Surveying For Construction
Lyric Maro
Construction surveying or building surveying (otherwise known as "staking", "stake-out", "lay-out", or "setting-out") is to provide dimensional control for all stages of construction work, including the stake out of reference points and markers that will guide the construction of new structures such as roads, rail, or buildings.[1] These markers are usually staked out according to a suitable coordinate system selected for the project.
Land surveys and surveys of existing conditions are generally performed according to geodesic coordinates. However, for the purposes of construction a more suitable coordinate system will often be used. During construction surveying, the surveyor will often have to convert from geodesic coordinates to the coordinate system used for that project.
In the case of buildings, an arbitrary system of grids is often established so as to correspond to the rows of columns and the major load-bearing walls of the building. The grids may be identified alphabetically in one direction, and numerically in the other direction (as in a road map). The grids are usually but not necessarily perpendicular, and are often but not necessarily evenly spaced. Floors and basement levels are also numbered. Structures, equipment or architectural details may be located in reference to the floor and the nearest intersection of the arbitrary axes.
Typically national mapping grids have significant distortion and are often not suitable for precise engineering design and construction. For major infrastructure projects specifically designed low distortion engineering grids can be used, an example being the Transport for London London Survey Grid, or tailored snake projections which can be suitable for long linear infrastructure such as high speed rail. Such grids not only minimise the impact of distortion due to the Earth's curvature but also have the benefit of defined relationships to a geodetic datum and therefore lack the arbitrary nature of localized grids.[4]
In other types of construction projects, arbitrary "plan north" reference lines may be established, using Cartesian coordinates that may or may not necessarily correspond to true coordinates. The technique is called localized grid.This method uses the plan building grids as their own ordinates. A point of beginning is established at the southwest cross grid, e.g. [N1000.000,E3000.000]. The grids are added together heading north and east to make each line its own ordinate.
Surveying equipment, such as levels and theodolites, are used for accurate measurement of angular deviation, horizontal, vertical and slope distances. With computerisation, electronic distance measurement (EDM), total stations, GNSS surveying and laser scanning have supplemented (and to a large extent supplanted) the traditional optical instruments.[citation needed]
The builder's level measures neither horizontal nor vertical angles. It simply combines a spirit level and telescope to allow the user to visually establish a line of sight along a level plane. When used together with a graduated staff it can be used to transfer elevations from one location to another. An alternative method to transfer elevation is to use water in a transparent hose as the level of the water in the hose at opposite ends will be at the same elevation. A double right angle prism verifies grid patterns, isolating layout errors. [citation needed]
Control of alignment and grade during construction may be established through the use of survey stakes. Stakes are generally made of wood in different sizes. Based on the use of the stake they are called alignment stakes, offset stakes, grade stakes, and slope stakes.[5][6]
Survey stakes are markers surveyors use in surveying projects to prepare job sites, mark out property boundaries, and provide information about claims on natural resources like timber and minerals. The stakes can be made from wood, metal, plastic, and other materials and typically come in a range of sizes and colors for different purposes. Sources can include surveying and construction suppliers, and people can also make or order their own for custom applications.
A survey stake is typically small, with a pointed end to make it easy to drive into the earth. It may be color-coded or have a space for people to write information on the stake. Surveyors use stakes when assessing sites to mark out boundaries, record data, and convey information to other people. On a job site, for example, survey stakes indicate where it is necessary to backfill with soil to raise the elevation, or to cut soil away to lower it. Stakes can also provide information about slope and grading for people getting a job site ready for construction.
A total station is used to record the absolute location of the tunnel walls' (stopes), ceilings (backs), and floors as the drifts of an underground mine are driven. The recorded data is then downloaded into a CAD programme, and compared to the designed layout of the tunnel.[citation needed]
The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the drift.[citation needed]
Building Surveying emerged in the 1970s as a profession in the United Kingdom by a group of technically minded General Practice Surveyors.[8] Building Surveying is a recognized profession within Britain and Australia. In Australia in particular, due to risk mitigation/limitation factors the employment of surveyors at all levels of the construction industry is widespread. There are still many countries where it is not widely recognized as a profession. The Services that Building Surveyors undertake are broad but include:[citation needed]
Clients of a building surveyor can be the public sector, Local Authorities, Government Departments as well as private sector organisations and work closely with architects, planners, homeowners and tenants groups. Building Surveyors may also be called to act as an expert witness. It is usual for building surveyors to undertake an accredited degree qualification before undertaking structured training to become a member of a professional organisation. For Chartered Building Surveyors, these courses are accredited by the Royal Institution of Chartered Surveyors. Other professional organisations that have building surveyor members include CIOB, ABE, HKIS and RICS.
With the enlargement of the European community, the profession of the Chartered Building Surveyor is becoming more widely known in other European states, particularly France.[citation needed] Chartered Building Surveyors, where many English speaking people buy second homes.[clarification needed]
In the United States, Canada, the United Kingdom and most Commonwealth countries land surveying is considered to be a distinct profession. Land surveyors have their own professional associations and licensing requirements. The services of a licensed land surveyor are generally required for boundary (also known as cadastral) surveys for
When we think about construction projects, our minds are inclined to jump straight to the process of building. However, before a single brick is laid, there is a tremendous amount of work that goes into construction. The work that goes into mapping and staking out a construction site prior to laying any foundation is known as construction surveying.
In recent years, the use of robotics in construction has skyrocketed. From using RTK-enabled drones for mapping and surveying to the actual act of building, the applications of robotics in construction surveying stand to drastically improve the field.
Construction surveying is a vital component of the building process, ensuring accuracy in measurements, layouts, and infrastructure placement. Construction surveying refers to the process of staking out a construction site before beginning to build.
Before building, vertical and horizontal control is needed. A construction surveyor determines this by taking accurate measurements before the implementation of the project. It is necessary to stake out markers and reference points so that contractors understand where to place the structure, including vertical and horizontal positioning, dimensions, and configurations.
Tasks involved in construction surveying include research, reconnaissance, control, and mapping of the project area. The preliminary survey focuses on data collection and establishing a survey control scheme for construction.
To get it right, construction surveying requires a high level of precision and accuracy. Given that one critical role of construction, surveying is to develop a precise map of the construction site, spatial positioning and mapping systems like the North American Datum of 1983 (NAD83) are often used by construction surveyors to establish common reference points for geographic data.
This ensures compatibility between various mapping and surveying efforts. NAD83 is commonly used in conjunction with the Global Positioning System (GPS) to facilitate accurate positioning and navigation.
However, these GPS systems are the most accurate when surveyors use GNSS corrections services, such as Real-Time Kinematic (RTK) technology. RTK correction is widely considered the gold standard in high-precision GNSS signal correction. This approach involves setting up a base station near the target area which then transmits a reference signal to the GNSS receiver, enabling precise positioning calculations
Evidence of construction surveying can be seen in even the most ancient structures. From the Great Wall of China to Machu Picchu, it can only be assumed that early surveying techniques were involved to plan the exact angles and make the structure fit seamlessly into the land.
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