Formwork MCQ with answer and solution

Concept

Formwork removal period for concrete slabs

Formula

NONE

Step-by-step solution

1. Formwork stripping time guidelines are specified based on structural element type and span length. 2. According to standard building codes, props to slabs spanning up to 4.5 m can be removed after 7 days. 3. For slabs spanning over 4.5 m, the required period for prop removal is 14 days. Answer: A

Explanation

According to standard concrete construction codes, vertical props supporting concrete slabs with spans up to 4.5 meters can be removed after 7 days, as the concrete gains sufficient initial strength. For slab spans exceeding 4.5 meters, the required period increases to 14 days. Therefore, 7 days is the required stripping time for a 4.5-meter span slab.

Why the other options are wrong

B) 14 days is required for props to slabs spanning over 4.5 m or props to beams spanning up to 6 m. C) 21 days is required for props to beams and arches spanning over 6 m. D) 28 days is the standard concrete curing duration, not the formwork removal time for 4.5 m slab props.

Shortcut

Props removal for slabs: 7 days for span up to 4.5 m; 14 days for span over 4.5 m.

Common mistake

Confusing the 7-day prop removal requirement for slabs up to 4.5 m with the 14-day period required for spans over 4.5 m.