#5 Tasks, sub-tasks and preceeding tasks in MS Project

We are building a model of the work activity in the computer which can be manipulated, more time or less time for specific tasks, increasing or decreasing resources,... add in cost factors,... then produce predictions of cash flow and potential profit.

This is just preliminary modeling, in reality the GC will use feedback from work in progress and previous projects to produce better predictions and target problem areas.

There is a limit to utility of fine grained task information for example;

-Concrete footings; date start, date completed.

or

-Concrete footings; establish rough grade, survey crew stake out and reference datum, excavate, test soil bearing, L&I inspector on site, set rebar, concrete slump/air entrain testing, pour concrete, protect concrete. Preceding tasks/event would be rebar shop drawings procedure and order for delivery, order concrete. Dependent tasks/events for which the concrete footings are a preceding event will be foundation walls and backfill.

The degree of information granularity will be driven by the needs of the information end user.

Information for use in the Request for Payment Voucher only requires completion or percentage completion of the item.

For a window system;

Internal GC tracking of required window system submittal materials will require dates for; contract documents provided to fabricator, fabricators shop drawing and delivery schedule, shop drawings received from fabricator, shop drawings submitted to arch/eng, shop drawing review received from arch/ eng, shop drawing review submitted to fabricator, fabricator delivery date, installation crew scheduled.

The GC's accounting system will track payments to the fabricator for shop drawings, partial payment to commence fabrication, payments for fabrication completion before shipping, payment upon deliver,... and installation crew costs.

Depending on the level of GC's management sophistication there will be an ability to predict if the task "window system" will be completed as scheduled and produce the targeted profit.

Column inputs;
MasterFormat numbers are a low priority at this time, but will be useful later for tracking items or create a link back to specification sections, if you have the time make a new excel column or change a heading on one of the columns you are not using.

Utility Trenching:
Trenching is by linear foot, same dimension for pipe or conduit length, when pricing this item as an assembly the assembly will have costs for bedding material and fill as part of the assembly.

If we cost for conduit trenching machine "DitchWitch" then it becomes a simple calculation based on machine rental with operator, installation crew and pipe or conduit material cost. A Ditch Witch type trenching machine for conduit or pipe up to about 6" diameter that can be assembled and jointed outside the trench has a cost advantage over a backhoe cut trench with 24" or 36" bucket, but large pipe sections that must be assembled and jointed in the trench will probably cost out lower with backhoe rather than the larger trenching machines. It is possible to install very large pipe with jointing outside the trench with a large trenching machine but economy of scale savings will not be present for short pipe runs or pipe runs with many lateral connections.

http://www.ditchwitch.com/trenchers-plows/heavy-duty

OSHA requires shoring of trenching more than 4ft deep for safety of workers in the trench and also for support of equipment adjacent to a trench. The type of shoring will be a function of soil type and trench width. A safe work space can be created without shoring by over excavating trench sides to produce benches at not more than 4ft vertical step, but requires more excavation, and will limit close proximity to the trench sides for large pieces of equipment. Use of DitchWitch type trenching machines reduces the need for the workforce to enter a trench.



The take-off assignment produces raw data that can be used with software to produce a base estimate, then GC will adjust with their own historical information from previous projects and call subcontractors or equipment rental companies to seek reductions in costs, reduce labor, reduce task duration time.

Assignment for Wednesday #6

Application and Certificate of Payment AIA form G702 and G703

Create an excel spreadsheet for G703 columns A through I add B2 Workforce, B3 Materials, B4 Equipment. B2 through B4 are for GC's internal use only and are not part of the Certificate for Payment:

Rows:

01 General Requirements

-Mobilization

-Erosion Control

03 Concrete

-Pads

-Light pole base

31 Earthwork

-Site Clearing

-Site Grading

-Cut and Fill

-Rip Rap

-Trenching

32 Exterior Improvements

-Asphalt Paving

-Curbs

-Striping and marking

-Fence

33 Utilities

-Potable water

-Sanitary Plumbing

-Stormwater system

Produce cost values for the above categories in B2 through B4, using National Construction Cost Estimator and unit quantities from the previous exercise. Use subtasks and assembly unit cost from the Estimator.

Coming next;
#6 Task cost estimate; workforce, materials, equipment.
#7 Task cost estimate; overhead, profit, competitive advantage
#8 Project bid cost estimate and documents required with bid
#9 Schedule of values /Project Schedule
#10 Payment voucher/cash flow