JOIST FOR PRODUCING CAST-IN-PLACE AND PRECAST BUILDING FRAME Russian patent published in 2017 - IPC B28B1/08 E04C3/20 

FIELD: construction.

SUBSTANCE: joist for producing cast-in-place and precast building frame is made cast-in-place and precast in the form of three-dimensional bodies with a precast lower broadened part and a cast-in-place upper part narrowed relative to the lower part in the form of an extended polyhedron with a cross section mainly in the form of a rectangle or trapezium forming a single bearing profile with local broadenings in the form of projections arranged along the length of the joist at a pitch corresponding to the pitch of hollows leaning against the joist of floor hollow slabs, together with the precast part. The projections are extended in the direction of the hollow axes, have a length not less than 1.3 of the thickness of the corresponding slabs, and are placed in the presupport and support zones of the slab hollows. In this case, the precast broadened part of the joist on one side consists of a main bearing element of rectangular cross-section and an auxiliary bearing element of rectangular cross-section parallel to it. The main and auxiliary elements are joined together by reinforced connecting elements of rectangular cross-section with a width of 0.68, a length of 0.568-0.795 of the hollow slab thickness and thermofillers made of thermal insulating materials with a bulk density of 35-200 kg/m³ are mounted between the main, auxiliary and connecting elements. In the cast-in-place joist part narrowed relative to the precast lower broadened part the projections are arranged on its other side at a pitch of the connecting elements of the precast lower broadened joist part and have a length of 0568-0795, a width of 0.68 of the corresponding plates thickness. The height of the projections must be not less than the height limited by the highest point of the cross section of the projections, which are inserted into the hollows of the slabs leaning against the joist. The cast-in-place upper joist part narrowed relative to the lower part is made with the possibility of mounting an outer layer of enclosure structures on the auxiliary elements of the joist, structures are made of piece materials of a height equal to or greater than the height of the cast-in-place part of the joist, which fulfils the role of form system for grouting the upper part narrowed relative to the lower part of the joist; as well as for grouting the frame joints and the building's overlap, thermofillers made of thermal insulating materials with a bulk density of 35-200 kg/m³ are mounted between the outer layer of enclosure structures, projections over the connecting elements of the precast lower broadened part of the joist, polyhedron at the cast-in-place part of the joist. U-shaped rods passing through all joist cross-section are mounted over the upper surface of the joist main elements along their longitudinal axis, are located between prestressed reinforcement of lower and upper layers of prestressed rods, and are required for mounting the upper working reinforcement of the joists.

EFFECT: reduction of labour and material costs while reducing production time of works and ensuring that they can be conducted in all weather conditions, in regions belonging to the harsh climate zones with low negative temperatures in winter as well, and providing straightness state of the joist surfaces at facade surfaces of buildings and structures.

16 cl, 6 dwg