Glossary

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A

Anchor Channel A steel channel with integrated anchors cast into concrete. Allows attachment points to be positioned anywhere along the channel length using T-bolts. Anchor The embedded portion of the fastening system that transfers loads into the concrete. In anchor channels, anchors are welded to or integral with the channel profile. Area Ratio (A_c,N/A°_c,N) The ratio of actual projected failure area to reference failure area. Reduced by edges, spacing, and member thickness limitations.

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B

Blow-out A concrete failure mode where the cover concrete between the anchor and a nearby surface fails. Relevant for shallow cover conditions. Bond The adhesive or mechanical connection between an anchor and the surrounding concrete. In cast-in channels, bond is primarily mechanical.

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C

Cast-in Fasteners placed in formwork before concrete is poured, as opposed to post-installed fasteners installed in hardened concrete. Characteristic Resistance (R_k) The resistance value with a 5% probability of not being achieved. Used as the basis for design resistance calculations. Combined Loading Simultaneous application of tension and shear forces, requiring interaction checks per EN 1992-4. Concrete Cone Failure A tension failure mode where a cone of concrete breaks out around the anchor. Often the governing mode for anchor channel design. Concrete Edge Failure A shear failure mode where concrete breaks out toward a free edge when shear acts toward that edge. Cracked Concrete Concrete assumed to have cracks passing through the anchor location under service conditions. Default assumption for most designs. Critical Edge Distance (c_cr) The edge distance below which capacity reductions occur. c_cr,N = 1.5 × h_ef for tension. Critical Spacing (s_cr) The anchor spacing below which capacity reductions due to overlapping failure cones occur. s_cr,N = 3 × h_ef for tension.

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D

Design Resistance (R_d) The calculated resistance value for design purposes. R_d = R_k / γ_M. Design Action (E_d) The factored load or load effect to be resisted. Determined from structural analysis. Ductile Failure Failure mode with significant deformation before fracture, typically steel failure modes.

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E

Eccentricity Offset between the point of load application and the centroid of the anchor group. Causes non-uniform load distribution. Edge Distance (c) The distance from the center of an anchor to the nearest concrete edge. c₁ and c₂ typically denote distances to perpendicular edges. Effective Embedment Depth (h_ef) The depth from the concrete surface to the effective load transfer point of the anchor. Critical parameter for concrete capacity. EN 1992-4 European standard for design of fastenings for use in concrete. The primary reference for anchor channel design in Europe. ETA (European Technical Assessment) Product-specific approval document containing design data, installation requirements, and performance characteristics for anchor channels.

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F

Failure Mode A specific mechanism by which a fastening system can fail (e.g., steel tension, concrete cone, pullout). Factored Load Load multiplied by appropriate partial safety factors (γ_F) for design purposes.

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G

Governing Failure Mode The failure mode with the highest utilization ratio, limiting the overall capacity of the connection. Group Effect Reduction in capacity when multiple anchors are close together, causing overlapping failure cones or stress fields.

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H

HDG (Hot-Dip Galvanized) Corrosion protection process where steel is coated with zinc by immersion in molten zinc bath. h_min Minimum member thickness required for a fastening system to achieve its stated capacity.

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I

Influence Length (l_i) The length of anchor channel engaged by a point load. l_i = min(12 × h_ef, 2 × c). Interaction The combined effect of tension and shear forces, typically checked using interaction equations.

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L

Limit State Design Design philosophy comparing factored loads (actions) against factored resistances. ULS checks safety; SLS checks serviceability. Load Combination Combination of different load types (dead, live, wind, etc.) with appropriate factors per EN 1990.

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M

Member Thickness (h) The depth of the concrete element receiving the fastening.

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N

N_Ed Design value of tension force (kN). N_Rd Design resistance in tension (kN).

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P

Partial Safety Factor (γ) Factor applied to characteristic values to account for uncertainties. γ_M for materials, γ_F for loads. Post-installed Fasteners installed in hardened concrete, as opposed to cast-in fasteners. Pryout A concrete failure mode where concrete breaks out on the back side of the anchor under shear loading. Relevant for short, stiff anchors. Pullout A failure mode where the anchor pulls out of the concrete without forming a full breakout cone.

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R

Reinforcement, Supplementary Reinforcement specifically designed to resist fastener loads and increase concrete breakout capacity. Resistance The capacity of a structural element to resist load, expressed as force (kN) or moment (kNm).

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S

Serviceability Limit State (SLS) Design verification for normal use conditions — deflection, cracking, durability. Less critical than ULS for anchor design. Shear Force acting perpendicular to the anchor axis, parallel to the concrete surface. Splitting A concrete failure mode where the concrete splits due to wedging action of the anchor, particularly in thin members or near edges. Stainless Steel Corrosion-resistant steel alloy containing chromium. Common grades for anchor channels: 1.4301 (304), 1.4404 (316L).

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T

T-bolt A bolt with a T-shaped head designed to slide into and lock within an anchor channel. The primary fixing component for connections to channels. Tension Force acting along the anchor axis, away from the concrete surface. Torque Rotational force applied when tightening T-bolts. Specified to ensure proper clamping without damage.

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U

Ultimate Limit State (ULS) Design verification for structural safety — ensuring loads don’t exceed capacities with adequate reliability. Uncracked Concrete Concrete where cracks are not expected to occur through the anchor location. Higher capacity but requires justification. Utilization Ratio (η) The ratio of design action to design resistance. η = E_d / R_d. Must be ≤ 1.0 for adequate design.

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V

V_Ed Design value of shear force (kN). V_Rd Design resistance in shear (kN).

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ψ (Psi) Factors

ψ_s,N Reduction factor for edge distance effects on tension capacity. ψ_re,N Factor accounting for presence (or absence) of supplementary reinforcement for tension. ψ_ec,N Reduction factor for eccentric tension loading. ψ_s,V Reduction factor for edge distance effects on shear capacity. ψ_h,V Reduction factor for member thickness effects on shear capacity. ψ_α,V Factor for load direction relative to the edge in shear. ψ_re,V Factor for edge reinforcement in shear.

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γ (Gamma) Factors

γ_Mc Partial safety factor for concrete failure modes. Typically 1.5. γ_Ms Partial safety factor for steel failure modes. Typically 1.0-1.2. γ_Mp Partial safety factor for pullout failure. Typically 1.5. γ_Msp Partial safety factor for splitting failure. Typically 1.5.