When tying the steel bars of the door frame wall, you must read the drawings carefully and construct in strict accordance with the drawings. The door frame wall can be divided into independent parts such as door frame side walls, upper retaining walls, and thresholds based on the surrounding embedded conditions and the relative size of the door opening. For civil air defense closed doors, explosion-proof swing door frames, and sealing frame door frame wall steel bars, the design unit generally needs to conduct design calculations separately and draw detailed reinforcement charts. Door frame walls cannot be confused with ordinary walls during construction, especially When the upper retaining wall of the door frame is higher, a reinforcing beam is generally provided at the lower edge of the upper retaining wall. The two ends of the beam should be anchored to the structural components on both sides and cannot be suspended in the air. According to the structural requirements, the thickness of the door frame wall should not be less than 300mm. Eight diagonal steel bars with a diameter of 16mm should be installed on both sides of the four corners of the door opening, and the length of each bar should not be less than 1m. Since the door frame wall of a civil air defense closed door does not directly bear the shock wave load, its steel bars are generally designed and constructed according to the opening reinforcement design.
The various civil air defense door frames indicated in the construction drawings of the civil air defense project should be poured together with the concrete of the door frame wall, and should not be chiseled and poured later. When pre-embedding, you should carefully check the drawings to determine the model of each door frame. You should pay attention to the difference in appearance between protective airtight door frames and airtight door frames. The four corners of the door frame are generally beveled in the former and rounded in the latter. ; It should also be noted that the locking holes of various door frames are all with the small opening pointing upward and cannot be turned upside down. Anchor steel bars should be welded around the door frame and anchored into the steel frame of the door frame wall. On the steel mesh of the roof, hooks should be pre-embedded to lift the door leaves when installing the civil air defense door leaves. These embedded parts must be carefully checked before pouring concrete and cannot be missed.
The door frame and its formwork must be firmly supported when pouring concrete to control displacement and ensure verticality. The "Quality Inspection and Assessment Standards for Civil Air Defense Projects" stipulates that the maximum allowable deviation of the verticality of reinforced concrete flat door frame walls is 5mm. This stipulation is to ensure that civil air defense doors can open and close freely and meet the requirements of the maximum allowable opening and closing force. It should be noted that the verticality of the door frame wall and the verticality of the door frame are two concepts that are both different and related. The determining factor of whether the door leaf can be opened and closed freely is the verticality of the door frame. When the verticality deviation of the door frame is within 5mm, the installed door leaf can be opened and closed freely by adjusting the components.