Shangguan Bing, Wang Feng, Su Qingtian, Matanmi Fawas O, Xu Jun
Department of Bridge Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Guangdong Yejian Construction Drawing Review Center Co., Ltd., Guangzhou 510062, China.
Materials (Basel). 2025 Mar 13;18(6):1278. doi: 10.3390/ma18061278.
Hybrid girder bridges achieve significant improvements in spanning capacity by utilizing lightweight and high-strength materials in the midspan beam segments. To quantitatively describe the enhancement in spanning capacity, this study introduces a simplified analytical model for hybrid girder components, avoiding complex factors, such as span ratio and boundary conditions, typically encountered in previous system-level analyses. The Leq method is proposed based on this new model, utilizing classical beam theory model to calculate and compare hybrid girder components with both uniform and variable cross-sections. The equivalent span increase coefficient, κ, is introduced for the first time, and a simplified formula for its calculation is derived. The calculation errors are kept within 8%, which meets the requirements for preliminary design. Validated through engineering practice, the formula is concise and reveals that κ is solely related to the hybrid ratio, μ, and the linear load ratio, γ. This method provides valuable guidance for the conceptual design and ultimate span prediction of hybrid girder bridges.
混合梁桥通过在跨中梁段使用轻质高强材料，在跨越能力方面取得了显著提升。为了定量描述跨越能力的增强，本研究引入了一种混合梁构件的简化分析模型，避免了先前系统级分析中通常遇到的复杂因素，如跨度比和边界条件。基于这个新模型提出了Leq方法，利用经典梁理论模型计算和比较具有均匀和变截面的混合梁构件。首次引入了等效跨度增加系数κ，并推导了其计算的简化公式。计算误差控制在8%以内，满足初步设计要求。经工程实践验证，该公式简洁，表明κ仅与混合比μ和线性荷载比γ有关。该方法为混合梁桥的概念设计和极限跨度预测提供了有价值的指导。
