Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_8 ( height_of_bridge_structure VARCHAR, opened VARCHAR, name VARCHAR )

### Question ###
How tall is the Anqing Bridge which opened prior to 2011?

### Accurate SQL ###

SELECT height_of_bridge_structure FROM table_name_8 WHERE opened < 2011 AND name = "anqing bridge"