Rebuild regular array to a multidimensional array

In that situation, I would use such a loop:

$outputArray = array();

$previousUserId = -1;

// Loop through all source records.
foreach ($inputRows as $row) {

   // If the current row has a different user id thn the row before,
   // add the output row to the final output array and prepare a new output row. 
   // If the current row has the same user id as the row before, 
   // just add further address information.
   // This handles also the start situation, $previousUserId = -1.
   if ($previousUserId != $row->user_id) {
       if ($previousUserId >= 0) {
           $outputArray[] = $outputRow;
       }
       $outputRow = array();

       // Copy main attributes
       $outputRow['users_info_id'] = $row->users_info_id;
       $outputRow['user_id'] = $row->user_id;
       $outputRow['user_email'] = $row->user_email;
       $outputRow['phone'] = $row->phone;
   }

   $previousUserId = $row->user_id;

   // Create a suitable address subarray and fill it.
   if ($row->address_type == 'BT') {
       $outputRow['bt'] = array();
       $outputRow['bt']['firstname'] = $row->firstname;
       $outputRow['bt']['lastname'] = $row->lastname;
       ...
   } 
   if ($row->address_type == 'ST') {
      // dito, but for ['st']
      // ...
   }
}

It is just a structure, you would have to finish it.

The code is looping through every record of your input table, let's call it $inputRows. It is important if the user_id changes, because this will start a new output row. As long as user_id remains the same, the code just adds further address types to the current output row. So, several input rows are grouped to one output row. All the output rows are then collected in an $outputArray.

Please note:

1) the dump you show in your question shows an array containing objects. In my answer, I create an array containing arrays as output. Usually, I prefer working merely with associative arrays as they offer more freedom in choosing names. If you want to work with objects, just alter the code accordingly. ($outputObject->name = ... instead of $outputObject['name'] = ...)

2) I assume that the user_id criteria is relevant for grouping input rows to new output rows. I hope this is correct ;-D

EDIT: If there are several records for address type, one could add an additional array layer like this:

   ...
   ...
   // Create a suitable address subarray and fill it.
   if ($row->address_type == 'BT') {
       // If the array that collects several bts has not been created, create it.
       if (!isset($outputRow['bt']) {
           $outputRow['bt'] = array();
       }

       // Create an array with the bt address data
       $addressData = array();
       $addressData['firstname'] = $row->firstname;
       $addressData['lastname'] = $row->lastname;
       ...

       // Add the bt address data to the collection of bts. 
       $outputRow['bt'][] = $addressData;
   } 
   if ($row->address_type == 'ST') {
      // dito, but for ['st']
      // ...
   }

With slightly more requirements, I recommend outsourcing the part that collects address data to an own function so the whole code remains readable.