The operation of guncrete seismic isolation elements under diagonal compression in extreme conditions

Introduction. Guncrete structures are mainly used as columns. In the columns of buildings, guncrete structures operate on central or off-center compression with small eccentricities. Guncrete structures have a number of indisputable advantages over steel and reinforced concrete structures. The guncrete seismic isolating support in the building is operated by central compression. Under seismic impact the support deviates from its vertical position, and the longitudinal axis of the support does not coincide with the vertical line of force from permanent and temporary loads. In this case, there is a complex stressed state, the so-called "oblique" or "diagonal" compression. With diagonal compression, plastic deformations develop under lower loads than with central compression. The manufacture of the reinforcement frame and the assembly of guncrete structures caused considerable difficulties. Therefore, it was decided not to install reinforcement in the central part of the sample, that greatly simplifies the manufacturing technology. In this regard, there was a need for an experimental study of the operation of a guncrete structure under diagonal compression to static and low-cycle loads. Aim. Conducting of the experimental studies of guncrete structures with diagonal compression for static and low-cycle loads without a reinforcing frame in the middle part of the element. Materials and methods. Experimental studies were carried out by testing prototypes of guncrete structures, without reinforcement in the central part for central, diagonal compression and under low-cycle load. Results. Experimental data on the operation of guncrete elements under central, diagonal compression and low-cycle load without a reinforcing frame in the middle part of the element have been obtained. Conclusions. The load-bearing capacity of guncrete structures during diagonal compression in the elastic stage is less than during central compression. The elastic operation of guncrete structures under low-cycle load practically does not differ from the operation of the element under monotonous loading.