The construction trade has a certain character for being a harsh environment in which brute force takes priority over calculated thought; 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 which is firmly grounded in the academic world. Moreover, this unseen work is essential to the success of the more visible operations.
One branch of this unnoticed work is site surveying, or more specifically pre-demolition and post-demolition topographical surveying. This sort of work demands a good balance of specific technical know-how 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 study of the physical features of a particular plot 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 landscapes, 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 many 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 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 gathered via a topographical survey.
Topographical surveys also have a major role to play in the construction industry. When people or companies are looking to build any kind of structure they will need to perform extensive surveys as part of the design stage of the project.
Surveys definitely play a key safety role 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.
To comply with particular safety legislation a demolition survey is usually demanded before demolition jobs taking place.
Types of Survey
The world of topography addresses a large number of physical characteristics so it is beneficial 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. Although the information gathered by the survey will be extremely accurate, and may be very extensive, the purpose of these surveys is to give a site summary.
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 can also include a level survey that will measure the elevation of the land and the numerous gradients that exist. A survey can be customised to specification though.
Building Surveys
Building surveys are more typically concerned with man-made structures on a site, including the surveying of special machines and even infrastructure features. This type of study is more commonly 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 precise plan of the external and internal proportions of a structure. Depending on the requirements of the job, a measured survey could provide basic building “footprint” measurements, or might produce a very detailed plan of the structure. This information can be used to create internal 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 that the demolition company 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 because any unmonitored destruction to pipes and cables carrying water, gas and electricity could be very dangerous.
Another aspect of the site study will often be an inventory of resources on the site. This type of survey 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 utilised as hardcore or even wood. By getting an accurate audit of site materials the construction firm can more precisely determine the need to import building resources, or they can re-use the materials on a different job.
Even though it is a needed immediate cost, a pre demolition survey may well produce economic benefits in the long-term by identifying potential issues.
Importance of Site Surveys
Possibly the most important reason to undertake a topographical site survey is to ensure the health and safety of the individuals who will be working on the site. The industrial sectors that most commonly call for site surveys are dangerous enough as it is without having to be concerned 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 difficulties 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 discovered once digging or demolition has begun.
The inventory of site supplies, as previously mentioned, can be of great value to a demolition or construction enterprise working on a project. Not only are construction materials themselves costly, but transporting them to the site may 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. 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 entry route or alternative equipment will need to be found. Equally, a suitable 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 phases of a building project, the equipment 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 occurred 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 survey, and retains a single point of contact for anybody who requires the topographical survey information. Most surveying companies will oversee this redeployment.
Project planners must think about secondary provisions such as concrete removal when scheduling various businesses to carry out work on a building project.
Who can Perform Site Surveys?
Because topographical site surveys can play such a crucial role in the success or failure of a construction or demolition project it is critical that they are undertaken carefully 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 sensible 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 performance on past projects. It may also be worth thinking about 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?
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 what pieces of information will largely 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 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 plan the construction phase. The more information that can be made available to project planners will aid the smooth running of the venture.
Demolition Experts
Demolition businesses will want to know about the internal and exterior properties of any building or structures that they are arranged to take down. Whilst every job will have individual requirements, demolition workers will generally need to know about the fundamental structure of a building and the materials it is made out of.
Site Engineers
Construction engineers on-site will be particularly interested in the survey statistics 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 required to create a stable foundation for any structure.