基于各墩协同受载的连续梁桥减震研究

It still does not make full use of the movable piers potential aseismic ability in aseismic design of continuous bridge. Aiming at the problem that the seismic demand of the only fixed pier force and beam end longitudinal displacement is too large under longitudinal earthquake, the aseismic design idea of continuous bridge is proposed based on co-loading thought of all piers. The wrap rope devices (WRD) activated by the relative acceleration of pier and girder, are installed between girder and moveable piers and WRD connection system of continuous bridge is established. At normal condition, WRD can meet the relative displacement demand between girder and movable piers caused by the changing of temperature. When seismic happened, it also can establish lock connection between movable piers and girder quickly in order to partake the seismic load with fixed pier. The seismic response characteristics and the mechanism of seismic response reduction of the continuous bridge with WRD system are studied systematically by theory analysis, numerical simulation and vibration table test. According to the principle of 'distribution according to ability' and 'ability protection', establish aseismic design theory of continuous bridge based on co-loading theory of all piers. Realize moveable piers share the seismic load with the fixed pier according to their potential aseismic abilities as well as preventing the moveable piers are damaged for overloading, reduce the seismic demand of fixed pier, and control the longitudinal displacement of girder, in order to improve the aseismic performance of continuous bridge. The study has high theoretical value and application prospect widely. The results can be used not only for aseismic design of continuous bridge, but also can be used for aseismic strengthening of exiting continuous bridge.

针对目前连续梁桥抗震设计还没有充分利用活动墩的既有抗震潜能，在纵向地震作用下固定墩内力需求和梁端纵向位移过大问题，提出基于各墩协同受载的连续梁桥减震设计思想。在梁体与活动墩之间设置以墩梁相对加速度激活的缠绕索连接装置（WRD），建立连续梁桥缠绕索连接体系。该装置正常情况下能满活动墩与梁体间因温差荷载等引起的变位需求，地震时能迅速地在梁体和活动墩之间建立瞬态锁死连接，使各活动墩与固定墩协同受载，共同分担纵向地震作用。通过理论分析、数值模拟和振动台试验，系统研究连续梁桥缠绕索连接体系的地震响应特性和减震机理。根据“按能分配”和“能力保护”原则，建立基于各墩协同受载连续梁桥抗震设计理论，实现各活动墩根据自身的抗震潜能共同分担纵向地震作用，降低固定墩的地震需求，控制梁端纵向位移，又要对其进行能力保护，提高连续梁桥整体抗震性能。其成果在新建连续梁桥抗震设计和既有连续梁桥抗震加固领域均有广泛应用前景。

目前连续梁桥在设计中固定墩与活动墩截面尺寸基本相同，在纵向地震作用下主要由固定墩承载地震荷载，导致固定墩内力需求和梁端纵向位移过大，而活动墩既有抗震潜能没有得到充分利用。针对这一问题，在纵向地震作用下提出基于各墩协同受载的连续梁桥减震设计思想，开发了一种设置在梁体与活动墩之间的基于粘滞阻尼器激活的缠绕索减震装置（简称WRD-D），建立连续梁桥WRD-D连接体系。.研发了基于粘滞阻尼器激活的缠绕索减震装置（简称WRD-D），对其工作机理和力学性能进行了理论与试验研究，研究了WRD-D关键参数对其力学性能的影响，建立了WRD-D本构模型。提出了连续梁桥固定墩应用WRD-D的连续梁桥WRD-D连接体系，通过理论分析、数值模拟和振动台模型试验揭示了连续梁桥WRD-D连接体系的地震响应特征和减震机理。基于某三跨连续梁桥确定了连续梁桥缩尺模型，通过数值模拟和振动台模型试验系统研究了不同场地类型、不同地震强度对连续梁桥WRD-D连接体系破坏模式和减震效果的影响，分别研究等高墩连续梁桥WRD-D连接体系和不等高墩连续梁桥WRD-D连接体系的破坏模式和减震效果，并进行了参数分析，提出了连续梁桥WRD-D连接体系最优参数和合理装置布置方案。研究结果表明，WRD-D是一种速度复合型减震装置，其滞回曲线饱满，具有良好的耗能能力。相比无减震装置的常规连续梁桥，连续梁桥WRD-D连接体系可以有效降低固定墩的地震响应，在强震作用下“延迟”了固定墩的屈服，提高了连续梁桥的整体抗震性能。WRD-D对梁端位移的减小效果明显，有效防止墩、梁之间的过大位移造成落梁震害。WRD-D在地震作用下被激活后，活动墩与上部结构建立摩擦滑移连接，活动墩内力响应显著增加，但活动墩的内力响应仍小于固定墩的内力响应。本项目的研究不仅具有较强的理论意义，且具有较好的实际应用价值。该项目已经发表SCI论文7篇，EI论文7篇，获批发明专利3项。