Piling and foundations: identify the incorrect statement
-
AThe wall (foundation) is made thicker at the base in a stepped fashion to spread load
-
BA long, vertical, load-transferring concrete element is called a concrete pile
-
CA pile that transfers load to soil through interface resistance is called a friction pile
-
DA pile that transfers load to a hard rock bed at depth is called a load-bearing pile
-
ENone of these
Answer
Correct Answer: A pile that transfers load to a hard rock bed at depth is called a load-bearing pile
Explanation
Introduction / Context:Foundation terminology distinguishes how piles transmit loads: by end bearing, by shaft friction, or by a combination. Accurate naming avoids confusion in design documents, specifications, and site communication.
Given Data / Assumptions:
- Spread footing walls are often stepped thicker at the base to disperse loads.
- Piles are long vertical elements used to transfer loads to deeper, stronger strata.
- Load transfer mechanisms include tip (end) bearing and skin friction.
Concept / Approach:The technically correct term for a pile that carries load to a firm stratum or rock at its tip is an end-bearing pile. While all piles are load-bearing in a general sense, using “load-bearing pile” as a specific type is imprecise and nonstandard; it should be “end-bearing.” Thus the statement that labels the type as “load-bearing” is incorrect.
Step-by-Step Solution:Verify a: stepped base spreads load → correct.Verify b: definition of a concrete pile → correct.Verify c: friction pile definition → correct.Evaluate d: incorrect terminology; correct name is “end-bearing pile.”
Verification / Alternative check:Codes and textbooks explicitly classify piles into end-bearing and friction (or combined) piles; “load-bearing pile” is a generic phrase, not a type.
Why Other Options Are Wrong:a, b, c accurately describe standard practices and definitions.e (None) is invalid because an incorrect statement exists (option d).
Common Pitfalls:Using loose site jargon in formal design notes; mixing general descriptors with specific technical classes.
Final Answer:A pile that transfers load to a hard rock bed at depth is called a load-bearing pile is the incorrect statement; the correct term is “end-bearing pile”.