Vertical construction joints in thick walls over 900mm width, will usually have the Hy-Rib fitted with the ribs horizontally, and supported by vertical timber or aluminium members. The total forces on this wide stop end will be much larger than that on narrow walls. In this orientation, the safe span of the Hy-Rib will be governed by the maximum applied Hy-Rib concrete pressure, which will occur at the bottom of the wall. The maximum clear distance between the vertical supports is determined from the table below. The vertical support members, timber or aluminium, the horizontal twin walings, steel or timber, and the external method of restraining the forces will all need careful design, but because the Hy-Rib concrete pressure will be less than that on conventional impermeable stop ends, the sizes of the members and the magnitudes of the forces will be reduced.
The properties assume that the Hy-Rib is used with the ribs pointing into the concrete to be placed, and spanning in the strong direction between the supports with the ribs parallel with the span. It is assumed that the Hy-Rib is simply supported. Even if the Hy-Rib is spanning over several supports, its lower bending strength at the support is such that it will yield as the full pressure is applied, making critical the bending at mid-span when analysed as a simply supported member.
