I just recently played around with a pure melee-type character using a two-handed great-sword and heavy armor. My two-handed skill is at around 58, and smithing is close to 60 right now, being able to forge orcish armor and weapons.
On my way to Riverwood (from Whiterun) I encountered a single giant, and I thought, well, give it a try.
Due to my armor and weapon I killed the giant, but could not prevent him dishing out a single blow that took more than half of my health, closer to three fourths actually, so that I popped a health potion to prevent an untimely death.

Now, can you somehow dodge the attacks? I tried to circle the giant to get behind, but then it had already dealt the damage, or do I have to keep myself out of reach of my opponents weapon?

Concerning smithing... the next step would be to forge ebony armour/weapons. Which level would be appropriate to deal with it, as I simply thing, a level 20 orc should just not have it yet. What does the construction kit state level-wise, as to when ebony equipment starts appearing?

Thank you in advance for your input.

About dodging the enemies attacks, you are wearing Heavy Armor, greatly reducing your speed. The easiest way to overcome this is to get a certain standing stone, or the perk in the Heavy Armor tree. Vashing with your weapon could also would, it'll give you a second to move and deal another blow.