A vertically alternating sequence of continuous insulating layers and continuous sacrificial material layers is formed over a substrate, and memory opening fill structures including vertical stacks of memory elements are formed through the vertically alternating sequence. Backside trenches are formed to divide the vertically alternating sequence into a plurality of alternating stacks of insulating layers and sacrificial material layers. Bridge structures are formed within each of the backside trenches. The sacrificial material layers are replaced with electrically conductive layers while the bridge structure are present within the backside trenches.