A high-efficient seismic optimization procedure for deployment of link beams in double-column tall pier bents

Double-column tall pier bridges are widely designed and constructed in mountainous regions of western China with high seismic hazard level. However, no sophisticated design procedure is provided for this type of tall piers, especially the deployment of link beams (including both numbers and distribution patterns) between the two columns to date. In this regard, this study proposes a high-efficient seismic optimization procedure based on an improved multi-mode response spectral analysis (IMRSA) method. This proposed procedure allows for the rapid determination of the optimal deployment of link beams considering various seismic performance objectives. Taking a typical double-column tall pier bent in the southwestern mountainous region as a case study, the effectiveness of the IMRSA method is first validated through comparing the responses with those obtained from nonlinear time history analyses of refined finite element models. Subsequently, employing the proposed optimization procedure, optimal link beams deployments are determined with the design objectives of minimizing pier bending moments and shear forces. A comparison of the obtained optimal deployments with existing research results, where various numbers of link beams are considered, validates the feasibility and efficiency of the proposed optimization procedure for such problems. The results indicate that while yielding link beams deployments similar to existing methods, the proposed procedure substantially reduces the time consumption from approximately 17 hours to around 1 hour, demonstrating its potential for application in engineering practice.