"I am" is an interpretation for "I Lived" also here in John 8. I Lived" is the trans-literal.
John 8:58
New International Version (NIV)
58 “Very truly I tell you,” Jesus answered, “before Abraham was born, I am!”
In Matthew 26 and Mark 14 we have the same story with two different acknowledgements.
Matthew 26
62 Then the high priest stood up and said to Jesus, "Are you not going to answer? What is this testimony that these men are bringing against you?"
63 But Jesus remained silent. The high priest said to him, "I charge you under oath by the living God: Tell us if you are the Christ, the Son of God."
64 "Yes, it is as you say," Jesus replied. "But I say to all of you: In the future you will see the Son of Man sitting at the right hand of the Mighty One and coming on the clouds of heaven."
Mark 14:60
Then the high priest stood up before them and asked Jesus, "Are you not going to answer? What is this testimony that these men are bringing against you?"
61. But Jesus remained silent and gave no answer.
Again the high priest asked him, "Are you the Christ, the Son of the Blessed One?"
62. "I am," said Jesus. "And you will see the Son of Man sitting at the right hand of the Mighty One and coming on the clouds of heaven."
Yahshua was asked if he was the messiah, for which he answered, yes.
(HA-YAH / the living) (ASHER / That) (HA-YAH lives)