ASSESSMENT OF SUSTAINABLE DESIGN STRATEGIES IN ENERGY-EFFICIENT HIGH-RISE MIXED-USE TOWERS IN TROPICAL CLIMATES

High-rise mixed-use towers in tropical climates, including Abuja's tropical savanna environment, face environmental conditions that can increase cooling demand, particularly high solar exposure, substantial diurnal temperature variation and the need for reliable environmental control. This study examines the extent to which sustainable design strategies are incorporated in selected mixed-use and high-rise precedents, with particular relevance to Abuja's Central Business District. A purposive case-study approach was employed to examine five precedents: World Trade Center Abuja, Pixel Building in Melbourne, The Edge in Amsterdam, PARKROYAL on Pickering in Singapore, and Oasia Hotel Downtown in Singapore. The cases were analysed thematically using architectural documentation, published project information, certification records and available performance literature. Recurring strategies included external solar shading, perforated and layered façades, controlled glazing, natural or mixed-mode ventilation, vertical functional zoning, atrium and void spaces, thermal buffering and integrated greenery. The analysis indicates that environmental performance in the selected precedents is generally approached through combinations of complementary architectural and building-system strategies rather than through a single intervention. The study contributes a precedent-based framework for translating climate-responsive strategies into high-rise mixed-use design within tropical savanna environments, with particular relevance to Abuja's Central Business District.