Question

In construction and accordance with OSHA,

1. Cement blocks (CMU) can be used to level a scaffold frame as long as the block is placed on its side with a scaffold base plate placed firmly on it.

2. For trench and excavation safety, shoring supports should be removed from the bottom up.

3. For trench and excavation safety, closed sheeting must be used in saturated or submerged soil.

Answer 1

1)Yes cement blocks can be used to level a scaffold frame with certain conditions as follows

a)The cement block should be a solid block and not hollow.

b)The cement block should be placed on well compacted soil ot concreted floor

c)The strength of the cement block should be sufficient to carry the point load from the scaffold.

2)No for the trench and excavation safety,shoring supports should be removed from top down.This is because the earth pressure will be more at the bottom.Removing the bottom shoring may lead to sudden sliding of the earth without any indication.Whereas, by removing from top down,we can avoid the sudden collapse of the soil.

3)Yes for the saturated and submerged soilclosed sheeting must be used.This is because the closed sheeting will ensure the soil from sliding into the trench.But holes must be provided on the sheeting ,so that the water flows into the trench and it should be dewatered continuously.If the holes are not provided,then along with earth pressure,water pressure will be added to the sheeting,and this may lead to damage of the sheeting and finally collapse of the soil