CDS CDS Structural Assessment & Demolition Methods 1 — Questions and Answers
Question 1: What is the primary purpose of a pre-demolition structural assessment?
- Estimate total labor costs for the project
- Identify structural systems, load paths, and potential collapse hazards (Correct answer)
- Select recycling and waste hauling vendors
- Obtain project insurance quotes from carriers
Correct answer: Identify structural systems, load paths, and potential collapse hazards
A pre-demolition structural assessment identifies load-bearing elements, structural systems, and hazards to plan a safe and controlled demolition sequence.
Question 2: Which demolition method uses long-boom excavators with attachments to systematically dismantle a structure from the top down?
- Implosion
- Wrecking Ball
- High-Reach Mechanical Demolition (Correct answer)
- Hydraulic Bursting
Correct answer: High-Reach Mechanical Demolition
High-reach mechanical demolition uses long-boom excavators equipped with demolition attachments to remove a structure from the top down in a controlled manner.
Question 3: Wrecking ball demolition is most appropriate for:
- Structures located directly adjacent to sensitive utilities
- Heavy reinforced concrete or masonry structures with adequate surrounding clearance (Correct answer)
- High-rise buildings over 20 stories tall
- Light wood-framed residential structures
Correct answer: Heavy reinforced concrete or masonry structures with adequate surrounding clearance
Wrecking ball demolition is most effective on reinforced concrete or masonry buildings where there is adequate clearance from adjacent structures.
Question 4: What is progressive collapse, and why is it a key concern during demolition?
- A planned sequence of floor-by-floor removals
- Uncontrolled sequential failure of structural elements beyond the intended demolition zone (Correct answer)
- A method of gradually sorting recyclable materials
- The slow settling of soil after excavation
Correct answer: Uncontrolled sequential failure of structural elements beyond the intended demolition zone
Progressive collapse is the uncontrolled failure of adjacent structural elements triggered by an initial collapse, posing a major safety risk during demolition.
Question 5: Which structural system typically requires temporary shoring before interior demolition to prevent premature collapse?
- Non-structural curtain wall cladding
- Load-bearing masonry walls (Correct answer)
- Glass storefront facades
- Suspended acoustical tile ceilings
Correct answer: Load-bearing masonry walls
Load-bearing masonry walls carry floor and roof loads, so they require temporary shoring before removal to prevent unplanned structural collapse.
Question 6: Implosion (explosive demolition) is best suited for:
- Small wood-frame residential buildings
- Large, isolated reinforced concrete or steel structures with an adequate fall zone (Correct answer)
- Structures immediately adjacent to occupied hospitals
- Sites with a high water table and weak soils
Correct answer: Large, isolated reinforced concrete or steel structures with an adequate fall zone
Implosion is most appropriate for large, isolated reinforced concrete or steel buildings where a sufficient exclusion zone can be established around the structure.
CDS CDS Structural Assessment & Demolition Methods 1
What is the primary purpose of a pre-demolition structural assessment?