Design methodology for cross-life structural health monitoring with unknown damage process

传统的结构健康监测通常用于a)监测已知的老化过程及其在旧的现有结构中的时间发展，或b)检查在高度创新的新结构设计中所做的假设。然而，在这些应用中，监测周期被限制在几个月到几年之间，并且要监测的物理参数及其影响位置被明确定义。在未来，长期电子监测将成为基础设施建筑维护的重要工具，这将带来以下新的挑战：-监测周期明显延长（几十年至整个结构的使用寿命）和-最初未知的损坏机制，发生时间和位置。这个子项目的目标是开发一种设计方法，可以用来可靠地为这个新的应用领域设计一个监测系统。开发过程可分为两部分：一部分与建筑有关，另一部分与测量系统有关。界面是待测物理参数的定义。本项目的重点是优先发展计划第一阶段与建筑有关的范畴。待开发的方法应首先限于预应力混凝土桥梁结构的应用，即使基本方法可转移到其他类型的结构。该研究项目的科学挑战是基于这样一个事实，即目前可用的测量方法只能以足够的分辨率监测有限的区域。由于监测是在结构的使用寿命开始时开始的，因此尚未对对象启动任何损坏过程。因此，完全基于传感器的监测将需要在整个结构上建立密集的传感器网络，这在经济上和技术上都不可行。因此，子项目的科学知识效益在于，在初始损伤机制、发生时间和位置未知的情况下，如何设计可靠的测量概念。主要问题是在特定结构上应记录何种分辨率（局部、时间、测量范围）的物理参数。为了回答这个问题，应用了两种交互方法：与集群相关的方法和与对象相关的方法。聚类相关方法是基于对现有相似结构的系统评价。为此，对特定对象形成具有相似特征的比较组。与对象相关的方法是基于对特定建筑的专门分析。为此，将现有结构的典型评估方法置于未来测量技术的背景下。这两种方法都将被整合到在Weserstrom桥上开发和测试的方法中。

Traditional structural health monitoring is usually used a) to monitor known deterioration processes and their temporal development in older existing structures or b) to check the assumptions made in the design of new structures with a high degree of innovation. In these applications, however, the monitoring period is limited to between a few months and a few years, and the physical parameters to be monitored and their effect locations are clearly defined. In the future, long-term electronic monitoring will become an important tool for the maintenance of infrastructure buildings, which is associated with the following new challenges: - significantly longer monitoring period (several decades up to the entire service life of the structure) and - initially unknown damage mechanism, time of occurrence and location. The objective of this sub-project is to develop a design methodology that can be used to reliably design a monitoring system for this new application area. The development process can be divided into two parts: one is related to the building and the other one is related to the measuring system. The interface is the definition of the physical parameters to be measured. The focus of this project is on the building-related area in phase 1 of the Priority Programme. The methodology to be developed shall be limited first to the application to prestressed concrete bridge structures, even though the basic methodology is transferable to other types of structures. The scientific challenge of the research project is based on the fact that presently available measurement methods can only monitor limited areas with sufficient resolution. Since monitoring is to begin at the start of the structure's service life, no damage processes have yet been initiated on the object. Complete sensor-based monitoring would, therefore, require a dense sensor network over the entire structure, which would be neither economically nor technically feasible. The scientific knowledge benefit of the sub-project is, therefore, how a reliable measurement concept can be designed with initially unknown damage mechanism, time of occurrence and location. The main question is which physical parameters with which resolution (local, temporal, measurement range) shall be recorded on a specific structure. To answer this question, two interacting approaches are applied: a cluster-related and an object-related approach. The cluster-related approach is based on the systematic evaluation of existing similar structures. For this purpose, a comparison group with similar characteristics is formed for the specific object. The object-related approach is based on a dedicated analysis of the specific building. For this purpose, the typical evaluation methods for existing structures are placed in the context of future measurement technologies. Both approaches are to be integrated into the methodology to be developed and tested on the Weserstrom bridge in the course of BAB A2.