Stairs are an essential structural component in buildings. Although they are a small part of construction, they should not be taken lightly. We have compiled the key points to note in the construction of staircase structures, which we will share with you below.
1Pre embedded steel bars
(1) Pour concrete and reserve reinforcing bars at corresponding locations according to the elevation and drawing dimensions. Control the exposed length to be 20 times the diameter of the short steel bar and 35 times the diameter of the long steel bar. Consider 50% of the joint between the long and short steel bars.
(2) Insert the reinforcing bars into the concrete for 25cm, and weld the steel bars of the reserved middle beam with the reinforcing bars on one side. Use BIM learning to connect the steel bars of the stair platform slab.
2Concealed acceptance
(1) After dismantling the shear wall formwork, snap the stair beam and slab lines on it, and support the stair formwork. Technical disclosure must be conducted before construction;
(2) Check whether the steel bars are firmly tied, whether the wire boxes, embedded parts, etc. are all pre embedded, and conduct concealed engineering acceptance.
3Template installation inspection
(1) On site production of staircase templates and triangular step boards, measurement of dimensions, on-site installation, first support the bottom formwork and then support the inverted triangular step formwork, paying attention to controlling the elevation.
(2) After installing all the templates, check if the joints are tight. For areas that are prone to leakage, apply sealing strips and pad with sponge.
(3) Check the verticality of the facade and adjust the diagonal support to ensure that the error is within the control range.
(4) The contact surface between the template and the concrete must be coated with release agent to prevent damage to the flatness of the concrete surface during demoulding; After template installation, check the strength, stiffness, stability, and reserved hole positions.
4. BIM workconcrete pouring
(1) Pour concrete from bottom to top, first compact the bottom plate, reach the step position, and then pour and compact together with the step concrete, and then continuously push upwards.
(2) Reduce the slump of the staircase concrete appropriately, control the structural dimensions and pouring elevation during pouring, and pay attention to checking whether the position of the formwork support and steel bars is affected during the vibration process.
(3) Watering is used for maintenance in summer, covering and insulation is used for maintenance in winter, and protective measures are taken for construction during rainy season, including covering and protection.
(4) The formwork can only be removed when the compressive strength of the concrete test block under the same conditions reaches 75% of the design strength. When removing the formwork, attention should be paid not to damage the step edges of the concrete surface.
5Reinforcement planting
(1) When planting reinforcement, use a grouting nozzle to control the injection of glue into the hole to avoid incomplete injection effect or insufficient bonding strength;
(2) Before planting steel bars, wipe the steel bars clean with acetone, insert them while rotating to strengthen the bonding effect, and prevent the steel bars from being disturbed before curing.
Article source: Architectural Technology Magazine
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