Chapter 23, Problem 23.18P

To determine

The correct readings of rod which are necessary on the batter board tops to set them properly.

  $5.61ft$

Given:

Floor elevation $1069.31ft$

Benchmark $A=1070.58ft$

Sight $A=5.34ft$

Concept Used:

This is one more method of layout of buildings, is to stake two points on the building, one of them with the total station instrument, take a backsight on the other and stack all the remaining points from that setup using pre -calculated angles and distances.

Calculation:

Calculate the height of instrument by adding bench mark $A$ and sight $A$ :

  $\begin{array}{l}HI=1070.58+5.34\\ HI=1075.92ft\end{array}$

Calculate the elevation value for batter roads by using the formula:

  $\begin{array}{l}{E}_b=Floorelevation+1ft\\ E_b=1069.31+1\\ E_b=1070.31ft\end{array}$

Now, we must determine the rod reading value at the batter rods by:

  $\begin{array}{l}{S}_{bb}=E_b-HI\\ S_{bb}=1070.31-1075.92\\ S_{bb}=-5.61ft\end{array}$

Conclusion:

Therefore, the rod readings are necessary on the batter board tops to set them properly is $5.61ft$ .