Precast concrete stairway construction method

A precast concrete staircase construction method comprising:

• a mold frame preparation step of forming a square cubic external structure, forming an upper surface stair landing at an upper surface of one side of the external structure and a central stair landing at a central portion of another side thereof, forming stair treads between the upper surface stair landing and the central stair landing, and preparing a first mold frame and a second mold frame so as to form a left structure and a right structure;
• a reinforcing bar arrangement step of assembling and arranging reinforcing bars in the first mold frame and the second mold frame, wherein the reinforcing bar arrangement step is performed after the mold frame preparation step;
• a concrete pouring and curing step of pouring and curing concrete in each of the first mold frame and the second mold frame;
• a divided structure manufacturing step of demolding, when curing of the concrete poured into each of the first mold frame and the second mold frame is completed, a first divided structure and a second divided structure from the first mold frame and the second mold frame, respectively, and manufacturing the first divided structure and the second divided structure in a form of vertically dividing the structure of the staircase into the left structure and the right structure;
• a structure adhesion step of forming the staircase by causing the second divided structure, which has stairs formed in an opposite direction from stairs of the first divided structure, in an upside-down state to contact the first divided structure such that open inner surface portions of the first divided structure and the second divided structure contact each other to be closed and the central stair landings of the first divided structure and the second divided structure are connected to each other to form a plane;
• and
• a structure bonding step of completing the staircase by bonding mutually contacting portions of the first divided structure and the second divided structure.