A Program Management Approach : Master Schedule

e must use time as a tool, not as a couch.”? - John F. Kennedy

There is a multitude of activities that need to take place before construction begins. A properly developed master schedule links the critical activities during the pre-construction period (including design deliverables, design reviews, permitting, authority approvals, procurement, etc.) in a logical fashion so that construction can proceed at the earliest moment and without interruption.??

Overlapping Design & Procurement Activities?

Excavation and foundation work for super-tall buildings with deep basements can take years.?In urban areas, there are generally traffic and work hour restrictions that limit the number of trucks that can go in and out of the site and, therefore, limit the amount of earth that can be excavated each day.?If one million cubic meters of the earth has to be removed for the foundations and the average excavation rate is 2,000 cubic meters per day, the excavation alone would take 500 days.?Therefore, a fast-track delivery method that reduces the overall project duration by overlapping the design, procurement, and construction activities is typically implemented. This is done by working with the project team to ensure that early work packages such as diaphragm wall, piles, and excavation be awarded in advance of the completion of the design of the rest of the project.?While the diaphragm wall, piles, and excavation work are underway, the design and procurement continue.??

Owner Priorities & Construction Phasing

Another early task would be to understand the developer’s priorities and to establish an agreed phasing of the construction and turnover of the building. The design work would then need to allow for the phased handover of the areas in the sequences identified.?Issues such as compartmentalization of fire life safety systems, central plant location, chilled water supply, and public access are design elements that have to be coordinated with a phased handover.

Last Planner System?

Super tall buildings typically have repetitive floor plates which provide contractors with opportunities to improve safety, quality, coordination, and floor cycle times as the superstructure rises.?There is arguably no better method to do this than to implement The Last Planner System ? (LPS) combined with Flowline Planning.?A “Last Planner” is defined as a supervisor in charge of a trade performing the work who are in the best position to make realistic commitments on behalf of their crews.?Actively involving the “Last Planners” in the planning process results in better production, better coordination, less downtime, and less out-of-sequence work.???

LPS Process.?The LPS looks at what SHOULD be done, what CAN be done, and what WILL be done, and then measures what they actually DID.?It consists of four levels of planning, as described below:

• 1st Level.?The master schedule defines what SHOULD be done.?It demonstrates the feasibility of completing the project to the owner’s prescribed milestones, shows phasing requirements, and identifies long lead items.
• 2nd Level.?Phased Production Planning is a refinement of the master schedule showing how portions of the work will be done.?It defines activity durations and interdependence.?Examples of phase schedules are demolition, excavation and substructure work, superstructure (core & shell) work, interior fit-out, and finishes, phased handovers of the podium and tower (or other portions of the building), and testing & commissioning.
• 3rd Level.?Make Ready Planning is done to show the work that CAN be done.?It is to a level of detail that allows trades to identify their work activities and both upstream and?·???????downstream activities of other trades that are required to complete the work.?Primary goals include 1) making work ready by identifying and removing constraints such as missing design information or availability of materials, 2) matching workflow with the amount of labor, equipment, and materials available, and 3) ensuring that an adequate backlog of work is maintained to assure continuous work.?Make Ready Planning is created out of the Phased Production Plan.
• 4th Level.?The Weekly Work Plan shows what WILL be done based on commitments made by the Last Planners. These commitments are measured in terms of what they actually DID or Percent Plan Complete (PPC).
• 5th Level.?The team of Last Planners meets daily to review how the work has progressed and to ensure that the next pieces of work are ready for the follow on trades.?This Daily Huddle approach is part of a management system meant to help identify if the work is ahead or behind every day.

Flow line schedules visualize efficiency and allow contractors to adjust for trade stacking and out-of-sequence work.?These schedules plot the building location vertically and time horizontally.?The individual lines represent trades or crews.?The optimal work flow is when all trades plotted are parallel to one another so the goal is for other trades to tune themselves to the same rhythm on a floor-by-floor basis.??

4-D Scheduling

4D schedules are widely used and are an excellent way to visualize either the schedule or sequence of work without manually flipping through pages and pages of schedule data.?Building information modeling software can now be synchronized with scheduling software inputs which effectively and visually “builds” the individual elements.??

Case Study:?Taipei 101 Master Scheduling, Taipei, Taiwan

To ensure that Taipei 101’s retail podium was put into operation well in advance of the completion of the tower, a temporary diaphragm wall was installed to isolate the Tower from the Podium.?Furthermore, the podium employed top-down construction while the tower employed bottom-up construction.?A summary of milestones is included in the table below:

Taipei 101 Progress Photos.?The following series of photos depicts the early progress of Taipei 101, as an example of the results that can be achieved with effective Master Scheduling techniques.?