It'll be clamped, lol. Clamped at 50 raw, which is ~5-6 more than heavy gauntlet punching damage from a strength build. Even if it isn't clamped, 1 + 45 + 11 = 57 raw. That's definitely a lot, 5PS +3 warhammer, but it's not as much as you think without speed bonus, hold bonus, etc. It'll do 15-25 damage to most at 57, 8-18 at 50.
Slightly more detailed of what I think would work
-New formula: Strength/3 + shield skill * 3 + max(shield weight, armor / 7)
-Defensive shield bash damage is divided by 2 instead of 5
-Blocking negates damage
-Clamp to 50 instead of 30