Construction Surveying
Core concepts
Construction surveying stakes the design. Candidates must understand horizontal and vertical alignment, stationing, cut and fill, slope staking, and as-built surveys. Tolerances, benchmark transfer, and the difference between design and as-built elevations are key. Layout of structures, utilities, and roadways all rely on control established before construction.
Traps
A common trap is sign confusion in cut and fill-cut means the existing ground is above design grade; fill means below. Another is stationing arithmetic: station 12+50 is 1,250 feet from the origin. Also watch for slope staking questions where the catch point must satisfy both the design slope and existing ground.
Worked example
Design grade at a station is 105.00; existing ground is 103.50. The difference is 1.50 feet of fill. If existing ground were 106.20, the cut would be 1.20 feet.
Rule of thumb
Cut = ground higher than design; Fill = ground lower than design. Station 10+00 = 1,000 feet.