FTG ENG | eBooks

Missing embeds, anchor bolt issues and elevation errors Before concrete is poured, anchor bolts and steel embeds must be placed in the correct location, requiring you to inspect, lay out, and perform QA/QC on these components before the erection process begins. If any of these elements are missed or incorrectly positioned, you could be looking at expensive back charges and rework. Elevation is critical as well. The elevation of the top of bolts must allow for proper grout beds, base plates, washers, and double nuts to lock in the columns. Embeds that are just 1" too low can mean the top of the beam is not properly welded or bolted into place, requiring a complete tear out or re- engineering. Lack of information and improper fabrication Factory-produced steel components require accurate measurements. You must be able to gather dimensions for basic installation, and oftentimes for complex shapes and curves as well, so you can provide it to the fabrication shop. But when dimensions have to be tracked down, you waste time and hurt your productivity. And if those measurements are off and the critical structural components are improperly fabricated, you'll be looking at expensive rework. In addition to the hefty costs involved in refabricating the steel components themselves, you'll also have to invest additional equipment, resources, and energy to correct the issue. Incorrect rebar placement The integrity of the entire project is dependent on accurately positioning structural rebar in their correct locations, such as around door openings, block outs, sleeves, and corners, to ensure a lasting structure and less rework in the field. If there are errors at this phase of construction, though, it can impact the way concrete covers the rebar. Cover is the single most important factor in protecting reinforcing steel from corrosion. It's also necessary to assure that the steel bonds to the concrete well enough to develop its strength. Incorrect placement of these core infrastructural components can lead to unpredicted corrosion and concrete structural failures.

• Cover