Corrugated core panels manufactured by methods of superplastic forming concurrent with diffusion bonding (SPF / DB) are promising for the production of high specific strength articles. One of serious problems arising in forming of corrugated core panels is concerned with the formation of outer folds. The cause of folding is uneven deformation of the skin sheets. In this study, the process of forming a corrugated core panel from a titanium alloy VT6 (analogue of Ti-6Al-4V) by computer simulation is considered. Finite element modeling is carried out using ANSYS software. The formulation of the boundary value problem is stated in terms of the theory of creep. It is shown that after completion of the formation of stiffening ribs, it is possible to increase the working pressure to a maximum without damaging the structure. The results of numerical simulation show that increasing the pressure and holding time allows one to eliminate folds. However, the pressure value is technically limited, and increasing the holding time reduces the economic efficiency of the process. It is noted that the process of forming a corrugated core panel has two characteristic stages. In the first stage, the core sheet is deformed under the conditions of superplasticity, stiffening ribs are formed. The first stage continues until the skin sections joined to the core touches the surface of the die. The second stage proceeds under conditions of creep up to smoothing the outer folds.

The paper presents the results of experimental studies on the strength and deformations of lightweight concrete, mortar matrix and hardened cement paste under triaxial compression. Tests on samples were carried out using short-term triaxial proportional σ1 > σ2 = σ3 loading (i.e. axial compression + lateral hydrostatic pressure). During the loading, the ratio of the main stresses (both axial and lateral) was kept constant up to the end of tests. The experimental studies were carried out for different low ratios of σ2/σ1. A theoretical estimation has been discussed to approximate experimental results and prediction of triaxial strength values for different types of lightweight concrete. An estimation of the confining pressure parameter K has been done for the used mode of loading.

To improve the transport infrastructure of the Republic of Uzbekistan, the monolithic structure of bridges and overpasses began to be used. The article presents the calculation of a monolithic overpass on the 1083rd km of the M-39 highway passing through Samarkand. The results of the calculation of a monolithic overpass from dynamic load are presented based on the records of two real seismograms for two dangerous earthquakes for the system with spectral composition: Gazli (Uzbekistan) and Manjil (Iran). The calculations show that to ensure guaranteed seismic safety of transport structures, it is necessary to carry out design calculations based on sets of records of earthquakes that occurred, close in dominant frequencies to the characteristics of the construction site. Such a provision should be introduced into the relevant regulatory documents.

Experimental studies of concrete static fatigue require quite laborious and time-consuming tests. Insufficient data on static fatigue for concrete and the absence of an adequate theoretical base until recently did not allow using a generalized approach to estimate static fatigue parameters for different types of concrete. The paper presents the results of extensive experimental studies on static fatigue strength under tension and compression for lightweight concrete, mortar matrix, and hardened cement paste. A theoretical equation based on the fracture mechanics approach has been proposed and discussed for approximating experimental results and predicting static fatigue strength, which can be used for normalization of this parameter. The proposed equation displays better estimates compared to this used in the energy approach and empirical formulas.