Services requested by engineers are similar to those demanded by the construction and transportation sectors. Indeed we serve many engineers working within these areas.

Services provided to engineers:

Surveying the site

Assessing the condition of the site is the first step in any design or conservation project. It is important to have suitable plans, to know the topography of the land, the structures present on the site and the conditions or land use on adjacent areas.

The main provision of such information is through a topographic survey conducted by a team of surveyors. Alternatively photogrammetry can be used to extract topographical information from aerial photography. Typically a survey captures building footprints, paving, roads, vegetation, services and levels.

Mason Land Surveys have more than 30 years experience of providing high quality topographic site surveys both from conventional survey and photogrammetry. Digital output can be layered into a customer’s schema of choice.

Underground service tracing (UST)

Tracing of underground services requires training and specialised equipment. Mason have performed UST on many projects, including extensive work at Heathrow Terminal 5.

Services need to be traced to provide a safe working environment for construction staff, to reduce disruption to the service networks and minimise cost. Once services have been traced their locations are surveyed and provided in CAD form to the customer.

The process often begins with a review of existing plans available for the site. A suitable strategy is then devised. Service providers for the various utilities are contacted to identify the locations of their services across the site for subsequent survey.

The survey team then enters the site to lift manholes and other service covers. Information about the pits beneath the covers can be measured, recorded and reported back to the customer. The pipes and cables within the pits then provide initial locational information for the services, which can be traced outwards. Other services will extrude through the ground, so again their positions can be surveyed and their routes traced.

To trace metallic cables, C.A.T. (detector) and Genny (transmitter) equipment are typically used by the trained surveyor. To trace the routes of storm water or foul water drains, non-toxic dyes can be used. A sonde attached to the end of a cable and inserted into pipes is sometimes used to trace routes deeper under the ground.

Engineers working in many different sectors need to know what services exist within their project areas.

Control grids and datums

Masons have provided local control grids on a number of projects. Once coordinates have been computed, a field survey team will place Permanent Ground Markers (PGMs) around the site. The brass studs used are punched to indicate the exact coordinate position to millimetre accuracy. On temporary or delicate surfaces other forms of marking position are used, such as adhesive targets and drawn marks.

Datums are surveyed and marked around the site before and throughout the construction process to assist contractors with structure positioning. Grid coordinates are often passed to Mason for marking up on a site.

Setting out

As directed by the customer, Masons will set out to any level of accuracy requested. For structural steel work and other building materials this can be down to the order of millimetres, whilst for features such as paint lines it can be to centimetres. The surface to be set out over will dictate the type of marker used.

Monitoring

During the construction phase new structures can be monitored in a variety of ways. For large structures, such as the new Heathrow control tower, Mason have employed a positional monitoring network utilising automated total stations and GPS equipment. Surveyors can revisit a structure on a regular basis to check its position and alignment. A common task is checking the position of steel beams and their verticality.

Monitoring services are also provided to engineers working within the rail and tunnelling sectors. Insert hot link to Rail & Tunnel Mon. page.

Dimension checking

A valuable service provided by Mason to site managers as construction progresses. Dimension checking involves measuring the location and height of objects as they are built into the structure. Sometimes this can relate to structural features such as steelwork, so that clearances are maintained. Other times this service is performed within structures as services and other items are installed. Within today’s complex buildings ensuring that these items are in their correct position is critical. It is a time consuming and costly problem to fix if many fixtures once installed subsequently have to be moved.

As-built survey

During construction as-built surveys provide an up to date picture of the site to project managers, enabling designers and quantity surveyors to plan better. On completion of the project a complete as-built survey provides an invaluable data source for future development.

Industrial infrastructure survey

Mason Land Surveys have completed projects for engineers working within industrial plants or on specialised platforms. Quite often precision survey of pipework and other plant features are required.

It is possible to use conventional survey techniques with a total station to survey features. However, where access is more restricted then close-range photogrammetry and laser scanning are used as alternative methods of data capture.

With both of these methods raw data can be collected in the field relatively quickly, without direct physical contact to the features and the majority of the processing is completed off site. Such techniques are particularly useful when features to be surveyed are in close proximity to dangerous gases, high voltage electricity elements or radioactive materials.

Notable projects