CHST Concrete, Masonry, and Formwork Safety

Question 1

Under OSHA 29 CFR 1926.703, who must design formwork shoring systems that support cast-in-place concrete?

Accepted Answer

A qualified person such as a licensed engineer

Answer

OSHA 1926.703(a)(1) requires formwork shoring to be designed by a qualified person — in practice a licensed engineer — who accounts for construction loads, lateral pressures from fresh concrete, and dynamic effects. A foreman or 30-hour card holder does not meet this design standard.

Question 2

What is the minimum rated compressive strength concrete must achieve before formwork and shoring can be removed?

Accepted Answer

Sufficient strength to support its own weight and construction loads, as determined by a qualified person

Answer

OSHA 1926.703(e) requires that formwork not be removed until the concrete has gained enough strength to support itself and any construction loads, as determined by a qualified person — typically via cylinder testing or maturity monitoring. There is no universal fixed time or single percentage threshold; it depends on mix design, curing conditions, and structural loading.

Question 3

OSHA requires masonry walls over what height to have adequate bracing to prevent overturning during construction?

Accepted Answer

10 feet

Answer

OSHA 29 CFR 1926.706(b) requires that masonry walls over 8 feet in height be adequately braced to prevent overturning and collapse until permanent supporting elements are in place. The 8-foot threshold triggers the mandatory bracing requirement.

Question 4

During a concrete pour, a form suddenly bulges outward at the base. The FIRST corrective action should be:

Accepted Answer

Stop the pour immediately and evacuate workers from the affected area

Answer

Form bulging indicates imminent failure from excess lateral pressure. The immediate priority is life safety — stop the pour and evacuate all personnel from the hazard zone. Continuing the pour at any rate risks progressive collapse. Engineering consultation follows evacuation, not precedes it.

Question 5

What specific hazard does OSHA address in 29 CFR 1926.702 regarding bulk cement storage silos?

Accepted Answer

Engulfment hazard from entering an in-service silo

Answer

OSHA 1926.702(j) prohibits workers from entering bulk cement storage bins, tanks, or silos that are in service due to the engulfment hazard from flowing cement, which can bury a worker in seconds. This is analogous to grain entrapment in agriculture and is specifically addressed in the concrete subpart.

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST Concrete, Masonry, and Formwork Safety