Quite a tricky one. There are a couple of steps to take.
1. Create a calculated field to concatenate your Model and Attribute Ids. We'll use this in the next calculation to tell Tableau to restart a calculation
[Model id] + [Attribute Id]
2. Create a calculated field to find the next threshold value - which is required to start the value range calculation. I called this Calculation1 but you can give a better name.
3. Create a calculated field, Value Range.
IF ISNULL([Calculation1]) THEN STR(SUM([Threshold])) + '+'
ELSE STR(SUM([Threshold])) + '-' + STR([Calculation1]-1)
This is the biggest challenge - make sure the Calculation1 is calculating correctly. It needs to restart for every Model Id/Attribute Id combination. Check the screenshot which is provided by Edit Table Calculation when clicking on the triangle of the field within the worksheet.
This checks if the value from Calculation1 is empty - if so you want to put a + sign on the end. If it's not null then we use the value to create the range.
4. Create a simple field for the Integer label. This is a calculated field with the formula 'Integer' (quotation marks required).
This is the finished product. It requires some headers to be hidden to replicate what you expect to see. Hopefully this is clear.