I figured it out.
1. In my child theme, in any php files that I edited (archive.php, search.php, etc) i changed ‘span8’ -> ‘col-md-8’
2. In order for style.css override bootstrap.css I copied the theme header and created my child header.php. Then copied this
<link href=”<?php echo get_stylesheet_directory_uri(); ?>/style.css” rel=”stylesheet”>
****(/style.css your child css style sheet)****
directly BELOW ‘<?php wp_head(); ?>’ line of code in header.php
Here’s the link where I found the solution link