Reinforcement-confined circular steel tube member with enhanced end stiffness

A reinforcement-confined circular steel tube member, comprising:

• a first end plate;
• a first connecting annular plate;
• a first end sleeve;
• a second end plate;
• a second connecting annular plate;
• a second end sleeve;
• a circular steel tube;
• a plurality of restraint rings;
• and
• a plurality of reinforcing steel bars;
• wherein the first end plate, the first connecting annular plate, the plurality of restraint rings, the second connecting annular plate and the second end plate are sequentially arranged;
• a first end of the first end sleeve is connected to the first end plate, and a second end of the first end sleeve is connected to the first connecting annular plate;
• a first end of the second end sleeve is connected to the second end plate, and a second end of the second end sleeve is connected to the second connecting annular plate;
• a first end of the circular steel tube passes through the first connecting annular plate to be inserted into the first end sleeve and fixed to the first end plate, and a second end of the circular steel tube passes through the plurality of restraint rings and the second connecting annular plate in turn to be inserted into the second end sleeve, and fixed to the second end plate;
• the circular steel tube is in contact with an inner wall of a center through hole of each of the plurality of restraint rings;
• and a first end of each of the plurality of reinforcing steel bars is provided with a first limit part, and a second end of each of the plurality of reinforcing steel bars passes through the first connecting annular plate, the plurality of restraint rings, and the second connecting annular plate in turn, and is provided with a second limit part;
• a first Belleville spring and a first washer are provided between the first end plate and the first connecting annular plate;
• the first Belleville spring and the first washer are sleeved on the first end sleeve;
• and the first Belleville spring is provided between the first washer and the first end plate;
• and
• a second Belleville spring and a second washer are provided between the second end plate and the second connecting annular plate;
• the second Belleville spring and the second washer are sleeved on the second end sleeve;
• and the second Belleville spring is provided between the second washer and the second end plate.