the face plate 12 when it is desired to block or close an opening 52 in the face plate 12 which extends from the front side 30 through to the rear side 32 a plug element 22 may be held by the opposing ribs 54 and 56 the plug 22 preferably is provided of aluminum or other durable material but may also be provided of synthetic resin or rubber and includes a central substantially cylindrical body 72 and wings 74 extending diametrically opposite therefrom the body 72 may be placed in the opening 52 with the ribs 54 and 56 holding the wings 74 as shown in fig1 3 and 5 the pairs of reinforcing ribs 14 are also useful to grip a fastening element 20 such as a nail 76 driven through the face plate 12 the nail 76 penetrates the face plate 12 which is typically of aluminum and then may be gripped between the rods 64 as shown in fig4 to provide steel to steel contact and thus avoid wear to the face plate 12 the cantilevered arrangement of the ribs 54 and 56 permitting them to yield and thus grip the nail nails 76 or other fastening elements 20 are useful if a piece of wood 77 needs to be attached to the forming panel 10 or when an anchor 78 is used when a tensioning cable 79 received in a surrounding sleeve not shown is passed through the pouring area and connected to the anchors 78 for anchoring an end of the cable 79 the head of the nail 76 may.