Using Topographical Surveying as a Pre-Demolition Tool
The construction trade has a particular reputation for being a harsh atmosphere in which brute force takes precedence over calculated thought; however this image is far from appropriate. There is a substantial amount of work that happens behind the scenes of the demolition and construction industry which is firmly grounded in the academic arena. Moreover, this unseen work is critical to the success of the more visible operations.
One part of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This sort of work calls for a good balance of specific technical know-how as well as experience of the industry and a genuine intuition for the intricacies of the job. This article explores the ins and outs of this work.
Topographical Surveys
A topographical survey is a report of the actual features of a given plot of land. The aim of a topographical survey is to map the naturally occurring and man-made traits of a specific landscape to a high degree of precision. Whilst topography itself can refer to the surface of virtually any object, it is more commonly associated with the surface of the Earth.
Topographical surveys could 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 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
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, 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 industry. 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 phase of the project. These surveys are often an important 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 terrain, such as demolition and infrastructure. Organisations in these fields will use surveys to prepare their projects, but also to be sure that they can guarantee the safety of their staff on site.
General topographical surveys are concerned with physical properties of terrain although building demolition surveys concentrate on man-made structures which have been marked for destruction.
Types of Survey
The world of topography addresses a large number of physical characteristics so it is beneficial to determine what form 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 designed to create a summary of the physical properties of any given plot of land. Whilst the information gathered 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 usually include a boundary survey that sets out to define 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 measure 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 machines and even infrastructure features. This type of survey is more regularly associated with the demolition sector since it can give a detailed plan of the building to be demolished. It can be used on other projects as well.
A building survey will probably include a measured survey, which entails creating a precise plan of the external and interior proportions of a building. Depending on the requirements of the project, a measured survey could provide basic building “footprint” measurements, or might produce a very 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 needed so the demolition company can plan a demolition that is both satisfactory and safe.
Surveys will often include information about the energy 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 might be very dangerous.
Another aspect of the site study will often be an inventory of resources on the site. This type of survey will be a quantity survey of the various kinds 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 firm can more precisely determine the need to import building resources, or they can re-use the materials on a different job.
Modern construction and demolition businesses supply information within their own corporate website so customers may view case studies or references for past projects.
Importance of Site Surveys
Possibly the most important reason to undertake a topographical site survey is to ensure the health and safety of the people who will be doing work on the site. The industrial sectors that most commonly 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. 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 highlight any potential difficulties that may arise because of the physical characteristics of the area. Particular things will 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 deal with these problems, or at best they will be costly problems to solve.
The inventory of site materials, as previously stated, can be of great value to a demolition or construction company 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 reused on site offers an opportunity to save development time and money. Only by taking an accurate audit of these supplies can a company properly plan its imported material needs.
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 particular vehicles or machinery then a new entry route or alternative machinery will need 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 period of a project since the equipment is both costly and sensitive.
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 collecting to take place for a post-demolition study, and retains a single point of contact for anybody who requires the topographical survey information.
Because of its popular use within the building industry, concrete demolition is a fundamental branch of operations for all demolition companies.
Who can Perform Site Surveys?
Because topographical site surveys can play such a vital role in the success or failure of a construction 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 qualifications associated with it. Finding surveyors with these specific qualifications will certainly be beneficial.
When choosing a company to undertake the surveying work required for your project it will be wise to choose a business with a good reputation and a proven track record. Ask to see examples of their previous work and try to get 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 team.
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 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 midway through construction for example.
Project Planners
Project planners will generally need access to all of the information gathered by a topographical survey, although 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. The more information that can be made available to project planners will help the smooth running of the project.
Demolition Experts
Demolition companies will want to know about the internal and exterior properties of any building or structures that they are arranged to take down. Whilst every project will have individual requirements, demolition workers will typically 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 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 required to create a stable foundation for any structure. They will want this information before and in the course of the construction stage of a job.
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