Product Technical Guides : US-EN Cast-In Anchor Channel Fastening Technical Guide | Page 222

1. Anchor Channel Systems 2. HAC Portfolio 3. HAC Applications Corner distance shall be considered as the shortest distance between the anchor and the edge. The straight line is drawn from the end of the headed stud of anchor channel. The line is extended until it intersects the edge of the acute angle corner. The point of intersection is extended back to the face of slab edge as shown in the Figure 9.2.2.8. The side edge distance C a2 is used for analyzing the tension breakout capacity of anchor channel which reduces the tension concrete breakout capacity by introducing the corner factor as seen in the equation below. c cr , N = b ch + 2 c a 1 ³ 1.5 h ef h cr, V = 2c a1 + 2h 5. Base material £ 1.0 c cr, V = 0.5 × s cr, V = 2c a1 + b ch in .( mm ) y co,V 8. Reinforcing Bar Anchorage 9. Special Anchor Channel Design 10. Design Software 11. Best Practices 12. Instructions for Use 13. Field Fixes 14. Design Example b 1 y h, V = ç ç h æ c a2 = ç ç c è cr,V 7. Anchor Channel Design Code ESR-3520 Equation (38) ch æ h ö ÷ ÷ è cr, V ø 6. Loading Acute corners: Tension analysis 4. Design Introduction ö ÷ ÷ ø ESR-3520 Equation (37) ESR-3520 Equation (36) 0.5 £ 1.0 ESR-3520 Equation (35) Figure 9.2.2.11 — Acute corner — Longitudinal shear — Section view. ESR-3520 Equation (14) If c a2 < c cr,N 0.5 £ 1.0 ESR-3520 Equation (16) Figure 9.2.2.12 — Acute corner — Longitudinal shear — Plan view. 9.2.3 — H  AC AND HAC-T DESIGN: FACE OF SLAB OUTSIDE CORNER WITH PAIR OF ANCHOR CHANNEL LOADED SIMULTANEOUSLY 90° corners Figure 9.2.2.9 —Acute corner— Perpendicular shear — Section view. Outside corners where two anchor channels are present and are loaded simultaneously are outside the scope of AC232. Most of the AC232 provisions can be applied to this type of application. However, the influence of the adjacent anchor channel shall be considered, as the concrete strength may be negatively impacted. Figure 9.2.2.8 — Acute corner — Tension. Figure 9.2.2.10 — Acute corner — Perpendicular shear — Plan view. Acute corners: Longitudinal Shear analysis The straight line is drawn limiting the height of the substrate. The line is extended until it intersects the edge of the acute angle corner. The point of intersection is extended back to the face of slab edge as shown in the Figure 9.2.2.11 and Figure 9.2.2.12. By limiting the height of the substrate we will reduce the A cv in a basic longitudinal shear capacity which in turns reduces the longitudinal capacity. V cb, x = ( A vc / A vco ) × ψ ed, V × ψ c, V × ψ h, V × ψ parallel, V .V b Figure 9.2.3.1 — 90° corner with anchor channels on both sides — Failure planes does not intersect. Tension For the concrete failure modes in tension, the stresses in the concrete induced by the two anchors of the anchor channels closer to the corner change the concrete behavior. The concrete crack instead of following the idealized failure plane (C cr,N ), it takes the path of least resistance at the corner. This concept is illustrated in figure 9.2.3.2. Hilti uses applicable provisions of AC232 to analyze this type of anchor application. To account for the influence of the adjacent corner anchor channel, the corner distance is reduced by assuming the concrete crack follows the path of 222 Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019 223 A path of least resistance line is drawn emitting from the headed stud a 3 as shown in Figure 9.2.2.9, intersecting thee edge 2 at 90°. A straight line is drawn limiting the height of the substrate going through the intersection of path of least resistance and edge 2. This straight line that limits the height of the substrate is drawn parallel to edge 1 as shown in Figure 9.2.2.9. The distance of path of least resistance is measured and modelled as c a2 in profis anchor channel software. By limiting the side edge distance to c a2 , we will reduce the perpendicular shear capacity. This is done by introducing stringent corner factor reflecting an acute angle corner effect. The substrate height is also measured and modelled in Profis anchor channel software. By limiting the height of the substrate we will introduce the height reduction factor, hence further reducing the overall capacity of perpendicular shear. Please refer to Figure 9.2.2.9 and Figure 9.2.2.10. The concrete at the corner is shared by the two anchor channels and therefore, using the AC232 provisions with the actual corner distance for analysis purposes can yield very unconservative concrete strengths. The crack will propagate along the path of least resistance at the corner instead of following idealized failure plane. Figure 9.2.3.1 shows an example of a FOS corner, where anchor channels are installed at the distance away from the corner that the failure planes do not intersect, hence there will not be any reduction in concrete breakout capacity in tension. A side edge distance of h eff + C cr,N at the corner should be provided to make sure that the planes do not intersect. Acute corners: Perpendicular Shear analysis æ c ö then y co,N = ç a2 ÷ ç c ÷ è cr,N ø