The construction industry has a certain character for being a tough environment in which brute force takes precedence over calculated thinking; however this impression is far from correct. There is a huge amount of work that goes on behind the scenes of the demolition and construction sector that is firmly grounded in the academic world. Furthermore, this unseen work is critical to the success of the more visible operations.
One part of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This kind of work demands a great balance of specific technical know-how as well as experience of the industry and a natural intuition for the complexities of the job.
Topographical Surveys
A topographical survey is a report of the physical features of a given piece of land. The purpose of a topographical survey is to map 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 developments 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
Perhaps the most extensively used, and most generally recognised application for topographical surveys is cartography, or map making. Modern maps include a great deal 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 key 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 stage of the project. These surveys are often an essential part of any application for planning permission too.
Surveys definitely play a key safety role in primary industries like mining, or in other industrial sectors that interact with the terrain, such as demolition and infrastructure. Organisations in these industries will use surveys to plan their projects, but also to be sure that they can ensure the safety of their workforce on site.
The newly appreciated health risks of asbestos make asbestos demolition surveys critical to jobs where older structures are being destroyed.
Types of Survey
The arena of topography covers a large number of physical features so it is beneficial to identify what type of topographical survey is appropriate for a particular scenario. A few of the more typical types of survey necessary for construction sites are reviewed below.
“Lie of the land” Surveys
These types of topographical surveys are designed to create a summary of the physical properties of any given plot of land. Although the information 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 include 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 can also include a level survey that will measure the elevation of the land and the numerous gradients that exist.
Building Surveys
Building surveys are more generally concerned with man-made constructions on a site, including the surveying of special apparatus and even infrastructure features. This type of study is more regularly associated with the demolition sector because it can give a detailed plan of the structure to be demolished.
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 job, a measured survey might provide basic 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 always include the details gathered by the types of boundary and building surveys described above. This information will be required so that the demolition company can plan a demolition that is both satisfactory and safe. More often than not these surveys will also be legally requested.
Surveys will often include information about the energy services that are present on a site before any demolition or construction work happens. 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 might also be used to plan new buildings, 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 study will be a quantity survey of the various sorts of materials that can be found on site, for example, tiles and masonry, concrete that can be used as hardcore or even wood. By getting an accurate audit of site materials the construction firm can more accurately gauge the need to import building materials, or they can re-use the materials on a different job.
Contemporary construction and demolition companies supply information within their own corporate website where clients may view case studies or references for past projects.
Importance of Site Surveys
Perhaps the most significant reason to undertake a topographical site survey is to ensure the safety of the people who will be doing work on the site. The industries 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 suitable survey done is to highlight any potential problems that may arise because of the physical characteristics 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 begun.
The inventory of site materials, as previously mentioned, can be of great value to a demolition or construction organisation working on a project. Not only are building materials themselves costly, but transporting them to the site could 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 materials can a company properly plan its imported material requirements.
Topographical surveys can also highlight other areas that will be of use to the project managers. For example, if the gradients on a site would be prohibitive to particular vehicles or equipment then a new access route or alternative equipment will have to be found. Equally, a suitable 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 building project, the apparatus required for the physical surveying of the site and control of the survey data 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 expensive and sensitive.
Once the demolition has occurred 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 efficient data gathering to take place for a post-demolition survey, and maintains a single point of contact for anybody who needs the topographical survey information.
The demand for strict measurement as well as preparing is critical in garage demolition projects given that homes and other buildings may be close by.
Who can Perform Site Surveys?
Because topographical site surveys can play such a crucial role in the success or failure of a building or demolition project it is vital 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 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 performance on past projects. It may also be worth thinking about how a company can deliver the 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?
Once 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.
Project Planners
Project planners will generally require 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 inventory before they can plan 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 set to take down. Whilst every project will have individual 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 particularly interested in the survey information about the relief and topography of the site. It is normally the case that they will need to build on a flat surface, so they will use information about the natural lay of the land to calculate what work will be required to create a stable foundation for any structure. They will want this information prior to and during the construction stage of a project.