Twin 451.9 m (1482 ft) tall towers just completed in Kuala Lumpur, Malaysia, presented a variety of design challenges related to tall buildings and slender members under wind load, and to construction methods in the Far East. Cast-in-place high-strength concrete for the core, perimeter columns and ring beams provides economical vertical load-carrying ability, stiff lateral load resistance, and inherent damping for occupant comfort. Steel beams on metal deck slabs provide efficient, economical and quickly-erected long-span floors which are easily adaptable to future changes in openings and loadings. The unusual tower plan has alternating cantilevered points and arcs, only 16 main tower columns, haunched wind frame ring beams 8.2 to 9.8 m (27 to 32 ft) long. Vierendeel outriggers at mid-height and sloped columns at setbacks. A unique arch-supported skybridge spans 58.4 (190 ft) between towers at levels 41 and 42, where the towers move more than 300 mm (1 ft) in any direction. A stainless steel pinnacle tops each tower. Extensive analytical, force balance and aeroelastic wind studies addressed individual tower behavior, influences between towers, pinnacle behavior, skybridge overall behavior and arch leg behavior. No supplementary damping was needed for the towers. Pinnacles have simple chain impact dampers. Each of the four arch legs has three tuned mass dampers for the three main modes of vortex excitation. © 1997 John Wiley & Sons, Ltd.