Post-Demolition Site Surveys
The construction trade has a certain character for being a harsh atmosphere in which brute force takes priority over calculated thinking; however this impression is far from correct. There is a huge amount of work that happens behind the scenes of the demolition and construction industry that is firmly rooted in the academic arena. Furthermore, this unseen work is vital to the success of the more visible operations.
One part of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This sort of work demands a good balance of specific technical knowledge as well as experience of the industry and a genuine intuition for the complexities of the job. This article explores the ins and outs of this work.
Topographical Surveys
A topographical survey is a study of the physical features of a given piece of land. The purpose of a topographical survey is to map the naturally occurring and man-made features of a particular landscape to a high degree of accuracy. Whilst topography itself can refer to the surface of virtually any object, it is more commonly associated with the surface of the planet.
Topographical surveys could be carried out on a very wide range of environments, from open countryside to urban developments and across a variety of reliefs and land surfaces. Surveys can be developed to take into account a great many factors, such as ground variables or vegetation, and as such can be used for a number of tasks.
Common Applications for Topographical Surveys
Probably the most widely used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal of detail about the terrain they relate to, including waterways, reliefs and ground surface, all of which will have been gathered via a topographical survey.
Topographical surveys also have a major role to play in the construction industry. When people or organisations are looking to construct 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 role in primary industries such as mining, or in other industries that interact with the terrain, such as demolition and infrastructure. Businesses in these fields will use surveys to prepare their projects, but also to be sure that they can guarantee the safety of their workforce on site. As such, topographical surveys are often a legal prerequisite for these types of projects.
The newly understood health risks of asbestos help make asbestos demolition surveys vital for jobs where older buildings are being demolished.
Types of Survey
The world of topography addresses a large number of physical characteristics so it is beneficial to identify what form of topographical survey is suitable for a particular situation.
“Lie of the land” Surveys
These types of topographical surveys are designed to create a summary of the physical properties of any given plot of land. Whilst the information collected by the survey will be very accurate, and might be very extensive, the objective of these surveys is to provide a site summary.
These surveys will generally incorporate a boundary survey that sets out to determine the extent of the site and spotlight any specific restraints that are determined by the geography of the site. They may also include a level survey that will plot the elevation of the land and the various gradients that exist.
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 regularly associated with the demolition industry since it can give a detailed plan of the building to be demolished. It may be used for other projects as well.
A building survey will almost certainly include a measured survey, which entails creating a precise plan of the external and internal dimensions of a structure. Depending on the requirements of the job, a measured survey could provide basic building “footprint” measurements, 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 information 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 secure.
Surveys will often include information about the utility services that are present on a site before any demolition or construction work happens. This is an important safety factor because 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 study will often be an inventory of materials on the site. This type of survey will be a quantity survey of the various types of materials that can be located on site, for example, tiles and masonry, concrete that can be used as hardcore or even timber. By taking an accurate audit of site materials the construction firm can more precisely determine the need to import building resources, or they can re-use the materials on a different job.
Topographical surveys and material quantity reviews make up one faction of demolition services offered by modern businesses that conform with industry best practices.
Importance of Site Surveys
Possibly the most important reason to perform a topographical site survey is to ensure the safety of the individuals who will be doing work on the site. The industrial sectors 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.
Another critical reason to get a proper 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. By then it may be too late to deal with these problems, or at best they will be costly problems to solve.
The inventory of site materials, as previously mentioned, can be of great benefit to a demolition or construction company working on a project. Not only are construction materials themselves costly, but transporting them to the site could be a very expensive task in itself. Any time that material can be reused on site offers an opportunity to save development time and money.
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 machinery then a new access route or alternative machinery will have to be found.
Positioning of Survey Control
During the surveying and construction phases of a building project, the equipment required for the physical surveying of the site and control of the survey information will often be stored on-site. This is obviously a problem when it comes to the demolition stage of a project since the machinery is both costly and sensitive. It is therefore sensible to move this equipment off-site during demolition.
Once the demolition has occurred and the site has been deemed safe for workers to return to it, the surveying equipment can be restored to its original position on site. This will allow for effective data gathering to take place for a post-demolition study, and retains a single point of contact for anyone who requires the topographical survey information. Most surveying companies will oversee this redeployment.
On the surface it might seem that demolition of a building requires little preparation, although the reality of the issue is extremely different.
Who can Perform Site Surveys?
Since topographical site surveys can play such a crucial role in the success or failure of a building or demolition venture it is vital that they are undertaken carefully by the right people. There are different branches of site surveying and each one will have unique certificates associated with it.
When choosing a company to undertake the surveying work necessary for your project it will be sensible to choose a company with a good reputation and a proven track record. Ask to see examples of their previous work and try to get feedback about their overall performance on past projects.
Who will use the Survey Information?
Once an adequate level of information has been accumulated by a site survey it must be passed out to the appropriate people on-site. Who gets what pieces of information will mostly depend on the job roles being executed, but can also rely on the stage that a project is at.
Project Planners
Project planners will usually need access to all of the information gathered by a topographical survey, though they will particularly need to use information about the physical relief of a site before the design phase, and a site materials inventory before they can prepare the construction phase.
Demolition Experts
Demolition businesses will want to know about the interior and exterior properties of any building or structures that they are set to take down. Whilst every job will have individual requirements, demolition workers will generally need to know about the fundamental structure of a building and the materials it is made out of.
Site Engineers
Construction engineers on-site will be mainly interested in the survey information about the relief and topography of the site. It is normally the case that they will want to assemble 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 stable footing for any building.