Concrete, Masonry, and Metals
Concrete, Masonry, and Metals covers the three structural material trades and the inspection and testing that prove compliance: FBC Chapters 19, 21, and 22, ACI 318 for concrete, TMS 402/602 for masonry, and AISC 360 with AWS D1.1 for steel. FBC Chapter 17 special inspections tie them together.
Concrete
- Acceptance is based on 28-day compressive strength from standard-cured cylinders, not the seven-day break, which is informational only.
- Sampling frequency: at least once each day concrete is placed, at least once per 110 cubic yards, and at least once per 5,000 square feet of slab or wall surface.
- Watch slump, air content, and placement temperature; hot-weather and cold-weather provisions apply, and curing is typically seven days of moist curing.
- Required cover, reinforcement placement, formwork removal, and reshoring are all inspection points.
Masonry
- Mortar type (M, S, N) follows the design; joints are nominally 3/8 inch, fully filled, with tooled concave joints for weather resistance.
- Grout, vertical and horizontal reinforcement, and embedment of anchor bolts must match the drawings; reinforced masonry requires special inspection.
- Flashing, weeps, and a drainage cavity are the water-management essentials.
Structural steel
- Welding follows AWS D1.1 with qualified procedures and welders; high-strength bolts follow the RCSC specification.
- Special inspection of welds and bolted connections applies to the structural systems listed in FBC Chapter 17.
- Field modifications of structural members are prohibited without the engineer of record.
Worked example
A slab project places 330 cubic yards over 22,000 square feet of surface, cast across two days. Frequency checks: once per day gives 2 sets; 330 / 110 = 3 sets; 22,000 / 5,000 = 4.4, so 5 sets. The area requirement governs - specify 5 sets, distributed so that at least one set is cast each placing day. Taking only 2 sets because there were 2 pour days would violate the volume and area rules.
Traps that cost marks
- Accepting concrete on a favorable seven-day break.
- Sampling per truckload instead of per the ACI frequency rules.
- Assuming mortar type is interchangeable, or leaving head joints unfilled on the exterior wythe.
- Cutting a beam flange or web for a pipe without engineering approval.
- Skipping special inspection on a welded moment connection because the shop is certified.