Back to Basics 2 - Scheduling 101

15th August 2016 | By TBH

4D modelling is used to plan and schedule projects and offers better clarity to all project team members on how the project is to be delivered. This particular screenshot is of the Centre for Obesity, Diabetes and Cardiovascular Disease (CODCD).

To deliver important and significant projects, you must have a good plan in place to draw up a schedule. A reliable schedule is crucial to ensuring your project is completed on time with a minimum of stress and delays.

Delays don’t just mean cost blow-outs. In many circumstances, and more significantly, they also mean missed opportunities and foregone revenue when a project is held-up.

Planning and scheduling are two separate but connected parts and each part is only as good as the other. At TBH, our experience and knowledge can help you build the foundations for an interconnected plan and schedule that will help you achieve your project aims.

Once you have your plan in place, the next step is to produce a schedule, which can take many forms.

The most commonly used schedule is called a gantt chart or linked bar chart where activities are laid out as bars on a timescale and the activities are connected to each other by logic. The simplest example is if you’re building a house, you start by building the floor, then the walls and then the roof.

In most projects, it’s much more complicated than that but a linked bar chart demonstrates how the activities in a project are connected and depend on each other.

We then apply a “critical path method analysis” which establishes how long it takes to finish the project once all the activities are connected. The critical path controls when the project will be delivered and tells us which of the activities are most critical to achieving the end date.

Contingencies for delays are built into a schedule in two primary ways.

The first is by adding a discreet activity at the end of the bar chart and calling it the ‘delay allowance’. The second way is to take each activity on the chart and apply a contingency allowance to all of them. However, this should not be applied uniformly but as depending on the type of activity and the impact the delay event would have on it.

For example, in the early stages of a building project, when there is excavation work, we’ll add extra contingency time of potentially 20% while the project is still in the ground for the additional effects of inclement weather. Nearer the end of that same project, we may apply only an extra 5% to an activity because by then the work has moved above ground or is primarily internal.

Another form of scheduling we use is called the time chainage diagram. This is appropriate for projects that have an element of repetition such as high-rise buildings, rail or road projects. This kind of scheduling reflects that, for example, when you build 40 kilometres of road, you build a one-kilometre stretch and then effectively repeat that same process 40 times.

For big projects, time chainage diagrams also allow for the work to progress in a way that isn’t necessarily from beginning to end. You could be building several stretches of the road simultaneously and linking them if necessary.

For example, when TBH planned for Vodafone’s 3G/4G roll-out, it was clear 2000 relay towers over Australia were not going to be built one by one. A time chainage diagram allows for crews to build multiple relay towers at once and shows how crews and resources are to be deployed around the country.

More often we are also using 4D modelling to plan and schedule our clients’ projects. In this way we maximise the use of visualisation to test planning assumptions, logical conflicts and offer better clarity to all project team members on how the project is to be delivered.

On any given project, there is always the possibility for a worse-case scenario that cannot reasonably be allowed for. But there are always variables that can be taken into account before you break ground and good planning and scheduling are your tools to delivering the project (with changes included) on time, on budget and meeting your objectives.

Not sure what all 4D modelling is about? Click here to view our 4D Showreel.

Disclaimer: This article does not constitute advice, legal or otherwise, and is provided only as general commentary. Appropriate professional advice should always be obtained before taking or refraining from taking any action in relation to such information and/or the application of applicable law. This article and the materials contained in it are provided on the basis that all liability for any loss or damage, whether direct or indirect, arising out of or in connection with any use or reliance upon this article is excluded to the fullest extent permitted by law.