Ivanov B. Correction of pre-deformed steel constructions by local thermal influences

In dissertation summarizes the current state of the issue and sets the research objective, outlines the main prerequisites for the possibility of correcting pre-deformed double-T elements of steel constructions operating in compression. It is noted that the strengthening of steel constructions is an integral part of a series of measures to increase the reliability of their operation. The possibilities of strengthening constructions under existing production conditions are considered. Substantiates the conditions and the possibility of correcting pre-deformed compressed members of steel constructions by melting single rollers on the edges of flanges of double-T elements. Methodologies on determination of welding parameters for correction by melting of single rollers are developed. The methodology for calculating the steel members stability after smoothing is given. The methodology is based on the preconditions and assumptions that are made to solve similar problems. Of the study, the methodology is developed and new results of experimental research of residual stresses in members from steel double-T profile after correction by melting of single rollers are obtained. The methodology of experimental studies of the bearing strength of steel double-T elements after primary loading, unloading, further smoothing and secondary loading is presented. After initial compression tests, the experimental specimens were leveled under the press or by melting of single rollers on protuberant edges. The new results of the experimental determination of the samples bearing strength after unloading and leveling are given. Test results showed that the bearing strength for most samples after smoothing was no lower than the bearing strength of the samples at previous tests. Presents the results of the comparison obtained experimentally and during calculations using the methods developed by the author. In the course of the calculations, the stress-strain state and the load-bearing strength of the pre-deformed compressed elements after smoothing were determined in various ways. The conditions are determined and the possibility of correction of pre-deformed double-T elements by melting of single rollers at strengthening of constructions is substantiated. The methodology of determining the residual resource by comparing the load-bearing strength of constructions with the existing ones is outlined. The data on practical application of the research results in determining the technical condition and residual resource of steel columns are cited.