Parametric flyover optimization framework

Abstract

Rapid urbanization in Tier-II Indian cities demands systematic approaches to grade separation infrastructure. Conventional iterative design often fails to integrate geometric, economic, geological, and regulatory constraints. This study develops a parametric optimization framework for urban flyover design, demonstrated through a case study in Chhatrapati Sambhaji Nagar (Aurangabad), Maharashtra. Independent design parameters (design speed: 60−80 km/h, gradient: 3−4%, vertical clearance: 5.5−6.0 m) were defined per IRC and AASHTO standards. Dependent parameters (sight distance, curve lengths, ramp lengths) were computed using IRC formulae. Geological constraints (Deccan Trap basalt, black cotton soil), regulatory restrictions (heritage buffer, military clearance), and environmental limits were integrated into a weighted multi-criteria decision matrix. Sensitivity analysis quantified parameter influence, and lifecycle cost evaluation was performed using discounted cash flow over 50 years. Sensitivity analysis showed design speed variations of ±10 km/h altered stopping sight distance by 18−22%, while gradient changes of ±0.5% affected vertical curve length by 12−15%. Comparative evaluation demonstrated flyover construction costs 62% lower than tunnel alternatives ($4.2M vs $11.1M per km). Parabolic curves achieved higher constructability indices (0.87 vs 0.73 for splines). The framework yielded 28% reduction in land acquisition, 15% improvement in construction timeline, and 34% enhancement in lifecycle cost efficiency compared to conventional methods. The integrated parametric framework validates its methodological robustness against IRC and AASHTO standards, while addressing geological and regulatory constraints specific to Deccan Trap formations. Its replicability across Tier-II cities highlights potential for sustainable, resilient infrastructure planning. By reducing costs, minimizing land acquisition, and ensuring compliance, the framework advances SDG 9 (Industry, Innovation, Infrastructure) and SDG 11 (Sustainable Cities and Communities).