SHANG KAI HIGH RIBBED FORMWORK
Forward
SHANG KAI HIGH RIBBED FORMWORK (FORMWORK) is a well designed product which is fabricated from hot-dipped galvanized steel sheets by expanding and roll-forming methods. The product is light in weight and can easily be cut and bent into required shapes and sizes.
Usage
The FORMWORK is used wildly large building and construction projects. The usual project examples are nuclear power plants, tunnels through mountain and under water, aqueducts, waterpool, shipyard, valve and gate systems, retaining walls, bridges, zoo, sewage treatment plants and marine engineering works and high rise building projects etc.
Products description / design
Material :
The FORMWORK is manufactured from hot-dipped galvanized steel sheets which are in compliance with most of the popular international standards. e. g. CNS, EN, JIS, BS, ASTM, etc.
Shape / Size :
Each piece of FORMWORK has an effective width of 445mm, carrying six ribs of 2lmm height each. These ribs give the product strength along the longitudinal direction. Between the ribs are the specially designed cut-and-bent expanded "keying region" for the plastering and concrete slurry. The standard length of FORMWORK is 2,500mm and 5,000mm. For special large quantity requirement, FORMWORK in non-standard lengths can also be supplied.
Outstanding Features of Formwork
- 1.Light in weight :
- The weight of each standard FORMWORK ranged from 3.39kg/m2 to 6.34kg/m2, easy for installation of concrete joints.
- 2.Easy cutting :
- A pair of tailor's scissors is strong enough to cut through the "keying region'. At the ribs, one can make use of a plier type cutter to do the job. (See Fig. 1)
- 3.Going through holes :
- The FORMWORK can be rolled up longitudinally into a tube form to slip through holes of say 150mm diameter. This ability enable the product to be placed in the un-accessible areas so far as other rigid form formworks are concerned.
- 4.Keying effect :
- The "keying regions" between the ribs enable the cement to go through it from one side partially, letting the air and excess water to escape and drain off from the other side. When the concrete/cement is set, the other side is left with a rough surface with excellent surface feature to receive with adjacent concrete pour.
- 5.Easy jointing :
- The FORMWORK can build up to a large area easily by over-lapping at the side on one rib; and across the standard width of the product at the ends. (Please see Application)
- Technical advantages
-
- Joints produced by the application of FORMWORK by successive concrete pouring to both sides of the FORMWORK is strong and not easy to develop cracks.
- In general, during the pouring of concrete, the openness of the FORMWORK at the "keying region" allows for visual inspection at the concrete levels during the pours. At the same time, the openness allows for the escape of trapped air and draining off of any excess water. Aeration at the FORMWORK helps to set the concrete quickly.
- The non-rib side FORMWORK is always ready to receive plastering and/or tiling wherever is required.
- Concrete pressure at the base of the FORMWORK is always less than that of conventional formwork.
- Formwork support :
- The ribs of FORMWORK are at one side only. The placement of the support is usually at the non-rib side. Based on actual situation and experience, the number and positioning of the supports are carefully decided.( See Fig.2.3.4.5.6.7.8.etc) The product can be bent and curved to suit toggle joints. For angles, the products can be cut partially at the ribs and then bent at the cutting. When the FORMWORK is used in construction joint applications, the support distance of the FORMWORK against the height of successful concrete pours is very important. The table below is a recommendation for engineer's reference.
|
Concrete Depth(M) |
Distance Between Supports (M) |
||
|
SKH28 Formwork |
SKH26 Formwork |
SKH24 Formwork |
|
|
3.00 |
0.22 |
0.25 |
0.35 |
|
2.50 |
0.27 |
0.30 |
0.40 |
|
2.00 |
0.35 |
0.40 |
0.50 |
|
1.50 |
0.50 |
0.60 |
0.70 |
|
1.00 |
0.60 |
0.70 |
0.85 |
|
0.50 |
0.70 |
0.85 |
1.00 |
|
0.25 |
0.80 |
1.00 |
1.20 |
Concrete suitability :
The application of the FORMWORKS is suitable in most concrete mixes with slump between 70mm to 150mm When the application is with concrete slump of 125mm and over, a little cementations liquid is expected to seep through the openness of the "keying region" of the FORMWORK During the initial stage of the concrete pour. However this will not weaken the strength of the concrete core. In this application no vibrator is used.
Use of vibrator :
The placement of vibrator shall be at least 450mm away from the FORMWORK . If a nearer distance must be used, the vibration must be intermitant in 5 to 10 seconds burst each time.
Pouring of concrete :
Concrete shall not be poured directly against the FORMWORK. The concrete shall be poured at about 0.5M distance away from the FORMWORK and let it flow towards the FORMWORK. In general, the pour (or initial pour) of concrete should be effected against the ribbed side of the FORMWORK. The placement of the FORMWORK is so designed.
Building up a large area :
The FORMWORK Shall be overlapped with a minimum distance of 150MM at the end-laps. Overlapping of the side lap shall be on one rib only. For the end lappings, the overlapping shall be fixed together by galvanized wires or nailing onto the supports. For side laps, a standard maximum distance of 150mm between fixing point applies. It is important that the end-laps shall always be on a supporting member. ( see Fig 8. )
