Which component is essential for providing positive moment tension in a concrete deck?

The essential component for providing positive moment tension in a concrete deck is primary reinforcement. Primary reinforcement refers to the main steel bars or mesh that are strategically placed within the concrete to withstand tensile forces that occur due to bending moments. In a concrete deck, positive moments typically occur at mid-span, where the deck experiences upward deflection under load.

The use of primary reinforcement is critical in ensuring the structural integrity of the deck by allowing it to effectively handle these forces without cracking or failing. The placement and configuration of the primary reinforcement are designed to counteract the tensile stresses, ensuring that the concrete, which is strong in compression but weak in tension, remains stable and functional under loading conditions.

Other components, while they play roles in the overall construction and performance of the bridge deck, are not focused on providing the specific positive moment tension. Negative anchorage, secondary support beams, and grid webbing may contribute to structural support or load distribution but do not primarily address the tension required to manage the positive moment within the deck itself.