How the 3D-scanner allowed to refuse the full-scale control assembly of the bridge

The Voronezhstalmost enterprise (the former Voronezh Bridge Plant) was founded in 1948 and is the leading Russian company manufacturing metal bridge span structures of any type, size and complexity. The production area of ​​the plant and the equipment available allow to produce up to 55 thousand tons of metal structures per year, the company employs more than 1,800 workers and engineers. The company makes extensive use of computer technology in its work, the quality management system and the welding industry are certified in accordance with international standards.

Production tasks

Voronezhstalmost makes separate elements of bridges, spans of buildings, which are sent to the site, where the installation is carried out by the builders. In the manufacture of such elements it is necessary to ensure to the customer that all dimensions are accurately maintained, there are no distortions, and the assembly is carried out with high quality, so that problems do not manifest themselves during installation.

Classic working principle

Until recently, such an inspection was carried out in an open area on the factory premises. The workers did a test assembly — they assembled some difficult, challenging places, after which the engineers measured out all the constructions for compliance with the technical task. In case of detection of inconsistencies, their causes were localized, and the problematic elements of the structures were sent for revision.

“This process was long and complicated,” said Idayat Kuliev, chief process engineer of Voronezhstalmost. - Despite the fact that we collected only separate parts of the structures, even they had impressive dimensions and required considerable time and labor for their construction. We needed a solution that would allow the control assembly to be translated into virtual mode, made it possible to check for inconsistencies on a computer without physical installation. ”
')
First, the company acquired a total station - an electronic geodetic instrument from the class of theodolites, designed to measure distances. “He allowed us to determine the distances between points,” says Idayat Kuliev. “We are still taking some measurements with it, however, practice has shown that the control assembly after such measurements is not always successful, since the data on the distances themselves are very much, they are scattered, the risk of error in the calculations increases.”

It became clear that a more sophisticated solution is needed that would allow to remove all the necessary data on control points at a time and transfer to the software the model of the desired element for the virtual control assembly.



Laser Surphaser 25HSX 3D-scanner

The new principle of working with Surphaser 25HSX

This solution was the 3D laser scanner Surphaser 25HSX. This device implements a phase method for determining the distance, due to which a high scanning speed is achieved (up to 1.2 million points per second). Surphaser scanners are specially prepared for solving problems of analyzing and controlling the geometrical parameters of large objects of complex shape, which fully complied with the requirements of the Voronezhstalmost enterprise.

The inclusion of a three-dimensional laser scanner in the process allowed us to completely abandon the full-scale control assembly. Now the elements of the bridge (such as, for example, fifteen-meter blocks of 3.5 meters in width and height) are scanned directly into the workshop. The resulting point clouds are checked for compliance with the model in the design software. In the virtual model, shortcomings, inconsistencies of control points, deviations from drawing data are immediately visible. In the case of their discovery element is sent for revision.

“The construction blocks are scanned from several positions,” says Evgeny Kuprin, head of the plant construction bureau. “The resulting survey is stitched using the Geomagic Studio program, trimmed, cleaned from“ junk ”data, scaled and converted into an XYZ coordinate grid.” Collected and cleaned clouds of individual structural elements on a 1: 1 scale are superimposed in Autodesk Revit on a 3D model of the bridge that the customer provides. This allows not only to see possible shortcomings and check the convergence, but also to take measurements for the manufacture of linings.

“Bridges consist of hundreds of elements,” says Idayat Kuliev. “In the case of a full-scale control assembly, we did not have the physical ability to assemble them all for testing, so we chose difficult places for which engineers had concerns in terms of geometry. Now we have the opportunity to carry out a virtual test assembly not only of these complex elements, but also of the entire structure. ” At the beginning of using the scanner, the company's specialists conducted several additional control assemblies of structures already tested on a virtual model created using a scanner. No new gaps have been identified.



Software-developed digital model and practical result of the project

Benefits of using a 3D scanner

“A full-scale control assembly is a hard and long job,” said Idayat Kuliev. - Three or four people collect part of the bridge on the street, in any weather, they need a crane, a strapping device, jacks, levels, and a few days time. Scanning is also not an easy task; it takes two to four hours to clean and prepare one element, but this is the work of one engineer in the office at the computer. ”

3D scanning reduces the likelihood of human error. “Earlier, when we performed the control assembly, we made a protocol, where we made all the deviations and shortcomings,” says Idayat Kuliev. - Then the assembly was dismantled, the necessary changes were made to the products, but sometimes on the assembly it was suddenly discovered that someone had overlooked something, missed some error. And the control assembly has already been disassembled, there is nothing to reveal a discrepancy, to make sure that this is our mistake. Now we always have a ready-made model in the computer, we can study the problem on it, show it to the customer. In addition, the percentage of detection of problem areas increased due to the high accuracy of the device and the ability to check all components of the structure, and not only those indicated by the engineers. ”

“We recently switched to this technology,” the expert sums up, “and until we have not fully mastered it, there is something to strive for. However, we can already say with certainty that it completely suits us and we are definitely not going back to the method of control assemblies. ”