Q: Acceptance criteria?

Check the flatness of the cover plate (deviation ≤ 2mm), continuity of the sealant, and deviation of the waterstop position (≤ 5mm)

Question 1

What are the types of deformation joints?

Accepted Answer

There are three main types of deformation joints: expansion joints, settlement joints, and seismic joints.

Question 2

What are the functions of expansion joints?

Accepted Answer

To cope with expansion and contraction caused by temperature changes, disconnect above the foundation, with a width generally ranging from 20-30mm (for concrete structures) or 30-50mm (for masonry structures)

Question 3

What are the functions of settlement joints?

Accepted Answer

To prevent uneven settlement of the foundation from causing structural cracking, it is necessary to completely disconnect from the foundation to the roof, with a width of 30-120mm. The differential settlement of the foundation should be controlled within 30mm.

Question 4

What are the functions of seismic joints?

Accepted Answer

Reduce structural collisions during earthquakes, with the width determined based on the building height and seismic intensity (e.g. 100mm is required for heights below 15m in the 8-degree zone)

Question 5

What are the issues with installing the cover plate?

Accepted Answer

Material not up to standard: Galvanized iron sheet is prone to corrosion and detachment. Stainless steel or aluminum alloy cover plates should be selected and purchased according to standard drawings.

Question 6

What are the leakage issues?

Accepted Answer

1. Sealing failure: silicone sealant is not used or the filling is not dense, so it is necessary to add backing materials (such as polyethylene foam rod) and fill glue in layers.
2. The waterproof layer is damaged: the middle buried waterstop is offset or broken, so it should be installed in the middle and the finished product protection should be strengthened.
3. Condensate accumulation: the deformation joint is not filled with thermal insulation materials (such as rock wool), resulting in moisture and frost heaving of the wall, so it needs to be fully filled and sealed.

Question 7

Acceptance criteria?

Accepted Answer

Check the flatness of the cover plate (deviation &le; 2mm), continuity of the sealant, and deviation of the waterstop position (&le; 5mm)

Question 8

What is the main function of armor seams?

Accepted Answer

1. Adapt to expansion and contraction deformation: absorb the thermal expansion and contraction stress of concrete caused by temperature changes, and prevent floor cracking.

2. Protecting concrete edges and corners: Metal edge protection is used to prevent vehicles from crushing or collapsing the concrete edges.

3. Transmission and stability: Vertical load transmission is achieved through a sheathed transmission plate, reducing the phenomenon of misalignment caused by differences in foundation settlement.

Question 9

What is the difference between armor joints and traditional expansion joints?

Accepted Answer

1. The armor seam does not require cutting or formwork, comes with a force transmitting plate and sheath, and is directly embedded in the concrete, serving as a template and saving construction time.

2. The traditional method requires cutting the floor, supporting the formwork, and installing the transmission rod, which can easily lead to leakage and cracking due to corner damage in the later stage.

Question 10

What are the key steps in the installation process?

Accepted Answer

1. Leveling of the base layer: The cushion layer should be accurately level, and the height of the armor joint should be 10-40mm less than the thickness of the floor.

2. Positioning and laying out: Use a theodolite or laser level to determine the position, adjust the elevation by pulling a line, with an error of ≤ 2mm.

3. Cross connection fixation: Spring pins and easily breakable bolts are used for fixation. Four fixing points are required for cross connections, and three fixing points are required for T-shaped connections.

4. Concrete pouring: The vibration should be compacted to ensure that there are no honeycombs around the transfer plate, and poured until the edge is level.

Q What are the types of deformation joints?

Q What are the functions of expansion joints?

Q What are the functions of settlement joints?

Q What are the functions of seismic joints?

Q What are the issues with installing the cover plate?

Q What are the leakage issues?

Q Acceptance criteria?

Q What is the main function of armor seams?

Q What is the difference between armor joints and traditional expansion joints?

Q What are the key steps in the installation process?

Quick Links

Expansion Joint

Armor Joint