The demolition 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 industry which is firmly grounded in the academic arena. Furthermore, this unseen work is essential to the success of the more visible operations.

One part of this unnoticed work is site surveying, or more precisely pre-demolition and post-demolition topographical surveying. This type 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.

Topographical Surveys

A topographical survey is a study 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. 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 could be carried out on a very broad range of landscapes, 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 variables or vegetation, and as such can be used for a number of tasks. A few of the more common uses are discussed below.

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 deal of information about the terrain 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 provided online.

Topographical surveys also have a key role to play in the construction business. When people or companies are looking to construct any kind of structure they will need to carry out extensive surveys as part of the design phase of the project.

Surveys definitely play a key safety part in primary industries such as mining, or in other industrial sectors that interact with the terrain, such as demolition and infrastructure. Organisations in these fields will use surveys to plan their projects, but also to make sure that they can guarantee the safety of their workforce on site.

Types of Survey

The arena 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 situation.

“Lie of the land” Surveys

These types of topographical surveys are fashioned to create a summary of the physical properties 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. They will usually 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 spotlight 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 apparatus and even infrastructure characteristics. This type of study is more commonly associated with the demolition industry 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 comprehensive plan of the exterior and interior proportions of a structure. Depending on the requirements of the project, 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 definitely include the details gathered by the types of boundary and building surveys mentioned above. This information will be required 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 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 could be very dangerous. The information can 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 resources 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 utilised as hardcore or even timber. By taking an accurate audit of site materials the construction company can more precisely gauge the need to import building materials, or they can re-use the materials on a different project. These surveys could be made pre-demolition and post-demolition.

For demolition jobs throughout city locations, topographical demolition surveys could uncover potential problems concerning the disruption of utilities and infrastructure in the region.

Importance of Site Surveys

Possibly the most significant reason to perform a topographical site survey is to ensure the safety of the individuals who will be doing work on the site. The industrial sectors that most frequently call for site surveys are dangerous enough as it is without having to worry about the condition of the ground on which they are working.

Another critical reason to get a proper survey done is to highlight any potential difficulties that may arise because of the physical properties of the area. Certain things will not be evident on the surface of the site and will only be discovered once digging or demolition has started.

The inventory of site supplies, as previously stated, can be of great value to a demolition or construction enterprise working on a project. Not only are building materials themselves costly, but importing them to the site may be a very expensive task in itself. Any time that material can be recycled on site offers an opportunity to save development time and funds. Only by taking an accurate audit of these materials can a company properly plan its imported material needs.

Topographical surveys can also identify 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 access 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 building project, the equipment 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 phase of a project since the equipment is both expensive and sensitive.

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 initial position on site. This will allow for efficient data gathering to take place for a post-demolition survey, and retains a single point of contact for anybody who needs the topographical survey information.

It is essential to perform surveys prior to and also following the demolition of buildings since damage of electric services must be monitored carefully.

Who can Perform Site Surveys?

Because topographical site surveys can play such a vital role in the success or failure of a construction or demolition project it is vital that they are carried out carefully by the right people. There are different branches of site surveying and each one will have specific certificates associated with it. Finding surveyors with these specific qualifications will certainly be advantageous.

When choosing a company to undertake the surveying work required for your project it will be wise to choose a company with a good reputation and a proven track record. Ask to see examples of their previous work and try to get feedback about their overall performance on previous projects. It may also be worth considering 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 team.

Who will use the Survey Information?

When an adequate level of information has been accumulated by a site survey it needs to be passed out to the appropriate personnel on-site. Who gets what pieces of information will mostly 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, although 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 help the smooth running of the venture.

Demolition Experts

Demolition companies 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 typically need to know about the fundamental framework 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 data about the relief and topography of the terrain. It is usually the case that they will need to build on a flat surface, so they will use details about the natural lay of the land to calculate what work will be needed to create a steady footing for any building.