BIM for Quantity Surveying

BIM technology has taken the construction industry by storm globally during these recent years. In 2015, Singapore will also continue to enhance the implementation of BIM technology. But how can we actually utilise BIM more? Do we really understand its potential usage? Glodon, who has been providing construction Information Technology (IT) system to the construction industry for more than 16 years, shares on how BIM can be used for quantity surveying.

1. Q:  How can BIM be used for quantity take-offs and cost estimation in the construction industry and what are the benefits for using BIM to carry out such activities?
A:  There are many BIM software with different functionalities in the market today. These range from software for modelling, quantities take-off and costing, project management to cloud-based BIM. Typically, software for quantities take-off and costing can open 2D drawings or 3D models created by BIM design or modelling software for viewing and quantity extraction. The generation of quantities should be according to the standards method of measurements to produce the Bills of Quantities. These include concrete volume with same or different mix, classification of formwork in stages, reinforcement bars, interior finishes areas, and can be separated into building works, architectural works, landscaping works and MEP works. 

Using BIM for quantity surveying has the following benefits:

  • Provide fast, effective and efficient quantity take-off and cost estimation.
  • Produce reliable and accurate quantities as well as competitive cost estimates.
  • Auto computation of calculations reduces human errors.
  • Generate cost estimation reports categorized according to areas, blocks, concrete grades, subcontractor and other relevant reports and this increases the speed of deliverables.
  • Improve visualisation of the elements/items for measurement and minimise omissions.
  • Hand over project to another party more quickly and reduce double handling.
  • Enhance communication and collaboration amongst team members.
  • Improve cost database management which reduces loss of information.

2. Q:  What are some of the information that the consultants could provide in a BIM model to facilitate the quantity take-off and cost estimation process?
A:  Different BIM software produces models in different file formats. This can cause an issue when exchanging information between consultants. buildingSMART, an industry-led body has developed the Industry Foundation Classes (IFC) as a universal language to improve communication and interoperability between the different software platform for the construction industry. With this file format, model information from one software can be exported and imported to another software platform for sharing and further use. Information from a 3D model created using BIM can be exported to another BIM tool for estimating and costing purposes. 

Some things to bear in mind when creating the model for export:

    • Elements should be created according to the standard rules of measurement;
    • Elements modelled should not overlap;
    • Naming of elements should be in accordance to standards and specifications;
    • Each element or item should be categorised under its respective “layer”;
    • Every element should be properly connected to each other without any gaps between them.

3. Q:  What are some of the features that a BIM tool should have to perform estimating and costing efficiently?
A:  A BIM tool for performing estimating and costing efficiently should have the following features (not exhaustive):

  • Able to read and import different file formats;
  • Able to perform automated calculation for basic quantities e.g. concrete volume, formwork area etc.
  • Able to read, measure, trace and do mark-ups for quantity take-off;
  • Integrate with the standard rules of measurement used locally in the industry;
  • Able to generate different reports for different purposes e.g. for Bills of Quantities for tender awards or tender reports;
  • Allow users the flexibility to add build-up rates or refer rates from cost libraries or previous projects;
  • Allow project team members to collaborate, access or retrieve the information easily and securely;
  • Able to track changes, record variations and perform checks.

4. Q: Share two local projects which have used BIM for quantity surveying successfully. How has the use of BIM for estimating and costing benefited these 2 projects?
A: China Jingye – Executive Condominium Housing Development

China Jingye ProjectThe contractor, China Jingye, implemented the Glodon take-off software during the construction period for the Forestville project. The time taken for the quantity take-off was reduced by 25%. The quantity surveyors imported the model and integrated it with the initial take-off model into the software to automatically generate the quantities for the required elements and for procurement, project budgeting etc.

Mr Kinson, Senior Quantity Surveyor from China Jingye said, “The system has helped us in visualising the actual elements such as rebar and mesh installation which was not possible previously. It reduces the risk of missing out on elements during the quantity take-off. It has also provided us with valuable and confident information when reporting to the management for cost analysis, progress claims, sub-contractor’s progress payments and final settlement during the construction phase.

 

Ken-Pal (S) Pte Ltd – Public Housing Development

Ken-Pal (S) Pte Ltd

Mr Michael Tong, Quantity Surveyor from Ken-Pal (S) Pte Ltd has this to say: “The availability of 3D visualisation of the building has greatly reduced the omission of items especially the finishes areas. It has also increased the speed in taking-off, hence, producing better cost estimates and more efficient materials procurement.

Ken-Pal made use of the quantity take-off software to generate the quantities and produce the necessary quantity reports during the construction stage for their public housing development project at Tampines.

In some cases, when they combine the structural and architectural QTO models, they also managed to find some differences between the two models e.g. location and sizes of columns differ in both models. Ken-Pal believes that using BIM help their quantity surveyors improve their quantity take-off process and accuracy.


5. Q: Any advice for companies who would like to use BIM for cost related activities and management?
A:  Every software tool has its own merits and it is greatly dependent on the organisation and the environment in which it is to be implemented. BIM tools for quantity take-off, cost estimates and project management can be used by the consultants, contractors, developers or suppliers. However, users must be well trained to ensure that the tools are used effectively to meet the goals of a project. Other than having the domain knowledge of quantities take-off and costing, ideally, the users should also be involved in or have the experience in handling contractual administrative work in projects. With the use of BIM tools, quantity surveyors could greatly increase their efficiency in producing costing, reports and contracts and make better informed decisions related to costs.

Contact Person:Mr Justin Bong
Products Manager
Glodon International Pte Ltd
(Certified by buildingSMART International)
Email: justinbong@glodon.com
Website: http://en.glodon.com