PPP Notes - Scheduling

(These notes are compiled from Spreiregen's ARE Exam Review)

CHAPTER TWELVE - SCHEDULING OF DESIGN AND CONSTRUCTION

ARCHITECTURAL PROCESS

After the planning process has been concluded, and the site has been selected, the architectural team will begin to focus on the project, including the project's buildings and related infrastructure.  

Traditionally, the architect is faced with four components to every design decision:

1. Cost

2. Function

3. Aesthetics

4. Time

The new, sustainable ecological paradigm adds one additional component to form a pentagon of concerns.

5. Sustainability

The ingredients of the normal process have been discussed previously, but the new ingredient, sustainability, changes the meaning of all these pieces of this architectural process.

1. COST

As architects put together budgets for their clients, they are always concerned with the first costs of the design components - the initial cost to purchase and install the design element.

Sustainable design has made the economic decision process more holistic.  The decision to select a design element (such as a window, door, flooring, exterior cladding, or mechanical system) is now concerned with the "life-cycle" cost of the design.

1.1 LIFE-CYCLE COSTING

Life-cycle costing is concerned not only with the first cost, but the operating, maintenance, periodic replacement, and residual value of the design element.

For example, two light fixtures (A and B) might have different first costs: Fixture A has a 10 percent more expensive first cost than B.  But when the cost of operation (the lamps use far less energy per lumen output) and the cost of replacement (the bulbs of A last 50 percent longer than the bulbs of Fixture B) is evaluated.  Fixture A has a far better life-cycle cost and should be selected.

In this kind of comparison, the life-cycle cost may be persuasive; the extra cost of Fixture A may be recovered in less than two years due to more efficient operation and replacement savings.  

In this situation the architect justified Fixture A to the owner, who benefits from more energy efficient lighting that continues to save the owner operating costs for the life of the building.

1.2 MATRIX COSTING

While designing a typical project, the architect faces numerous alternate decisions, a process that may be both intriguing and complex.

In nearly all projects, there is an established budget and program (including all the owner's functional requirements).  The architect must balance the functional issues with the budgetary and aesthetic issues.

Sustainable design adds an ingredient to this matrix of decisions that may actually help the composition.

For example, decisions that allow the improved efficiency of the building envelope, light fixtures, and equipment may permit the architect to allow the engineer to reduce the size of the HVAC system, resulting in a budgetary trade-off.  The extra cost of the improved envelope may be economically balanced by the diminished cost of the mechanical system.

This type of economical analysis, which evaluates cost elements in a broad matrix of interaction, is a very valuable architectural skill.  The ability to understand the interaction between different building systems in a creative and organized fashion can differentiate an excellent architectural design from a simply adequate one.

2. FUNCTION

Functionality is one of the primary standards of architectural design.  If the building doesn't perform according to the client's needs, then the building design has failed.

Sustainability adds a facet to functionality that even the owner may not initially appreciate.

As previously mentioned, life-cycle costing will affect the decisions in which elements are finally selected to form the final design.  However, the search for sustainability may increase the dimensions of functionality.

Years ago, the design element could perform at the highest level regardless of its impact on the environment or energy use.

The fact that many industrial and residential buildings are operating much more efficiently now than in 1960 is evidence that the building design and construction process is learning how to tune buildings to a higher degree of energy operation.  But, with diminishing natural resources and increasing pollution of the environment, even more efficient design is necessary.

Today, architects will include sustainability in the selection of optimal functional design components.

For example, a roof system must be able to withstand a variety of weather conditions, be warranted to be durable a minimum of years, be able to be applied in a range of weather conditions, and have a surface with reflectivity that does not add to the urban heat effect.

3. TIME

The schedule of a project is always a difficult reality of the design process.  Time is a constraint that forces a systematic and progressive evaluation of the design components.

The sustainable component of the architectural process may add to the amount of time the architect will spend on the research for the project.

The architect may spend more time on a sustainable design with the result being a more integrated, sustainable project.

4. AESTHETICS

The aesthetic of a project is the combination of the artistry of the architect and the requirements of the project.

Sustainable design has the reputation of emphasizing function and cost over beauty and appeal.

It is the architect's responsibility to keep all the design tools in balance.  A project without aesthetic consideration will fail the client, its user, and the potential client that may be deciding between the normal design process and one that considers a broader, integrated, sustainable approach.

5. SUSTAINABILITY

The fifth point in the calculus of the architect is a new component that leads to a new, holistic evaluation of the design process.  Because a piece of any living element must be part of the cycle of nature in order to survive, all manmade elements should now consider the mantra, "do not harm and be designed to be integrated within the cycle of all living things."

Architectural designs should create by-products, that can be recycled with other natural elements and not cause depletion of natural resources necessary for the health of future generations.

Sustainable designs should have four goals:

1. Designs that use less

2. Designs that recycle components

3. Designs that have components that are easily recyclable

4. Designs that have components that are fully biodegradable

DESIGN SCHEDULING

ESTABLISHING A SCHEDULE

In furnishing professional services, an architect must prepare a time schedule that encompasses all phases of production, from initial conceptual planning to the start of construction.  The architect must plan the judicious and efficient use of manpower and resources to achieve an economical, functional, and harmonious design, executed within a reasonable period of time, and with an efficient utilization of personnel.  The managerial skills required for such planning and scheduling are based on experience and judgment.

To organize the schedule, the architect first separates the design effort into phases, which generally correspond to phases of the AIA standard owner-architect agreements as follows:

1. SCHEMATIC DESIGN

Consisting of schematic drawings and other documents which describe the general relationships and space requirements of the project, along with a cost estimate.

2. DESIGN DEVELOPMENT

Consisting of preliminary drawings, outline specifications, and other documents which describe the form, size, and materials of a project, and the structural, mechanical, and electrical systems to be utilized.  A preliminary cost estimate is also prepared during this phase.

3. CONSTRUCTION DOCUMENTS

Consisting of working drawings, final specifications, and a final cost estimate.

4. BIDDING OR NEGOTIATION

Which includes the receipt and evaluation of bids or negotiated proposals.  It may also include preparing addenda to the contract.  

5. CONSTRUCTION ADMINISTRATION

Consisting of the services rendered by the architect after bidding or negotiation to assure that the structure is built in accordance with the construction documents.  In this place the architect may issue change orders, approve shop drawings, choose or approve materials and colors, and issue payment approvals.

In complex projects, the five phases described may not be adequate.  For example, schematic design may be divided into conceptual design and schematic design.  Similarly, the construction documents phase may be organized into several subdivisions, so that work on one subdivision may be completed and bid before the next phase is begun.

The architect must estimate the time required for each phase of the work.  The schematic design phase is the most difficult to estimate, since it has the greatest amount of variability.  This phase of the work is usually done  by a small design team, generally headed by a chief designer, and possibly including an engineer and other specialists.  The design concept must be developed out of the skill and experience of the design team working closely with the client and each other.  Among the factors affecting the time required for schematic design are:

1. THE SIZE AND COMPLEXITY OF THE PROJECT

Complexity is generally considered more critical than size.

2. THE QUALITY AND COMPLETENESS OF THE PROGRAM INFORMATION SUPPLIED BY THE CLIENT

If the architect does not have an adequate statement of the client's requirements - a conclusive program - then it will be necessary to prepare one, or to improve what exists.  In contrast, an experienced client will often furnish the architect with a thorough and reliable catalog of needs, thereby enabling the architect to begin work immediately.  Such a client may provide the architect with information such as project goals, area requirements, functional relationships, zoning information, a site survey, and a budget.

3. THE DECISION-MAKING ABILITY OF THE CLIENT

If the client has a decisive representative who has the authority to make decisions, schematic design can proceed at a rapid pace.  On the other hand, if decisions require committee approval, or if they cannot be made expeditiously, schematic design time will be prolonged, with consequent loss of momentum.  If the client and architect do not have an effective communication system, the process is further delayed.

4. THE NATURE OF THE DESIGN TEAM

If the team is well balanced, if they work together harmoniously, if they are skilled and experienced, if they are able to work on the project without interruption, and if they can communicate readily with the client, then schematic design time will be kept to a minimum.

These factors illustrate it is difficult to plan a time schedule for schematic design.  For a simple, conventional project, schematic design can often be completed in one or two months.  It is not unusual, however, for the schematic design of a complex project to require 12 months or more.

The design development and construction documents phases of the work are much more predictable than schematic design, assuming schematic design has been thorough and there are no program changes.  A team of architects and drafters, headed by a project architect and/or job captain, develops the schematic design into preliminary design drawings, which are then developed into working drawings.  If the project is large in scope, staffing must be increased commensurately.  The length of time required to produce these drawings may not be directly proportional to the size of the project.  A $10,000,000 project, for example, may require only 50 percent more time than a $2,000,000 project.  The complexity of a project, rather than its size, determines scheduling and staffing requirements.  During the preliminary design and design development phases, close coordination between consultants, client, and designers is vital.

Design development for a typical project takes from two to four months; the construction documents phase may typically require from three to seven months.  The bidding or negotiation phase usually requires three to six weeks, regardless of the size of the project.

A less obvious factor that may influence the work schedule is project financing.  Whether the client is an individual, a partnership, a corporation, or a public agency, money is required to convert a design into reality.  Private clients may borrow money from a bank, while a public agency may have to obtain a bond issue.  The client may use the time between work phases to obtain a financial commitment and may, in some cases, postpone authorization to the architect to proceed with a successive phase until financing is secured.  This may take weeks or months for a private client and even longer for a public agency.

Client review and approval is customary between phases, and the time required for this will depend on the size and complexity of the project, as well as the ability of the client to make decisions.

Some projects require more than one client approval, which may lengthen the review period.  For example, many public school projects require the approval of a state department of education as well as a local school district.  Client review and approval usually takes between one week and one month, unless complications arise.

The time required for approval of plans by a building department or other public agency varies considerably, depending on the locality and type of project.  For example, a state hospital project, which may require approval by a state agency as well as the local building department, may require up to three months for plan checking.  In localities where the checking of plans is less critical, a building permit may be obtained within a week.

Application for a building permit requires the filing of construction drawings and specifications and this is often done near the conclusion of the construction documents phase so that the building permit is obtained at about the same time the construction contract is let.  This is not always the case, however.  Sometimes the application for the building permit is not made until after the bidding period, while in other cases, the permit is obtained before the bidding phase.  Whatever order is followed, the time required for plan approval should be considered by the architect in preparing the time schedule.

In completing the time schedule, the architect assembles all the time estimates into a bar graph, as shown in Figure 12.1.  The bar graph indicates ranges of time for each phase.  In an actual project, however, a specific period of time would be assigned for each phase.

CONTINGENCIES

In organizing the architectural production schedule, the architect must consider the possibility of unexpected problems that may arise.  There may be delays with the building department, consultants may need additional time because of unique problems inherent in the project, there may be staffing problems in the architect's office if the work load changes suddenly, or the client may be less decisive than expected.  For these and other reasons, it is wise to include a contingency factor in the schedule.  If the architect estimates the total required time to be eight months, an additional allowance of at least two to four weeks seems prudent.  

The schedule should be flexible and responsive to changing conditions.  For example, if the schematic design phase extends beyond its scheduled completion date, it should be possible to reduce the time allotted to design development and construction documents.

WORKING WITH A BUILDER

The preceding discussion assumes a conventional sequence of events in which the construction documents are completed before bidding or negotiation begins.  In recent years, however, closer methods of work coordination between the architect-engineer team and the builder have been developed.  Man architects now work closely with a contractor from the conceptual phase through the completion of working drawings.  A result of this cooperation is often a guarantee of maximum project cost, furnished to the owner by the contractor, upon completion of contract documents.  This is referred to as a GMP - a "guaranteed maximum price."

Working closely with a builder has a significant effect on the architect's production schedule.  More time must be given to schematic design if the architect is to produce a concept that the contractor considers economical.  Design development, likewise, may take more time; however, construction documents will probably take the same time.  Since the time during which the drawings are being prepared overlaps actual construction, overall project time is generally shortened.  But there are risks in this procedure that the building design may not be fully developed or the components fully resolved.

Regardless of the procedure followed, the working drawings and specifications must be complete, clear and correct.  In some cases where the architect works closely with the contractor who will construct the project, the documents may be less specific, allowing the contractor leeway in procedures, details, and materials.  But this practice can be risky for both, and hence, should be restricted to common or repetitive projects.  With close architect/builder cooperation, the bidding and negotiation phase may be omitted entirely, since these activities become a continuous process.

The total scheduled production time is usually similar to what it would be if the project were done conventionally.  The architect's staff hours, however, may be greater because of the time spent coordinating with the contractor and possible redesigning.  There are no short cuts; architectural projects require attention to detail, and invariably that takes time.

EXTENDING THE SCHEDULE

All creative activity requires time, which should be enough to absorb information and develop ideas, but not so much that momentum and interest lag.  For architectural design, an optimum work schedule is one in which the necessary work can be accomplished comfortably without expanding or shortening the schedule.

On a project with an extended schedule, principal team members may retire or take other positions before completion of the work.  A recent state college project was delayed four years, between design development and construction documents, because of lack of funding.  When the project resumed, the original project architect, mechanical and structural engineers, and key client personnel had made career changes.  The resumption of work entailed starting over.  The groundwork had to be re-established, resulting in wasted time and effort. 

One of the most significant effects of an extended design schedule is the increased cost due to inflation.  In the recent past, inflation ran as high as 1 percent per month.  At that rate, a $10,000,000 project that is delayed two months would cost the owner an additional $200,000.  The additional cost resulting from the delay of a project may cause it to be terminated or reduced in scope.  For example, in the case of the state college project mentioned above, the original project budget could not be increased during the four-year delay, and therefore the scope of the project had to be reduced by about one-third.  The facility as finally built was smaller and of lower quality than it would have been without the four-year delay.

SHORTENING THE SCHEDULE

Clients often want their projects completed in as short a time as possible.  During periods of inflation, there is additional pressure to shorten the design schedule.  The purpose of any schedule, however, is to make optimum use of staff effort and resources.  Therefore, to achieve significant reductions in time, one or more of the follow methods must be employed:

1. The architectural team works overtime.  While this saves time, it is costly and inefficient.  A person working a ten-hour day over a long period of time cannot consistently produce 25 percent more work than someone working an eight-hour-day.

2. Hire more people, bring in part-time freelance staff, or subcontract work to another firm.  All of these solutions are possible and will probably save time, but they are also costly and inefficient.  New staff people will not be familiar with office procedures or the particular project, and their competence is unknown.  Part-time people may be experienced and competent, but they are usually expensive.  Subcontracting to another firm is feasible, but this is expensive, and coordination and supervision may be awkward.

3. Reduce the man-hours spent on the project.  This generally results in a lower-quality job.  Quality work requires adequate time to produce, and if that time is not available, an incomplete set of working drawings and specifications may result.  Under these circumstances, one can expect documents which are incomplete, unclear, and likely to contain errors and inconsistencies.  That, in turn, implies future problems, delays, and excessive change orders during construction.

Thus, the net effect of a reduced time schedule is likely to be a higher cost for design, a higher cost for construction, and a lower quality project.  During periods of high inflation, an owner may be willing to tolerate a degree os increased costs with decreased quality, but this decision should be made only with the client's full appreciation of the consequences.

Methods of shortening both the design and construction schedule, simultaneously, will be described shortly.

CONSTRUCTION SCHEDULING

ESTABLISHING A SCHEDULE

By their very nature, all construction projects are complicated, since they involve the work of numerous trades and subcontractors, all of which must be coordinated.  Equipment must be utilized efficiently; materials must be ordered, stored, and used in a logical sequence; and accurate time schedules and costs must be recorded.

When a contractor prepares a construction schedule for a project, it is generally based on past experience.  But no two projects are alike, no two site are the same, and therefore construction scheduling estimates must be tempered with judgment.  Contractors must consider a number of factors, including the following:

1. THE CONSTRUCTION DOCUMENTS

If these have been well prepared, relatively few problems or delays may be expected.  Conversely, a poor set of working drawings or specifications will lead to disputes among the architect, contractor, and subcontractors.  Such disputes consume considerable time.

2. THE ARCHITECT-ENGINEER

Some architects and engineers are extremely demanding regarding the interpretation of the contract documents.  Others are less demanding and more amenable to changes.

3. THE SUBCONTRACTORS

The contractor must evaluate their ability to perform the work properly and on time, and to coordinate their work with others.

4. THE CONTRACTOR'S ORGANIZATION

The skills of the project manager, field superintendent, and the office and field staffs must be considered in relation to the specific project.  Some managers and superintendents are more capable of expediting the work than others.  Also, the particular work load of the contractor will influence his ability to divert staff and equipment to and from the project under consideration.

5. MATERIAL DEALERS

The contractor must assess their reliability in meeting delivery schedules on time and correctly.

6. THE SIZE AND COMPLEXITY OF THE PROJECT

Complexity is one of the most critical elements in planning a construction schedule.

7. SITE CONDITIONS

The size and accessibility of a construction site work area are critical factors in schedule planning.  So is the condition of the site itself - its drainage, vegetation, subsoil, etc.

8. THE WEATHER

This is important, especially in the colder areas of the country, where projects may have to be shut down during snowstorms, heavy rainstorms, or periods of extreme cold.

9. THE POSSIBILITY OF LABOR TROUBLES

10. THE POSSIBILITY OF MATERIAL SHORTAGES

Or the delay in obtaining critical equipment.

The contractor must estimate the time required for each construction operation and the sequence of these operations in order to establish the schedule.

CPM (CRITICAL PATH METHOD)

The first step in developing a "critical path" is the planning phase, in which a diagram is drawn indicating the order in which the various operations comprising the project are to be accomplished.  The project is divided into concise tasks called "activities," and these are represented by arrows on the CPM chart.

Each activity has a definite start and finish represented by circles, and referred to as "events" or "nodes."  An "event" is defined as that moment when a preceding activity has been completed and the following activity may begin.  Important points in the construction process, such as the roofing of a new building, are referred to as "milestone events."

In CPM planning there is no indication of time; the arrows are not drawn to a time scale.  The tail of an arrow indicates the start of an activity and the head of an arrow, the finish, and each arrow is associated with a start and finish event.  No new activity can be started until activities represented by all the previous arrows have been completed.

The completed CPM diagram is known as a network diagram.  The network must be continuous, with no gaps or discontinuities.

(Visuals in book)

In the network diagram shown in Figure 12.2, activity A starts at event 1 and terminates at event 2.  Activities B and C cannot start until A is completed.  Activities B and C can proceed simultaneously; however, activity D cannot start until C is completed.  Activity E, starting with event 4 and finishing with event 5, cannot start until both activities B and D are completed.  The construction of a footing support on drilled cast-in-place concrete piers will now be considered.

Excavation of earth, construction of footing forms, and procurement of reinforcing steel can all proceed independently of each other.  Drilling of piers follow excavation.  Pier steel cannot be set until after both drilling of piers and procurement of pier steel have been completed.  Pouring the piers follows setting of pier steel.  Footing forms are set after both pouring of piers and construction of footing forms have been completed.  Setting footing steel proceeds after both setting footing forms and procurement of footing reinforcing steel are completed.  Finally, pouring footing follow setting footing steel.

The network diagram for the work described above is shown in Figure 12.4.  Note that each activity starts and finishes with an event, shown as a numbered circle, and that the end event, always has a higher number than the starting event.  Each event number occurs only once in the network.

While the pier-supported footing is a simple project, it serves to illustrate the value of CPM in job planning.  The network is a model of the project, and its preparation requires the contractor to analyze the job logically from start to finish.  The diagram communicates the job logic far better than any verbal description or bar graph.

Sometimes different portions of a project are planned separately, with separate network diagrams.  For example, a project may consist of two buildings with connecting utilities.  Events common to both networks are called interface events, and are usually shown as in Figure 12.3.

CPM SCHEDULING

After the project has been divided into concise activities and their logical sequence has been determined and charted in the network diagram, the time required for the project must be determined.  Thus far, only the activities and their relationships have been considered; now the element of time is applied to the chart.

The contractor estimates the time required for each activity, based on past experience.

A normal working day is taken as the unit of time.  The assumption is made that materials and labor will be readily available, and that a normal level of labor and equipment will be utilized.  Where subcontractors are involved, the contractor may consult with them regarding the time required to perform their specific activities.  The estimated activity times in working days are now noted on the network diagram below each arrow.

In preparing an accurate time estimate, the reliability of the subcontractors is critical.  A general contractor, therefore, should be familiar with the subcontractors and their work, and consider only those who are pre-qualified or otherwise highly dependable.

CRITICAL PATH

The simple project illustrated in the network diagram includes several paths, from start to finish, and each has a varying total time duration.  For example, path 1-2-3-4-5-6-7-8 requires a total time of 1+1+1+1+2+1+1=8 days.  Path 1-5-6-7-8 requires 2+2+1+1=6 days.  Since each path must be traversed to complete the project, the total project time is established by the path with the longest total required time.  This is known as the critical path, and is generally shown as the heavy line.  In this diagram in Figure 12.5, the critical path is 1-6-7-8, with a total time of 14+1+1=16 days.

The activities along the critical path are called critical activities - in this case consisting of procuring reinforcing steel, setting footing steel, and pouring footings.  If a critical activity is delayed, it will delay the completion of the project.  These activities, therefore, must be carefully monitored during construction in order to keep the project on schedule.

FLOAT

All paths in the network diagram, other than the critical path, are called float paths.  The float is the difference in time duration between the critical path and any other path.  Path 1-2-3-4-5-6-7-8, which requires 8 days, has a float value of 9, since it is 8 days shorter than the critical path time of 16 days.  Similarly, Path 1-5-6-7-8, which requires 6 days, has a float value of 10.  The float, then, is a measure of the extra time available for an activity or group of activities.

As long as float time is not exceeded, no delay in project completion time will result.  The path 1-2-3-4-5-6-7-8, for example, which we have determined to have a float value of 8, can be delayed up to 8 days without delaying project completion.  This delay can occur in one or more activities along the path, providing the total delay does not exceed 8 days.  The delay may occur only in activities from 1 through 6, since 6-7 and 7-8 form part of the critical path.

PROJECT CALENDAR

The contractor, having determined that the finish date of the project is 16 working days after its start, now converts this to calendar days by multiplying by 7/5, since there are five working days in each seven-day week.  (16 x 7/5 = 22.4, say 23 calendar days).  Knowing the project starting date, the contractor can calculate the completion date, as well as the start and finish dates of all activities.  He now establishes a project calendar, indicating the scheduled starting and completion dates of all the activities within the project.  Critical activities are noted in color or boldface, since any delay in the schedule of these activities will delay completion of the project.

If the job schedule has been prepared carefully and realistically, the field work will proceed at an efficient pace.  If excessive time has been allowed for certain activities, a more relaxed pace may result, leading to increased labor and overhead costs.

There can be great variation in the duration of construction projects, depending on the factors mentioned previously.  However, most building construction projects require from 9 to 18 months.

CONTINGENCIES

A realistic schedule should incorporate an allowance for project delays caused by weather or other unforeseen events.  A reasonable allowance can be made for the number of working days expected to be lost because of weather, depending on the season and the activity.  Obviously, it is impossible to be precise regarding potential delaying factors such as accidents or labor strikes.  Some contractors add a fixed percentage to the total estimated time to allow for such possibilities, or they may incorporate contingency provisions in the construction contracts.

CPM CALCULATIONS

The example of a pier-supported footing describes a simple project; however, the same logic and scheduling technique is used on large and complex projects.  CPM programming can be done at a simple level or a complex one.  Computer programs designed for CPM have proven very useful, once the basic activity sequencing and activity times are known.  CPM is an extremely helpful planning and management tool, and its use in construction planning and scheduling has become almost universal.

BAR GRAPHS

Bar graphs have long been used for planning and scheduling construction projects.  They indicate the starting and finishing dates of major phases of the work and can be clearly understood by all concerned.  Their main disadvantage is that they do not indicate the relationship between the sequence of activities, or the dependency of an activity on the completion of a previous activity.  The bar graph therefore is inferior to CPM as a management tool, but superior to CPM as a means of visual communication.  Bar graphs, such as the one shown in Figure 12.6, continue to be widely used in construction.

SHORTENING THE SCHEDULE

There are a number of reasons why an owner may want the use of his building as quickly as possible.  Among these are the demands of business, which is often the case for commercial or industrial facilities.  Other reasons may be to minimize the effects of inflation, inclement weather, or the persistent costs of interest on borrow construction funds.

The CPM method demonstrates that one of the most effective methods to save construction time is to reduce the critical path time.  Although the activities on the critical path may amount to only 25 or 30 percent of all the project activities, reducing them reduces the whole construction schedule.

Shortening the durations of the critical activities will very likely increase direct cost, because inefficiency is increased through added overtime work.  Increasing the number of workers is also inefficient because supervision and coordination become more difficult.  In general, the contractor's direct costs increase as the schedule is compressed into a shorter-than-normal time.  

On the other hand, the contractor's overhead decreases as the schedule time is shortened.  Since the total project cost is the sum of direct costs and overhead, and their effects by shortening the schedule are opposite, a contractor may find it worthwhile to analyze their effects and determine a balance which represents the lowest total project cost.  A computer can be highly useful in doing this for a complex job.

Maintaining quality control becomes more difficult as the schedule time is shortened.  Errors are more likely to occur because of the increased difficulty of proper supervision.  The highest project quality is achieved when the project schedule is normal, that is, neither extended nor shortened.

If it is necessary to shorten the project schedule, the CPM network diagram can be analyzed to determine if the job logic can be modified, or if certain activity durations can be condensed.  Individual activity times can be expedited by adding man-hours and equipment, recognizing that this will result in higher direct costs and will place greater demands on supervision.

FAST-TRACK SCHEDULING

Shortening design and construction schedules generally results in higher design costs, higher construction costs, and reduced quality.  However, by combining the architect/engineer's design schedule with the builder's construction schedule, it is possible to realize an overall saving of time in completing the entire project.  This technique is known as "fast-track," "accelerated," or "telescoped" scheduling.  In this procedure, the architect first determines the major building elements, such as the column spacing, foundation system, mechanical systems, etc., before the detailed arrangements are worked out.  The architect then produces detailed working drawings for a portion of the work on which the contractor may begin construction - site work, utilities, foundations, or possibly framing.  Meanwhile, further detailed architectural design continues so that the architect produces his work just slightly ahead of the construction crews.

This approach requires close coordination among architect, engineers, client, and contractors.  Since the design concept of building elements is established very early, oversights must be expected, and the correction of errors is generally an integral part of fast-track scheduling.  However, major design revisions are all but precluded, except at very great cost.

Fast-track scheduling usually requires staged bidding, in which the project is organized into a number of separate stages or contracts - as many as 20 or 30 - that are awarded to different contractors at different times.  Thus, it may not be possible to obtain a fixed price for the entire project in advance of construction, as with conventional contracting that employs one general contractor.  However, to assure some degree of cost and time control and establish responsibility, a construction manager (CM) may be used to supervise the construction process.  Most contractors are able to function either as general contractors or construction managers.

Construction management may also be performed by architectural firms.  But large and complex jobs are usually better served by those who expertise is in the actual construction of buildings.

A comparison of conventional and fast-track scheduling for a $7,000,000 hospital is shown in Figure 12.7, indicating that the construction would be completed seven months earlier if fast-track scheduling were used.  As design and construction become more complex and the use of building systems more widespread, we can expect that methods of design and construction scheduling will become more logical, increasing the use of computers for planning and management.

SUMMARY

Some architects may find their roles expanded to that of developer, builder, or manager.  Whatever the role, it will be essential for the architect to become familiar with new management techniques, since they will have an increasing influence over how future construction work is done.