Surveying requirements can change considerably from one project to another.
A topographic survey may require documenting the existing elevations and physical features of a developed site before design work begins. On another project, an as-built survey may be required after construction to record what was actually built and provide dependable information for engineering review.
Recent fieldwork by Geo Vision Surveying Inc provides good examples of both situations.
Our projects included topographic surveying in Cambridge and London, Ontario, along with as-built surveying on a bridge construction project in Brantford.
Although the sites and objectives were different, each project depended on accurate field measurements and reliable survey information.
Topographic Surveying in Cambridge, Ontario
A topographic survey provides a detailed picture of the existing physical conditions of a site.
For our recent Cambridge project, the fieldwork involved collecting elevations and visible site features that could be used to accurately represent the existing conditions.
This type of information is often important before engineers, designers or contractors begin making decisions about proposed work.
Depending on the project requirements, topographic survey information may include:
- existing ground elevations;
- changes in slope;
- buildings and other structures;
- walkways and hard surfaces;
- landscaping and vegetation;
- drainage-related features; and
- other visible site conditions relevant to the proposed design.
Why Existing Conditions Matter
Design decisions should be based on what actually exists on the ground.
Even relatively small elevation differences can influence grading, drainage and how proposed construction connects with existing surfaces.
This is why careful field collection is important.
The objective is not simply to collect a large number of points. The surveyor must identify which features are relevant and collect enough information to create a useful representation of the site.
For the Cambridge topographic survey, our field approach focused on documenting those existing conditions accurately and efficiently.
Topographic Surveying in London, Ontario
Our London project also involved topographic surveying, but every site requires its own field strategy.
For this assignment, Spectra robotic total station technology was used to collect elevations and visible site features.
A robotic total station allows a surveyor to precisely observe individual points throughout a site while working efficiently from established survey control.
However, the instrument is only part of the process.
Successful topographic fieldwork also requires decisions about:
- where the instrument should be positioned;
- how reliable survey control will be maintained;
- which features need to be observed;
- how obstacles or restricted visibility will be handled; and
- whether the collected information adequately represents the site.
These decisions are important because the quality of the final survey information depends heavily on the quality and completeness of the field observations.
From Field Measurements to Useful Site Information
A completed topographic plan may appear straightforward, but behind it can be hundreds or thousands of individual observations.
Each measurement represents part of the physical site.
When combined, these observations allow engineers and designers to better understand existing elevations, slopes, structures and other relevant features before developing their plans.
For project teams working in London and surrounding communities, accurate topographic information can provide a stronger basis for engineering, grading and construction planning.
As-Built Surveying on a Brantford Bridge Project
The Brantford assignment involved a different stage of the construction process.
Instead of documenting conditions before design, our work involved as-built surveying on a bridge project after portions of the structure had been constructed.
Construction drawings show what is intended to be built.
An as-built survey records the position and elevation of what was actually constructed in the field.
Using Trimble surveying technology, Geo Vision Surveying Inc collected observations on the bridge structure to document completed construction and provide information that could be compared with the project design.
Why Are As-Built Surveys Important?
Construction projects develop in stages.
Before subsequent work proceeds, engineers and contractors may need confirmation that critical elements have been constructed at the expected position or elevation.
As-built surveying can help provide that information.
Depending on the requirements of a project, as-built surveys can support:
- verification of constructed locations;
- elevation checks;
- engineering review;
- construction quality control;
- project documentation;
- record drawings; and
- coordination before subsequent stages of construction.
On infrastructure projects such as bridges, this verification can be particularly important because later construction may depend directly on components already completed.
Plans Show the Design — As-Builts Record the Result
There is an important distinction between construction layout and as-built surveying.
During construction layout, design information is transferred from the drawings to physical points in the field.
During an as-built survey, measurements are taken from completed construction to record where elements were actually built.
In simple terms:
Construction layout helps show where something should be built.
As-built surveying helps document where it was built.
Both play important roles at different stages of a construction project.
Different Projects Require Different Surveying Methods
The Cambridge, London and Brantford projects demonstrate the range of field conditions surveyors regularly encounter.
In Cambridge, the objective was documenting existing conditions for a topographic survey.
In London, Spectra robotic total station technology was used to collect detailed topographic information.
In Brantford, Trimble surveying equipment was used to perform as-built observations on an active bridge construction project.
There is no single instrument or field method that is appropriate for every situation.
The surveyor must consider the site conditions, required accuracy, project objectives and information needed by the client before deciding how the work should be completed.
The Value of Reliable Survey Information
Survey information often becomes the foundation for decisions made by other professionals.
Engineers may use topographic information during design.
Contractors may rely on construction layout when positioning proposed work.
Project teams may use as-built information to verify completed construction.
Because other decisions depend on these measurements, field procedures, survey control and careful checking remain important throughout the process.
The objective of Geo Vision Surveying Inc is to provide information that clients can confidently use as their projects progress from existing conditions through design and construction.
Surveying Services Across Southern Ontario
Geo Vision Surveying Inc provides surveying support for engineering, construction and development projects throughout Southern Ontario.
- topographic surveying;
- construction layout;
- building layout;
- grading surveys;
- as-built surveying;
- monitoring surveys;
- drone surveying;
- LiDAR scanning; and
- specialized geomatics services.
Our field equipment includes Trimble and Spectra surveying technology, selected according to the requirements of each project.
We regularly support projects in communities including Brantford, Hamilton, Cambridge, London, Simcoe, Guelph, Kitchener-Waterloo and surrounding areas.
Planning a Project in Brantford, Cambridge or London?
Getting the surveyor involved early can help clarify the required field information, project control, deliverables and timing before construction or design progresses.
Whether your project requires an existing topographic survey, construction layout or as-built verification, Geo Vision Surveying Inc can help determine the appropriate surveying approach.
Phone: 519-410-3981
Email: info@geovisionsurveying.com
Website: geovisionsurveying.com