Question

A ten story hospital has to constructed with the footprint of 45,000 ft^2. Subsurface soil consist of soft clay layer of 10 ft. Deep pile foundation will be used for supporting the building. The depth of pile foundation will be the 15ft.

Required:
a. Determine number of the boring to be used for the subsurface investigation using NYC Code Mandate discussed in the class.
b. Also determine the depth of the boring to be used for subsurface investigation.

Answer 1

a) approximately, the number of bores to be used is 17

b) depth of the boring is 25 ft from ground level

Explanation:

Given the data in the question;

we know that; The New York City Code mandate; deep foundation clause Number 1802.4.1 states that required number of borings shall not be less than two boring

i.e a minimum Number of 1 boring per 2000 square foot for the first 20,000 square foot and one boring per every additional 4000 square foot

so;

number of the boring to be used for the subsurface investigation using NYC Code Mandate will be;

⇒ 20,000/2000 + [( 45,000 - 2000)/4000]

= 10 + 6.25

= 16.25 ≈ 17

approximately, the number of boring to be used is 17

b)

the depth of the boring to be used for subsurface investigation will be;

⇒ 10 ft + 15 ft

= 25 ft

Therefore, depth of the boring is 25 ft from ground level