Building repairs — what is the term for supporting an existing structure by adding supports beneath it? Identify the correct name for the technique of giving additional support to an existing building or structural element by introducing new support directly under the existing foundation or load path.

Introduction / Context:
During renovations, foundation settlement remediation, or when adjacent excavations threaten stability, engineers may need to support an existing structure. Different techniques exist, and it is crucial to use the correct terminology to communicate scope and method in drawings, specifications, and permits.

Given Data / Assumptions:

• Existing structure requires additional support beneath existing foundations.
• Goal is to transfer loads to deeper or stronger strata or to widen the bearing area.
• Temporary vs. permanent support distinctions are relevant.

Concept / Approach:

Underpinning specifically refers to introducing new supports below the existing foundation level to strengthen or stabilize the structure. Approaches include pit underpinning, mini-pile underpinning, beam-and-base, and resin injection methods. Shoring, by contrast, braces walls laterally (e.g., against earth pressure) and is usually temporary. Jacking is an action (lifting with jacks), not the overall technique. Piling forms deep foundations for new construction or as part of underpinning but is not itself the name of the remedial scheme in general context.

Step-by-Step Solution:

Verification / Alternative check:

Standard building codes and repair manuals categorize underpinning separately from shoring; method statements for underpinning include excavation in short lengths, sequencing, and monitoring for settlement/tilt.

Why Other Options Are Wrong:

• (a) Shoring provides lateral/temporary support, not new foundation support.
• (c) Jacking is a lifting operation, often used within underpinning but not the method name.
• (d) Piling is a foundation type; without context it is not synonymous with underpinning.

Common Pitfalls:

• Using “shoring” and “underpinning” interchangeably in BOQs can cause scope errors.
• Ignoring staged excavation and load transfer sequencing can endanger stability.

Final Answer:

Underpinning.