Innovative and integrated developments designed to maximise land use and connectivity is becoming commonplace in the land-scarce Singapore. On the other hand, the construction industry is experiencing labour shortage as the island has tightened its workforce policy on foreign labour. To maintain quality urban living, development of the physical infrastructure for housing, transport and facilities must be ramped up to meet the projected population estimate of 6.5- 6.9 million by 2030 as against the present 5.31 million in 2012.
This gives impetus to improving the productivity of the Singapore construction industry through BIM.
Benefits of BIM implementation
Singapore promotes the use of BIM through the Building Construction Authority (BCA). As the agency to lead, engage and guide the professionals, BCA also offers incentives through productivity funding, training and education to build up the BIM capability and capacity in the industry. BCA has mandated the phased implementation of BIM e-submissions from July 2013 to July 2015.
Primarily led by architects and engineers, the focus of many BIM developments is defined in terms of the technical requirements, submission requirements and practice of these professionals. In addition, they have enjoyed significant lead time in training, evaluating and testing of BIM models as compared to land surveyors. As with the adoption of any new technology and innovation, land surveyors must examine the existing work processes, evaluate how these processes could be adapted and consider how these re-framed processes propagate to the stakeholders.
To address this, the Singapore Institute of Surveyors, representing the registered land surveyors in Singapore, is collaborating with the BCA and the Singapore Land Authority on a pilot project on BIM for land surveyors. The BCA BIM Steering Committee was formed to lead the development of standards and supporting resources to facilitate the collaborative use and implementation of BIM. It comprises various interest groups and disciplines, including government agencies and professional bodies. Recent representation of land surveyors in this committee is a platform to ensure the industry participation and contributions by land surveyors to the construction industry.
Unlike BIM, CAD and GIS are more mature and established technologies where interoperability, data structure and design are less of an issue as are computing power, space and workarounds. BIM demands a steep learning curve and some investment in new survey equipment, software and hardware from land surveyors, many of whom are conditioned in traditional surveying processes. While it is undisputed that BIM models are a rich source of information, they have huge file sizes, leading to demands on the hardware. Also, there are interoperability issues between different BIM software products with inter-conversion resulting in some extent of data loss.
Balancing the expectations
3D geospatial data and models can be detailed, accurate and precise but the cost-effectiveness of the BIM survey has to be considered first. For instance, the accuracy of a BIM site model for design purpose may not be as stringent of that required in a topographical survey. Further, it would be wasteful to provide too much detail for structures within a development site which will be demolished before construction.
BIM architectural models have been defined in varying level of details or complexity for different stages of the design, and it is useful to have a general understanding of these models as well as how geospatial data interacts with them. Just as 3D geospatial data can be confusing with its array of data source, contents, standards and platforms, the same appears to apply to BIM.
The primary requirement by the clients is land survey deliverables that satisfy the existing statutory requirements and submissions. Arising from BIM implementation, they could now impose additional requirements to the same survey deliverable.
Land surveyors provide the geolocation information in BIM. The existing site contours and location need to be modelled based on the surveyed information. Surface models and condition, model orientation and site configuration as well as the georeferencing of the BIM model must be provided by the surveyor. There are requirements on the data capture and format of topographic surveys to support BIM formats.
Some clients or designers implementing BIM end up having to rework the data when they are unable to obtain BIM-compatible data. For development work on existing buildings, it is critical that the measured building is surveyed in BIM or BIM-compatible format and accurate as-built survey data are available. For design of more complex structure, more details and 3D visualisation of the site may be required.
Land surveyors may need to evaluate the combination of more than one survey technique to measure the data and provide them in a format that best suits the requirements of a project after advising the client accordingly. It is also imperative to present the accurate 3D survey data as accurate 3D models to a BIM-centric process as the land development industry embraces BIM.
BIM to field
Beyond ‘Field to BIM’, land surveyors can also look forward for ‘BIM to Field’. Mergers and acquisitions of surveying equipment companies have led to the integration of BIM into surveying equipment. One such development is the acquisition of Tekla by Trimble. The land surveyor can literally bring the BIM model into the field during actual construction, resulting in smoother workflows and communication between the two.