Problems of scientific and technical support of frame buildings, built on in the construction process

Abstract

To date, during significant fluctuations on the real estate and construction materials market, in order to increase investment feasibility more and more often developers have a desire to superstructure objects during construction. The complex of issues associated with the preparation and obtaining permits is beyond the scope of this paper. It should be noted that a significant change in the object types not put into operation is associated with lower material costs compared to the commissioning of facilities, given that the enhancement (if necessary) is much easier to implement. Although most often the idea of a heightening occurs at the stage of completion of the frame and wall filling. With this type of heightening comes a whole group of problems. The experience of such heightening shows that with a slight increase in the number of floors in the range of 10%, and sometimes more, the problem of deficit bearing capacity is solved by applying reduction factors to the useful load, clarified the application of all loads (if it was not done in the original preparation of the model). Sometimes this kind of solutions also allows to solve the problem of deficit of load-carrying capacity of lower floor structures. The increase in the number of floors within 10% of the original is cost-effective, acceptable from a financial point of view is the strengthening of individual vertical load-bearing elements of the lower floors. In the work, on the example of a 20-storey building under construction, the reserve of the bearing capacity of the vaulted part for the increase in the number of floors is investigated and the main problematic issues are identified. The solution of such a number of problems on a specific object is devoted to this study. A separate group of complications should include the need to perform not only the calculation by the spectral method, but also behind the nonlinear static method. The application of these methods resulted in a discrepancy of one additional floor. But in order to meet the requirements for floor misalignment, it became necessary to reinforce the vertical load-bearing elements for the second floor, not based on their strength requirements, but based on their stiffness requirements.