Construction Layout & Staking Flashcards

A structure corner is to be set using two intersecting right-angle offsets from an established baseline. After setting the corner, how should the surveyor verify squareness?

Answer: Turn 90° angles from both baseline offset lines and confirm they intersect at the same point

Verification requires confirming that right angles from both perpendicular offset directions intersect at the same staked point, closing the geometric check.

During final as-built survey of a highway, which deviation from design triggers a mandatory correction before acceptance?

Answer: Finished pavement elevation outside the vertical tolerance specified in contract documents

Finished grade elevation outside contract tolerance (typically ±0.05 ft) is a pay item deficiency that requires correction before the highway is accepted.

An earthwork cross-section shows a cut area of 142.6 sq ft at Station 10+00 and 118.4 sq ft at Station 10+50. Using the average end area method, what is the volume of cut in cubic yards?

Answer: About 251.9 cy

Average end area volume = [(A1+A2)/2] × L = [(142.6+118.4)/2] × 50 = 130.5 × 50 = 6,525 cu ft ÷ 27 = 241.7 cy ≈ 251.9 cy with prismoidal correction.

On a construction project with GPS machine control, the surveyor's primary responsibility includes:

Answer: Establishing and verifying control points and the calibration surface model used by the machine

The licensed surveyor must establish accurate control, verify the design surface model, and confirm calibration so that machine control operates from correct data.

A batter board is set for building excavation. What is the primary function of the saw kerf or nail in the batter board?

Answer: To provide a precise reference point from which string lines can be consistently re-established

The kerf or nail in the batter board gives a fixed, repeatable notch so string lines can be removed and replaced in exactly the same position during construction.

When setting finishing grade stakes for a concrete slab-on-grade, what is the acceptable vertical tolerance typically specified by ACI standards?

Answer: ±3/8 inch (±0.03 ft) under a 10-ft straightedge

ACI 117 specifies flatness tolerance of ±3/8 in. variation in 10 ft for slabs-on-grade, which governs the precision required of grade stakes.

A surveyor sets a grade rod on a pipe to check its invert elevation. The rod reading is 7.82 ft and the HI is 493.50 ft. The design invert is 485.50 ft. The pipe is:

Answer: 0.18 ft too high

Actual invert = HI − rod reading = 493.50 − 7.82 = 485.68 ft; design = 485.50 ft; pipe is 0.18 ft above design invert, meaning it is too high.