The construction trade has a particular reputation for being a harsh environment in which brute force takes precedence over calculated thought; however this image 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 grounded in the academic arena. Furthermore, this unseen work is essential to the success of the more visible operations.
One branch of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This sort of work calls for a great balance of specific technical understanding 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 physical features of a given piece of land. The aim of a topographical survey is to map the naturally occurring and man-made features of a particular landscape to a high degree of accuracy. Whilst topography itself may refer to the surface of 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 landscapes, from open countryside to urban areas and across a variety of elevations 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. A few of the more common uses are outlined below.
Common Applications for Topographical Surveys
Probably the most widely used, and most generally 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.
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 undertake extensive surveys as part of the design stage of the project.
Surveys also play a key safety part in primary industries such as mining, or in other industries that interact with the land, such as demolition and infrastructure. Businesses in these fields will use surveys to prepare their projects, but also to be sure that they can ensure the safety of their workforce on site. As such, topographical surveys are often a legal requirement for these types of projects.
Most construction and demolition firms within the United Kingdom conduct demolition surveys on jobs they may be working on.
Types of Survey
The world of topography covers a large number of physical characteristics so it is important to identify what type 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 characteristics of any given plot of land. Whilst the data collected by the survey will be very accurate, and might 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 determine the extent of the site and highlight any particular 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. A survey can be customised to specification though.
Building Surveys
Building surveys are more generally concerned with man-made constructions on a site, including the surveying of special equipment and even infrastructure characteristics. This type of study is more commonly associated with the demolition sector since it can give a detailed plan of the structure to be demolished. It can be used on other projects as well.
A building survey will probably include a measured survey, which involves creating a comprehensive plan of the exterior and interior dimensions of a structure. Depending on the requirements of the job, a measured survey could provide simple 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 mentioned above. This information will be necessary so that the demolition firm can plan a demolition that is both adequate and safe.
Surveys will often contain information about the energy services that are present on a site prior to any demolition or construction work happens. This is an important safety aspect because any unmonitored destruction 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 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 company can more accurately gauge the need to import building materials, or they can re-use the materials on a different project.
Topographical surveys and resource quantity surveys make up one particular branch of demolition services provided by contemporary companies that conform with industry best practices.
Importance of Site Surveys
Possibly the most significant reason to perform a topographical site survey is to ensure the safety of the people who will be working 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 important reason to get a proper survey done is to highlight any potential difficulties that may arise because of the physical characteristics of the area. Certain things will 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 benefit 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 recycled on site offers an opportunity to save development time and funds. Only by taking an exact audit of these materials can a company correctly plan its imported material requirements.
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 entry route or alternative equipment will have to be found. Equally, an appropriate site will need to be found for the base of management 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 building project, the apparatus required for the physical surveying of the site and control of the survey information 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.
Once the demolition has taken place and the site has been deemed safe for staff 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 keeps a single point of contact for anybody who requires the topographical survey information. Most surveying firms will oversee this redeployment.
The types of companies which call for plant demolition will have often worked with demolition firms on jobs in the past.
Who can Perform Site Surveys?
Since 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 undertaken thoroughly by the correct people. There are different divisions of site surveying and each one will have specific 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 examples of their previous work and try to obtain feedback about their overall performance on previous projects.
Who will use the Survey Information?
When an adequate level of details has been accumulated by a site survey it must be passed out to the appropriate personnel on-site. Who gets which pieces of information will largely depend on the job roles being executed, but can also rely on the stage that a project is at.
Project Planners
Project planners will usually need access to all of the information gathered 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 record before they can plan the construction phase.
Demolition Experts
Demolition companies will want to know about the internal and external properties 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.
Site Engineers
Construction engineers on-site will be mainly interested in the survey statistics about the relief and topography of the site. It is normally the case that they will need to assemble on a flat surface, so they will use details about the natural lay of the land to determine what work will be required to create a steady footing for any building.