The construction industry has a certain reputation for being a harsh environment in which brute force takes precedence over calculated thought; however this impression is far from correct. There is a huge amount of work that happens behind the scenes of the demolition and construction industry that is firmly rooted in the academic arena.
One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This sort of work calls for a great balance of specific technical know-how as well as experience of the industry and a natural 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 particular plot of land. The aim of a topographical survey is to chart the naturally occurring and man-made features of a particular landscape to a high degree of precision.
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 designed 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.
Common Applications for Topographical Surveys
Perhaps the most extensively used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal of detail about the landscape 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 made available online.
Topographical surveys also have a major role to play in the construction business. When people 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 essential part of any application for planning permission too.
Surveys also play a key safety role in primary industries like mining, or in other industrial sectors that interact with the land, such as demolition and infrastructure. Businesses in these fields will use surveys to plan their projects, but also to be sure that they can guarantee the safety of their staff on site.
To comply to particular safety legislation a demolition survey will be required before demolition jobs taking place.
Types of Survey
The world of topography addresses a large number of physical characteristics so it is beneficial to determine what type of topographical survey is appropriate for a particular scenario.
“Lie of the land” Surveys
These types of topographical surveys are designed to create an overview of the physical properties of any given plot of land. Although the data gathered by the survey will be very accurate, and can be very extensive, the objective of these surveys is to provide a site summary.
These surveys will generally incorporate a boundary survey that sets out to determine the extent of the site and spotlight any particular restraints that are determined by the geography of the site. They may also include a level survey that will plot the elevation of the land and the various gradients that exist.
Building Surveys
Building surveys are more typically concerned with man-made constructions on a site, including the surveying of special machines and even infrastructure features. This type of study 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 for other projects as well.
A building survey will almost certainly include a measured survey, which involves creating a detailed 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” 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 definitely include the information 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 satisfactory and safe. Often these surveys will also be legally required.
Surveys will often include information about the energy services that are present on a site before any demolition or construction work takes place. This is an essential safety factor since any unmonitored destruction to pipes and cables carrying water, gas and electricity might be very dangerous. The information could also be used to plan new buildings, based upon the existing availability of these ammenities.
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 located 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 project.
Undertaking a thorough , comprehensive house demolition survey ensures the health and safety of residents in the immediate vicinity of the work site.
Importance of Site Surveys
Maybe the most important reason to undertake a topographical site survey is to ensure the safety of the individuals who will be working 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 condition 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 identify any potential problems that may arise because of the physical properties of the region. 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 deal with these problems, or at best they will be costly issues to solve.
The inventory of site supplies, as previously stated, 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 reused on site provides an opportunity to save development time and money. Only by taking an exact audit of these materials can a company correctly 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 specific vehicles or equipment then a new entry route or alternative machinery will need to be found.
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 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 wise 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 effective data collecting to take place for a post-demolition study, and maintains a single point of contact for anyone who requires the topographical survey information. Most surveying companies will oversee this redeployment.
Who can Perform Site Surveys?
Since topographical site surveys can play such a critical role in the success or failure of a building or demolition project it is critical that they are undertaken carefully by the correct 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 required for your project it will be wise to choose a business 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. It may also be worth considering how a company can deliver their survey data, 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 details has been gathered by a site survey it must be passed out to the appropriate personnel on-site. Who gets what pieces of information will mostly depend on the job roles being executed, 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 usually require 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 plan the construction phase.
Demolition Experts
Demolition companies will want to know about the interior and exterior 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 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 information about the relief and topography of the terrain. It is normally 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 calculate what work will be needed to create a steady footing for any building.