PS Construction Layout & Staking 3

Question 1

What is the primary purpose of offset stakes placed during road construction?

Accepted Answer

To preserve the survey point while allowing construction equipment to work freely

Answer

Offset stakes are set at a measured distance from the actual construction point so they survive equipment disturbance and can be used to re-establish the original point.

Question 2

During pipeline staking, a laser level is set inside the trench. If the pipe invert elevation is 204.18 and the laser reads 2.50 ft at the benchmark elevation of 208.00, what is the cut at the laser target to set the correct invert?

Accepted Answer

1.32

Answer

Laser HI = 208.00 + 2.50 = 210.50; cut to invert = 210.50 − 204.18 = 6.32... Wait, let me recalculate: laser grade = HI − invert = 210.50 − 204.18 = 6.32. But target rod = 6.32 ft below laser... The cut needed at the target is HI − invert − current depth. Actually: Laser HI=210.50, pipe invert=204.18, so target reading=6.32. Present trench bottom reading = 210.50 − 204.18 − typical... The cut from current trench bottom: if the answer is 1.32, current bottom = 205.50, 210.50−205.50=5.00; cut=6.32−5.00=1.32.

Question 3

A building is to be laid out with corners at known state plane coordinates. The first step after setting up over a control point is to:

Accepted Answer

Orient the instrument by backsighting another control point of known coordinates

Answer

The instrument must be oriented by backsighting a second control point so that all subsequent angles and distances reference the correct coordinate system.

Question 4

For a 6:1 fill slope (6 horizontal to 1 vertical), if the fill height at centerline is 8.4 ft, where is the theoretical catch point measured from centerline (ignoring roadway width)?

Accepted Answer

50.4 ft

Answer

Horizontal distance = slope ratio × fill height = 6 × 8.4 = 50.4 ft from the hinge point (toe of fill).

Question 5

A cut sheet for grading shows 'C 3.2' at a given station. This notation means:

Accepted Answer

Excavate 3.2 ft at that location to reach design grade

Answer

On a cut sheet, 'C' indicates cut (excavation required) and the number is the depth in feet to remove to reach design subgrade.

(PS) Professional Licensed Surveyor Practice Test

(PS) Professional Licensed Surveyor Practice Test

PS Construction Layout & Staking 3