Structural Steel Design Using 3D Laser Scanning
Updated: Aug 28
A mechanical engineering client engaged Scan Hub to provide accurate existing-condition information for a hospital extension involving new structural steel foundations. New steel beams had to be designed and installed between existing concrete walls and columns, which made precise measurement critical to successful fabrication and installation.
This is a clear example of how accurate 3D laser scanning underpins structural steel design, where new steel has to marry up with an existing structure that was never built to perfect dimensions. This is a look at how the scan was carried out, why precise measurement matters so much for steel fabrication, and how the survey helped the steel fit the first time with no rework.
Why Steel-to-Existing Connections Are So Demanding
Designing new structural steel to fit into an existing building is one of the most measurement-sensitive tasks in construction. Steel is fabricated off-site to exact dimensions, so if the measurements of the existing structure are even slightly wrong, the beams will not fit when they arrive on site. On this project, the existing concrete structure included irregular surfaces and curved faces that would have been very difficult to measure accurately using traditional survey methods.
The consequences of getting it wrong are significant. Any measurement error could have led to costly fabrication issues, steel that does not fit, and installation delays, all of which cost time and money on a live construction project. When new steel has to slot precisely between existing concrete walls and columns, there is very little tolerance for error, and this is exactly the situation where 3D laser scanning proves its value.
Our Approach
Scan Hub completed a detailed 3D laser scanning survey of the structure, then produced an accurate point cloud and supporting 3D modelling data for the engineering design team. The scan captured the true condition of the existing concrete, including the irregular and curved surfaces that manual methods struggle with, giving the design team a reliable record to work from.
The project ran like this:
1. Planning: we confirmed the areas to capture and the accuracy and deliverables the steel design required.
2. Site capture: we scanned the existing concrete structure, capturing the irregular surfaces, curved faces, walls and columns in full.
3. Processing: individual scans were registered into one accurate point cloud of the existing structure.
4. Modelling: supporting 3D modelling data was produced for the engineering design team to design the new steel against.
5. Delivery: the point cloud and modelling data were provided so beams could be designed and fabricated to fit the real structure.
Accuracy That Gave Engineers Confidence
The survey achieved measurement accuracy of approximately +/1 1.5mm. For structural steel work, that level of precision is what gives engineers confidence throughout the design and fabrication process. Instead of designing against assumed or approximate dimensions, the team worked from a measured record of the existing structure, accurate to a millimetre and a half.
That confidence carries through the project. The designers know the geometry is right, the fabricators can cut and weld to those dimensions, and the installers can be confident the steel will fit on site. Accuracy at the start removes risk at every stage that follows.
Project Outcome
The structural steel was manufactured and installed without fitment issues, reducing rework and helping the project remain on schedule. This is the outcome that matters most on a steel project: the beams fit the first time. This project highlights how accurate 3D laser scanning improves engineering outcomes while reducing risk across construction and infrastructure projects throughout Australia.
What Clients Do With the Data
Accurate existing-condition data supports structural steel and construction work in a range of ways, including:
● Designing new steel to fit precisely into an existing structure
● Fabricating beams and connections to the real dimensions of the site
● Avoiding fitment issues, rework and installation delays
● Capturing irregular and curved surfaces that traditional survey struggles with
● Providing engineers with a reliable point cloud and model to design against
● Keeping construction projects on schedule and reducing risk
Frequently Asked Questions
How does 3D laser scanning help structural steel design?
Steel is fabricated off-site to exact dimensions, so it only fits if the existing structure is measured accurately. Scanning captures the real geometry of the existing building, letting engineers design steel that fits the first time.
How accurate is the scan for steel fabrication?
On this project, the survey achieved accuracy of approximately +/- 1.5mm. That level of precision gives engineers and fabricators confidence throughout the design and fabrication process.
Why not use traditional survey methods for this?
Existing structures often include irregular surfaces and curved faces that are difficult to measure accurately by hand. Errors lead to costly fabrication issues and installation delays. Scanning captures everything precisely and completely.
Can you scan existing concrete structures?
Yes. We regularly capture existing concrete walls, columns and slabs, including irregular and curved surfaces, to provide accurate existing-condition data for new steel and other structural work.
What deliverables do you provide for steel projects?
We provide a detailed point cloud of the existing structure and supporting 3D modelling data for the engineering design team to design and fabricate against.
How does scanning reduce rework on construction projects?
By giving the design and fabrication team accurate dimensions from the start, scanning helps ensure new steel fits the first time, which reduces rework, avoids delays and helps keep the project on schedule.
Can you scan on active construction and hospital sites?
Yes. We have experience working within the access and safety requirements of live construction and sensitive sites such as hospitals, planning the capture to minimise disruption.
What is a point cloud used for in steel design?
A point cloud is an accurate 3D record of the existing structure. Engineers use it to design new steel to the site's real geometry rather than assumed dimensions.
How long does a structural scan take?
It depends on the area's size and complexity, and the required accuracy. We plan the capture around your site and confirm timeframes before we start.
Do you support construction projects Australia-wide?
Yes. Scan Hub provides 3D laser scanning and 3D modelling for construction and infrastructure clients across Australia.
Talk to Scan Hub About Your Steel Project
If you are designing new structural steel to fit an existing building, accurate existing-condition data helps the steel fit the first time. Scan Hub has the experience and technology to capture your structure precisely. Contact us to discuss your project and get a fixed-price quote.