so as to avoid
"省得(shěng de)" means to avoid something from happening. Normally the thing here indicates to either a bad incident or something unnecessary. "省得" is usually put in the latter clause, and the former one is always about a suggestion or a persuasion. "省得" can also be equivalent to "免得".
Wǒ bǎ dōngxi dài guòlái le, shěngde nǐ zài pǎo yí tàng le.
I brought the thing here so spare you another trip.
Kuài gàosu fùmǔ ba, shěngde tāmen zháojí.
You'd better inform your parents as soon as possible so that they won't get worried.