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Steel Duct

Metal bellows are metal pipes and connecting pipes made of galvanized or non-galvanized low-carbon steel strips with spiral folded joints.

Used for drilling holes in post-tensioned prestressed concrete structures or components.

Metal pipes can be selected as seamless pipes or corrugated pipes according to the designed strength. The purpose of pre-embedded metal in the post-tensioning method is to leave space for placing steel tendons.

The use of bellows can reduce channel friction and reduce losses.

Spec.

Parameters for circular duct : (mm)

ID 50 60 65 75 90 100 105 115 125 130
OD 55 65 70 80 95 105 110 120 130 135
Deviation tolerance ±0.50
Thickness of standard steel strip >0.3
Thickness of reinforced steel strip >0.32 >0.4 >0.6

Note:

  1. Ducts with special specification not shown in the table can be supplied as per actual requirement.
  2. Subject to modification.

Parameters for slab duct : (mm)

Short Axis Length 24 24 24 24 24 24 24 24
Deviation tolerance +3/0 +3/0
Long Axis Length 55 65 75 95 55 65 75 95
Deviation tolerance ±1/0 ±2/0
Thickness of steel strip 0.3
  1. The short side can be straight or curve, when the short side is curve, the radius is the half of that along short axis.
  2. Ducts with special specification not shown in the table can be supplied as per actual requirement.
  3. Subject to modification

Min Center Distance

Type Min center distances(mm) support distances up to(m) Type Min center distances(mm) support distances up to(m)
T13-04 90 1 T15-04 108 1
T13-07 108 1 T15-07 117 1
T13-12 117 1 T15-12 162 1
T13-15 162 1 T15-15 180 1
T13-19 162 1 T15-19 180 1
T13-22 180 1 T15-22 189 1
T13-25 189 1 T15-25 207 1
T13-27 189 1 T15-27 207 1
T13-31 189 1 T15-31 207 1

Min support distance conform to the standard of public construcation commission.


Plastic Duct

Corrgated plastic duct ase usually used at the project of un-bonded bridge or outer post-tensioning design.

The beneficial parts for plastic duct than steel duct are the lower production cost, stronger durability, and last for environment consideration.

the less consume for steel material, the better for our earth.

Spec.

Parameter for circular duct : mm

ID OD Thickness
50 56 3
55 61 3
60 66 3
65 71 3
70 76 3
75 81 3
80 86 3
85 91 3
90 96 3
95 101 3
100 106 3
105 111 3
110 116 3
115 121 3
120 126 3
125 131 3
130 136 3

Parameter for slab duct : mm

ID OD Thickness
41 45 2
46 42 2
55 61 2
60 33 2
72 78 2
90 96 2