Connection structure, concrete-encased concrete-filled steel tube column and construction method

A concrete-encased concrete-filled steel tube (CFST) column connection structure comprising:

• a core positioning sleeve, a plurality of longitudinal bar sleeves, a hoop restraining sleeve and an external sealing sleeve, wherein:
• the core positioning sleeve is sized and shaped to position and connect two exposed steel tubes opposite to each other;
• an inner diameter of the core positioning sleeve is substantially the same as an outer diameter of the exposed steel tubes;
• a plurality of slurry-flowing holes on a side wall of the core positioning sleeve facilitate a slurry inflow between the two exposed steel tubes positioned in the core positioning sleeve;
• and an inner side wall of the core positioning sleeve is circumferentially provided with a plurality of cushions for bracing the exposed steel tubes;
• and
• additionally wherein:
• the plurality of longitudinal bar sleeves are sized and shaped to connect two exposed longitudinal bars opposite to each other;
• an inner diameter of the longitudinal bar sleeve is larger than an outer diameter of the exposed longitudinal bars;
• the hoop restraining sleeve restrains the position of the core positioning sleeve and the longitudinal bar sleeves;
• each longitudinal bar sleeve is fixedly connected to an inner side wall of the hoop restraining sleeve;
• the hoop restraining sleeve is sleeved outside the core positioning sleeve and fixedly connected to an outer side wall of the core positioning sleeve through first connection keys;
• and,
• the external sealing sleeve seals a space between a first split concrete-encased CFST column and a second split concrete-encased CFST column when these columns are positioned in the core positioning sleeve;
• and the external sealing sleeve is sleeved outside the hoop restraining sleeve and fixedly connected to the hoop restraining sleeve through a second connection key.