Product Technical Guides : US-EN Cast-In Anchor Channel Fastening Technical Guide | Page 356

1. Anchor Channel Systems 2. HAC Portfolio 3. HAC Applications 4. Design Introduction 5. Base material 6. Loading 11.5.1 COMPOSITE SLABS Composite slabs are one of the most common methods of steel frame floor construction; therefore, it is common substrate for anchor channels. Naturally, the use of anchor channels in composite slabs may bring additional challenges, especially for applications where anchor channel with rebar anchors or shear confinement plate is required. 9. Special Anchor Channel Design 10. Design Software 11. Best Practices 12. Instructions for Use 13. Field Fixes 14. Design Example 11.5.2 ALL-LIGHTWEIGHT CONCRETE VS SANDLIGHTWEIGHT CONCRETE ACI 318 and AC232 provide a modification factor for lightweight concrete (λ). Light weight concrete is sub-classified into two types; all-lightweight concrete and sand-lightweight concrete. The modification factor for all-lightweight concrete is equal to 0.75 while the modification for sand-lightweight concrete is equal to 0.85. Addressing the following potential conflicts before installation of the anchor channel system takes place may avoid issues, field fixes, and speed up the installation. Moreover, each condition can be evaluated based on actual conditions. 8. Reinforcing Bar Anchorage 11.5 SUBSTRATE CONSIDERATIONS 7. Anchor Channel Design Code POTENTIAL CONFLICTS ARE AS FOLLOWS: • Clashing of rebar with column • Clashing of rebars with metal deck • Corner conditions at corner columns • If rebars extend into the deck, check adequacy of rebar cover. The use of lightweight concrete in composite slabs is quite common. Generally speaking, anchor channels are constrained by the strength of the concrete. Lightweight concrete is commonly specified for composite slabs. Hence, the concrete strength due to an anchor channel is constrained even further. It is always a good practice to verify the type of concrete specified in the project. On one hand, simply assuming sand-lightweight concrete can result in unconservative results. On the other hand, assuming all-lightweight concrete when sand-light weight concrete is present can yield to more expensive designs. Chapter 5 (Base Material) provides additional information about all-lightweight concrete and sand-lightweight concrete. Determining what type of lightweight concrete use can present a challenge, as this information is not clearly specified all times. Aggregate grading specification Concrete unit weight pcf Normal-weight Fine: ASTM C33 Coarse: ASTM C33 145-155 Sand-lightweight Fine: ASTM C33 Coarse: ASTM C330 105-115 All-lightweight Fine: ASTM C330 Coarse: ASTM C330 85-110 ASTM concrete type Determination of lightweight concrete type 1) Check General Notes of project’s structural drawings. 2) Check concrete specifications of the project. 3) Reach out to the structural engineer of records for confirmation. Anchor channel in composite slabs; face of slab application 356 If there is project where there no enough evidence to support the use of sand-lightweight concrete for design purposes of the cast-in anchor channel, always assume all-lightweight concrete, as this is always the most conservative choice. Anchor channel in composite slabs; top of slab application Cast-In Anchor Channel Product Guide, Edition 1 • 02/2019 357