English to Portuguese Tech/Engineering Construction / Civil Engineering

Precisava de ajuda com esta expressão. Entendo o que é, mas não sei como fica em PT. Eis a definição que encontrei: "A fundamental concept during the design and construction phases is the pay item, the individual component that road construction and improvement projects are broken down into (so named because they dictate how the contractor will be paid for the work performed). An example of a pay item is sidewalk. If there is sidewalk to be constructed as part of the project, then the quantity of this pay item is estimated during design and measured after construction. The contractor is then paid based on the agree-upon unit price for sidewalk. Each pay item has a description (4.5 foot wide concrete sidewalk, four inches in thickness). Its unit property (linear feet in this example) specifies how it will be measured for payment."

Agradeço a ajuda que me puderem dar :)