CDS Materials & Equipment Knowledge 3

Question 1

What equipment is used to conduct a 'structure-borne vibration' assessment during near-structure demolition blasting?

Accepted Answer

Seismograph

Answer

A seismograph measures ground vibration velocity (in/s) to ensure blasting does not exceed damage thresholds for adjacent structures.

Question 2

Which crane attachment configuration provides the highest level of reach and precision for high-rise demolition work?

Accepted Answer

Long-reach excavator with shear attachment

Answer

Long-reach excavators with hydraulic shear attachments can precisely cut structural steel and concrete at elevated heights while maintaining stability.

Question 3

What is the OSHA-required minimum safe standoff distance factor when using explosive demolition near occupied buildings?

Accepted Answer

It is calculated based on charge weight and must conform to OSHA 1926.909 and ATF requirements

Answer

Safe standoff distances for explosive demolition are calculated using the charge weight-to-distance formula per OSHA 1926.909 and applicable ATF regulations.

Question 4

Which property makes post-tensioned concrete slabs uniquely hazardous during demolition compared to conventionally reinforced concrete?

Accepted Answer

Cutting tendons releases stored tensile energy that can propel debris violently

Answer

Post-tensioned tendons are under high stress; cutting them releases sudden energy that can cause concrete to fracture explosively and fling debris.

Question 5

What is the primary advantage of using a wire saw for cutting thick concrete walls compared to other methods?

Accepted Answer

It can cut virtually unlimited thicknesses without repositioning

Answer

Diamond wire saws can cut through sections of any thickness and are ideal for large or irregular concrete elements that exceed other saw capacities.

(CDS) Certified Demolition Supervisor Practice Test

(CDS) Certified Demolition Supervisor Practice Test

CDS Materials & Equipment Knowledge 3