The construction industry has a certain character for being a tough atmosphere in which brute force takes priority over calculated thought; however this image is far from correct. There is a huge amount of work that goes on behind the scenes of the demolition and construction sector which is firmly rooted in the academic arena. Furthermore, this unseen work is essential 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 understanding 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 report of the physical features of a particular plot of land. The purpose of a topographical survey is to map the naturally occurring and man-made traits of a specific landscape to a high degree of accuracy. Whilst topography itself may refer to the surface of virtually any object, it is more commonly associated with the surface of the Earth.
Topographical surveys can 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 variables or vegetation, and as such can be used for a number of tasks. A few of the more common uses are discussed below.
Common Applications for Topographical Surveys
Perhaps the most extensively used, and most generally recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal of information about the terrain they relate to, including waterways, reliefs and ground surface, all of which will have been collected via a topographical survey.
Topographical surveys also have a major role to play in the construction industry. When individuals or organisations are looking to construct any kind of structure they will need to perform extensive surveys as part of the design stage of the project.
Surveys also 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. Companies in these fields will use surveys to plan their projects, but also to make sure 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.
Engineers and building workers use building demolition surveys for specific measurements of internal and exterior structures.
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 suitable for a particular scenario.
“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 data gathered by the survey will be very accurate, and may be very extensive, the purpose of these surveys is to provide a site summary.
These surveys will usually include 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 measure the elevation of the land and the various gradients that exist.
Building Surveys
Building surveys are more generally concerned with man-made constructions on a site, including the surveying of special apparatus and even infrastructure characteristics. This type of survey is more commonly associated with the demolition industry since it can give a detailed plan of the structure to be demolished.
A building survey will probably include a measured survey, which involves creating a comprehensive plan of the exterior and interior dimensions of a building. Depending on the requirements of the project, 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 definitely include the details 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 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 factor because any unmonitored destruction to pipes and cables carrying water, gas and electricity might be very dangerous. The information can also be used to plan new structures, based upon the existing supply of these utilities.
Another aspect of the site study will often be an audit of materials on the site. This type of survey will be a quantity survey of the various kinds of materials that can be found 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 gauge the need to import building materials, or they can re-use the materials on a different job.
It is an apparent truth that prior to construction demolition must be done within sites containing existing houses and other structures.
Importance of Site Surveys
Maybe the most important reason to undertake a topographical site survey is to ensure the health and safety of the individuals who will be doing work on the site. The industries that most commonly call for site surveys are dangerous enough as it is without having to worry 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. Certain things may not be evident on the surface of the site and will only be uncovered once digging or demolition has started.
The inventory of site materials, as previously mentioned, can be of great value to a demolition or construction company working on a project. Not only are building materials themselves costly, but importing them to the site could 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.
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.
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 kept on-site. This is obviously a problem when it comes to the demolition phase 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 taken place and the site has been deemed safe for personnel 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 survey, and keeps a single point of contact for anybody who needs the topographical survey information.
One of the more technical parts of industrial demolition concerns disposal of dangerous substances that may be harmful to the natural environment.
Who can Perform Site Surveys?
Because topographical site surveys can play such a critical role in the success or failure of a construction 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.
When choosing a company to undertake the surveying work necessary for your project it will be sensible 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 past projects.
Who will use the Survey Information?
When an adequate level of information has been accumulated by a site survey it must be handed out to the appropriate personnel on-site. Who gets what 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, though they will particularly need to use information regarding the physical relief of a site before the design phase, and a site materials record before they can prepare the construction phase.
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 different requirements, demolition workers will typically need to know about the fundamental structure 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 mainly interested in the survey data about the relief and topography of the terrain. 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 calculate what work will be needed to create a stable footing for any structure.