It was not until the first world war that simple bar charts were employed by the British army for planning military exercises. The construction of the Empire State building (which began in 1930, well before the invention of modern scheduling techniques) was a marvel of scheduling excellence. The site in downtown Manhattan was so congested there were virtually no lay down areas. Expediters at the materials’ source had to arrange for delivery to coincide precisely with installation. The building’s 58,000 tons of structural steel were erected in six months at the remarkable rate of 4.5 floors per week, all without the aid of a critical path method (CPM) schedule or a computer.
With the development of cheap, powerful computers, scheduling entered a new era. Today’s project schedules can usually be handled by one person and result in sophisticated graphical output. A word of caution, however: a schedule that is produced by one person in a vacuum, without input from those who will actually build according to the schedule, will be absolutely useless.
The Need for Construction Schedules
Owners and contractors agree that completing a project as quickly as possible is a common goal, although for different reasons. And with different expectations. Contractors will use the schedule as a planning and management tool that determines the overall approach to the job, organizes and plans labour and equipment, and helps organize materials purchasing and deliveries, sub-contract awards, and shop drawing submittals.
Owners will use the contractor’s schedule to monitor progress and see when the job will be completed. The schedule will help to plan and monitor cash flow requirements and determine when owner-supplied materials and equipment must be delivered.
Construction projects continue to increase in size and complexity. So does the demand to build more quickly and economically. In 1982 (reprinted in 1992), The Business Roundtable issued a report entitled “Modern Management Systems, A Construction Industry Cost Effectiveness Project Report” in which the authors state –
“The construction industry has been criticized, to a large extent justifiably, for its slow acceptance and use of modern management methods to plan and execute projects. Many people both inside and outside the industry view this as the primary cause of serious delays in schedules and large cost over-runs that have plagued the construction industry in recent years. Yet there is no lack of modern, cost effective management systems that provide project managers with all the controls they need. But many owners do not seem to be aware of the economic payoff from the appropriate use of modern management systems, and therefore are unwilling to incur the costs of operating the system.”
While there are obvious benefits to proper scheduling – and potentially saving money is a pretty compelling reason – why do many contractors not want to provide owners with a schedule? Why do owners not seem willing to pay for the scheduling from which they will ultimately benefit? Over the years, we have heard many reasons like high expense, lack of usefulness, too much effort required, and, “We’ve only been on the job for six months and the owner says we’re seven months behind schedule. How can that be?”
This final example illustrates a fundamental lack of knowledge about how to read and understand the schedule, and demonstrates a frequently encountered problem. There is generally a lack of proper training in the preparation, understanding, and use of schedules in the construction industry. This is apparent not only in contractors but also owners, architects, and engineers. The other issues listed above are more challenging to resolve, but there are solutions.
Today, many universities and technical colleges offer scheduling courses, and many excellent books have been written on the subject. There are also companies that provide customized in-house training in scheduling.
Construction companies require sufficient sales volume to justify employing a full time scheduler. Unfortunately, this is often an entry-level position for a recent graduate who may know how to manipulate software but knows little about construction. In most small and medium sized firms, the project manager is often the scheduler. Having a project manager who has been properly trained to create schedules makes good fiscal sense; the benefits will ultimately far outweigh the cost of training.
The “Partnered” Approach to Scheduling
A partnered project is one where all the project stakeholders – owner, contractor, architect, engineer and consultants – get together and agree to work together to successfully achieve the common goals of the project. A dispute resolution process or ‘ladder’ is established clearly, setting out the method, roles, and responsibilities of each party. The basic principles of partnering can be applied to assist project teams in working together to plan and schedule complex projects.
A case in point was a complex bridge rehabilitation project running behind schedule due to weather and an extreme shortage of skilled labor. The owner was also anxious to make up the lost time and accelerate the work to achieve an early completion. Rather than argue about who was responsible for the delays and their associated costs, the contractor and owner held joint or ‘partnered’ schedule update meetings. During these meetings, detailed discussions were conducted regarding the previous month’s progress and the issues to be dealt with by the
stakeholders. Having the computerized schedule projected on the wall during the process allowed the participants to examine the issues and study the matter, generating good constructive dialog. Both parties had time to present their concerns and to ask questions of the other. Delays were noted and agreement was usually reached on responsibility for the individual delays. This approach requires goodwill and an honest attempt by all parties to progress the job, save cost, and avoid litigation. It may not be easy to achieve, but it can and has been done very successfully.
Resource and Cost Loaded Schedules
The critical path of a schedule is usually defined as the sequence of activities that will take the longest time to complete, and is calculated by summing the duration of each activity falling on the critical path. To be useful, the duration of scheduled activities must be based on factual data and not guesswork or the use of horoscopes and crystal balls.
For example, if we know one crew can install 10 widgets in a day, there are 100 widgets to be installed, and only one widget installation crew is available, it will take 10 days – no less – to install all the widgets. The critical path is often driven by the resources available to complete activities that lie on the critical path. In other words, the critical path flows through the resources.
A simple illustration would be a high-rise apartment building with one tower crane. The project schedule may call for pre-cast concrete panels to be installed externally on the tower, at the same time that formwork is to be relocated on the adjacent underground parking structure, and the elevator rails are to be lifted into the elevator shaft. Clearly one tower crane cannot perform these three tasks simultaneously. If at the outset of the project the schedule had the tower crane defined as a resource and scheduled accordingly, the conflicting resource usage would have been detected and the work rescheduled.
This is known as resource loading the schedule. The properly resource loaded schedule allocates all resources, including labour and equipment, for each activity on the schedule, allowing the project manager to plan the most efficient and effective use of the resources available and to monitor productivity. It also records the planned sequence of events and the logical relationships between them.
Computerized Schedules vs. Squared Paper
Built in the1930s, the Empire State Building was obviously planned and scheduled without the aid of powerful computers and modern scheduling software; it was most likely scheduled using squared paper and a pencil. The success of the project is testament to the power of such a ‘primitive’ scheduling system.
There are many situations today where a piece of paper and pencil are better and faster than using a computer. For example, a project manager may produce a so-called “fragnet” on site to plan a specific sequence of tasks to be performed in a short period of time. A ‘squared paper’ schedule may also be used to schedule the use of a material hoist or tower crane. The big advantage of a hand produced schedule in such cases is that a computer and printer are not required and the schedule can be put to use immediately and is easily adjusted. The usefulness of a hand-drawn schedule should not be under-estimated, providing, of course, that the information contained in the schedule is accurate.
There can be no question, however, that computerized schedules have made the once daunting task of producing and updating large complex schedules much faster and easier. In addition, most scheduling software allows a project manager to examine alternate sequences of events by performing a ‘what-if’ analysis.
The time and effort spent preparing a proper initial project schedule, and performing subsequent regular monitoring is well spent and pays dividends on the final result of the project. As stated by the Business Roundtable, “Owners are the ultimate beneficiaries of improvements in cost, schedule, and quality of their construction projects”. Perhaps owners should give serious consideration to recognizing the importance of schedules and adding an independent bid item for scheduling. Since contractors will also benefit from properly prepared and updated schedules, consideration should be given to investing in schedule training and continuing education for key contractor employees.
Rest assured that, in construction at any rate, it is not a good idea to plan your project on the basis that “the sooner we get behind schedule the more time it gives us to get caught up.”