The demolition industry has a certain reputation for being a harsh atmosphere 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 grounded in the academic world. Moreover, this unseen work is critical to the success of the more visible procedures.
One part of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This type of work calls for a great balance of specific technical understanding as well as experience of the industry and a natural intuition for the complexities of the job.
Topographical Surveys
A topographical survey is a study of the physical features of a particular plot of land. The purpose of a topographical survey is to chart the naturally occurring and man-made features of a particular landscape to a high degree of precision.
Topographical surveys can be carried out on a very wide range of environments, from open countryside to urban developments and across a variety of elevations and land surfaces. Surveys can be developed to take into account a great number of 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 generally recognised application for topographical surveys is cartography, or map making. Modern day maps include a great amount of detail about the landscape they relate to, including waterways, elevations and ground surface, all of which will have been collected via a topographical survey. This information is also being provided online.
Topographical surveys also have a major role to play in the construction business. When individuals or organisations are looking to build any kind of structure they will need to carry out extensive surveys as part of the design stage of the project.
Surveys definitely play a key safety part in primary industries like mining, or in other industries that interact with the land, such as demolition and infrastructure. Businesses in these industries will use surveys to plan their projects, but also to ensure that they can ensure the safety of their workforce on site. As a result, topographical surveys are often a legal requirement for these types of projects.
Whilst it is not always the perfect solution, any demolition survey can always be carried out while preparation work is happening on-site.
Types of Survey
The world of topography addresses a large number of physical features so it is beneficial to determine what form of topographical survey is suitable for a particular scenario.
“Lie of the land” Surveys
These types of topographical surveys are designed to create a summary of the physical characteristics of any given plot of land. Whilst the data collected by the survey will be extremely accurate, and may be very extensive, the purpose of these surveys is to give a site summary.
These surveys will generally include a boundary survey that sets out to determine 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 terrain and the numerous gradients that exist. A survey can be customised to specification though.
Building Surveys
Building surveys are more generally concerned with man-made constructions on a site, including the surveying of special machines and even infrastructure features. This type of study is more commonly associated with the demolition sector since it can give a detailed plan of the structure to be demolished.
A building survey will almost certainly include a measured survey, which involves creating a precise plan of the external and interior dimensions of a structure. Depending on the requirements of the job, a measured survey might provide basic building “footprint” dimensions, or might produce a very detailed plan of the structure.
Content of a Topographical Site Survey
A survey of a demolition site will almost definitely include the information gathered by the types of boundary and building surveys mentioned above. This information will be required so the demolition company can plan a demolition that is both adequate and secure. More often than not these surveys will also be legally required.
Surveys will often contain information about the energy services that are present on a site before any demolition or construction work happens. This is an important safety aspect since any unmonitored destruction to pipes and cables carrying water, gas and electricity could be very dangerous. The information can 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 inventory of materials 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 used as hardcore or even timber. By getting an accurate audit of site materials the construction company can more accurately determine the need to import building resources, or they can re-use the materials on a different job.
Although it is one required immediate expense, a pre demolition survey could produce financial gains in the long-term by highlighting potential issues.
Importance of Site Surveys
Perhaps the most important reason to perform a topographical site survey is to ensure the safety of the people who will be doing work on the site. The industries that most frequently call for site surveys are dangerous enough as it is without having to be concerned about the condition of the ground on which they are working. Taking a detailed topographical survey can help to mitigate safety risks of this nature.
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 region. Particular things will not be evident on the surface of the site and will only be discovered once digging or demolition has begun.
The inventory of site supplies, as previously stated, can be of great value to a demolition or construction organisation working on a project. Not only are construction materials themselves costly, but transporting them to the site may be a very expensive task in itself. Any time that material can be recycled on site offers an opportunity to save development time and funds. Only by taking an accurate audit of these materials can a company correctly plan its imported material needs.
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 certain vehicles or equipment then a new entry route or alternative machinery will have to be found.
Positioning of Survey Control
During the surveying and construction phases of a building project, the apparatus required for the physical surveying of the site and control of the survey data will often be stored on-site. This is obviously a problem when it comes to the demolition stage of a project since the equipment 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 personnel to return to it, the surveying equipment can be restored to its original position on site. This will allow for efficient data collecting to take place for a post-demolition study, and maintains a single point of contact for anyone who requires the topographical survey information. Most surveying companies will oversee this redeployment.
On the surface it may seem that demolition of a building requires little planning, but the reality of the matter is very different.
Who can Perform Site Surveys?
Since topographical site surveys can play such a crucial role in the success or failure of a construction or demolition project it is vital that they are undertaken thoroughly by the correct people. There are different branches of site surveying and each one will have unique qualifications associated with it. Getting surveyors with these specific qualifications will certainly be beneficial.
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 obtain feedback about their overall performance on previous projects. It may also be worth considering how a company can deliver the survey information, i.e. in 3-D models or CAD ready formats, for ease of integration with other members of the project staff.
Who will use the Survey Information?
Once an adequate level of information has been accumulated by a site survey it needs to be passed out to the appropriate people on-site. Who gets which pieces of information will mostly depend on the job roles being performed, but can also rely on the stage that a project is at.
Project Planners
Project planners will usually require access to all of the information collected by a topographical survey, although they will particularly need to use information concerning the physical relief of a site before the design phase, and a site materials record before they can plan the construction phase.
Demolition Experts
Demolition organisations will want to know about the internal and exterior properties of any building or structures that they are set to take down. Whilst every job will have individual requirements, demolition experts will typically need to know about the fundamental framework of a building and the materials it is made out of. They will need this knowledge before demolition can take place.
Site Engineers
Construction engineers on-site will be particularly interested in the survey statistics about the relief and topography of the terrain. It is usually the case that they will want to build on a flat surface, so they will use information about the natural lay of the land to calculate what work will be required to create a stable footing for any building. They will want this information before and in the course of the construction stage of a project.