Curved structure below floor

[eiidrovo]

Hi, I'm new on reddit and I'm trying to draw on it strucrures below the floor, that has variable height wood reinforcements and a transversal curved element, How can I add that below the floor and those wood reinforcements (separated by 250 mm) to adjust their heights beetween the plywood below the  floor and the curved transvesal reinforcement

Here's an example in paint

 

[barthbradley]

Join the geometry to a overlapping Variable Height sloped Floor (in the correct Join Order) and then hide the sloped Floor in the Views.  Join Geometry will remove volume at the union.