Reservation tool for bay joint

The utility model discloses a reservation tool for a bay joint. The reservation tool is characterized by comprising two body plates, a force transmitting piece and a force transmitting sleeve. The two body plates are arranged back to back and connected through connecting components. Square gratings are arranged on the long sides of the body plates, the sides, connected with the body plates, of the square gratings are protection sides, and the protection sides are perpendicular to the body plates. The two sides, connected with the protection sides, of the square gratings are bent inwards. The force transmitting piece penetrates through the two body plates and then is connected with the force transmitting sleeve in a sleeved mode. The force transmitting piece is in parallel with the protection sides. The reservation tool is simple in structure and can protect the edges of the bay joint and help the two sides of the bay joint to be stressed evenly, uneven settlement happens on the two sides of a floor is prevent