The demolition trade has a particular character for being a tough atmosphere in which brute force takes precedence over calculated thinking; however this image is far from appropriate. There is a huge amount of work that goes on behind the scenes of the demolition and construction industry which is firmly grounded in the academic world.
One branch 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 understanding as well as experience of the industry and a genuine intuition for the intricacies of the job.
Topographical Surveys
A topographical survey is a report of the physical features of a given 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 accuracy.
Topographical surveys could be carried out on a very wide range of landscapes, from open countryside to urban areas and across a variety of elevations 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 number of tasks.
Common Applications for Topographical Surveys
Perhaps the most extensively used, and most generally recognised application for topographical surveys is cartography, or map making. Modern day maps include a great amount of information about the landscape they relate to, including waterways, reliefs and ground surface, all of which will have been obtained via a topographical survey. This information is also being provided online.
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 stage of the project. These surveys are often an indispensable part of any application for planning permission as well.
Surveys definitely play a key safety role in primary industries like mining, or in other industrial sectors that interact with the land, such as demolition and infrastructure. Businesses in these industries will use surveys to plan their projects, but also to be sure that they can guarantee the safety of their workforce on site. As a result, topographical surveys are often a legal requirement for these types of projects.
Engineers as well as building workers use building demolition surveys for specific sizes of interior and external constructions.
Types of Survey
The arena of topography covers a large number of physical characteristics so it is beneficial to identify what type of topographical survey is suitable for a particular scenario. A few of the more typical types of survey necessary for construction sites are discussed below.
“Lie of the land” Surveys
These types of topographical surveys are fashioned to create an overview of the physical characteristics of any given plot of land. Although the data gathered by the survey will be very accurate, and might be very extensive, the purpose of these surveys is to give a site summary. They will usually 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 define the extent of the site and highlight 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. A 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 equipment and even infrastructure features. This type of survey is more commonly associated with the demolition sector because it can give a detailed plan of the building to be demolished.
A building survey will probably include a measured survey, which entails creating a precise plan of the external and interior proportions of a structure. 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. This information can be used to produce interior floor plans and even roof plans.
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 the demolition firm can plan a demolition that is both satisfactory and secure. More often than not these surveys will also be legally requested.
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 since any unmonitored damage to pipes and cables carrying water, gas and electricity could be very dangerous.
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 found 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 firm can more accurately determine the need to import building materials, or they can re-use the materials on a different job.
Project planners may uncover financial benefits after topographical demolition surveys collect material quantities available on-site that can be re-used.
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 risky 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 highlight any potential problems that may arise because of the physical properties 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 started.
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 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. Only by taking an accurate audit of these supplies can a company correctly plan its imported material requirements.
Topographical surveys can also highlight other areas that will be of use to the project planners. For example, if the gradients on a site would be prohibitive to certain vehicles or machinery then a new entry route or alternative equipment will have to be found.
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 information will often be stored on-site. This is obviously a problem when it comes to the demolition period of a project since the equipment is both expensive and sensitive.
Once the demolition has occurred and the site has been deemed safe for staff 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 retains a single point of contact for anybody who requires the topographical survey information. Most surveying firms will oversee this redeployment.
Who can Perform Site Surveys?
Since topographical site surveys can play such a critical role in the success or failure of a building or demolition project it is critical that they are carried out thoroughly by the correct people. There are different divisions of site surveying and each one will have unique 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. It may also be worth considering how a company can deliver the survey data, 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?
When an adequate level of details has been accumulated by a site survey it must be handed 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. There will be less need for materials information midway through construction for example.
Project Planners
Project planners will generally 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.
Demolition Experts
Demolition organisations will want to know about the internal and external characteristics of any building or structures that they are set to take down. Whilst every project will have different 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 knowledge 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 terrain. It is usually the case that they will want to assemble on a flat surface, so they will use information about the natural lay of the land to determine what work will be required to create a steady footing for any building.