HDB Shear Rail
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HALFEN SHEAR RAIL Punching shear reinforcement calculation according to European Technical Approval ETA-12/0454

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT System Description - HDB Shear Rails as Punching Shear Reinforcement Point-load supported slabs with no enlarged column heads Reinforced concrete slabs with no beams and no enlarged column heads are inexpensive to manufacture and provide good conditions for optimal use of space and further constructionwork without obstructions. Particular advantages are: • low formwork costs • no obstructions to further construction (piping, ventilation ducts) under the slab • oor heights can often be reduced The problem: punching shear verication around...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Introduction Advantages of HDB Shear rails Installation: • simple and quick installation • reduced build-time • no caging required as with stirrup reinforcement • installed after placing the main upper and lower longitudinal reinforcement Planning: • building authority approved as punching shear reinforcement in slabs, foundation slabs and footings • HDB Shear rails can also be used in precast elements and semi-precast elements • also approved for non- predominantly static loads • standardised product range for typical dimensions Safety:...

HALFEN HDB-S SHEAR RAIL ‒ SHEAR REINFORCEMENT System Description - HDB Shear Rails as Shear Reinforcement Linear supported slabs — Verication of shear load capacity Shear load capacity for reinforced concrete slabs must be veried according to EN 1992-1-1:2011-01 in all shear cross-sections. The regulations according to the National Annex must also be observed. Shear failure near support Support with HDB-S Shear reinforcement The problem: complex installation of shear reinforcement According to EN 1992-1-1:2011-01, high-load slabs (VEd > ⅓ × VRd,max) require stirrup reinforcement to be...

HALFEN HDB-S SHEAR RAIL ‒ SHEAR REINFORCEMENT Introduction Advantages of the HDB-S Shear rails Installation: • simple and quick installation • reduced build-time • no caging required as with stirrup reinforcement • installed after placing the upper and lower longitudinal reinforcement Planning: • HDB Shear rails can also be used in precast elements and semi-precast elements • also approved in Germany for non- predominantly static loads • standardised product range for typical dimensions Safety: • simple visual control of installed elements • negligible slippage of anchorage in the shear...

HALFEN HDB / HDB-S SHEAR RAIL ‒ PUNCHING SHEAR / SHEAR REINFORCEMENT Introduction The product as punching shear and shear reinforcement Double-headed stud Is made of reinforcing steel B 500 (smooth or ribbed): supplied in Ø dA 10 - 12 - 14 - 16 - 18 - 20 - 25 mm The stud head diameter is 3 times the bar diameter dA: dK = 3 · dA HDB Elements The double-headed studs are connected using a welded-on spacer-bar. Clip bars are used to secure the spacer-bar to the reinforcement. Clip bars can be attached anywhere on the spacer-bar (order separately, see page 23). Two variants HDB System elements •...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Calculation: Basic Principles Point-load supported slabs with no enlarged column heads Design concept in accordance with EN 1992-1-1:2011-01 (Eurocode 2) EN 1992-1-1:2011-01 determines the maximum punching shear capacity for at slabs analogically to the strength of the compression strut of beams. However, test evaluations prove that this method is not applicable for at slabs. Particularly in tests using stirrups as punching shear reinforcement, the level of safety required by EN 1990:2010-12 was not achieved. This is why an improved...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Calculation: Basic Principles Verication outside of the punching shear reinforced area (Longitudinal reinforcement in the column width area increased each side by 3dm, compare with no. 7 on page 10) fck = characteristic concrete compressive strength fcd = design value for concrete compressive strength fyd = design yield strength for reinforcement steel no punching shear reinforcement necessary outermost stud punching shear reinforcement necessary uout The empirical pre-factor CRd,c is dependent on the respective column perimeter u0 / dm...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Design: Basic Principles 4. Calculating the required punching shear Stud spacing reinforcement Apart from the static relevant boundary conditions, further geometric specications have to be observed when placing studs and elements: Required punching shear reinforcement in region C As,req = VEd · β · η/fyd • the distance of the rst stud from the column edge must be between 0.35 dm and 0.50 dm • maximum studs spacing in radial direction must be ≤ 0.75 dm • maximum tangential anchors spacing at a distance of 1.0 d from the column edge must be...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Calculation: Basic Principles 1.5 dm Additionally for wall ends and wall corners, the following generic load factors can be used: = 1.35 for wall ends = 1.20 for wall corners The more precise method of assuming a plastic shear distribution as in EN 1992-1-1:2011-01 can be used as an alternative or as soon as the span width of adjoining slabs deviate more than 25% from one another. Minimum bar lengths — example for interior column Bar length lbar = b + 2 · ls + 2 · 1.5 dm + 2 · lbd ≥ b + 2 · 3 dm + 2 · lbd = anchorage length according to...

HALFEN HDB SHEAR RAIL ‒ PUNCHING SHEAR REINFORCEMENT Calculation: Basic Principles Case 1 Rectangular interior column with: b ≤ a ≤ 2b and (a + b) · 2 ≤ 12 dm dm = mean effective static depth Recommended load factor is β = 1.15 Case 6 Circular edge column 2.0 dm Recommended load factor β = 1.4 Case 7 Circular corner column Case 2 Rectangular edge column Edge parallel to a with: Recommended load factor β = 1.5 Recommended load factor is β = 1.4 Case 8 Wall corner Case 3 Rectangular edge column Edge parallel to b Recommended load factor β = 1.2 Recommended load factor β = 1.4 Recommended load...