Question

You are responsible for the grading and excavation on the work site. Your level (transit) reads 6.4 ft on a leveling rod that has been set up on top of a benchmark that has a given elevation of 100.0 ft. The finish grade as shown on the blueprints is 96.80 ft. Calculate what the rod reading should be on the finished grade after all fill has been placed, compacted, and graded?

3.20 ft
-3.20 ft
6.40 ft
9.60 ft

Answer 1

The new rod reading after grading and excavation to achieve the finished grade of 96.80 ft, when starting from a benchmark elevation of 100.0 ft with a current rod reading of 6.4 ft, is 3.20 ft.

Step-by-step explanation:

The question asks to calculate the new rod reading once the grading and excavation work has been completed to achieve the finished grade level on a construction site. Given that the current level reads 6.4 ft on top of a benchmark with an elevation of 100.0 ft, and the finish grade is 96.80 ft, we can calculate the rod reading at the finished grade.

The difference in elevation between the current benchmark elevation and the finish grade is 100.0 ft - 96.80 ft = 3.20 ft. Therefore, once the site has been lowered to the finish grade, the transit should read the current reading minus the difference, which is 6.4 ft - 3.20 ft = 3.20 ft. This will be the rod reading on the finished grade after all work has been done.

To calculate the rod reading on the finished grade after all fill has been placed, compacted, and graded, you need to find the difference between the benchmark elevation and the finish grade elevation.

In this case, the difference is 100.0 ft - 96.80 ft = 3.20 ft. Since the transit reading at the benchmark is 6.4 ft, you subtract the difference from the benchmark reading: 6.4 ft - 3.20 ft = 3.20 ft.