The construction trade has a particular character for being a harsh atmosphere in which brute force takes priority over calculated thought; however this impression is far from correct. There is a substantial amount of work that happens behind the scenes of the demolition and construction sector that is firmly rooted in the academic arena.
One part of this unnoticed work is site surveying, or more precisely 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 particular piece of land. The purpose of a topographical survey is to map the naturally occurring and man-made features of a specific landscape to a high degree of precision. 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 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 designed to take into account a great number of factors, such as ground conditions or vegetation, and as such can be used for a number 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 information about the terrain they relate to, including waterways, elevations and ground surface, all of which will have been obtained via a topographical survey. This information is also being made available online.
Topographical surveys also have a key role to play in the construction business. When individuals or organisations are looking to construct any kind of structure they will need to carry out 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 industrial sectors that interact with the land, such as demolition and infrastructure. Companies in these industries will use surveys to prepare their projects, but also to be sure that they can guarantee the safety of their workforce on site.
Most construction and demolition firms within the UK carry out demolition surveys for projects they are working on.
Types of Survey
The world of topography covers a large number of physical characteristics so it is beneficial to determine what type of topographical survey is appropriate for a particular situation.
“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. Whilst the data collected by the survey will be extremely accurate, and may be very extensive, the objective of these surveys is to provide a site summary.
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 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 apparatus and even infrastructure features. This type of survey is more commonly associated with the demolition sector since it can give a detailed plan of the building to be demolished. It may be used on other projects as well.
A building survey will almost certainly include a measured survey, which involves creating a precise plan of the external and interior dimensions of a structure. Depending on the requirements of the project, a measured survey might provide simple building “footprint” dimensions, or might produce a highly detailed plan of the structure. This information can be used to generate interior floor plans and even roof plans.
Content of a Topographical Site Survey
A survey of a demolition site will almost definitely include the information 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 adequate and secure. Often these surveys will also be legally requested.
Surveys will often contain information about the power services that are present on a site before any demolition or construction work happens. This is an important safety factor since any unmonitored damage to pipes and cables carrying water, gas and electricity could be very dangerous. The information could also be used to plan new structures, based upon the existing supply of these ammenities.
Another aspect of the site survey 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 getting 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.
Topographical surveys and resource quantity reviews form one branch of demolition services provided by contemporary organisations that comply with business best practices.
Importance of Site Surveys
Perhaps the most significant reason to perform a topographical site survey is to ensure the health and safety of the individuals who will be doing work on the site. The industrial sectors that most frequently 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 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 begun. By then it may be too late to fix these problems, or at best they will be costly issues to solve.
The inventory of site materials, as previously stated, can be of great benefit to a demolition or construction organisation working on a project. Not only are building materials themselves expensive, but transporting them to the site could be a very expensive task in itself. Any time that material can be recycled on site provides an opportunity to save development time and money.
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 specific vehicles or equipment then a new access route or alternative machinery will need 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 phases of a construction project, the apparatus required for the physical surveying of the site and control of the survey information will often be stored on-site. This is clearly a problem when it comes to the demolition stage of a project since the machinery is both costly and sensitive.
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 original position on site. This will allow for effective data collecting to take place for a post-demolition survey, and keeps a single point of contact for anybody who requires the topographical survey information.
The need for strict measurement and planning is critical in garage demolition projects because houses and other buildings may be nearby.
Who can Perform Site Surveys?
Since topographical site surveys can play such a critical role in the success or failure of a construction or demolition venture it is vital that they are undertaken thoroughly by the correct people. There are different branches of site surveying and each one will have specific qualifications associated with it. Getting 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 sensible to choose a company with a good reputation and a proven track record. Ask to see reviews 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 passed out to the appropriate personnel 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.
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 record before they can prepare the construction phase.
Demolition Experts
Demolition businesses will want to know about the interior and external characteristics of any building or structures that they are arranged to take down. Whilst every job 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 mainly interested in the survey statistics about the relief and topography of the site. It is usually the case that they will need 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 stable footing for any structure.
Mar 10 2010