Before dismantling PP hollow boards, the following key details need to be considered:

1、 Concrete strength

Before dismantling, it is necessary to ensure that the concrete has reached the specified strength value. This is the foundation of demolition work, and only when the concrete strength is sufficient can the safety of the demolition process and the stability of the structure after demolition be ensured.

2、 Demolition principle

Demolition from top to bottom in layers:

When dismantling, the PP hollow board should be dismantled layer by layer according to the principle of top-down. This can avoid damage to the underlying structure caused by the impact force during the demolition process, while also helping to maintain the orderly progress of the demolition work.

When dismantling the first layer of hollow board, the operator should first remove the column hoops or connecting parts such as column bolts, vertical ribs, and opposite clamps, and then gently tap the hollow board with a wooden hammer to separate it from the concrete surface of the column. Then gradually detach the hollow slab from the concrete surface layer by layer, and it is forbidden to use a pry bar to pry it directly from the corner of the column.

Dispersed Demolition:

In order to better ensure the quality and safety during demolition, the method of dispersed demolition can be adopted. That is, first remove the slant support, and then remove the split bolts, internal and external steel ribs, heterosexual clamps and other connectors.

During the dismantling process, always pay attention to whether the surrounding hollow boards will break with the internal corner mold. If necessary, a wooden hammer can be used to strike the upper opening on the outer side of the hollow board, and the two sides of the hollow board can be loosened with a pry bar to separate it from the concrete surface.

3、 Demolition steps and precautions

Dismantling column hoops and clamps:

When dismantling the segmented hollow panels, the principle of top-down should be followed, first removing the column hoops, vertical ribs, and two diagonal opposite clamps. If necessary, temporary supports can be added and a main bolt can be reserved at the column mouth.

Lifting and demolding:

Divide the hollow board into two pieces, hang the hook, remove the temporary support, and finally perform demolding and lifting. During this process, it is necessary to ensure that the ropes and lifting rings used for hoisting are firm and reliable to prevent accidents.

Classification and organization:

The removed PP hollow boards and accessories should be collected and organized for future use. At the same time, the removed hollow boards should be classified and numbered for easy management and use.

Safety precautions:

When dismantling molds at high altitude, sufficient safety passages should be left and safe operating areas should be clearly defined. Construction personnel are not allowed to stand under the dismantling formwork to prevent falling accidents.

The dismantling frame should be erected separately from the formwork support system. The removed horizontal board should be supported by someone above and below, and throwing it randomly is strictly prohibited.

During the demolition process, excessive force or hard prying should be avoided to prevent damage to the hollow board and concrete structure.

4、 Special case handling

For arches, thin shells, curved roofs, and beam structures with spans greater than 8 meters:

Appropriate methods should be taken to evenly relax the formwork supports to avoid harmful stress on any part of the structure when the concrete separates from the floor slab.

For templates of circular roofs and funnel-shaped silos:

Starting from the bracket at the center of the structure, it should be dismantled towards the periphery of the structure in a concentric and symmetrical manner.

Concrete quality issues were discovered during the demoulding process:

If significant quality issues such as voids, interlayers, cracks, etc. are found in the concrete that affect the safety of the structure or components, the demolition work should be suspended and relevant departments should be promptly communicated for handling.

In summary, before dismantling PP hollow boards, it is necessary to fully consider multiple aspects such as concrete strength, dismantling principles, dismantling steps and precautions, and special case handling. Only by doing these preparations and precautions well can the safety of the demolition process and the stability of the structure after demolition be ensured.