Product Technical Guides : US-EN Cast-In Anchor Channel Fastening Technical Guide | Page 180

1. Anchor Channel Systems 2. HAC Portfolio 3. HAC Applications 4. Design Introduction 5. Base material 6. Loading 11. Best Practices 12. Instructions for Use 13. Field Fixes 14. Design Example Uncracked Concrete ψ c,V = 1.4 Anchor channels located in a region of a concrete member where analysis indicates no cracking at service load levels. If c a2 < c cr,V then ψ co,V = (c a2 /c cr,V ) 0.5 ESR-3520 Equation (35) where: c cr,V = 0.5 · s cr,V = 2c al + b ch in. (mm) ESR-3520 Equation (36) Note: if cracked concrete conditions are assumed, and supplementary edge reinforcement as defined in ESR-3520 Section 4.1.3.3.3 is used, ψ c,V can be increased to either ψ c,V = 1.2 or ψ c,V = 1.4. The modification factor for anchor channels located in a concrete member with h < h cr,V , ψ cr,V (an example is given in Figure 7.4.2.7), shall be computed in accordance with Eq. (37). c a1 is measured perpendicular to the anchor channel longitudinal axis, and is considered when calculating the basic concrete breakout strength in shear (V b ) and the modification factor for member thickness (ψ h,V ). - b h - 2 h ch ö æ c c a 1, red = max ç a 2,max ch , ÷ , in . ( mm ) 2 2 ø è ESR-3520 Equation (39) where c a2,max is the largest of the edge distances perpendicular to the longitudinal axis of the channel. For this example, the value of c a1,red is obtained by moving the failure surface forward until it intersects the corner as shown. No supplementary reinforcement With supplementary reinforcement æ ö h ÷ y h, V = ç ç ÷ h è cr, V ø ESR-3520 Equation (38) • Cracked concrete with edge reinforcement (#4 min.) h cr,V = 2c a1 + 2h ch h ch … height of anchor channel β 1 ... G  iven in ICC-ESR alternatively a default value of 0.50 shall be used h cr,V … critical member thickness Cracked concrete ψ c,V = 1.0 b 1 £ 1.0 ESR-3520 Equation (37) ψ c,V = 1.2 180 Figure 7.4.2.8 — Example of an anchor channel influenced by two corners and member thickness (in this example c a2,2 is decisive for the determination of c a1,red ) Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019 181 • Cracked concrete with edge reinforcement (#4 min.) and stirrups (#4 min.) spaced at 4” O.C. Cracked concrete conditions with no supplementary reinforcement → ψ c,V = 1.0 ESR-3520 Equation (34) Where an anchor channel is located in a narrow member (c a2,max < c cr,V ) with a thickness h < h cr,V (see Figure 7.4.2.8), the edge distance c a1 in Eq. (31), (33), (36) and (38) shall not exceed the value c a1,red determined in accordance with Eq. (39). If c a2 ≥ c cr,V then ψ co,V = 1.0 ψ h,V : The modification factor for member thickness. Anchor channel influenced by two corners and member thickness (c a1,red ) ψ c,V : T  he modification factor for cracked/uncracked concrete. Figure 7.4.2.7 — Example of an anchor channel in a member with a thickness h < h cr,V Figure 7.4.2.6 — Example of an anchor channel loaded in shear with anchors a) influenced by one corner and b) influenced by two corners. Concrete is typically assumed to be cracked under normal service load conditions. If cracked concrete conditions are assumed, an increase in V cb,y is permitted via the modification factor ψ c,V if supplementary edge reinforcement is used. If uncracked concrete conditions are assumed, an increase in V cb,y is likewise permitted via the modification factor ψ c,V . Reference ESR-3520 Section 4.1.3.3.3 for more information. Note: in order to activate the reinforcement, concrete has to crack. Therefore, if uncracked concrete is assumed, supplementary reinforcement does not impact this factor. ψ co,V : T  he modification factor for corner effect for an anchor loaded in shear perpendicular to the channel, shall be computed in accordance with Eq. (34) or (35). If an anchor is influenced by two corners (as shown in Figure e), then the factor ψ co,V shall be computed for each corner in accordance with Eq. (34) or (35) and the product of the values of ψ co,V shall be inserted in Eq. (30). 10. Design Software ψ c,N = 1.4 1 1.5 1.5 1.5 é æ ù é ö æ s ö V ù s ö V ù é æ s V 1 + ê ç ç 1 - 2 ÷ ÷ × 2 ú + ê ç ç 1 - 3 ÷ ÷ × 2 ú + ê ç ç 1 - 4 ÷ ÷ × 2 ú ê è s cr, V ø V 1 ú ê è s cr, V ø V 1 ú ê è s cr, V ø V 1 ú ë û ë û ë û Figure 7.4.2.5 — Example of an anchor channel with different anchor shear forces. 9. Special Anchor Channel Design y s, v,1 = 8. Reinforcing Bar Anchorage The parameter s cr,V corresponds to the maximum distance that is assumed with respect to the influence of an anchor element on the anchor element being considered. Any anchor elements that are within s cr,V from the anchor element being considered are assumed to have an influence on that anchor element. The calculated value for s cr,V will be the same for each anchor element if the c a1 value is the same for each element; however, the number of anchor elements within the distance s cr,V from the anchor element being considered may not always be the same. Reference ESR-3520 Equation (33) for more information on how to calculate s cr,V . Example for finding s cr,v is demonstrated below. 7. Anchor Channel Design Code