Methods and apparatuses for connecting concrete structural elements

An apparatus comprising:

• a first concrete structural element comprising a first duct that is pre-cast therein, the first duct having an end adjacent a second surface of the first concrete structural element, at least a portion of a surface of the first duct adjacent the end comprises a first coupling portion;
• a second concrete structural element comprising a second duct that is pre-cast therein, the second duct having an end adjacent a first surface of the second concrete structural element, wherein the first surface of the second concrete structural element and the second surface of the first concrete structural element face each other and are spaced apart, the first and second surfaces defining a joint therebetween;
• and
• a duct coupler comprising an engagement portion, the engagement portion having a first end, a second end, and at least one wall extending between the first and second ends, wherein a central axis of the duct coupler extends between the first and second ends, and the at least one wall has an internal surface and an external surface, the internal surface faces the central axis of the duct coupler and defines a channel that extends between openings defined by the first end and the second end of the duct coupler, and at least a portion of the wall adjacent the first end of the duct coupler comprises a second coupling portion,
• wherein the second coupling portion is coupled to the first coupling portion to couple the first duct and the duct coupler, and the second end of the engagement portion is disposed closer to the first surface of the second concrete structural element than the first end of the engagement portion,
• wherein the first and second ducts and the at least one wall are annular shaped,
• wherein the second coupling portion comprises one or more protrusions that extend radially outwardly from at least a portion of the external surface of the annular shaped wall, and the first coupling portion comprises one or more recesses defined by an internal surface of the first duct, the one or more protrusions engaging the one or more recesses, and
• wherein the one or more protrusions are helical threads.

An apparatus comprising:

• a first concrete structural element comprising a first duct that is pre-cast therein, the first duct having an end adjacent a second surface of the first concrete structural element, at least a portion of a surface of the first duct adjacent the end comprises a first coupling portion;
• a second concrete structural element comprising a second duct that is pre-cast therein, the second duct having an end adjacent a first surface of the second concrete structural element, wherein the first surface of the second concrete structural element and the second surface of the first concrete structural element face each other and are spaced apart, the first and second surfaces defining a joint therebetween;
• a duct coupler comprising an engagement portion, the engagement portion having a first end, a second end, and at least one wall extending between the first and second ends, wherein a central axis of the duct coupler extends between the first and second ends, and the at least one wall has an internal surface and an external surface, the internal surface faces the central axis of the duct coupler and defines a channel that extends between openings defined by the first end and the second end of the duct coupler, and at least a portion of the wall adjacent the first end of the duct coupler comprises a second coupling portion;
• and
• a splice duct, the splice duct having a first end and a second end that is axially spaced apart from the first end, the splice duct further comprising an internal surface that faces a central axis of the splice duct that extends between the first and second ends, the internal surface comprising a third coupling portion and a fourth coupling portion, wherein the third coupling portion is adjacent the first end of the splice duct and engages the first coupling portion of the first duct, and the fourth coupling portion is adjacent the second end of the splice duct and engages the second coupling portion of the duct coupler, wherein the first duct and the duct coupler are coupled via the splice duct and the second end of the splice duct is closer to the facing surface of the first concrete structural element than the first end of the splice duct,
• wherein the second coupling portion is coupled to the first coupling portion to couple the first duct and the duct coupler, and the second end of the engagement portion is disposed closer to the first surface of the second concrete structural element than the first end of the engagement portion, and
• wherein the first and second ducts and the at least one wall are annular shaped.

A duct coupler for extending between a first duct that is pre-cast within a first concrete structural element and a second duct that is pre-cast within a second concrete structural element, the duct coupler comprising:

• an engagement portion for coupling with the first duct, the engagement portion having a first end, a second end, and at least one wall extending between the first and second ends, wherein a central axis extends between the first and second ends, wherein the at least one wall has an internal surface and an external surface, the internal surface faces the central axis and defines a channel that extends between openings defined by the first end and the second end, and at least a portion of the wall adjacent the first end comprises a coupling portion, wherein the at least one wall is an annular shaped wall;
• and
• a head portion comprising an annular ring having a first annular surface and a second annular surface, the first and second annular surfaces being axially spaced apart along a central axis of the annular ring, wherein the first annular surface of the head portion is coupled to the second end of the engagement portion, the second annular surface of the head portion is coupled to the first surface of the second concrete structural element, the central axis of the head portion is coaxial with the central axis of the channel of the engagement portion and central axes of the first and second ducts, and an outer diameter of the annular ring is greater than an outer diameter of the second end of the engagement portion.