep calculations which serve as an overview of the punchingshear process. In most cases, this reaction is the one from the column acting against the slab. Footings example 1design of a square spread footing of a sevenstory building. The action of concentrated loads is on a smaller area in the structural members. Design step 7 design of substructure prestressed concrete.
Punching shear is a type of failure of reinforced concrete slabs subjected to high. It was of interest to compare the proposal with the current punching shear design provisions. The sample calculation is based on a twostory home with a 8foot by 4 foot footprint and a mean roof height of 6 feet above grade. The aim of this master thesis was to compare the punching shear resistance obtained in accordance with both design codes. Pile supported foundation pile cap analysis and design based on a geotechnical study, a pile supported foundation is required to support a heavily loaded building column. Punching shear stress check and reinforcement design based. The resulting stresses are verified along defined control perimeters around the loaded area. Twoway punching shear calculations are performed to ensure that the concrete slab design shear strength, vn, shall be greater than or equal to the factored shear stress, vu. European commission joint research centre institute for the protection and security of the citizen contact information address. Jul 31, 2012 the formulation for punching shear is presented in context help, which is available within the safe interface through help documentation verification aci318. The first punching model alternative is proposed in dafstb beton kalender 2011, and the second punching model alternative is established in swedish concrete association report no. Pdf a new punching shear equation of normal and high.
Aug 14, 2017 the concrete shear strength in oneway action is defined by the expression. Therefore, the slab can be reinforced with shear reinforcement complying with detailing rules defined in subclause 7. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that punches through. Punching shear at the basic control perimeter without reinforcement a basic control perimeter length. For pier caps, the magnitude of the torsional moments is typically small relative to the torsional cracking. Punching shear strength of reinforced concrete slabs. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. The provisions for punching shear design according to eurocode 2 cannot be applied efficiently without a software solution. The punching shear strength predicted by the fuzzybased model is compared with those predicted by current punching shear strength models widely used in the design practice, such as aci 31805. The design shear force v d is below the maximum punching strength v rd,max. Punching shear reinforcement punching shear worked example from worked examples to ec2. The concrete shear strength in oneway action is defined by the expression.
Oct 12, 2017 shear reinforcement is also provided around the column to reduce the effect of the punching shear. In this video, we investigate how to analyze a slab for punching shear, how to design rebar and stud rails, and some theory, tips and tricks. Punching shear calculations are provided for columnspedestals that land on concrete slabs. Halfen hdb punching shear and shear reinforcement 4 7 hdb punching shear reinforcement 5 hdbs shear reinforcement 6 product overview 8 halfen hdb as punching shear and shear reinforcement 8 calculation. Aci 318r emphasizes the importance of anchorage details and accurate placement of the shear reinforcement, especially in thin slabs. Design of acitype punching shear reinforcement to eurocode 2 article pdf available in magazine of concrete research 621. Punching shear how to design against punching shear forces. A general procedure for evaluation of the punching shear strength of slab. Design of reinforced concrete slabs 103 calculated punching shear stress at perimeter ui shear force per unit width for bending about xaxis shear force per unit width for bending about yaxis maximum crack width mm depth of neutral axis from compression face distance from edge in ldirection to start of a yield line. Punching shear calculation applies to columnsupported slabs, classified as twoway structural systems. Punching shear strength of reinforced concrete slabs without. Joint research centre, via enrico fermi 2749, tp 480, 21027 ispra va, italy. This verification example provides stepbystep calculations which serve as an overview of the punching shear process. Punching shear analysis of reinforced concrete flat plates.
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