To simplify staircase construction work and to shorten a construction period by constructing a staircase using a placing form facilitating the width adjustment of the staircase in a reinforced concrete structure.
The upper edge of a form body 1 of a channel shape with a width D2 along the proceeding direction of the staircase is formed in a stair shape in which stepboard supporting parts 4 and riser parts 7 are continuous. The form bodies 1, 1 lined up at a space D1 are connected by connecting members 29, 30 laid in positions of the stepboard supporting parts 4, 4, to constitute a staircase form 35. The staircase form 35 is laid across beam forms 50, 50 on upper and lower floors, and the form body 1 is fittingly inserted and fixed in guide members 53 of the beam forms 50 or the like. In this state, a safe use is allowed as a working staircase. The necessary arrangement of reinforcements is then made, and concrete is placed in the staircase form 35 together with a skeleton. The staircase form 35 is left as the placing form, and stepboards 40, 40 are mounted on the connecting members 29, 30 in addition to floor finishing construction work to complete the construction of the staircase.
Kenichi Wakui
Norihiro Yamamoto