Striking off period in work program

Post date: Jun 20, 2015 5:02:58 PM

As a Planner or Project Manager, our work program often being scrutinized before being implemented to the project. It is a good practice to have an experienced executive from Client-side to review the period, resources and sequence of activities in the work program. However, at certain project we may encounter certain comments such as "the work program should indicate curing for substructures, just like the super structures". 

We can assume that such comments came from inexperience personnel (in site management) or over-smart personnel who try to implement JKR Building Standard without literally understood the criterion or criteria dictated in the specification.

As most engineers understand there is a need for some curing time before strike off. Now, please refer to Table 10 of Building Specification 2005 and Table 6.2 of BS 8110-1, then try to understand one thing in that table. 

Table 10 from JKR Building Standard Specification 2005

Table 6.2 from British Standard BS8110-1 Structural use of Concrete

The keyword for this respond is "Props" which make reference to false-works or temporary works which support the soffit of the cast structures. In the light of the use of prop for substructure does not make sense since most of these substructure soffits are fully supported by consolidated earth or lean concrete. Moreover, substructures are propped forever by the earth and its bearing capacity. Aside from that the lean con also props it after casting aside from giving clean working area. Removal of formworks for Superstructure may need prop accordingly on the slab soffit or bottom side of the beam.

Top: The sequence for substructures without need of waiting time prior to striking-off formworks

Bottom: The sequence for superstructures with additional waiting time prior to stricking-off formworks

The argument will arise when someone missed the important essence of the whole sentence and the definition reflected in the table. 

Aside from that, 

a. That 3 days for vertical side for column doesn't affect the construction of stumps since it doesn't affect the work on top of the foundation.

b. the side of the ground beams will remain as it is for ground slab casting.

c. the lag between concrete casting of the stumps and the trenching of the beam and lean con is more than 3 days.