The quality of a building project is determined by various criteria. The list of obligatory items during the examination includes: composition of the material, reliability of the joints, compliance of the structures with safety requirements, etc. The exposure of the geometric lines along which the installation work was carried out is also considered separately. To prevent miscalculations and deviations in the process of building structures, engineers use theodolite. This is a measuring device that allows you to evaluate the correctness of the formation of angles vertically and horizontally. The device, although it is a small device, requires special preparation in operation. Therefore, before construction activities, it is worthwhile to understand the question of how to use theodolite in order to get the most accurate results.
Theodolite device
The classic design is a combination of a sight pipe and struts that hold it. A special sight is provided for guidance guidance - such settings can be implemented differently depending on the model. The pipe allows you to measure the vertical angle, and horizontal operations are performed using the appropriate circle, which includes the limba and alidade.
Using magnifying optics, the surveyor can view the target object at large distances from it. And not necessarily such devices should be included in the basic kit. It is possible to increase the range of the tool without loss of accuracy using special optical equipment. For ease of viewing, the instrument is equipped with an eyepiece having cross-division of scales. In addition, geodetic models are provided with protective equipment. In particular, a theodolite ruler designed to be fixed in one position may have a casing preventing the risk of a change in position.
The principle of the tool
In general terms, the operation of the instrument can be characterized as an analog of the function of classical levels and goniometers. But in this case, the complicated "filling" allows you to perform similar actions with higher accuracy and convenience. All operations are based on the principles of geometric computing. The initial data are the readings obtained during the installation of the tool. Actually, the main part of the work is the correct setting of the instrument. Further, the principle of operation of theodolite depends on the type of equipment - it can be a traditional optical, electronic or laser device. In the first case, the user must independently install physical objects that act as reference points for calculations. If the electronic model is used, then zero marks will be fixed automatically. In the future, it all depends on the object for which the calculations are made. Information is also provided on the required operations, and in a matter of moments the device provides information on errors and deviations. Now it is worthwhile to examine in more detail the most common variations of this device.
Varieties of theodolites
The most common optical theodolite, which includes a microscope that provides the ability to visually determine errors. From the point of view of ergonomics and accuracy of measurements, this is the least profitable option, although the cheapest. The user of such an instrument is required to independently determine deviations in horizontal and vertical planes with respect to the installed object. The disadvantage of optical models is the dependence on external conditions. For example, many beginner surveyors are wondering how to use theodolite if there is not enough daylight. Only the optional addition in the form of a mirror for backlighting will help. It can also be built into the body of the device, but in any case, you need to have it at hand.
Electronic models are equipped with sensors that read measurements and transmit them to the display. That is, the user is not required to look at the screen and independently calculate the optical readings. However, such models are sensitive to mechanical stress. So, in portable operations the ruler of theodolite in the form of alidade and tribrach will help to eliminate the risk of damage and shock. In this case, do not take the device by the telescope. As for laser modifications, they are a subspecies of the electronic device. The differences of this apparatus include the possibility of more accurate laser alignment of control points.
Checking theodolite on a round level
Most often, when working with theodolite, verification of a round level and a grid of threads is required. In the first case, calibration is performed in order to ensure the parallelism of two axes - from the aforementioned round level and the plane of rotation of the level. It should be noted that theodolite calibration and adjustment are always carried out using special regulators. In this case, verification is implemented by manipulating the lifting screws, which allow you to bring the bubble to zero point. In parallel with this action, the relative position of the two target axes is monitored.
Thread grid verification
In the case of a grid of threads, the goal is to ensure the perpendicularity of the horizontal stroke. In this case, the vertical stroke should go parallel to the axis of rotation of the level. Verification by a vertical line is carried out using a plumb line, suspended 25 m from the level. On a round level it is necessary to bring the axis into a vertical position. Next, the two axes are aligned in accordance with the calibration requirements. Regarding the horizontal, it should be noted that this parameter is guaranteed by the manufacturer. True, in some models, theodolite can be calibrated and adjusted in a complex way by changing the play in the holes of the fixing screws. Experienced surveyors can change the position of such axes, if this possibility is provided by the design.
Tool alignment
This procedure is performed in order to eliminate deviations caused by inaccurate tuning of the mechanical components of the tool. For example, the reason for this type of calibration can be an incorrectly adjusted cylindrical level of the theodolite, in which the alidade shows an unacceptable displacement of the bubble. Direct adjustment involves the adjustment of the guide screws, which, in turn, adjust the parameters of the alidade so that the horizontal circle becomes the reading with the correct reading.
Angle measurement
At the points where it is planned to erect building structures, it is necessary to provide a temporary frame. Using a theodolite, an eyepiece is sent to one of the selected points of the installed structure, which will be taken as zero. In order to initially provide correct readings, you should consider how to use theodolite on uneven terrain. For this, it is important to provide a reliable foundation in the first place. Further, support posts are introduced into the ground, it is also advisable to perform additional fixation.
Then you can start calculating the angles. In relation to the starting point, a position is selected from which further calculations will be made. It can be both a vertical angle and horizontal calculations. A scale with coordinates will allow measurements to be made with a small error. In the case of electronic models, calculations are done automatically in a few seconds.
Theodolite Manufacturers
This segment can be characterized as highly specialized and designed for professional design. Accordingly, there are few companies in this niche either. Traditionally, high-quality measuring equipment for the construction industry is produced by ADA, in the line of which you can find models for different tasks. For example, the ADA Vertical line is specifically designed for vertical design. For universal use, the Vega Teo theodolite is suitable, the features of which include the presence of two displays that provide calculated data with high accuracy. However, a lot of money will have to be paid for the ergonomics and functionality of such equipment - about 50-60 thousand rubles.
Conclusion
It would seem that standard goniometers and self-leveling devices may well solve design problems. But with the increasing complexity of construction technologies, the requirements for the accuracy of geometric measurements also grow. Therefore, questions about how to use theodolite and its high-tech equipment are increasingly common. It’s not enough to have basic skills with an optical scale. For the effective use of digital and laser meters, you should also have an idea of calibrations and adjustments. Calibration, on which the accuracy of measurements depends, provides for the implementation of the associated settings of the mechanical part and the optics of the instrument. In the future, increasing the complexity of design operations is reflected in increasing the quality of construction projects, so the use of modern theodolites is fully justified.