超高性能混凝土连接装配式桥墩设计理念与实践

Design Concept and Practice of Ultrahigh Performance Concrete Connected Fabricated Pier

摘要:

超高性能混凝土连接装配式桥墩钢筋无需绑扎或焊接、 施工快速、 钢筋定位要求低，且适用于束筋布置，成为一种较好的连接形式。该连接形式目前包括3种连接形式： 扩头式、类承插式和环缝式。结合该连接形式中对超高性能混凝土的受力和施工要求， 列出了超高性能混凝土的性能指标要求和相应的测试依据。该连接形式的设计理念为超高性能混凝土连接段的安全度大于预制段， 即破坏发生在预制段。设计目标为在静力、 E1地震作用和E2地震作用下，分别采用强度设计理论和延性设计理论进行验算，并保证超高性能混凝土应变应小于极限拉伸应变（2 000 με）。标准设计案例表明，对于环缝式连接形式，墩身截面尺寸为2.2 m×1.5 m，墩高10 m、超高性能混凝土壁厚350 mm时，满足预定设计目标，构造合理。

Abstract:

Lanzhou is located in the northwest inland of China with collapsible loess widely distributed. In the process of construction of Lanzhou New Area, the subgrade treatment of collapsible loess needs to compare multiple schemes, and the feasible scheme is determined on the premise of considering economic and technical indexes. Combined with Lanzhou New Area NCE10# Road Project, some experiences in the treatment of collapsible loess subgrade are summarized, which can be used as reference for road professionals.