Allied Works has drafted plans for an ambitious US$50m (£38.6m, €45.7m) upgrade for the stadium belonging to Major League Soccer (MLS) franchise the Portland Timbers.

The privately financed project would see the capacity of Providence Park expanded by 4,000 and would add a 93-foot high covered structure to the east side of the stadium.

Four new levels will be added to the expanded east side – three of which would be for reserved and group seating sections.

A pedestrian-friendly public arcade is also being planned along the surrounding SW18th Avenue.

If the club gets the go-ahead following discussions with the local government and neighbourhood association, work could begin in either 2017 or 2018, with an estimated construction period of two years.

The stadium is owned by the city of Portland, and Timbers president Mike Golub said the improvements would be “win-win for everyone involved”.

“Providence Park is one of the most special stadiums in sport,” he added.

“With our proposed expansion, we will enhance the incomparable fan experience and intimacy and provide the opportunity for some of the more than 13,000 members of the waiting list to become season ticket holders.”