alternative permalink of post

I added this code:

add_action('generate_rewrite_rules', 'work_list');

function work_list($wp_rewrite) {
    $newrules = array();
    $newrules['(.*)/scheda-tecnica.html$'] = 'index.php?pagename=$matches[1]&tipopg=scheda-tecnica';
    $wp_rewrite->rules = $newrules + $wp_rewrite->rules;
}

but now the url with “scheda-tecnica.html” redirect to normal url post