Gantt chart
The timeline bar chart, Gantt diagram or Gantt chart was conceived by the American engineer Henry L. Gantt between 1903 and 1917. The basic technique is quite simple, consisting of a graphic representation based around two axes: the vertical axis features tasks and the horizontal axis shows time.
Gantt attempted to solve the activity scheduling problem so that the duration of a basic task was seen on a horizontal bar,showing its start and completion date, and in the same way the total time required in executing an activity. It is the most widespread scheduling method as it adapts well to both small and large projects of all types, assuming they are not overly complex. It is the most commonly used method of scheduling works in the construction industry and can be easily understood, even by those less familiar with scheduling tools.
The preparation of the chart may include a range of basic data spread over columns:
- Activities, according to the order in which they are carried out.
- Budget or cost.
- Quantity in its corresponding units.
- Predicted performance for working equipment.
- Duration of the activity.
The time unit used may be days (short projects), weeks (medium term projects) or months (long-term projects). The beginning and end of each horizontal bar represents the start and completion date for the corresponding task and so the length of the bar is therefore proportional to the duration. The last two rows of the chart may detail the cost or budget per unit of time in addition to that accumulated since the project began.
The figure below shows a simplified Gantt diagram, indicating the tasks and their monthly distribution for the first break-down level as well as the tasks which comprise the critical path and the float.
Gantt charts can be very effective in the initial planning stages, but the graphics can become confusing when changes are made and they have serious limitations for complex projects. It was these difficulties which gave rise to the development of more complex network diagrams.
The text in this article is based on an extract from CONSTRUCTION MANAGEMENT, by Eugenio Pellicer, Víctor Yepes, José M.C. Teixeira, Helder Moura and Joaquín Catala. Valencia, Porto, 2008. The original manual is part of the Construction Managers’ Library – created within the Leonardo da Vinci (LdV) project No: PL/06/B/F/PP/174014, entitled: “COMMON LEARNING OUTCOME FOR EUROPEAN MANAGERS IN CONSTRUCTION”. It is reproduced here in a modified form with the kind permission of the Chartered Institute of Building
--CIOB
[edit] Related articles on Designing Buildings Wiki
- Acceleration.
- Activity schedule.
- Construction project management software.
- Contract programme.
- Contractor's master programme.
- Critical path method.
- Design web.
- Earned value.
- Information release schedules.
- Key performance indicators.
- Line of balance (LOB).
- Milestones.
- Pareto analysis.
- Precedence diagram method.
- Programme float.
- Programme consultant.
- Project crashing.
- Time-location chart.
- Time management of construction projects.
- Work breakdown structure.
[edit] External references
Featured articles and news
Heat pump announcements, what homeowners need to know
An 'ultimate guide to heat pumps' from a heating company.
Construction contract awards reach £7.1bn in February
Their highest level in seven months.
The journey to sustainability in heritage
Research is the key to better understanding.
Heritage approaches to adaptation, mitigation and loss.
Bridging the gap between policy, finance and installation.
Development on brownfield land
Definition, background, policy and the latest consultation.
With the Design Framework for Building Services.
Retrofit of Buildings, a CIOB Technical Publication
Pertinent technical issues, measures and the roles involved.
ECA joins HSE campaign to support mental health
Working Minds’ five simple steps based on risk assessment.
Mental health in the construction industry
Mental health issues in brief with related articles.
Transitional arrangements, Building Control and the BSR.
For pre-October buildings with substantial progress by April.
How to write an inspection and test plan
ITPs for quality control and assurance particular elements.
Why quality counts in domestic ventilation systems
From products, to systems to the installation.
Empowering the Future with CIOB Academy
Lifelong learning, upscaling, and reskilling for the built environment.
Winners of the 2024 ASBP Awards
Project, Product and Initiative according to the 6 pillars.