Cold Weather Protection

We are using this document to estimate durations for certain activities on civil engineering
projects. The document is one used by the US Military and reflects the productivity rates of
military personnel. Commercial civil engineering contractors would have better productivity
rates. We will use an adjustment factor of 1.7 to convert from the military rate to the
commercial rate.
Units – The manual uses imperial units. We therefore have to convert to metric units. Note
that conversion factors are given in Appendix D.
Labour Estimates (Chp 4)
A man-day is a unit of work performed by one person in 8 hours. The “man-day” is set as
standard and does not change. The number of hours for an assigned workday may change,
but a man-day is always 8 hours.
Steps in the Labour Estimating Process

1. Create a list of construction tasks that require labour. Decide on the size of the
   labour gang that will be applied to the task.
2. Create a labour estimating worksheet for each construction activity and list
   subordinate construction work elelments on the estimating worksheet
3. Identify each construction activity’s quantity of work (i.e. material quantity) from the
   material and equipment estimates
4. From the tables in Chp 5, select an appropriate work rate. Note that the rates are
   presented as man-hours per unit e.g. 0.007 man-hours per square foot - it takes
   0.007 man hours to complete one square foot.
   Example
   We will look in more detail at reinforced concrete construction. It is important to
   understand what is included in the rates given. The explanations on pages 5-13, 5-14 are
   key and you need to read and understand these. Taking two examples:
5. Labour for Forming: Labour required for forming includes fabrication; handling into
   place; erection and oiling; installing form ties, tie wire, struts, chamfer strips, and
   screed guides; bracing and shoring; erecting runways and scaffolds; and checking
   forms during placement of concrete. Stripping includes removing, cleaning, and
   reconditioning forms. Forming is usually computed in square feet of contact surface,
   which is the area of concrete in direct contact with forms or in linear feet of form
   length required. Screed guides should be computed as the equivalent form length of
   an edge form.
6. Labour for Reinforced Concrete. Concrete is reinforced with steel bars or with
   welded steel wire mesh that is used for reinforcing slabs, gunite, and precast
   concrete. In some applications, wire mesh and bars are used in combination for
   Duration Estimating using US Military Construction Estimating Edition Dec 2010, Ver 1.0 last revised 30/11/20
   Page 2 of 3
   reinforcing. Some tables show both bars and mesh, so that the appropriate
   manhours per unit may be used. Reinforcing steel is computed in tons of bars.
   Reinforcing mesh is computed in square feet of the area. Labour for reinforcing steel
   includes handling into place, tying, supporting, and any cutting that becomes
   necessary at the site, such as cutting around embedded materials or cutting stock
   lengths of straight bars to fit slab dimensions. Labour for wire mesh reinforcing
   includes handling into place, cutting to fit, tying at overlaps, and pulling up into
   position during placement of concrete.
   Additional descriptions are given for
7. Labour for mixing concrete – this would be an unusual task as we generally use ready
   mixed concrete
8. Labour for placing Concrete
9. Labour for Finishing Concrete
10. Labour for Curing Concrete
11. Fine Grading Process
12. Vapour Barrier Placement
13. Expansion Joints
14. Cold Weather Protection