Topographical survey plans are of course needed for the design work but, in addition, we provide laser scan data of the structure’s surroundings to enable visualisation for the planners and public. The initial design can be modelled and placed within a 3D model for viewing from all angles. The new work can even be seen using virtual reality (VR). If the surroundings are captured (by ground based laser scanning, aerial lidar or photogrammetric methods) then additional analyses can be undertaken such as right to light, noise studies, the effects of wind tunnelling and monitoring of movements during construction.
Some major projects split the survey tasks in to ‘feasibility’ and then design. The idea being to keep costs low before the final project go-ahead is given. However it is often the case nowadays, using modern laser scanning methods or lidar, that we can capture data suitable for both feasibility and final design at one stage with minimal cost differences.
As mentioned above, clients may choose to gather the survey data in one commission. However, if considerable time has passed since the feasibility survey, then an update can often be required to ensure no changes have taken place on the site or surroundings. It is important to ensure that there is some permanent survey control on site and available to the contractors. Topomaster Limited are experts in installing and surveying high precision survey control networks.
The design drawings should use the same coordinate system and height datum, as was used for the site survey, but this may not always be the case. In which case, expert surveyors need to do some transformation work to ensure the engineer or architect’s plans are set out correctly on site. Progress measurement can be undertaken by updating the BIM model from ground based scanning, or overall site monitoring using UAV or drone imagery. Rapid 360° imagery can also be provided on a regular basis to enable ‘immersive’ views of the progress of the project.
As Built Survey
On completion, as-built surveys are often commissioned to prove that the structure, building or plant has been built to spec. They are created to see that it matches the design drawings and to act as base plans and models (often as BIM models nowadays) for the future management and maintenance of the asset. This is often very advisable for mapping and modelling the utility services installed – the Heating, Ventilation and Air Conditioning (HVAC) ducts and cables plus drainage. Plus MEP – Mechanical, Electrical and Plumbing services. It is often the case that they are not always installed precisely where planned!
Facilities Management (FM) – The building or structure that has been constructed will need to be maintained and having accurate as-built survey data ensures efficient management. It makes any modifications to the structure much safer and easier and, of course, doing this via the BIM model is becoming increasingly the chosen method.
Yes, this is the opposite of construction, but surveyors can be called in to make rapid BIM models of large buildings so that the demolition can be planned safely and economically. What are the floor thicknesses? Can they bear the weight of demolition machinery/plant ? What are the overall quantities or volumes of concrete, number of steel columns and beams?
If you would like to discuss the services we provide to the construction sector in detail and to determine how we can benefit your project, please contact our team of topographic surveyors.