Structural Health Monitoring in Performance Based Design of Bridges

本研究的目的是将结构健康监测（SHM）程序纳入桥梁的基于性能的设计（PBD）。这将有助于桥梁设计师确保根据加拿大公路桥梁设计规范（CHBDC）的规定设计的任何桥梁符合规范中规定的性能标准。 2014年版CHBDC要求在地震区的生命线和主要路线桥梁设计中采用基于性能的抗震设计（PBD）。这种设计方法是该规范先前版本中允许的传统基于力的设计方法的更有前途的替代品。PBD的基本前提是实现多个性能目标，这些目标是根据多个危险等级下的可用性条件和结构损伤来定义的。桥梁必须满足在容许结构损伤和适用性目标方面定义的某些性能目标，在50年的恢复概率中，三个危险等级为10%，5%和2%。规范建议采用非线性时程分析来评估结构的损伤性能指标。虽然设计方法已被要求的代码，一些挑战仍然存在成功的实施设想的要求。显然，有必要促进CHBDC基于性能的设计方法的实施，并且有许多方法可以实现这一点。其中之一是将桥梁过去性能的知识（主要来自监测计划和从极端事件中吸取的经验教训）作为设计程序的一部分，并帮助减少与非线性时程分析相关的不确定性，以预测损坏程度，以及这种损坏如何影响结构的安全性。一旦桥梁建成，就可以实施SHM程序，以验证桥梁的性能是否符合设计时的预期。建议在SHM程序中实施数据科学方法，使用记录的桥梁过去的性能。这将有助于以更高的置信度预测极端荷载下桥梁的预期性能，并确定预期损坏是否在可接受的PBD标准范围内。为了根据诊断结果准确地确定结构的可靠性，重要的是确定低估导致结构失效的损伤严重程度的概率。需要制定确定实际损害发生概率分布的方法。人们还设想，这些程序可用于解决损害量化和损害预测的问题。本研究的结果将有助于使SHM成为可靠、有效的工具，用于评估遭受强烈地面振动的结构的安全性，并确保使用PBD设计的桥梁能够满足CHBDC中规定的预期性能目标。

The goal of this research is to incorporate Structural Health Monitoring (SHM) procedures into the Performance-based Design (PBD) of bridges. This will help bridge designers ensure that any bridge designed according to the provisions of the Canadian Highway Bridge Design Code (CHBDC) meets the specified performance criteria in the code. The 2014 edition of the CHBDC mandates performance based seismic design (PBD) for design of lifeline and major route bridges in seismic zones. This design approach is a more promising substitute to the traditional force based design approach permitted in the previous editions of the code. The basic premise of the PBD is to achieve multiple performance objectives defined in terms of serviceability conditions and structural damage at multiple hazard levels. Bridges must meet certain performance objectives defined in terms of tolerated structural damage and serviceability objectives, at three hazard levels of 10%, 5%, and 2% in 50 years' probabilities of exceedance. Nonlinear time history analysis is recommended by the code to assess the damage performance objectives. While the design approach is already required by the code, several challenges still exist for successful implementation of the envisioned requirements. There is clearly a need to facilitate the implementation of the CHBDC performance based design approach, and there are many ways to achieve this. One of these is to incorporate the knowledge of past performance of bridges, mainly from monitoring programs and lessons learned from extreme events, as part of the design procedure and help reduce the uncertainty associated with nonlinear time history analysis to predict the extent of damage, and how this damage could affect the safety of the structure. SHM procedures can be implemented as soon as a bridge has been built to verify that the bridge is performing as was expected when it was designed. It is proposed to implement in the SHM procedures Data Science methods using recorded past performance of bridges. This will help predict with higher confidence the expected performance of a bridge under extreme loads and to determine if the expected damage is within the accepted PBD criteria. To accurately determine the reliability of a structure based on diagnostic results, it is important to determine the probability of underestimating the severity of damage which causes structural failure. Methods for determining the probability distribution of occurrence of true damage need to be developed. It is also envisioned that these procedures could be used to address the issues of damage quantification and damage prognosis. The results of this research will contribute to make SHM a reliable and efficient tool for assessing the safety of structures subjected to strong ground shaking and for ensuring that a bridge designed using PBD can meet the expected performance objectives specified in the CHBDC.