CDS CDS Structural Assessment & Demolition Methods 2 — Questions and Answers
Question 1: What is the primary purpose of a demolition sequence plan?
- List approved recycling and salvage vendors
- Specify the order of structural element removal to maintain stability and worker safety (Correct answer)
- Calculate disposal fees and tipping charges
- Identify all permit requirements for the project
Correct answer: Specify the order of structural element removal to maintain stability and worker safety
A demolition sequence plan defines the order in which structural elements are removed to control the demolition process and prevent unplanned collapse.
Question 2: Robotic demolition equipment is primarily deployed:
- For large open-air demolitions of isolated structures
- In confined spaces or high-hazard areas too dangerous for an operator (Correct answer)
- To replace all traditional mechanical demolition methods
- Exclusively for exterior facade removal
Correct answer: In confined spaces or high-hazard areas too dangerous for an operator
Robotic demolition machines are deployed in confined, low-headroom, or high-hazard environments where it is unsafe to place an operator inside.
Question 3: How does selective demolition differ from total demolition?
- Selective demolition uses only explosive methods
- Selective demolition removes specific components while preserving the rest of the structure (Correct answer)
- Selective demolition applies only to residential buildings
- Selective demolition does not require permits
Correct answer: Selective demolition removes specific components while preserving the rest of the structure
Selective demolition targets specific components — walls, floors, or systems — for removal or salvage while leaving the remainder of the structure intact.
Question 4: What is the key structural hazard when demolishing a post-tensioned concrete floor system?
- The dark color of the concrete surface
- Stored tension in steel tendons that can release violently if improperly cut (Correct answer)
- The decorative finish applied over the slab
- The age of the original concrete mix design
Correct answer: Stored tension in steel tendons that can release violently if improperly cut
Post-tensioned tendons are under significant prestress; improper cutting can cause sudden, violent release of stored energy, posing a serious safety hazard.
Question 5: In a pre-demolition structural assessment, what does a load path analysis determine?
- The preferred truck routing for debris haul-off
- How gravity and lateral loads are transferred through the structure to the foundation (Correct answer)
- The total weight of demolition debris generated
- The routing of electrical circuits within the structure
Correct answer: How gravity and lateral loads are transferred through the structure to the foundation
A load path analysis traces how gravity and lateral loads flow through structural members to the foundation, informing the safe sequence of removal.
Question 6: What is the primary hazard associated with demolishing older steel-framed buildings with riveted connections?
- Accelerated corrosion of nearby rebar
- Unexpected release of residual stress causing sudden member movement or collapse (Correct answer)
- High electrical conductivity of the steel
- Low recycling value of riveted steel sections
Correct answer: Unexpected release of residual stress causing sudden member movement or collapse
Riveted steel connections can retain residual stress, and their removal can cause sudden, unexpected movement or collapse of adjacent structural members.
CDS CDS Structural Assessment & Demolition Methods 2
What is the primary purpose of a demolition sequence plan?