What is the standard unit weight used for concrete in shoring calculations?

• A. 35 pcf
• B. 150 pcf
• C. 490 pcf
• D. 100 pcf

Answer: (B)

In shoring calculations you convert the volume of material to a weight by using a standard unit weight. For normal-weight concrete, that standard is 150 pounds per cubic foot. This value reflects typical mix designs, aggregate, and compaction, and it’s the baseline used in field manuals and structural guidelines. So, any volume of concrete you’re designing around is multiplied by 150 lb/ft^3 to estimate the load the shores must carry. For quick context, 1 cubic yard of concrete equals 27 cubic feet, which weighs about 4,050 pounds (27 × 150).

Other unit weights don’t fit typical concrete: one option is far too light for concrete, another is lighter than standard concrete, and another approximates steel rather than concrete. The 150 pcf figure remains the standard for most shoring calculations unless you’re specifically dealing with lightweight concrete or specialty mixes, which would require adjustment.