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.

A modular unit connection system for jointing together pre-fabricated rectangular modular building units to form a multistory building. The building units can be completely fitted out and this connection system allows for positive structural connection using liquid grout filled columns, without bolting or welding and without the requirement for access to the connections from inside the pre-finished building module interiors. The four corner columns of the box-shaped modules are steel square hollow sections. This connection system uses a unique connector tube passing from the bottom of the column above, through a horizontal connector plate containing a guidance system and into the top of the hollow column below, and then a system of grouting the inside of the column, from an access position on top the upper most module to form the final positive structural connection.

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.

A prefabricated column assembly includes a hollow tubular column having a longitudinal axis. A gusset plate assembly includes a plurality of gusset plates connected to the column and extending laterally outward from the column in planes generally parallel to the longitudinal axis of the column. A first pair of the gusset plates extends laterally outward from the column along a first axis and defines a space for receiving an end portion of a first beam for mounting the first beam on the first pair of gusset plates. A second pair of the gusset plates extends laterally outward from the column along a second axis that is nonparallel and non-coincident with the first axis. The second pair of gusset plates defines a space for receiving an end portion of a second beam for mounting the second beam on the second pair of gusset plates to provide a bi-axial joint connection.

A modular unit for constructing a modular structure is described. The modular unit comprises a structural frame, which includes at least one upper beam, at least one lower beam, and at least one column extending between said upper and lower beams and connected therebetween. At least one of said upper or lower beams is arranged to define at least one chamber for receiving a building material therein along at least a portion of its length, said column being connected to said portion of said beam. Part of said beam is removed along said portion of said beam to define at least one opening to said chamber.

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.

A prefabricated column assembly includes a hollow tubular column having a longitudinal axis. A gusset plate assembly includes a plurality of gusset plates connected to the column and extending laterally outward from the column in planes generally parallel to the longitudinal axis of the column. A first pair of the gusset plates extends laterally outward from the column along a first axis and defines a space for receiving an end portion of a first beam for mounting the first beam on the first pair of gusset plates. A second pair of the gusset plates extends laterally outward from the column along a second axis that is nonparallel and non-coincident with the first axis. The second pair of gusset plates defines a space for receiving an end portion of a second beam for mounting the second beam on the second pair of gusset plates to provide a bi-axial joint connection.

A method for quantitative analysis of a cavity at the top of a concrete-filled steel tube is disclosed. By substitution of the determined inner radius of the steel tube, the thickness of the steel tube wall and the propagation speed of ultrasonic waves in the steel tube and in the concrete, the propagation time of the ultrasonic wave between the top and the bottom of the concrete-filled steel tube enables calculation of the height of the cavity. The method can be used to quantify the cavity height at the top of the concrete-filled steel tube, with small relative errors and high accuracy.

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 press-fit nut for an assembly, a press-fit nut-bolt assembly, and a method of constructing a steel-concrete composite structure using same, wherein a process is simple and a base material does not become deformed during an installation process. The press-fit nut-bolt assembly of the present invention includes a press-fit nut, a stud bolt, a counter nut, and a washer. The press-fit nut includes: a head part formed in a typical nut shape; and a press-fitting part that is formed extending from one of the two surfaces of the head part so as to have an outer diameter less than that of the head part, and that is inserted, through press-fitting, into a base material (M) that is an object requiring fastening. A hollow having threads is continuously formed in the head part and the press-fitting part. The stud bolt includes a body part that is coupled to the press-fit nut by passing therethrough, and a pin tail which is formed extending from an end of the body part and to which a mechanism for rotating the body part is coupled. The body part includes a first threaded portion and a second threaded portion which are formed on the outer surface of the body part along the lengthwise direction of the body part and spaced apart from each other.