Precast concrete framing consists of concrete beams, columns, hollow-core floor planks, and other components manufactured in a controlled factory environment and transported to the construction site for assembly. Factory production allows quality control, consistent curing, and reusable forms, often reducing overall cost compared to cast-in-place concrete. Precast members are typically post-tensioned (using high-strength steel cables tensioned against the concrete) to improve strength and reduce deflection. Hollow-core floor planks are rectangular concrete members 6 to 12 inches thick, 2 to 4 feet wide, and up to 60 feet long. The hollows reduce weight while maintaining structural strength and allow flexibility in roof and floor design. Pretensioning (applying tension to reinforcement before concrete is placed) or post-tensioning (after concrete hardens) provides efficient strength. Manufacturing quality is consistent due to controlled temperature, humidity, and curing conditions. Precast concrete is transported by truck and lifted into place using cranes. The large size of typical precast members (20 to 50 tons) requires heavy-duty equipment and rigging. Assembly on site involves setting members on temporary supports and making connections with bolts, welds, or epoxy. Concrete connections must develop adequate strength to transfer loads. Some connections use bent-plates welded to embedded plates; others use bearing and bolt connections. The erection sequence is critical; temporary bracing prevents lateral movement until permanent connections are complete. Hollow-core planks must be supported properly to prevent cracking during lifting. Topping concrete (2 to 4 inches) is often poured over precast floor systems to create composite action and provide a uniform surface for floor finishes.