PRESTRESSED SOLID STEEL SPAN STRUCTURE OF A BRIDGE AND METHOD OF ITS MANUFACTURING Russian patent published in 2019 - IPC E01D12/00 

FIELD: construction.

SUBSTANCE: invention relates to bridge construction and can be used in construction of bridges in prestressed solid steel-concrete span structures for combining a monolithic reinforced concrete plate with metal structure. Prestressed solid steel-concrete span structure of the bridge includes a reinforced concrete plate combined with a steel beam by means of welded to the steel contact sheet fixed on a beam and fixed plates fixed in the body of a support plate. Steel contact sheet is fixed on the belt of the steel beam by means of high-strength bolts through holes made in it, having in the middle part of the pressure zone immediately above the support body the shape of the circle, and on the rest part - made oval with location of the large axis along the longitudinal axis of the superstructure. Reinforced concrete plate is divided along the length of the span into three types of sections: pressure ones located above the intermediate support of the bridge, central ones located outside the zone of intermediate supports, and buffer ones located between pressure and central sections. At that, the pressure section is prestressed with high-strength reinforcement, and the steel contact plate together with the thrusts welded to it is made independent on the pressure sections. Length of the maximum oval hole on the steel contact plate is determined considering the diameter of the high-strength bolt, the distance from the axis of the support to the center of the hole of the support section and temperature of concrete self-heating relative to the beam. In production of prestressed solid steel-concrete span structure, concreting of its sections is carried out in series, at first central ones located outside the zone of intermediate supports, then pressure ones located above intermediate supports, then buffer ones, which are located between pressure and central ones. At that, before concreting of pressure section only bolts are completely tightened, located directly above supports (along support axis) in round holes, the rest are tightened partially, and then completely attenuated through time τ after termination of concreting, defined by set of concrete strength R=0.3R₂₈, and completely tightened after the process of temperature and strength deformations. Thus, plate of prestressed solid steel-concrete span structure works on entire length without formation of cracks in compressed state, which provides higher efficiency of concrete for tension in reinforced concrete plate, reduced deformation and increased crack resistance. Higher strength and reliability of reinforced concrete plate provides higher durability of superstructure in general.

EFFECT: higher efficiency of concrete for tension in reinforced concrete plate, avoiding formation of cracks in reinforced concrete plate during cooling (self-heating) of concrete during hardening, selection of optimum length of oval hole in steel sheet, increased strength and reliability of reinforced concrete plate and increased durability of span structure in general.

4 cl, 5 dwg, 1 tbl