【摘要】 复杂严酷的外部载荷作用下，跨海大桥有可能从某一部位发生损伤，进而持续演化并造成整体结构的性能退化甚至破坏。对于大跨度桥梁，难以直接采用三维全实体有限元模型对桥梁的全局响应进行建模和分析，因此基于实体单元-梁单元耦合建模提出了针对跨海大桥的构件-结构耦合多尺度模拟方法，对钢-UHPC(超高性能混凝土)组合梁跨海大桥的整体建模过程进行了简化，仅对关键部位的损伤演化以及整体结构承载能力进行精细化分析，在节省计算成本的同时，实现对相应工程问题的高效求解。通过UHPC材料力学性能试验，验证了UHPC宏观本构模型以及数值算法的有效性；同时通过跨海大桥多尺度数值模拟和实体数值模拟结果的对比，验证了多尺度建模方法的可行性。考虑到纯UHPC桥面板的工程造价较高，提出了一种新型的UHPC/C40混凝土/UHPC夹层桥面板，多尺度分析表明：与传统C40混凝土结构相比，新型夹层桥面板的抗弯承载力提高15%,抗撞击承载力提高130%;在控制工程造价的同时提高了跨海大桥在地震等极端荷载作用下的抗损伤能力及结构延性。更多还原

【Abstract】 Under the action of complex and harsh external loads, damage may occur at a certain part of a cross-sea bridge, which then evolves continuously and leads to the performance degradation or even failure of the overall structure. For long-span bridges, it is difficult to directly model and analyze the global response using a three-dimensional full-solid finite element model. Therefore, a component-structure coupled multi-scale simulation method for cross-sea bridges was proposed based on solid element-beam element coupled modeling. This method simplified the overall modeling process of steel-UHPC(Ultra-High Performance Concrete) composite beam cross-sea bridges, focusing only on the refined analysis of damage evolution in key parts and the bearing capacity of the overall structure. While saving computational costs, efficient solution to the corresponding engineering problems is achieved. The effectiveness of the UHPC macroscopic constitutive model and numerical algorithm was verified through mechanical property tests of UHPC materials. Meanwhile, the feasibility of the multi-scale modeling method was confirmed by comparing the results of multi-scale numerical simulation and solid numerical simulation of the cross-sea bridge. Considering the high construction cost of pure UHPC bridge decks, a new type of UHPC/C40/UHPC sandwich bridge deck was proposed. Multi-scale analysis shows that compared with the traditional C40 concrete structure, the flexural bearing capacity of the new sandwich bridge deck is increased by 15%, and the impact resistance is improved by 130%. It reduces the construction cost while enhancing the damage resistance and structural ductility of the cross-sea bridge under extreme loads such as earthquakes.更多还原