March 10, 2010
Post-Demolition Site Surveys
The demolition trade has a particular character for being a harsh environment in which brute force takes precedence over calculated thought; however this image is far from correct. There is a huge amount of work that happens behind the scenes of the demolition and construction industry which is firmly grounded in the academic world. Moreover, this unseen work is essential to the success of the more visible operations.
One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This kind of work demands a good balance of specific technical understanding as well as experience of the industry and a natural 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 actual features of a given piece 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 broad range of environments, 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 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 day maps include a great amount of information about the landscape they relate to, including waterways, elevations and ground surface, all of which will have been obtained via a topographical survey.
Topographical surveys also have a major role to play in the construction business. When people or companies 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 essential part of any application for planning permission as well.
Surveys also play a key safety role in primary industries like mining, or in other industries that interact with the land, such as demolition and infrastructure. Businesses in these industries will use surveys to plan their projects, but also to ensure that they can guarantee the safety of their staff on site.
Engineers as well as building staff employ building demolition surveys for in depth dimensions of interior and external structures.
Types of Survey
The world of topography addresses 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 common types of survey required for construction sites are discussed below.
“Lie of the land” Surveys
These types of topographical surveys are designed to create an overview of the physical characteristics of any given plot of land. Whilst the information gathered by the survey will be very accurate, and can be very extensive, the objective of these surveys is to give a site summary. They will often be the first type of topographical survey that is carried out on a project.
These surveys will generally include 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 can 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 structures on a site, including the surveying of special equipment and even infrastructure characteristics. 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 may be used for other projects as well.
A building survey will probably include a measured survey, which involves creating a comprehensive plan of the external and internal proportions of a building. Depending on the requirements of the job, 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 create interior floor plans and even roof plans.
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 needed so that the demolition firm can plan a demolition that is both satisfactory and safe.
Surveys will often contain 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 might be very dangerous. The information can also be used to plan new buildings, based upon the existing supply of these utilities.
Another aspect of the site study will often be an inventory of resources on the site. This type of study will be a quantity survey of the various sorts of materials that can be located on site, for example, tiles and masonry, concrete that can be utilised as hardcore or even wood. By taking an accurate audit of site materials the construction company can more accurately determine the need to import building resources, or they can re-use the materials on a different job. These surveys can be made pre-demolition and post-demolition.
For demolition projects throughout city locations, topographical demolition surveys may uncover possible issues with the disruption of utilities and infrastructure in the region.
Importance of Site Surveys
Perhaps the most significant reason to undertake a topographical site survey is to ensure the health and safety of the people who will be working on the site. The industrial sectors that most frequently call for site surveys are risky 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 highlight any potential problems that may arise because of the physical properties of the area. Particular things may 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 value to a demolition or construction company working on a project. Not only are construction materials themselves costly, but transporting them to the site may be a very expensive task in itself. Any time that material can be recycled on site offers an opportunity to save development time and money. Only by taking an exact audit of these supplies can a company correctly plan its imported material needs.
Topographical surveys can also identify 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 equipment then a new access route or alternative machinery will have to be found. Equally, an appropriate site will need to be found for the base of control operations for the project. Good site surveying can help out in these less tangible ways.
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 phase of a project since the machinery is both expensive 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 initial position on site. This will allow for efficient data collecting to take place for a post-demolition survey, and maintains a single point of contact for anybody who needs the topographical survey information. Most surveying companies will oversee this redeployment.
Many towns and cities around our nation need home demolition before building of modern housing estates can begin.
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 carried out thoroughly by the correct people. There are different divisions of site surveying and each one will have unique certificates associated with it. Finding surveyors with these specific qualifications will certainly be advantageous.
When choosing a company to undertake the surveying work required 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 obtain feedback about their overall performance on past projects.
Who will use the Survey Information?
Once an adequate level of information has been gathered 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 require access to all of the information gathered by a topographical survey, although 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 plan the construction phase. The more data that can be made available to project planners will aid 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 experts 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 statistics about the relief and topography of the terrain. 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 required to create a steady footing for any building.
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