Insert wp-header in php file in a folder

I have added a new folder in my root. (foldername)

In that foldername I added a new php file and want to have my wordpress header menu in it, I tried adding

<?php require('require('wp-blog-header.php'); ?>
<?php include 'header.php'; ?>

<?php require('require('./../wp-blog-header.php'); ?>
<?php include 'header.php'; ?>

I cannot see my wp-header on those files. Can someone tell me what should I do to get header on those files.