The demolition industry has a certain character for being a tough environment in which brute force takes priority over calculated thought; however this image is far from correct. There is a substantial amount of work that goes on behind the scenes of the demolition and construction industry that is firmly grounded in the academic arena. Moreover, 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 type of work demands a good balance of specific technical know-how as well as experience of the industry and a natural intuition for the intricacies of the job.
Topographical Surveys
A topographical survey is a report of the physical features of a particular plot of land. The aim of a topographical survey is to map the naturally occurring and man-made features of a particular landscape to a high degree of accuracy.
Topographical surveys can be carried out on a very wide range of landscapes, from open countryside to urban areas and across a variety of reliefs and land surfaces. Surveys can be developed to take into account a great many factors, such as ground conditions or vegetation, and as such can be used for a number of tasks.
Common Applications for Topographical Surveys
Perhaps the most extensively used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal of information about the landscape they relate to, including waterways, elevations and ground surface, all of which will have been gathered via a topographical survey. This information is also being made available online.
Topographical surveys also have a major role to play in the construction industry. When people or companies are looking to build any kind of structure they will need to perform 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 industrial sectors that interact with the land, such as demolition and infrastructure. Businesses in these fields will use surveys to plan their projects, but also to be sure that they can ensure the safety of their staff on site.
New developments built on previously lived on land demand demolition surveys to minimise interruption to utilities and services for the surrounding community.
Types of Survey
The world of topography covers a large number of physical features so it is beneficial to identify what form of topographical survey is appropriate for a particular situation. A few of the more typical types of survey required for construction sites are reviewed below.
“Lie of the land” Surveys
These types of topographical surveys are fashioned to create an overview of the physical properties of any given plot of land. Although the data collected by the survey will be very accurate, and can be very extensive, the objective of these surveys is to provide a site summary. They will often be the first type of topographical survey that is carried out on a job.
These surveys will usually incorporate a boundary survey that sets out to determine the extent of the site and highlight any specific 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. A survey can be customised to specification though.
Building Surveys
Building surveys are more typically concerned with man-made constructions on a site, including the surveying of special apparatus and even infrastructure features. This type of study is more commonly associated with the demolition sector because 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 proportions of a building. Depending on the requirements of the project, a measured survey might 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 details gathered by the types of boundary and building surveys mentioned above. This information will be required so that the demolition firm can plan a demolition that is both satisfactory 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 essential safety aspect 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 buildings, 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 sorts of materials that can be found 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 company can more accurately gauge the need to import building materials, or they can re-use the materials on a different project. These surveys can be made pre-demolition and post-demolition.
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Importance of Site Surveys
Possibly the most significant reason to undertake a topographical site survey is to ensure the safety of the individuals who will be working on the site. The industrial sectors that most commonly 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 properties of the area. Certain 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 mentioned, can be of great benefit to a demolition or construction organisation working on a project. Not only are building materials themselves expensive, 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. Only by taking an accurate audit of these supplies can a company correctly plan its imported material needs.
Topographical surveys can also highlight 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 need to be found. Equally, a suitable site will need to be found for the base of management operations for the project. Good site surveying can help out in these less tangible ways.
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 equipment is both expensive and sensitive.
Once the demolition has occurred 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 effective data collecting to take place for a post-demolition study, and retains a single point of contact for anyone who requires the topographical survey information.
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Who can Perform Site Surveys?
Because topographical site surveys can play such a crucial role in the success or failure of a building or demolition project it is vital that they are undertaken thoroughly by the right people. There are different branches of site surveying and each one will have specific qualifications associated with it. Finding surveyors with these specific skills will certainly be advantageous.
When choosing 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 examples of their previous work and try to obtain feedback about their 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 handed out to the appropriate personnel on-site. Who gets which pieces of information will largely depend on the job roles being performed, but can also rely on the stage that a project is at. There will be much less need for materials information half way through construction for example.
Project Planners
Project planners will usually require access to all of the information collected by a topographical survey, though they will particularly need to use information regarding the physical relief of a site before the design phase, and a site materials inventory before they can plan the construction phase. The more data that can be made available to project planners will help the smooth running of the venture.
Demolition Experts
Demolition organisations will want to know about the internal and exterior characteristics of any building or structures that they are arranged to take down. Whilst every job will have individual requirements, demolition workers will generally need to know about the fundamental framework 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 particularly interested in the survey information about the relief and topography of the site. It is usually 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 determine what work will be needed to create a steady footing for any building. They will want this information prior to and during the construction stage of a project.
