Indicative clear distance between supports at slab joints
| Overall depth of slab joint | Max.Concrete Pressure | Clear distances between the Hy-Rib supports | |||
| Theoretical * Table2 CIRIA 108 |
assummed for Hy-Rib |
Grade 2411 |
Grade 2611 |
Grade 2811 |
|
| mm | kN/m² | kN/m² | mm | mm | mm |
| 250 | 6.25 | 3.20 | 1250 | 1025 | 950 |
| 500 | 12.50 | 6.30 | 900 | 725 | 675 |
| 750 | 18.75 | 9.50 | 725 | 600 | 550 |
| 1000 | 25.00 | 12.70 | 625 | 500 | 475 |
| 1250 | 31.25 | 15.80 | 575 | 450 | 425 |
| 1500 | 37.50 | 19.00 | 525 | 425 | 400 |
| 2000 | 50.00 | 25.30 | 450 | 375 | 350 |
| 2500 | 62.50 | 31.70 | 400 | 325 | 300 |
| 3000 | 75.00 | 38.00 | 375 | 300 | 275 |
The Hy-Rib is used in horizontal sheets with the ribs pointing into the concrete to be placed, and spanning in the strong direction between vertical supports. * The theoretical maximum pressure is that calculated using Table 2 in CIRIA Report 108 (Ref. 2) with a concrete density of 25 kN/m3, for EITHER a wall, a base or a column; AND applies to concrete Groups 1 to 5 inclusive. The Hy-Rib pressure diagram up to 3m in height of joint is assumed to be triangular – refer to Technical Information – Assumed Concrete Pressure Data. The permissible spans calculated from an uniformly applied concrete have been increased by a factor of 1.2 to allow for the triangular shape of the concrete pressure diagram. The maximum pressure only applies at the very bottom of the slab joint.
