The present invention relates to a concrete-filled steel tubular column-steel plate concrete ring beam joint, comprising: a concrete-filled steel tubular column, a steel plate concrete ring beam and reinforced concrete frame beams. The steel plate concrete ring beam comprises: a steel plate and a reinforcing cage, wherein concrete grouting holes are arranged in the middle of the steel plate; both the steel plate and the reinforcing cage are of a ring shape, and the ring-shaped steel plate and the reinforcing cage are coaxially arranged; the steel plate concrete ring beam is sheathed and fixed on the outer side wall of the concrete-filled steel tubular column; and an end of the reinforced concrete frame beam extends into the steel plate concrete ring beam, and stressed reinforcements of the reinforced concrete frame beam are connected to the steel plates. The steel plate concrete ring beam is of a centrosymmetric ring-shaped or eccentric ring-shaped construction. The stressed reinforcement of the reinforced concrete frame beam is anchored by the ring beam joint through the steel plates, so that the seismic performance of the connection joint is ensured, the section width of the steel plate concrete ring beam can be significantly reduced, and the spatial applicability of the joint is improved. The present invention also relates to a construction method of a concrete-filled steel tubular column-steel plate concrete ring beam joint, belonging to the field of building structures.

The system and method for connecting a square concrete-filled steel tubular column to a reinforced concrete footing includes a short steel pipe partially embedded in the footing, the pipe having a top end having flanges extending radially therefrom, the top end extending into a cavity in the footing having an elliptical top opening and circular base, the flanges extending above the base. An elliptical base plate is welded to the bottom of the tubular steel column, the base plate having a circular opening defined therein and a plurality of spaced flange slots depending therefrom. The bottom end of the column is lowered into the cavity, the elliptical base plate passing through the elliptical opening in the cavity, and the column is rotated 90° to interlock the flanges with the flange slots. The cavity is filled with concrete grout, and the square or rectangular steel column is filled with concrete.

The invention discloses a calculation method of ultimate moment resistance and moment-rotation relation for steel beam to concrete-filled steel tube column connections with bidirectional bolts, wherein the calculation method as follows: calculate ultimate moment resistance values of the connection for different failure modes, i.e. yielding of the endplate or T-stub in bending, failure of bolts in tension, failure of column in transverse compression, failure of panel zone in shear, and yielding of the steel beam in bending; the smallest one in the five ultimate moment resistance values is taken as the ultimate moment resistance of the connection; obtain the initial rotational stiffness of the connection by the test, simulation or theoretical calculation; then, the moment-rotation curve of the connection is obtained by substituting the initial rotational stiffness and the ultimate moment resistance into the proposed exponential model for the moment-rotation relation.

The disclosure presents a composite column formwork which utilizes a fiber reinforced polymer (FRP) stay in place container which incorporates horizontally coplanar support chairs bonded to the interior surface, closed ties bonded to the support chairs and a plurality of longitudinal rebar enforcements bonded to the closed ties. All of the components in a preferred embodiment are formed of a fiberglass material.

The disclosure presents a reconfigurable composite floor formwork which defined by a plurality of interlocking fiberglass panels formed into profiles which may be moved and adapted to provide a concrete form for a floor or ceiling. All of the components in a preferred embodiment are formed of a fiberglass material.

The present invention relates to a concrete-filled steel tubular column-steel plate concrete ring beam joint, comprising: a concrete-filled steel tubular column, a steel plate concrete ring beam and reinforced concrete frame beams. The steel plate concrete ring beam comprises: a steel plate and a reinforcing cage, wherein concrete grouting holes are arranged in the middle of the steel plate; both the steel plate and the reinforcing cage are of a ring shape, and the ring-shaped steel plate and the reinforcing cage are coaxially arranged; the steel plate concrete ring beam is sheathed and fixed on the outer side wall of the concrete-filled steel tubular column; and an end of the reinforced concrete frame beam extends into the steel plate concrete ring beam, and stressed reinforcements of the reinforced concrete frame beam are connected to the steel plates. The steel plate concrete ring beam is of a centrosymmetric ring-shaped or eccentric ring-shaped construction. The stressed reinforcement of the reinforced concrete frame beam is anchored by the ring beam joint through the steel plates, so that the seismic performance of the connection joint is ensured, the section width of the steel plate concrete ring beam can be significantly reduced, and the spatial applicability of the joint is improved. The present invention also relates to a construction method of a concrete-filled steel tubular column-steel plate concrete ring beam joint, belonging to the field of building structures.

A concrete fillable steel joist includes a generally U-shaped member and a top chord. The generally U-shaped member has spaced apart webs and a bottom chord. The top chord is operably attached to the U-shaped member. The top chord has a plurality of spaced apart top chord holes. The U-shaped member and the top chord define a volume that is fillable with concrete when opposed ends of the U-shaped member have joist ends operably attached thereto. The joist ends may be a pair of end plates. Alternatively, the joist ends may be structural members. A concrete fillable steel joist system includes a plurality of spaced apart concrete fillable steel joists, and metal decking. The metal decking is operably attached between the spaced apart steel joists. The concrete fillable steel joist and the metal decking are configured to receive concrete.

The disclosure presents a composite column formwork which utilizes a fiber reinforced polymer (FRP) stay in place container which incorporates horizontally coplanar support chairs bonded to the interior surface, closed ties bonded to the support chairs and a plurality of longitudinal rebar enforcements bonded to the closed ties. All of the components in a preferred embodiment are formed of a fiberglass material.

The disclosure presents a composite concrete structure formwork which comprises stay in place fiberglass profiles and reinforcement to form various building and shelter structures. The structures include an interior container maintained at a set distance within an exterior container to form a void. The void is filled with wet concrete which is allowed to cure. All of the components in a preferred embodiment are formed of a fiberglass material.

The disclosure presents a composite conduit formwork structure which includes a cylindrical outer casing adapted to bond with a cylindrical inner casing which are maintained at a fixed distance apart by a plurality of radial stanchions. The inner casing and outer casing form an interior void which is filled with concrete during manufacture. The outer casing and inner casing remain in place to protect the structure once completed. A novel method of assembly is also provided whereby radial stanchions are rotated between the outer casing and inner casing. All of the components in a preferred embodiment are formed of a fiberglass material.