The construction trade has a particular character for being a harsh atmosphere in which brute force takes precedence over calculated thought; however this image is far from correct. There is a substantial amount of work that goes on behind the scenes of the demolition and construction industry which is firmly grounded in the academic arena.
One part 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 knowledge 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 report of the physical features of a particular piece 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 accuracy. Whilst topography itself can refer to the surface of any kind of object, it is more commonly associated with the surface of the planet.
Topographical surveys can 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 variables or vegetation, and as such can be used for a multitude of tasks.
Common Applications for Topographical Surveys
Probably the most widely used, and most commonly recognised application for topographical surveys is cartography, or map making. Modern maps include a great amount of information about the terrain they relate to, including waterways, reliefs and ground surface, all of which will have been collected via a topographical survey.
Topographical surveys also have a key role to play in the construction industry. When individuals or companies are looking to build any kind of structure they will need to perform extensive surveys as part of the design phase of the project.
Surveys also 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. Organisations in these industries will use surveys to prepare their projects, but also to be sure that they can ensure the safety of their workforce on site. As a result, topographical surveys are often a legal prerequisite for these types of projects.
New projects built on previously inhabited land need demolition surveys to minimise interruption of utilities and services for the surrounding area.
Types of Survey
The arena of topography addresses a large number of physical characteristics so it is beneficial to identify what type of topographical survey is appropriate for a particular situation. A few of the more typical 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 properties of any given plot of land. Although the information gathered by the survey will be extremely accurate, and might be very extensive, the purpose of these surveys is to provide a site summary.
These surveys will generally include a boundary survey that sets out to determine the extent of the site and spotlight any specific restraints that are determined by the geography of the site. They may also include a level survey that will measure the elevation of the terrain 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 apparatus and even infrastructure characteristics. This type of survey is more regularly associated with the demolition sector because 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 entails creating a detailed plan of the exterior and interior proportions of a structure. Depending on the requirements of the job, a measured survey might provide simple 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 definitely include the information gathered by the types of boundary and building surveys mentioned above. This information will be needed so the demolition company can plan a demolition that is both adequate and safe. More often than not these surveys will also be legally requested.
Surveys will often contain information about the utility services that are present on a site prior to any demolition or construction work happens. This is an important safety factor since any unmonitored damage to pipes and cables carrying water, gas and electricity might be very dangerous.
Another aspect of the site survey will often be an audit of resources on the site. This type of study will be a quantity survey of the various sorts 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 firm can more precisely determine the need to import building materials, or they can re-use the materials on a different project. These surveys can be made pre-demolition as well as post-demolition.
Practically all building sites need topographical demolition surveys now laws and safety have become critical requirements.
Importance of Site Surveys
Maybe 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 industries that most commonly 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. 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 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 started. By then it may be too late to fix these problems, or at best they will be expensive problems to solve.
The inventory of site materials, 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 transporting them to the site could be a very expensive task in itself. Any time that material can be recycled on site provides an opportunity to save development time and funds.
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 machinery then a new entry route or alternative equipment will have to be found.
Positioning of Survey Control
During the surveying and construction stages of a construction 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 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 workers 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 retains a single point of contact for anyone who requires the topographical survey information. Most surveying companies will oversee this redeployment.
On the surface it might seem that demolition of a building demands minimal planning, but the reality of the matter is extremely different.
Who can Perform Site Surveys?
Because 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 carried out thoroughly by the right people. There are different branches of site surveying and each one will have specific qualifications associated with it. Finding surveyors with these specific qualifications will certainly be beneficial.
When choosing a company to undertake the surveying work necessary 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 previous projects.
Who will use the Survey Information?
When an adequate level of information has been gathered by a site survey it needs to be handed 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. There will be much less need for materials information half way through construction for example.
Project Planners
Project planners will usually need access to all of the information collected 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 data that can be made available to project planners will aid the smooth running of the venture.
Demolition Experts
Demolition organisations will want to know about the interior and external characteristics of any building or structures that they are arranged to take down. Whilst every job will have different requirements, demolition experts will typically need to know about the fundamental structure 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 mainly interested in the survey statistics about the relief and topography of the site. It is usually the case that they will want to build 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 stable footing for any structure. They will want this information prior to and during the construction stage of a job.