An anchor bolt suspending array comprises a biodegradable bridging structure attachable across a concrete form or in cantilever from one side thereof conformed by folding longitudinally a corrugated cardboard panel into overlying segments each provided with a set of spaced openings that are aligned upon folding to receive the shank of an anchor bolt therein. A retainer either formed as a frustoconical cardboard pulp structure dimensioned to capture the anchor bolt shank end, or as an accordion folded corrugated cardboard strip perforated by spaced holes conformed to grasp the shank, is then useful to suspend the bolt from the bridging structure into the poured concrete. Both the retainers and the bridging structures can be color coded by a biodegradable coating in accordance with the size of the anchor bolt that is receivable therein.