Flow Analysis and Damage Assessment for Concrete Box Girder Based on Flow Characteristics

Abstract

For a system such as the concrete structure, flow can be the dynamic field to describe the motion, interactions, or both in dynamic or static (Eulerian description) states. Further, various kinds of flow propagate through it from the very start to the end of its lifecycle (Lagrangian description) accompanied by rains, winds, earthquakes, and so forth. Meanwhile, damage may occur inside the structure synchronously, developing from micro-to macro-scale damage, and eventually destroy the structure. This study was conducted to clarify the content of flow which has been implicitly used in the damage detection, and to propose a flow analysis framework based on the combination data space and the theory of dissipative structure theory specifically for nondestructive examination in structural damage detection, which can theoretically standardize the mechanism by which flow characteristics vary, the motion of the structure, or the swarm behavior of substructures in engineering. In this paper, a destructive experiment (static loading experiment) and a following nondestructive experiment (impact hammer experiment) were conducted. According to the experimental data analysis, the changing of flow characteristics shows high sensitivity and efficient precision to distinguish the damage exacerbations in a structure. According to different levels of interaction (intensity) with the structure, the information flow can be divided into two categories: Destructive flow and nondestructive flow. The method used in this research is named as a method of "flow analysis based on flow characteristics", i.e., "FC-based flow analysis".Sustainability 2019, 11, 710 2 of 32 that do not affect or harm the test material, component, or system, such as ultrasonic testing (UT), radiographic testing (RT), infrared thermography (IT), and acoustic emission (AE), among others. In the laboratory experiment, the NDE is often conducted to test the damage after some static loading experiment (one kind of destructive experiments, which would cause damage to the structure). If we view the above methods from a general point, many of the NDE methods share a common concept to show the change of structural status: "dynamic field [5]" or otherwise named as "flow". The dynamic field (flow) is a term defining a field with smooth uninterrupted movement or progress in physics, very commonly used in fluid mechanics nowadays, and also implicitly used in NDE methods; for example, the electromagnetic field in RT and the sound field in AE. Simultaneously, in the static loading experiment, there is a stress field [6] and crack-tip stress field [7] in the static stress-strain response.According to Newton's third law, in the research of damage detection, a global system consists of three parts: The target structure, the environment (referring to everything outside the target structure with a limit domain), and interactions (often described as one kind of flow). In the common sense, an equilibrium state is the state in which the system state variables remain unchanged, as origin...

Closing the Policy Gap in the Academic Bridge

“…For correlations, the following classification strength was utilized: No correlation [0, 0.3), weak correlation [0.3, 0.5), moderate correlation [0.5, 0.8), and strong correlation [0.8, 1] [35]. This was subsequently also used for comparison tests.…”

Flexural Behavior of a 30-Meter Full-Scale Simply Supported Prestressed Concrete Box Girder

“…Structural damages have received much attention in recent years from different directions [17,18]. On one hand, structural health monitoring (SHM) [19][20][21] and damage detection technologies [22,23] have been developed to report structural health status and damage situations by using various integrated sensors [24][25][26] and advanced algorithms with the goal of issuing early warnings in the presence of structural damage. On the other hand, destructive tests are conducted on various structures to better understand the structural behavior under failure [27,28].…”