1. **Problem Statement:** Determine the value of $b'_c$ (the effective flange width or concrete cover dimension) in the context of the beam or slab design. 2. **Understanding $b'_c$:** In reinforced concrete design, $b'_c$ often refers to the effective width of the compression flange or the concrete cover to the reinforcement, depending on context. 3. **Formula and Rules:** If $b'_c$ is the effective flange width, it can be calculated based on code provisions, typically involving the beam width plus a portion of the slab width on either side. If $b'_c$ is concrete cover, it is usually a specified value for durability and fire protection, often given in the problem or design codes. 4. **Without explicit data, $b'_c$ cannot be calculated directly.** 5. **Recommendation:** Please provide more context or data about $b'_c$ (e.g., is it flange width, concrete cover, or another parameter) or any dimensions related to it. **Final answer:** Cannot determine $b'_c$ without additional information.