This campgate has fifteen rows...I can't recall seeing an example with more, though I only casually note the rows. Other neat stuff too, with decorated top and bottom row and dotted border on left and right and archway.
Constantine I
A.D. 328-9
19mm 3.4g
CONSTAN-TINVS AVG; Laureate head right
PROVIDEN-TIAE AVGG; camp gate with 15 rows, two turrets, no doors, ✶ above.
in ex. ASIS double crescent
RIC VII Siscia 214