The demolition trade has a certain reputation for being a tough environment in which brute force takes precedence over calculated thought; however this impression is far from correct. There is a huge amount of work that goes on behind the scenes of the demolition and construction industry that is firmly rooted in the academic world. Moreover, this unseen work is essential to the success of the more visible operations.
One branch of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This kind of work demands a good balance of specific technical knowledge as well as experience of the industry and a genuine intuition for the intricacies of the job.
Topographical Surveys
A topographical survey is a study of the actual features of a given piece of land. The aim of a topographical survey is to map the naturally occurring and man-made traits of a particular landscape to a high degree of accuracy. Whilst topography itself can refer to the surface of any kind of object, it is more commonly associated with the surface of the planet.
Topographical surveys can be carried out on a very broad range of environments, from open countryside to urban developments and across a variety of reliefs and land surfaces. Surveys can be designed to take into account a great many factors, such as ground conditions or vegetation, and as such can be used for a multitude of tasks.
Common Applications for Topographical Surveys
Perhaps the most widely used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern day maps include a great deal of detail about the terrain they relate to, including waterways, elevations and ground surface, all of which will have been obtained via a topographical survey.
Topographical surveys also have a key role to play in the construction business. When individuals or organisations are looking to build any kind of structure they will need to undertake extensive surveys as part of the design phase of the project.
Surveys definitely play a key safety role in primary industries such as mining, or in other industrial sectors that interact with the terrain, such as demolition and infrastructure. Companies in these industries will use surveys to plan their projects, but also to be sure that they can ensure the safety of their workforce on site.
Whilst it is not always the best option, a demolition survey could be performed while preparation work is taking place on-site.
Types of Survey
The arena of topography addresses a large number of physical characteristics so it is important to identify what form of topographical survey is appropriate for a particular scenario. A few of the more typical types of survey required for construction sites are discussed below.
“Lie of the land” Surveys
These types of topographical surveys are designed to create an overview of the physical properties of any given plot of land. Whilst the data collected by the survey will be very accurate, and might be very extensive, the purpose of these surveys is to give a site summary.
These surveys will usually incorporate a boundary survey that sets out to define the extent of the site and spotlight any particular restraints that are determined by the geography of the site. They can also include a level survey that will plot the elevation of the land and the various gradients that exist. Any survey can be customised to specification though.
Building Surveys
Building surveys are more generally concerned with man-made structures on a site, including the surveying of special machines and even infrastructure characteristics. This type of study is more commonly associated with the demolition industry because it can give a detailed plan of the structure to be demolished.
A building survey will probably include a measured survey, which entails creating a comprehensive plan of the exterior and internal proportions of a structure. Depending on the requirements of the job, a measured survey might provide basic building “footprint” dimensions, or might produce a highly detailed plan of the structure.
Content of a Topographical Site Survey
A survey of a demolition site will almost always include the details gathered by the types of boundary and building surveys described above. This information will be necessary so that the demolition firm can plan a demolition that is both adequate and safe.
Surveys will often include information about the power services that are present on a site prior to any demolition or construction work takes place. This is an important safety factor since any unmonitored damage to pipes and cables carrying water, gas and electricity might be very dangerous. The information might also be used to plan new structures, based upon the existing availability of these utilities.
Another aspect of the site survey will often be an audit of resources on the site. This type of study will be a quantity survey of the various sorts of materials that can be located on site, for example, tiles and masonry, concrete that can be utilised as hardcore or even timber. By taking an accurate audit of site materials the construction company can more precisely determine the need to import building resources, or they can re-use the materials on a different project. These surveys can be made pre-demolition and post-demolition.
For demolition projects in city areas, topographical demolition surveys may uncover possible problems concerning the disruption of utilities and infrastructure in the region.
Importance of Site Surveys
Perhaps the most important reason to undertake a topographical site survey is to ensure the health and safety of the individuals who will be working on the site. The industries that most frequently call for site surveys are dangerous enough as it is without having to worry about the integrity of the ground on which they are working.
Another critical reason to get a suitable survey done is to identify any potential difficulties that may arise because of the physical characteristics of the area. Certain things may not be evident on the surface of the site and will only be uncovered once digging or demolition has started. By then it may be too late to resolve these problems, or at best they will be costly problems to solve.
The inventory of site supplies, as previously stated, can be of great benefit to a demolition or construction enterprise working on a project. Not only are construction materials themselves costly, but importing them to the site may be a very expensive task in itself. Any time that material can be recycled on site provides an opportunity to save development time and funds.
Topographical surveys can also identify other areas that will be of use to the project managers. For example, if the gradients on a site would be prohibitive to specific vehicles or machinery then a new access route or alternative equipment will have to be found. Equally, a suitable site will need to be found for the base of control operations for the project. Good site surveying can help out in these less tangible ways.
Positioning of Survey Control
During the surveying and construction stages of a construction project, the equipment required for the physical surveying of the site and control of the survey data will often be stored on-site. This is clearly a problem when it comes to the demolition period of a project since the machinery is both costly and sensitive. It is therefore wise to move this equipment off-site during demolition.
Once the demolition has taken place and the site has been deemed safe for workers to return to it, the surveying equipment can be restored to its initial position on site. This will allow for efficient data gathering to take place for a post-demolition survey, and maintains a single point of contact for anyone who requires the topographical survey information.
Many towns and urban centers up and down the country require home demolition before development of modern housing estates can begin.
Who can Perform Site Surveys?
Because topographical site surveys can play such a crucial role in the success or failure of a construction or demolition venture it is critical that they are carried out carefully by the right people. There are different branches of site surveying and each one will have specific certificates associated with it.
When selecting a company to undertake the surveying work required for your project it will be wise to choose a company with a good reputation and a proven track record. Ask to see reviews of their previous work and try to get feedback about their overall performance on past projects.
Who will use the Survey Information?
When an adequate level of information has been accumulated by a site survey it must be passed out to the appropriate personnel on-site. Who gets which pieces of information will mostly depend on the job roles being executed, but can also rely on the stage that a project is at. There will be less need for materials information half way through construction for example.
Project Planners
Project planners will usually need access to all of the information collected by a topographical survey, though they will particularly need to use information concerning the physical relief of a site before the design phase, and a site materials inventory before they can prepare the construction phase. The more data that can be made available to project planners will aid the smooth running of the venture.
Demolition Experts
Demolition companies will want to know about the interior and external properties of any building or structures that they are arranged to take down. Whilst every job will have different requirements, demolition workers will typically need to know about the fundamental structure of a building and the materials it is made out of. They will need this information before demolition can take place.
Site Engineers
Construction engineers on-site will be mainly interested in the survey data about the relief and topography of the site. It is normally the case that they will need to build on a flat surface, so they will use details about the natural lay of the land to calculate what work will be needed to create a steady foundation for any building. They will want this information prior to and during the construction stage of a job.