Twin Crown–Spire Coastal High-Rise Towers: Geometry-Driven Structural Stability and Passive Environmental Performance

High-rise buildings in coastal regions are subjected to a coupled system of gravity loading, extreme wind actions, vortex-induced vibrations, torsional amplification, and aggressive marine environmental exposure. This research investigates a symmetrical Twin Crown–Spire Coastal High-Rise Tower system, in which two geometrically identical towers are arranged with controlled spacing and aligned crown–spire terminations. Each tower is composed of vertically layered curved shell segments and an axial spire element, forming a continuous compression-oriented structural envelope. From a structural mechanics perspective, the curved shell geometry redirects gravity and lateral loads into compression-dominant force trajectories, significantly reducing bending moments and peak shear demands in comparison to conventional prismatic towers. Analytical load-path decomposition indicates a 20–35% reduction in global bending stress and a 15–30% increase in effective lateral stiffness due to shell curvature and twin-tower interaction. The paired configuration further improves torsional resistance by aligning centers of mass and stiffness, leading to a measurable reduction in torsional rotation and cross-wind response under oblique wind loading. Aerodynamically, the crown–spire geometry disrupts coherent vortex shedding and mitigates wake synchronization between the towers. Parametric wind-response modeling demonstrates a 25–40% reduction in peak along-wind and across-wind acceleration, maintaining occupant comfort within internationally accepted serviceability thresholds. The inter-tower spacing and tapered crown profiles act as pressure-relief zones, lowering localized suction pressures at upper elevations. Environmental performance is intrinsically embedded within the architectural form. The vertically layered shells generate pressure differentials and buoyancy-driven airflow, enabling continuous natural ventilation enhanced by coastal wind regimes. Computational airflow approximations indicate 10–25% improvement in natural air exchange rates relative to flat-façade high-rise typologies. Solar exposure is moderated through self-shading curvature, reducing incident solar radiation on primary façades by 15–30% during peak sun angles, thereby lowering cooling demand and glare risk. Overall, the Twin Crown–Spire configuration demonstrates that geometry-driven design can function as a unified structural, aerodynamic, and environmental control system. By integrating load redirection, wind-response attenuation, and passive climate regulation within a single architectural logic, the proposed model offers a scalable, resilient, and energy-efficient framework for next-generation coastal landmark development. The study establishes a rigorous analytical foundation for future numerical simulation, wind-tunnel validation, material optimization, and real-world implementation. Please check the attachment for details