TKA produced the urban design breakthrough for the 'Kop van Zuid' Waterfront in Rotterdam with over a million square meters of mixed-use buildings. The Erasmus Bridge over the river has been completed and has given the city a new image.
Teun Koolhaas had an open mind to developments abroad. TKA was successful in an international field by competing in Berlin, Copenhagen, Boston, Vera Cruz/Mexico, Riyadh, Quetta/Pakistan, Cairo, and in Shanghai where TKA won the competition for Gaoqiao New Town in the Shanghai region.
In 2002 he developed a concept on a large scale of the city region of Amsterdam, Schiphol International Airport and Almere, as presented on the map titled `Delta Metropool Noord'.
TKA designed and built a wide range of buildings; residential, offices, clinics, a theatre complex, yacht clubs, the Dutch embassy in Cairo, railway stations, a number of educational facilities, etc. Several of these commissions were obtained through design competitions.