Search

• An equivalent damping ratio is proposed to characterize the TMD contribution. • A probability of failure in the TMD control of the VIV in bridges is formulated. • Three typical TMDs for the VIV mitigation are compared. This paper investigates the parameter determination of the tuned mass damper (TMD) for mitigating the vortex-induced vibration (VIV) in bridges. At present, there is no consensus on design formulas for the TMD in the VIV mitigation. An equivalent damping ratio is proposed to characterize the TMD contribution to the VIV mitigation based on a semi-empirical nonlinear model. The effects of the uncertainties in aerodynamic parameters and structural parameters on the control effect of the TMD are studied. Three typical design formulas for the TMD are compared from the perspective of the effectiveness, robustness, and reliability. The results show that the equivalent damping ratio depends only on the TMD parameters and is sensitive to the uncertainty in the stiffness of the bridge. The vortex-induced amplitude at lock-in is moderate to the uncertainties in aerodynamic parameters. The design formulas for the free-vibration suppression are the most robust option that avoids a high probability of failure, which are recommended for the TMD mitigating the VIV in bridges. At last, a numerical example of the deep-water non-navigable bridge of the Hong Kong-Zhuhai-Macao Bridge is performed to confirm the rationality of the suggested design formulas. [ABSTRACT FROM AUTHOR]

Modular construction is considered as the future of the construction industry. While the sector is growing rapidly in some areas, there are still barriers to overcome. For more than two decades, several regions and countries, such as mainland China, Hong Kong, and Singapore, were using prefabricated/precast components to construct high-rise buildings in both private and public sectors. Such practices suffered from several limitations, which warrant the need for modular construction. Modular construction method needs to evolve so as to meet different regional requirements and restrictions, namely regulations, economy, market and building types. But the regional requirements and constraints on adopting modular construction remain unexplored. These differences are not widely appreciated. Hence, this research aims to perform comparative analysis of modular construction practices in terms of policies, specifications, and real projects in Hong Kong, Singapore, and mainland China. The results of the comparative analysis indicate that Singapore has developed a relatively effective policy system to help the construction industry embrace modular construction, while the three regions have not issued authoritative specifications. In general, modular construction still needs more support from the government, especially in terms of technical guidance and innovation. Cases studies show that the sustainability performance of modular construction is not balanced in terms of the economic, social and environmental dimensions. The lessons and challenges of modular construction drawn from the cases are also summarized. The construction industry should work closely with the government to achieve sustainable construction of modular building. The developed research on modular construction will increase the understanding of common practices in close countries where the industry in each can benefit from such practices to advance the domain. Image 1042 • This study aims to perform comparative analysis of modular construction practices. • The three regions have not issued authoritative specifications. • The sustainability performance of modular construction is not balanced. • Construction industry should work closely with the government in modular building. [ABSTRACT FROM AUTHOR]