The construction trade has a particular reputation for being a harsh environment in which brute force takes precedence over calculated thinking; however this image is far from appropriate. 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 world. Furthermore, this unseen work is critical to the success of the more visible procedures.
One branch of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This type of work demands a great balance of specific technical understanding as well as experience of the industry and a genuine intuition for the intricacies of the job.
Topographical Surveys
A topographical survey is a report of the physical features of a given plot of land. The aim of a topographical survey is to chart the naturally occurring and man-made traits 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 can be carried out on a very wide range of environments, 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.
Common Applications for Topographical Surveys
Perhaps the most widely used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern day 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.
Topographical surveys also have a major role to play in the construction industry. When individuals or companies are looking to build any kind of structure they will need to undertake extensive surveys as part of the design phase of the project.
Surveys definitely play a key safety part in primary industries like mining, or in other industrial sectors that interact with the terrain, such as demolition and infrastructure. Businesses in these fields will use surveys to plan their projects, but also to be sure that they can ensure the safety of their staff on site.
To comply with specific health and safety regulations a demolition survey is usually demanded before demolition work happening.
Types of Survey
The world of topography addresses a large number of physical features so it is beneficial to determine what form of topographical survey is appropriate 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 fashioned to create an overview of the physical characteristics of any given plot of land. Although the data collected 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 undertaken on a job.
These surveys will generally incorporate a boundary survey that sets out to define the extent of the site and highlight any particular 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 equipment and even infrastructure characteristics. This type of survey is more regularly associated with the demolition industry because it can give a detailed plan of the structure to be demolished. It may be used for other projects as well.
A building survey will almost certainly include a measured survey, which entails creating a precise plan of the external and internal proportions of a structure. Depending on the requirements of the project, a measured survey could provide basic building footprint dimensions, or might produce a highly detailed plan of the structure.
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 required so that the demolition firm can plan a demolition that is both adequate and safe.
Surveys will often include information about the utility services that are present on a site before any demolition or construction work takes place. This is an essential 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 buildings, based upon the existing supply of these utilities.
Another aspect of the site study will often be an inventory of materials on the site. This type of study 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 utilised as hardcore or even wood. By taking an accurate audit of site materials the construction company can more precisely gauge the need to import building resources, or they can re-use the materials on a different project.
For demolition projects throughout urban locations, topographical demolition surveys might identify possible problems with the disruption of utilities and facilities in the area.
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 commonly call for site surveys are dangerous enough as it is without having to worry about the integrity of the ground on which they are working. Taking a comprehensive topographical survey can help to eliminate safety risks of this nature.
Another important reason to get a suitable survey done is to highlight any potential problems that may arise because of the physical properties 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 supplies, as previously stated, can be of great value to a demolition or construction organisation working on a project. Not only are building materials themselves expensive, but importing them to the site could be a very expensive task in itself. Any time that material can be reused 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 planners. For example, if the gradients on a site would be prohibitive to specific vehicles or machinery then a new entry 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 equipment 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 equipment 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 staff 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 study, and maintains a single point of contact for anybody who requires the topographical survey information. Most surveying companies will oversee this redeployment.
On the surface it could seem that the demolition of a building requires minimal planning, though the reality of the issue is extremely different.
Who can Perform Site Surveys?
Because topographical site surveys can play such a vital role in the success or failure of a building or demolition venture it is critical that they are undertaken thoroughly by the right people. There are different branches of site surveying and each one will have unique certificates associated with it.
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 reviews of their previous work and try to obtain feedback about their overall performance on past projects. It may also be worth thinking about how a company can deliver their survey information, i.e. in 3-D models or CAD ready formats, for ease of integration with other members of the project staff.
Who will use the Survey Information?
When an adequate level of information has been accumulated by a site survey it needs to be handed out to the appropriate people 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. There will be less need for materials information half way through construction for example.
Project Planners
Project planners will usually require access to all of the information gathered 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 inventory before they can prepare 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 organisations will want to know about the interior and external characteristics of any building or structures that they are set to take down. Whilst every job 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.
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 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 steady foundation for any structure. They will want this information prior to and in the course of the construction stage of a job.