Over the years, BSE has progressed from the type of work that requires a tape, a dumpy and a theodolite onto work using Trimble GPS, one man robotic total stations and using electronic data with laptops and survey software.
At the moment we have 4 teams. The distinction between surveying and setting out is becoming more blurred, but it would be true to say that two of the teams lean more towards site engineering than surveying, one is a bit of both and the other is undecided.
We try to increase knowledge within the company by sending people on training courses with Trimble, Leica and Topcon. We send our trainees on day release at local colleges.
We believe you get back what you put into people and that we know what we know. When we don’t, we ask.
We have found that reactions have varied when we arrive on site armed with laptops containing the electronic data necessary for the job that has previously been Emailed to us. Some more traditional contractors have viewed us with suspicion, even outrage claiming that taking co ordinates from CAD is the same as scaling. These types would have probably feared the wheel and still think the world is flat.
There are many advantages of using electronic data. So long as the drawings have been produced by professionals using CAD as a design package, who alter actual dimensions and adjust their designs rather than just text, the system we use is unbeatable at producing results. Of course we make sure that this is the case, rather than just make assumptions.
Our system reduces the amount of RFI’s generated, where dimensions are missing, we can take them straight off the plan.This cuts down drawing errors. How often have you had to question where a dimension starts and finishes? Hatching sometimes causes a problem, where a hatch intersection gets snapped to and dimensioned to rather than an actual corner.
Reduces setting out errors caused by calculations, human error remains of course but with better communication on site even this can be reduced.
Improves communication. Information can be collected from various plans and sections, and combined onto one that is easily read very quickly. Once done, numerous copies can be printed and issued to the men doing the work. If more people clearly understand what it is they are trying to achieve, they gain more interest and fewer errors occur.
Information can be easily communicated between the parties in real time that is to say as things occur, thus reducing delays.
More accurate measuring. You know you have set something into the correct position to the correct dimensions. So what if it is a dodecahedron with innumerable boxouts? You already have all the information you need to calculate the area.
We turn our EDM’s into multi axis lasers. One EDM can be used to set out and level anything from a stockpile to external works, once the DTM is formed, lets get to work!
Roads
On estate roads we find that contractors tend to bone along their length, typically with profiles 2m offset and set to a comfortable working height for the men on site. Typically FRL +1.5m…1.75m…2.0m etc.
Contractors vary the way in which they construct their roads. Some may lay their kerbs and then string across to get their road formation, others may stone the road and use a machine to lay the kerb lines. We have found that methods of road construction vary from contractor to contractor. However it is done, we will match our work to the contractors requirements.
On major highways we find that contractors like to bone across the carriageways. Where the road is cambered the profiles would be ‘double headers’, so we would calculate the level of the channel at the offset. The contractor would bone across the road using the corresponding profile heads.
At Isis Reach in Belvedere, whilst working for GSE Construction, we worked on a very challenging road project where the profile of the road, due to poor ground conditions was very similar to a bridge deck.
The construction was reinforced concrete, topped with a wearing course and consisted of ‘beams’ running along its length, with the road spanning across. The road was 400m in length, sat on piles, which had to be cut down to the correct level to enable the steel to work. The road included a roundabout.
The information was issued to us on A4 sheets with string lines relating to various parts of the road. The road was cast in a hit and miss fashion, each bay being 12m long.
Using our design software we were able to manually input the data on site simplifying what had appeared to be a complicated job. We were able to check the design by forming contours and viewing the road in 3D. We would carry out as built surveys at each stage of the construction, producing drawings directly comparing as built position and level to the design.
Buildings
We work on housing estates, small developments as well as large RC frames. The Laban Centre in Deptford was a pleasure to work on, due to its innovative design and high profile. A reinforced concrete structure, with sweeping curves, 2 spiral staircases and lots of fair face finish. The London building by Herzog & de Meuron won the 2003 RIBA Stirling Prize
We have also worked on the Radisson SAS hotel at Stanstead where we had to provide ‘as built’ surveys at every stage of construction. The hotel is a four-storey structure with a floor-to-floor height of 2.9m.
The facade is a curtain wall designed to accept a very low deflection of 8mm at midspan of slabs. We were responsible for all of the setting out during construction, and also the crushing of the cubes on site.
We provided a 1m level grid, each point was coordinated and superimposed onto Auketts floor plans. 2500 levels per floor per block.
We have also monitored the slabs deflection, to an accuracy of 0.3mm.
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