Punching Shear On Slab On Grade





	Concrete Slab on Grade Dowel Bar Spacing, s = 15. 4—Maximum joint spacing …. 23 Reinforced strip foundation design example – loads and bearing pressures. The punching shear capacity of a slab without shear reinforcement depends upon the strength of concrete, the area of tension reinforcement, the depth of the slab, and the column size. The original theory and equations. The slabs S3 & S4 have 43. Mar 13, 2019 ·  The “Slab on Grade” worksheet assumes a structurally unreinforced slab, ACI-360″Type B”, reinforced only for shrinkage and temperature. 5 (assumed friction factor between subgrade and slab) Slab Weight, W = psf: W = wc*(t/12) Reinf. 1 Failure criteria 15 3. The punhing shear load of control slab S1 and slab with CFRP of 1 rod and 1 strip at each side of loading slab S2 are observed and there is 31 % increase in the load carrying capacity of S2 in comparison with S1. The slab dropped one level due to punching shear (circle). The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. Reinforcement of slab in the longer direction = [email protected] (A s,prov. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. One way shear or beam shear is experienced or resisted by a single plane for example in beams and slabs. Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints. 4), nominal steel is provided, and if it is greater, shear reinforcement should be designed. In the example below an L-shaped slab has four concentrated loads from an equipment rack which is sitting atop the slab. Vertical transfer of load from slab to walls leads to a concentration of shear stress in the slab at wall ends and corners, which needs to be considered in punching shear design. Stresses with Eccentric Loading Combined axial and bending stresses increase the pressure on one edge or corner of a footing. The cement was partially replaced with GGBS at different percentages i. 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. 	7 12 A Tributary u ft2 V q 0. , 0 to 30 % at regular intervals of 10 %. Guide to Shear Reinforcement for Slabs Reported by Joint ACI-ASCE Committee 421 ACI 421. C flat slabs of NSF,WSF1,WSF2 are considered in the test programme to verify shear resistance mechanism of slab at critical punching shear zone of slab by addition of shear resistance elements. Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints. They also concluded that increasing the slab depth. Punching Shear and Critical Shear Crack Theory In Existing Column-Supported RC Slabs Safak Arslantürkoglu1, Roland Bärtschi2 1 Baertschi Partner Bauingenieure AG, Ehrendingen, Switzerland 2 Baertschi Partner Bauingenieure AG, Ehrendingen, Switzerland ABSTRACT: Punching shear failure is the major cause for brittle and sudden progressive. Contact Area, Ac = 86. shear area around the column, and resist punching shear forces. 1 The structural design and dimensioning of reinforced concrete slabs are often governed by deflection limits, punching shear resistance, and constraints imposed by mechanical, electrical, and plumbing (MEP) or architectural design requirements. based on the three ACI equations for two way or punching shear capacity of the slab. Description of test specimens The main features of the test specimens are summarized in Table 1. This is especially critical near corner and edge columns where the shear stresses in the slab are typically the highest. The spatial …. 1—Introduction 6. 	The cement was partially replaced with GGBS at different percentages i. The slab dropped one level due to punching shear (circle). Chapter 6—Design of unreinforced concrete slabs, p. 2—Thickness design methods 6. Using the Stud Rail system can also eliminate the need for forming column capitals or drop heads. Shearfix Punching Shear Reinforcement 4 PUNCHING SHEAR The weight of a slab supported on a column induces shear stresses in the slab. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. Joint Width, z = 0. The slab in each specimen was 2. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that "punches" through. 3—Reinforcement for crack-width control only. The slab specimens were cast using M30 grade concrete with HYSD bars. Experimental results showed that all specimens were destroyed by. Think about punching shear on a flat slab. Contact Area, Ac = 54. Aug 20, 2021 ·  Perimeter = 20×4 = 80mm. 		usually one and two-way spanning slabs • Punching shear -e. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. Underground parking structures often consist of flat slabs connected by columns, for which punching shear is often the most critical design criterion. These stresses, if sufficient and where additional reinforcement has not been provided, would result in the column ‘punching’ through the slab. Shearfix Punching Shear Reinforcement 4 PUNCHING SHEAR The weight of a slab supported on a column induces shear stresses in the slab. Full Stack JavaScript Development With MEAN With modern tools. Slab shear strength – two-way shear Check the adequacy of slab thickness for punching shear (two-way shear) at an interior column (Figure 4): Tributary area for two-way shear is 16 5. The action of concentrated …. However, there are only result of 2 non-corroded slabs in this report for the time being as corrosion of the other slabs takes quite a long time. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. Their efficiency depends on their reinforcement installation method with flexural reinforcement, layout of distribution, concentration and inclination with slab plane. Punching Shear and Critical Shear Crack Theory In Existing Column-Supported RC Slabs Safak Arslantürkoglu1, Roland Bärtschi2 1 Baertschi Partner Bauingenieure AG, Ehrendingen, Switzerland 2 Baertschi Partner Bauingenieure AG, Ehrendingen, Switzerland ABSTRACT: Punching shear failure is the major cause for brittle and sudden progressive. The tests show different potential. Punch Force (KN) = 80 x 3 x 0. One of the most critical aspects of slab on grade design is the consideration of punching shear due to …. Punching shear calculations require a demand value and a capacity value. Test results showed that for FRP-reinforced slabs with similar flexural strength as the steel reinforced control slab, the obtained punching load and stiffness were less. The traditional techniques for strengthening concrete flat slabs is to avoid abrupt punching shear failure, comprise and utilize steel plates linked to concrete slab with bolts or epoxy, externalize post-tensioning reinforcement, and increase the slab thickness in the region vicinity of column. The punching shear resistance of reinforced concrete ground supported slab represents a wide category of concrete structure and subsoil interaction problems. To improve the punching shear capacity and ductility of slab-column connections, a new type of slab-column connection embedded with a steel skeleton was proposed and studied. RE: punching capacity of unreinforced slab. Joint Width, z = 0. Introducing transverse reinforcement is the most common solution when the geometry of the slab-column connection has to be maintained and punching shear resistance has to be. 	It is considered as an efficient method in slab. Check Slab Punching Shear Stress: bo = in. Punch Force (KN) = 80 x 3 x 0. At Hilti we’ve come up with a new and easier way to apply punching shear reinforcement, by putting in anchors from only the lower side of a slab. Correct Representation of Punching Shear Failure. Test results showed that for FRP-reinforced slabs with similar flexural strength as the steel reinforced control slab, the obtained punching load and stiffness were less. Punching shear Punching shear symbols ui = ith perimeter. The sub-grade is the ground on which the floor is built. An example of punching shear failure is the collapse of the Pipers Row car park in Wolverhampton where the 4th floor slab failed under punching shear in 1997. , 0 to 30 % at regular intervals of 10 %. 1 W1 = a shear distribution factor –see 6. One way shear or beam shear is experienced or resisted by a single plane for example in beams and slabs. That is, the concentrated post or wheel load is assumed to be well away from a “free” slab edge or corner. If v ˂(vc+0. The tests show different potential. 	Experimental results showed that all specimens were destroyed by. 4—Maximum joint spacing Chapter 7—Design of slabs reinforced for crack-width control, p. rapt (Structural) 27 Jun 10 23:44. Grade C40 concrete has been specified. The slabs S3 & S4 have 43. Concrete Slab on Grade Dowel Bar Spacing, s = 15. It decreases the deformation capacity …. The slab dropped one level due to punching shear (circle). Reactive upwards design pressure for lateral reinforcement design. 1 Shear failure 15 3. CONCRETE SLAB ON GRADE ANALYSIS For Slab Subjected to Interior Concentrated Post or Wheel Loading Assuming ACI-360 "Type B" Design - Reinforced for Shrinkage and …. It is an empirical method that requires that the flexural reinforcing required for ultimate …. Slabs, pile caps, footings, raft foundations, etc. The cement was partially replaced with GGBS at different percentages i. Failure occurs in perimeter defined away from the concentrated load. The punching shear capacity of a slab without shear. ), as shown in. Slab thickness of 7 in. Subramanian (2005) has found that to enhance the punching shear strength of lat slab, the shear stud reinforcement is found to provide economic and aesthetic solution. These calculations are widely published in text books for square and rectangular shapes but rarely are discussed in detail for circular columns or column capitals. Joint Width, z = 0. Also, punching shear is an issue. Punching shear failure is a brittle failure mode in slab-column connections. 5 in f y = 60 kip/in2 d = 22. 3 Shear in concrete slabs 12 2. 		If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. The action of concentrated loads is on a smaller area in the structural members. The capacity of the slab is a function of the Modulus of Sub-Grade Reaction, the tensile …. Correct Representation of Punching Shear Failure. 2 Global collapse of the structure due to punching shear When the flat slab is exposed to a concentrated load larger than the capacity, the effect on the slab is referred to punching shear. Punching shear calculations require a demand value and a capacity value. Many hand calculations will consider a punching shear force against a punching shear capacity force. Shear Strength = 0. 0018 (h) (bw) I will have larger trucks parking on this slab so I wanted to check for punching shear. RE: punching capacity of unreinforced slab. Page 5 • TF 700-R-03 Update Figure 10 Slab 1 Slab 2 Where: d = Beam depth, in (mm) B = Sum of all widths, in (mm) M = Moment, kip-ft (N-m) l C = Cantilever length, ft (m) 3 664 Ml C B d = Combined Slabs Figure 11 d b b b t f(t) f(t) f(t) f(t) Effective Width of “T” Beams Slab. 2 Laboratory testings 20. It is considered as an efficient method in slab. This provides significant savings, since these column details are difficult to form and place. An example of punching shear failure is the collapse of the Pipers Row car park in Wolverhampton where the 4th floor slab failed under punching shear in 1997. ), as shown in. The cement was partially replaced with GGBS at different percentages i. Each stud is double-headed so the load transfer is equal at. 2 Punching shear failure 17 3. 	1R-08 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. May 25, 2015 ·  The results of twelve slabs tested in this programme are presented and discussed. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. This is not possible if there exists any form of the moment in the pedestal or the column. Two-way (Punching) Shear Calculations Two-way (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. , 0 to 30 % at regular intervals of 10 %. 23 Reinforced strip foundation design example – loads and bearing pressures. For more details about the shearing strength including how to calculate it, you can refer to the answer from Wikipedia. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. It decreases the deformation capacity …. June 18, 2018. 1 The structural design and dimensioning of reinforced concrete slabs are often governed by deflection limits, punching shear resistance, and constraints imposed by mechanical, electrical, and plumbing (MEP) or architectural design requirements. For ground floor slabs, an iterative method is given for determining design compression pre-stresses distribution in slab sections, taking into account the restrained effect created by the friction shear stresses in contact between the slab and the base. 2 Failure in slabs due to shear 13 2. Design Guidelines - Hilti Great Britain Design the shear reinforcement for M20 grade concrete. 1—Introduction 6. Test results showed that for FRP-reinforced slabs with similar flexural strength as the steel reinforced control slab, the obtained punching load and stiffness were less. 	Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints. Stresses with Eccentric Loading Combined axial and bending stresses increase the pressure on one edge or corner of a footing. Shearfix Punching Shear Reinforcement 4 PUNCHING SHEAR The weight of a slab supported on a column induces shear stresses in the slab. shear area around the column, and resist punching shear forces. Punching shear is a failure mechanism when structural elements subjected to concentrated load. 2 Failure in slabs due to shear 13 2. The ACI318 for punching shear do not ignore the normal reinforcing. If the failure did start at the grade-level slab, and spread to the tower, the. 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. Lubricate this end Stop. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. :(assuming subgrade drag method) Friction Factor, F = F = 1. The slab in each specimen was 2. , 0 to 30 % at regular intervals of 10 %. European Commission Joint Research Centre Institute for the Protection and Security of the Citizen Contact information Address: Joint Research Centre, Via Enrico Fermi 2749, TP 480, 21027 Ispra (VA), Italy. Lubricate this end. This can happen only if there exists shear alone in the system. The punhing shear load of control slab S1 and slab with CFRP of 1 rod and 1 strip at each side of loading slab S2 are observed and there is 31 % increase in the load carrying capacity of S2 in comparison with S1. The punching shear resistance of reinforced concrete ground supported slab represents a wide category of concrete structure and subsoil interaction problems. Two-way (Punching) Shear Calculations Two-way (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. 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; Ultimate axial force on column V Ed = 400 kN. Chart-2: ultimate load of slabs The punching shear capasity of four slabs are analysed. 		Unit Weight, wc = 150 pcf Top/Slab Reinforcing Yield, fy = 60000 psi Subgrade Modulus, k = 200 pci Concentrated Load, P = 10115. 2—Thickness design methods 6. One of the most critical aspects of slab on grade design is the consideration of punching shear due to posts/columns/racks which bear directly on the slab. 3 Shear in concrete slabs 12 2. (2011), developed7 full-scale specimens (3000×3000×250 mm) reproducing the support region of an actual flat slab with different layout of bent-up bars are presented. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. At Hilti we’ve come up with a new and easier way to apply punching shear reinforcement, by putting in anchors from only the lower side of a slab. Once a punching-shear failure has occurred at a slab-column joint, the shear capacity of that particular joint is almost completely lost and therefore, it must be prevented in regions of seismicity. The calculations of punching shear dealt within the design is based on the punching shear force that is punching against the thickness of the slab or foundation. rapt (Structural) 27 Jun 10 23:44. Failure occurs in perimeter defined away from the concentrated load. This video describes how ADAPT-Builder calculates the effective depth, 'd,' used in the calculation of punching shear for columns near slabs of different thi. 00 Dowel Bar Dia. of punching shear strength and ductility in slabs subjected to monotonically increased load, as described in the companion paper (Cheng and Parra-Montesinos 2010). 4), nominal steel is provided, and if it is greater, shear reinforcement should be designed. Slab on Grade Design with RISAFoundation. One of the most critical aspects of slab on grade design is the consideration of punching shear due to …. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. The failure occurs at the bottom compressed edge of the slab surrounding the column through punching. 3(3) Punching shear does notuse the Variable Strut inclination method. 	RE: Concentrated load - SLAB on GRADE. Apr 29, 2015 ·  Design for RC Flat Slabs Ir Prof Dr J Chiang Outline Definitions Punching shear problem Code provisions: BS8110 & EC 2 Analysis procedures Design preliminaries Design procedures Yield line method Definitions In BS8110 cl 1. I want to check punching shear with the equation Vc = 4*(sq Punching shear on slab on grade - Foundation engineering - Eng-Tips. In fire conditions, the punching load can increase due to restraint of the thermal curvature of the slab or due to the expansion of the columns. , 0 to 30 % at regular intervals of 10 %. It is an empirical method that requires that the flexural reinforcing required for ultimate strength be supplied and detailed as per the detailing rules of the code. Ground Granulated Blast Furnace (GGBS), Silica fume and Alkali resistant (AR) glass. This video shows the punching shear failure and punching shear mechanism in foundation and flat slab. The slab dropped one level due to punching shear (circle). Sep 08, 2021 ·  The analysis was done on bubble deck slab using both M25 and M30 grade of concrete. This paper analyses the Punching shear resistance of RC slab using different mineral admixtures like. The shear stud used is the same type as used in conventional steel/concrete composite beams. In the example below an L-shaped slab has four concentrated loads from an equipment rack which is sitting atop the slab. Consider an existing, 4" thick, unreinforced slab …. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. The sub-grade is the ground on which the floor is built. Guide to Shear Reinforcement for Slabs Reported by Joint ACI-ASCE Committee 421 ACI 421. 4 Punching Shear to EUROCODE2  structural layout of a one or two-way reinforced or partially post-tensioned beam / slab. At Hilti we’ve come up with a new and easier way to apply punching shear reinforcement, by putting in anchors from only the lower side of a slab. In these slabs, the sheer force per unit length can become high close to the area of loading. 0018 (h) (bw) I will have larger trucks parking on this slab so I wanted to check for punching shear. 	^2 Factor of Safety, FS = 2. The cement was partially replaced with GGBS at different percentages i. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. Full Stack JavaScript Development With MEAN With modern tools. Punching shear Punching shear symbols ui = ith perimeter. 728 KN Convert into tonnage: 82. Vertical transfer of load from slab to walls leads to a concentration of shear stress in the slab at wall ends and corners, which needs to be considered in punching shear design. Punching Shear-Design. The punching shear capacity of a concrete slab around the columns typically governs the thickness of the slab, thus, any openings at the intersection of column …. Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints. element is subjected to punching action and they need to be designed for it. The punhing shear load of control slab S1 and slab with CFRP of 1 rod and 1 strip at each side of loading slab S2 are observed and there is 31 % increase in the load carrying capacity of S2 in comparison with S1. The 'd' is the effective depth of the slab. It is vital to consider sub-grade preparation. If v ˂(vc+0. The sub-base, while not mandatory, can provide added benefits to the construction and performance of the slab. The shear design procedures for waffle slabs subjected to punching have not been considered in current Indian design codes. Ground Granulated Blast Furnace (GGBS), Silica fume and Alkali resistant (AR) glass. 		colu mn connection of the flat slab enhance more punching shear strength capacity than three and two side s supported. The cement was partially replaced with GGBS at different percentages i. Your shear failure planes will overlap and you don't get double your capacity just because you doubled your plate …. Page 5 • TF 700-R-03 Update Figure 10 Slab 1 Slab 2 Where: d = Beam depth, in (mm) B = Sum of all widths, in (mm) M = Moment, kip-ft (N-m) l C = Cantilever length, ft (m) 3 664 Ml C B d = Combined Slabs Figure 11 d b b b t f(t) f(t) f(t) f(t) Effective Width of “T” Beams Slab. The car park was a 120- tonne concrete structure which was constructed in 1965 and the punching shear failure at one column spread to approximately 8 others. footing is identical to a distributed load on a slab over a column when looked at upside down. May 09, 2019 ·  To investigate the punching shear behavior of flat slabs with a varying amount of shear reinforcement, three systematic test series without and with stirrups as shear reinforcement were conducted. Two-way (Punching) Shear Calculations Two-way (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. This provides significant savings, since these column details are difficult to form and place. :(assuming subgrade drag method) Friction Factor, F = F = 1. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. This is especially critical near corner and edge columns where the shear stresses in the slab are typically the highest. This paper analyses the Punching shear resistance of RC slab using different mineral admixtures like. The use of reinforcement with 80 or. Punching Shear Basics. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. Introduction Flat slabs are t he reinforced concrete slab whic h rests on the column without any beam. Lateral bending and shear b = 1000 mm. The sub-base is an optional layer located on top of the sub-grade and beneath the slab bottom (see Figure …. The experimental program included three reference tests without and eight tests with low and medium amounts of shear reinforcement. Reactive upwards design pressure for lateral reinforcement design. 	5 (assumed friction factor between subgrade and slab) Slab Weight, W = psf: W = wc*(t/12) Reinf. 3 Design for punching shear according to EC2 14 3 LITERATURE REVIEW 15 3. In fire conditions, the punching load can increase due to restraint of the thermal curvature of the slab or due to the expansion of the columns. shear stress in the slab adjacent to the column as shown in fig below. Failure occurs in perimeter defined away from the concentrated load. This is not possible if there exists any form of the moment in the pedestal or the column. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that "punches" through. Lubricate this end. Punching shear calculations require a demand value and a capacity value. 1 Failure criteria 15 3. , 0 to 30 % at regular intervals of 10 %. Punching shear is a failure mechanism when structural elements subjected to concentrated load. The experimental program included three reference tests without and eight tests with low and medium amounts of shear reinforcement. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. 1 m (108 x 108 x 4 in. 	2—Thickness design methods 6. 0uu u u A Tributary kips do O. If v ˂(vc+0. Therefore, the slab can be reinforced with shear reinforcement complying with detailing rules defined in subclause §7. This paper analyses the Punching shear resistance of RC slab using different mineral admixtures like. 00 Dowel Bar Dia. Figure (1) Different techniques of shear reinforcement in flat slabs. is adequate for one-way shear. 75 per ACI 318 The combined two-way (punching) shear stress, vu. Underground parking structures often consist of flat slabs connected by columns, for which punching shear is often the most critical design criterion. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. It is an empirical method that requires that the flexural reinforcing required for ultimate …. The car park was a 120- tonne concrete structure which was constructed in 1965 and the punching shear failure at one column spread to approximately 8 others. 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. Slab on Grade Design with RISAFoundation. 3—Shear transfer at joints 6. Joint Width, z = 0. 4), nominal steel is provided, and if it is greater, shear reinforcement should be designed. Contact Area, Ac = 54. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. dik (Structural) 4 Sep 03 14:17. This provides significant savings, since these column details are difficult to form and place. The tests show different potential. Concrete Slab on Grade Dowel Bar Spacing, s = 15. 		Contact Area, Ac = 54. This causes initiation of shear cracks at a distance of effective depth of the slab from the face of the column. I want to check punching shear with the equation Vc = 4*(sq Punching shear on slab on grade - Foundation engineering - Eng-Tips. The spatial …. The failure occurs at the bottom compressed edge of the slab surrounding the column through punching. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. However, despite an increasing popularity of waffle slabs a significant research has been carried out. ^2 Factor of Safety, FS = 2. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. 2 Punching shear failure 17 3. The traditional techniques for strengthening concrete flat slabs is to avoid abrupt punching shear failure, comprise and utilize steel plates linked to concrete slab with bolts or epoxy, externalize post-tensioning reinforcement, and increase the slab thickness in the region vicinity of column. Full Stack JavaScript Development With MEAN With modern tools. Punching shear calculations require a demand value and a capacity value. The original theory and equations. 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. Apr 29, 2015 ·  Design for RC Flat Slabs Ir Prof Dr J Chiang Outline Definitions Punching shear problem Code provisions: BS8110 & EC 2 Analysis procedures Design preliminaries Design procedures Yield line method Definitions In BS8110 cl 1. 16 determined the enhancement of punching shear strength due to the steel fibers based on their regression analysis of test data and proposed a …. However, there are only result of 2 non-corroded slabs in this report for the time being as corrosion of the other slabs takes quite a long time. Punching shear is a failure mechanism when structural elements subjected to concentrated load. 7 12 A Tributary u ft2 V q 0. The capacity of the slab is a function of the Modulus of Sub-Grade Reaction, the tensile …. The point load spreads across an area of slab which is a function of the soil subgrade modulus and the thickness of the slab. The punching shear capacity of a concrete slab around the columns typically governs the thickness of the slab, thus, any openings at the intersection of column …. 	The punching shear capacity of a slab without shear. , 0 to 30 % at regular intervals of 10 %. It is vital to consider sub-grade preparation. 1 One- and two-way action 13 2. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. 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; Ultimate axial force on column V Ed = 400 kN. The use of reinforcement with 80 or. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. The car park was a 120- tonne concrete structure which was constructed in 1965 and the punching shear failure at one column spread to approximately 8 others. A major difference between the shear stud behaviour in the proposed system and in composite beam is that in the proposed system, the amount of concrete available to resist punching shear is limited due to small depth of the flat concrete slab. 3 Intermediate shear failures 18 3. flat slabs and pad foundations Shear There are three approaches to designing for shear: • When …. The cement was partially replaced with GGBS at different percentages 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. The slab specimens were cast using M30 grade concrete with HYSD bars. Eventually the slab will fail. On the basis of the test data, a modijication to the existing plastic theory for conventional reinforced concrete is suggested for the design of open sandwich slabs against punching shear failure. Punching shear behavior is a topic that has attracted much attention from engineers in the last decades because of several collapses caused by punching shear failures. One of the most critical aspects of slab on grade design is the consideration of punching shear due to …. This video shows the punching shear failure and punching shear mechanism in foundation and flat slab. Unit Weight, wc = 150 pcf Top/Slab Reinforcing Yield, fy = 60000 psi Subgrade Modulus, k = 200 pci Concentrated Load, P = 10115. 3—Reinforcement for crack-width control only. An example of punching shear failure is the collapse of the Pipers Row car park in Wolverhampton where the 4th floor slab failed under punching shear in 1997. Punching shear is a phenomenon in flat slabs caused by concentrated support reactions inducing a cone shaped …. The ACI318 for punching shear do not ignore the normal reinforcing. 	0018 (h) (bw) I will have larger trucks parking on this slab so I wanted to check for punching shear. Your shear failure planes will overlap and you don't get double your capacity just because you doubled your plate …. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. Slab thickness of 7 in. element is subjected to punching action and they need to be designed for it. The ACI318 for punching shear do not ignore the normal reinforcing. 3 Intermediate shear failures 18 3. This normally is taken critical at a distance equal to depth of member from the support. The cement was partially replaced with GGBS at different percentages i. It is an empirical method that requires that the flexural reinforcing required for ultimate strength be supplied and detailed as per the detailing rules of the code. The point load spreads across an area of slab which is a function of the soil subgrade modulus and the thickness of the slab. These stresses, if sufficient and where additional reinforcement has not been provided, would result in the column ‘punching’ through the slab. footing is identical to a distributed load on a slab over a column when looked at upside down. , 0 to 30 % at regular intervals of 10 %. Punching shear on slab on grade. 		Check Slab Punching Shear Stress: bo = in. 1 Punching Shear failure Fig: 4. This provides significant savings, since these column details are difficult to form and place. If v ˂(vc+0. For the study, six slab–column connection specimens were constructed with varying flexural reinforcement and shear reinforcement, and were subjected to gravity load tests. Lubricate this end. 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 punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. The footing slab must resist bending, one-way shear and two-way shear (punching). :(assuming subgrade drag method) Friction Factor, F = F = 1. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. Correct Representation of Punching Shear Failure. , 0 to 30 % at regular intervals of 10 %. 23 Reinforced strip foundation design example – loads and bearing pressures. 1—Introduction 6. It is an empirical method that requires that the flexural reinforcing required for ultimate strength be supplied and detailed as per the detailing rules of the code. The cement was partially replaced with GGBS at different percentages i. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. Guide to Shear Reinforcement for Slabs Reported by Joint ACI-ASCE Committee 421 ACI 421. In most cases, this reaction is the one from the column acting against the slab. 	The punching shear perimeter is formed at a distance of d/2 from the edges of the column or the pedestal. 3 Punching Shear to ACI318 T. It decreases the deformation capacity, prevents the brittle punching failure, increases the ductility behavior of slab-column connections [4]. Acknowledgment This article is adapted with permission. 23 Reinforced strip foundation design example – loads and bearing pressures. Check Slab Bearing Stress: (assuming working stress) (Ref. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. Punching shear shows increase in slab thickness, decrease in flexural strength and. The punhing shear load of control slab S1 and slab with CFRP of 1 rod and 1 strip at each side of loading slab S2 are observed and there is 31 % increase in the load carrying capacity of S2 in comparison with S1. It is an empirical method that requires that the flexural reinforcing required for ultimate …. Correct Representation of Punching Shear Failure. RE: Concentrated load - SLAB on GRADE. 5 in f y = 60 kip/in2 d = 22. bo = 4*SQRT(Ac) (assumed shear perimeter) fv(actual) = psi: fv(actual) = P/(t*(bo+4*t)) Fv(allow) = psi: Fv(allow) = 0. Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that "punches" through. The slab specimens were cast using M30 grade concrete with HYSD bars. 75 per ACI 318 The combined two-way (punching) shear stress, vu. , 0 to 30 % at regular intervals of 10 %. 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; …. 	One of the most critical aspects of slab on grade design is the consideration of punching shear due to posts/columns/racks which bear directly on the slab. If v ˂(vc+0. 2—Thickness design methods 7. 1—Introduction 6. Perform the two-way (punching) shear calculations around the exterior and interior circular columns supporting a two-way flat plate concrete slab. Stresses with Eccentric Loading Combined axial and bending stresses increase the pressure on one edge or corner of a footing. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. The 'd' is the effective depth of the slab. It decreases the deformation capacity, prevents the brittle punching failure, increases the ductility behavior of slab-column connections [4]. on lightweight aggregate voided slab behavior under punching shear, three slabs having the same geometrical. Failure occurs in perimeter defined away from the concentrated load. RE: Concentrated load - SLAB on GRADE. Two-way (Punching) Shear Calculations Two-way (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. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. 3 Shear in concrete slabs 12 2. Dimension of column = 450 x 230 mm. Joint Width, z = 0. 4), nominal steel is provided, and if it is greater, shear reinforcement should be designed. 		Punching shear behavior is a topic that has attracted much attention from engineers in the last decades because of several collapses caused by punching shear failures. Punching shear is rarely a concern in the design of continuous wall footings and thus is usually checked only in the case of rectangular or circular footings with a heavily loaded pier or column that creates a large concentrated load on a relatively small area of the footing. Consequently, shear reinforcement is necessary. The action of concentrated loads is on a smaller area in the structural members. 22 psi fp(actual) =. Contact Area, Ac = 86. 0uu u u A Tributary kips do O. Punching shear is a failure mechanism when structural elements subjected to concentrated load. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. 1 Failure criteria 15 3. Chart-2: ultimate load of slabs The punching shear capasity of four slabs are analysed. In fire conditions, the punching load can increase due to restraint of the thermal curvature of the slab or due to the expansion of the columns. This report focuses on the punching shear strength of 10 Grade 40 concrete slab with various corroded reinforcement. (2011), developed7 full-scale specimens (3000×3000×250 mm) reproducing the support region of an actual flat slab with different layout of bent-up bars are presented. Shear Design Example CEE 3150 – Reinforced Concrete Design – Spring 2004 Design the shear reinforcement for the following beam: f0 c = 4 kip/in2 d0 = 2. the ratio of the stiffness of the slab to the stiffness of the foundation. For 6" to 10" thick slabs on grade with 'k' values between 100 pci and 200. Figure (1) Different techniques of shear reinforcement in flat slabs. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. 	Correct Representation of Punching Shear Failure. European Commission Joint Research Centre Institute for the Protection and Security of the Citizen Contact information Address: Joint Research Centre, Via Enrico Fermi 2749, TP 480, 21027 Ispra (VA), Italy. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. Jan 09, 2013 ·  Adopt a 1. on lightweight aggregate voided slab behavior under punching shear, three slabs having the same geometrical. 2 Global collapse of the structure due to punching shear When the flat slab is exposed to a concentrated load larger than the capacity, the effect on the slab is referred to punching shear. To improve the punching shear capacity and ductility of slab-column connections, a new type of slab-column connection embedded with a steel skeleton was proposed and studied. 2—Thickness design methods 6. Calculate total factored shear force [Vu] according to the following equation:. Punching Shear-Design. Slabs, pile caps, footings, raft foundations, etc. 1 Punching Shear failure Fig: 4. Calculations in Punching Shear. The punhing shear load of control slab S1 and slab with CFRP of 1 rod and 1 strip at each side of loading slab S2 are observed and there is 31 % increase in the load carrying capacity of S2 in comparison with S1. Mar 13, 2019 ·  The “Slab on Grade” worksheet assumes a structurally unreinforced slab, ACI-360″Type B”, reinforced only for shrinkage and temperature. 27*MR : Shrinkage and Temperature Reinf. If the failure did start at the grade-level slab, and spread to the tower, the. Stresses with Eccentric Loading Combined axial and bending stresses increase the pressure on one edge or corner of a footing. 	Ground Granulated Blast Furnace (GGBS), Silica fume and Alkali resistant (AR) glass. Shear Design Example CEE 3150 – Reinforced Concrete Design – Spring 2004 Design the shear reinforcement for the following beam: f0 c = 4 kip/in2 d0 = 2. It is the s. Unit Weight, wc = 150 pcf Top/Slab Reinforcing Yield, fy = 60000 psi Subgrade Modulus, k = 200 pci Concentrated Load, P = 8550. Two-way (Punching) Shear Calculations Two-way (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. The punching shear is a failure mechanism in structural members like slabs and foundation by shear under the action of concentrated loads. Aug 20, 2021 ·  Perimeter = 20×4 = 80mm. Shear Strength = 0. 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. Concrete Slab on Grade Dowel Bar Spacing, s = 15. Lateral bending and shear b = 1000 mm. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. Consequently, shear reinforcement is necessary. Their efficiency depends on their reinforcement installation method with flexural reinforcement, layout of distribution, concentration and inclination with slab plane. Description of test specimens The main features of the test specimens are summarized in Table 1. In the example below an L-shaped slab has four concentrated loads from an equipment rack which is sitting atop the slab. The slab specimens were cast using M30 grade concrete with HYSD bars. Figure (1) Different techniques of shear reinforcement in flat slabs. Punching shear is a failure mechanism when structural elements subjected to concentrated load. For 6" to 10" thick slabs on grade with 'k' values between 100 pci and 200. The shear stud used is the same type as used in conventional steel/concrete composite beams. Design Guidelines - Hilti Great Britain Design the shear reinforcement for M20 grade concrete. flat slabs and pad foundations Shear There are three approaches to designing for shear: • When …. ^2 Factor of Safety, FS = 2. 		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; …. Full Stack JavaScript Development With MEAN With modern tools. Punching shear is a failure mechanism when structural elements subjected to concentrated load. The sub-grade is the ground on which the floor is built. Chapter 6—Design of unreinforced concrete slabs, p. Once a punching-shear failure has occurred at a slab-column joint, the shear capacity of that particular joint is almost completely lost and therefore, it must be prevented in regions of seismicity. shear area around the column, and resist punching shear forces. Perform the two-way (punching) shear calculations around the exterior and interior circular columns supporting a two-way flat plate concrete slab. Reactive upwards design pressure for lateral reinforcement design. Concrete Slab on Grade Dowel Bar Spacing, s = 15. Using the Stud Rail system can also eliminate the need for forming column capitals or drop heads. This report focuses on the punching shear strength of 10 Grade 40 concrete slab with various corroded reinforcement. European Commission Joint Research Centre Institute for the Protection and Security of the Citizen Contact information Address: Joint Research Centre, Via Enrico Fermi 2749, TP 480, 21027 Ispra (VA), Italy. Introduction Flat slabs are t he reinforced concrete slab whic h rests on the column without any beam. Mar 13, 2019 ·  The “Slab on Grade” worksheet assumes a structurally unreinforced slab, ACI-360″Type B”, reinforced only for shrinkage and temperature. :(assuming subgrade drag method) Friction Factor, F = F = 1. This can happen only if there exists shear alone in the system. The failure occurs at the bottom compressed edge of the slab surrounding the column through punching. Reinforcement of slab in the longer direction = [email protected] (A s,prov. from ACI min equations for temp and shrinkage, the slab has equivalent reinforcing. 	1—Introduction 7. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. Flat slabs can be supported by a column capital or a drop panel in order to provide a good resistance to punching shear around the column. ^2 Factor of Safety, FS = 2. , 0 to 30 % at regular intervals of 10 %. 3—Shear transfer at joints 6. RE: Concentrated load - SLAB on GRADE. Original photo courtesy The Miami-Dade Fire Rescue. Apr 29, 2015 ·  Design for RC Flat Slabs Ir Prof Dr J Chiang Outline Definitions Punching shear problem Code provisions: BS8110 & EC 2 Analysis procedures Design preliminaries Design procedures Yield line method Definitions In BS8110 cl 1. The capacity of the slab is a function of the Modulus of Sub-Grade Reaction, the tensile …. Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. The failure occurs at the bottom compressed edge of the slab surrounding the column through punching. Sep 08, 2021 ·  The analysis was done on bubble deck slab using both M25 and M30 grade of concrete. The sub-grade is the ground on which the floor is built. 	dik (Structural) 4 Sep 03 14:17. Punching shear on slab on grade. The experimental program included three reference tests without and eight tests with low and medium amounts of shear reinforcement. Two-way (Punching) Shear Calculations Two-way (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. 0018 (h) (bw) I will have larger trucks parking on this slab so I wanted to check for punching shear. Therefore, the slab can be reinforced with shear reinforcement complying with detailing rules defined in subclause §7. This issue is not addressed in EN 1992 (2004) and only partially addressed in fib Model Code 2010 leaving engineers to resort to their own judgment. Original photo courtesy The Miami-Dade Fire Rescue. the ratio of the stiffness of the slab to the stiffness of the foundation. The slab specimens were cast using M30 grade concrete with HYSD bars. Reinforcement of slab in the longer direction = [email protected] (A s,prov. Joint Width, z = 0. Unit Weight, wc = 150 pcf Top/Slab Reinforcing Yield, fy = 60000 psi Subgrade Modulus, k = 200 pci Concentrated Load, P = 10115. Ground Granulated Blast Furnace (GGBS), Silica fume and Alkali resistant (AR) glass. The car park was a 120- tonne concrete structure which was constructed in 1965 and the punching shear failure at one column spread to approximately 8 others. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. To improve the punching shear capacity and ductility of slab-column connections, a new type of slab-column connection embedded with a steel skeleton was proposed and studied. the slab is kept symmetrical it does not seem to matter. The punching shear resistance of reinforced concrete ground supported slab represents a wide category of concrete structure and subsoil interaction problems. ^2 Factor of Safety, FS = 2. Introduction Flat slabs are t he reinforced concrete slab whic h rests on the column without any beam. 2 m wide × 350 mm deep reinforced strip foundation, using grade 35 concrete ( see Fig. 		The failure occurs at the bottom compressed edge of the slab surrounding the column through punching. Punching shear Punching shear symbols ui = ith perimeter. Full Stack JavaScript Development With MEAN With modern tools. CONCRETE SLAB ON GRADE ANALYSIS For Slab Subjected to Interior Concentrated Post or Wheel Loading Assuming ACI-360 "Type B" Design - Reinforced for Shrinkage and …. Punching shear behavior is a topic that has attracted much attention from engineers in the last decades because of several collapses caused by punching shear failures. For more details about the shearing strength including how to calculate it, you can refer to the answer from Wikipedia. dik (Structural) 4 Sep 03 14:17. usually one and two-way spanning slabs • Punching shear -e. Joint Width, z = 0. 1 Shear failure 15 3. 1 The structural design and dimensioning of reinforced concrete slabs are often governed by deflection limits, punching shear resistance, and constraints imposed by mechanical, electrical, and plumbing (MEP) or architectural design requirements. , 0 to 30 % at regular intervals of 10 %. The sub-grade is the ground on which the floor is built. Local shear at column face The shear at the face of the column should be checked. flat-plate concrete slabs. For ground floor slabs, an iterative method is given for determining design compression pre-stresses distribution in slab sections, taking into account the restrained effect created by the friction shear stresses in contact between the slab and the base. The punching shear capacity of a concrete slab around the columns typically governs the thickness of the slab, thus, any openings at the intersection of column …. However, there are only result of 2 non-corroded slabs in this report for the time being as corrosion of the other slabs takes quite a long time. 1R-08 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. Consider an existing, 4 thick, unreinforced slab on grade that must support a new concentrated load. Calculate total factored shear force [Vu] according to the following equation:. 	This provides significant savings, since these column details are difficult to form and place. The spatial …. Their efficiency depends on their reinforcement installation method with flexural reinforcement, layout of distribution, concentration and inclination with slab plane. the ratio of the stiffness of the slab to the stiffness of the foundation. 00 Dowel Bar Dia. This is done assuming k sys=2. 4—Maximum joint spacing Chapter 7—Design of slabs reinforced for crack-width control, p. is adequate for one-way shear. It is an empirical method that requires that the flexural reinforcing required for ultimate …. As 2870 Residential Slabs And  Shear And Punching Shear At Distance D/2 From The  Construction And Design Of Concrete Slabs On GradeConcrete Slabs On Grade 2012. The experimental program included three reference tests without and eight tests with low and medium amounts of shear reinforcement. The action of concentrated …. At Hilti we’ve come up with a new and easier way to apply punching shear reinforcement, by putting in anchors from only the lower side of a slab. Reinforcement of slab in the longer direction = [email protected] (A s,prov. May 24, 2021 ·  Download File PDF Punching Shear Strength Of Interior Concrete Slab Column A New Punching Shear Strengthening Technique for Reinforced Concrete Slabs at Interior Slab-column Connections Punching is considered to be one of the most difficult problems in structural concrete design and mechanical models or theoretical analyses were developed. The slab specimens were cast using M30 grade concrete with HYSD bars. 1R-08 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. PUNCHING SHEAR – ANALYSIS A concentrated load(N) on a slab causes shearing stresses on a section around the load; this effect is called. The punching shear capacity of a concrete slab around the columns typically governs the thickness of the slab, thus, any openings at the intersection of column strips should be considered carefully. 	The sub-base, while not mandatory, can provide added benefits to the construction and performance of the slab. Shear Strength = 0. The slab dropped one level due to punching shear (circle). Punching shear also known as two way shear. It is considered as an efficient method in slab. The two way slab specimens were subjected to punching shear load by in house fabricated apparatus. 728 KN Convert into tonnage: 82. 3 Intermediate shear failures 18 3. The sub-base is an optional layer located on top of the sub-grade and beneath the slab bottom (see Figure …. The point load spreads across an area of slab which is a function of the soil subgrade modulus and the thickness of the slab. They not enhance the shear capacity but also result in flexural failure of the slab and thus increasing the ductility of flat slab, which is very important in earthquake prone zone. An example of punching shear failure is the collapse of the Pipers Row car park in Wolverhampton where the 4th floor slab failed under punching shear in 1997. 2 Laboratory testings 20. If v > vc, shear reinforcement must be provided in slabs more than 200mm thick. 1 Shear failure 15 3.