Quasi real-time post-earthquake damage assessment of lifeline systems based on available intensity measure maps

Marco Torbol 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.5

In civil engineering, probabilistic seismic risk assessment is used to predict the economic damage to a lifeline system of possible future earthquakes. The results are used to plan mitigation measures and to strengthen the structures where necessary. Instead, after an earthquake public authorities need mathematical models that compute: the damage caused by the earthquake to the individual vulnerable components and links, and the global behavior of the lifeline system. In this study, a framework that was developed and used for prediction purpose is modified to assess the consequences of an earthquake in quasi real-time after such earthquake happened. This is possible because nowadays entire seismic regions are instrumented with tight networks of strong motion stations, which provide and broadcast accurate intensity measure maps of the event to the public within minutes. The framework uses the broadcasted map and calculates the damage to the lifeline system and its component in quasi real-time. The results give the authorities the most likely status of the system. This helps emergency personnel to deal with the damage and to prioritize visual inspections and repairs. A highway transportation network is used as a test bed but any lifeline system can be analyzed.

Long term monitoring of a cable stayed bridge using DuraMote

Torbol, Marco,Kim, Sehwan,Shinozuka, Masanobu Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.5

DuraMote is a remote sensing system developed for the "NIST TIP project: next generation SCADA for prevention and mitigation of water system infrastructure disaster". It is designed for supervisory control and data acquisition (SCADA) of ruptures in water pipes. Micro-electro mechanical (MEMS) accelerometers, which record the vibration of the pipe wall, are used detect the ruptures. However, the performance of Duramote cannot be verified directly on a water distribution system because it lacks an acceptable recordable level of ambient vibration. Instead, a long-span cable-stayed bridge is an ideal test-bed to validate the accuracy, the reliability, and the robustness of DuraMote because the bridge has an acceptable level of ambient vibration. The acceleration data recorded on the bridge were used to identify the modal properties of the structure and to verify the performance of DuraMote. During the test period, the bridge was subjected to heavy rain, wind, and a typhoon but the system demonstrates its robustness and durability.

The directionality effect in the seismic risk assessment of highway networks

Torbol, Marco,Shinozuka, Masanobu Taylor Francis 2014 Structure and infrastructure engineering Vol.10 No.2

Long term monitoring of a cable stayed bridge using DuraMote

Marco Torbol,김세환,Masanobu Shinozuka 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.5

DuraMote is a remote sensing system developed for the “NIST TIP project: next generation SCADA for prevention and mitigation of water system infrastructure disaster”. It is designed for supervisory control and data acquisition (SCADA) of ruptures in water pipes. Micro-electro mechanical (MEMS) accelerometers, which record the vibration of the pipe wall, are used detect the ruptures. However, the performance of Duramote cannot be verified directly on a water distribution system because it lacks an acceptable recordable level of ambient vibration. Instead, a long-span cable-stayed bridge is an ideal test-bed to validate the accuracy, the reliability, and the robustness of DuraMote because the bridge has an acceptable level of ambient vibration. The acceleration data recorded on the bridge were used to identify the modal properties of the structure and to verify the performance of DuraMote. During the test period, the bridge was subjected to heavy rain, wind, and a typhoon but the system demonstrates its robustness and durability.

Analytical fragility curves of a structure subject to tsunami waves using smooth particle hydrodynamics

Fritz Sihombing,Marco Torbol 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.6

This study presents a new method to computes analytical fragility curves of a structure subject to tsunami waves. The method uses dynamic analysis at each stage of the computation. First, the smooth particle hydrodynamics (SPH) model simulates the propagation of the tsunami waves from shallow water to their impact on the target structure. The advantage of SPH over mesh based methods is its capability to model wave surface interaction when large deformations are involved, such as the impact of water on a structure. Although SPH is computationally more expensive than mesh based method, nowadays the advent of parallel computing on general purpose graphic processing unit overcome this limitation. Then, the impact force is applied to a finite element model of the structure and its dynamic non-linear response is computed. When a data-set of tsunami waves is used analytical fragility curves can be computed. This study proves it is possible to obtain the response of a structure to a tsunami wave using state of the art dynamic models in every stage of the computation at an affordable cost.

Remote structural health monitoring systems for next generation SCADA

Kim, Sehwan,Torbol, Marco,Chou, Pai H. Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.5

Recent advances in low-cost remote monitoring systems have made it possible and practical to perform structural health monitoring (SHM) on a large scale. However, it is difficult for a single remote monitoring system to cover a wide range of SHM applications due to the amount of specialization required. For the remote monitoring system to be flexible, sustainable, and robust, this article introduces a new cost-effective, advanced remote monitoring and inspection system named DuraMote that can serve as a next generation supervisory control and data acquisition (SCADA) system for civil infrastructure systems. To evaluate the performance of DuraMote, we conduct experiments at two representative counterpart sites: a bridge and water pipelines. The objectives of this article are to improve upon the existing SCADA by integrating the remote monitoring system (i.e., DuraMote), to describe a prototype SCADA for civil engineering structures, and to validate its effectiveness with long-term field deployment results.

Parallel fault tree analysis for accurate reliability of complex systems

Sihombing, Fritz,Torbol, Marco Elsevier 2018 Structural safety Vol.72 No.-

<P><B>Abstract</B></P> <P>Fault tree analysis is one of the methods for the probabilistic risk assessment of components and subsystems of nuclear power plants. The algorithms that solve a fault tree have been until now serial. Instead, this study presents new algorithms that handle and solve a fault tree by taking advantage of the new state of the art in parallel computing: general purpose graphic processor unit (GPGPU). The subsystems of nuclear power plants are the target of this study. However, the method can be used on many others, complex, engineering systems. The different, developed, parallel algorithms are: one builder, which assembles the topology matrix of the fault tree and leads the computation of the three, developed, new solvers. A bottom-up solver, a cut sets solver, and a Monte Carlo simulation solver. The probability of the top event, and the probabilities of each cut sets are computed. The results shows that, given the same investment, a GPU can handle larger fault trees than a CPU implementation. The developed solvers are the foundation of the next generation parallel algorithms for the tree-based analysis of complex systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New algorithms are proposed to solve fault trees on parallel general purpose GPU architecture. </LI> <LI> The obtained framework execute fault tree analysis faster and better than existing serial software. </LI> <LI> More cut sets than ever before can be identified. </LI> <LI> Existing fault trees can be solved by the new parallel algorithms. </LI> </UL> </P>

Hybrid parallel smooth particle hydrodynamic for probabilistic tsunami risk assessment and inland inundation

Fritz Sihombing,Marco Torbol 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.2

The probabilistic tsunami risk assessment of large coastal areas is challenging because the inland propagation of a tsunami wave requires an accurate numerical model that takes into account the interaction between the ground, the infrastructures, and the wave itself. Classic mesh-based methods face many challenges in the propagation of a tsunami wave inland due to their ever-moving boundary conditions. In alternative, mesh-less based methods can be used, but they require too much computational power in the far-field. This study proposes a hybrid approach. A mesh-based method propagates the tsunami wave from the far-field to the near-field, where the influence of the sea floor is negligible, and a mesh-less based method, smooth particle hydrodynamic, propagates the wave onto the coast and inland, and takes into account the wave structure interaction. Nowadays, this can be done because the advent of general purpose GPUs made mesh-less methods computationally affordable. The method is used to simulate the inland propagation of the 2004 Indian Ocean tsunami off the coast of Indonesia.

Remote structural health monitoring systems for next generation SCADA

김세환,Pai H. Chou,Marco Torbol 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.5

Recent advances in low-cost remote monitoring systems have made it possible and practical to perform structural health monitoring (SHM) on a large scale. However, it is difficult for a single remote monitoring system to cover a wide range of SHM applications due to the amount of specialization required. For the remote monitoring system to be flexible, sustainable, and robust, this article introduces a new cost-effective, advanced remote monitoring and inspection system named DuraMote that can serve as a next generation supervisory control and data acquisition (SCADA) system for civil infrastructure systems. To evaluate the performance of DuraMote, we conduct experiments at two representative counterpart sites: a bridge and water pipelines. The objectives of this article are to improve upon the existing SCADA by integrating the remote monitoring system (i.e., DuraMote), to describe a prototype SCADA for civil engineering structures, and to validate its effectiveness with long-term field deployment results.

Operational modal analysis of reinforced concrete bridges using autoregressive model

Kyeongtaek Park,Sehwan Kim,Marco Torbol 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.6

This study focuses on the system identification of reinforced concrete bridges using vector autoregressive model (VAR). First, the time series output response from a bridge establishes the autoregressive (AR) models. AR models are one of the most accurate methods for stationary time series. Burg\'s algorithm estimates the autoregressive coefficients (ARCs) at p-lag by reducing the sum of the forward and the backward errors. The computed ARCs are assembled in the state system matrix and the eigen-system realization algorithm (ERA) computes: the eigenvector matrix that contains the vectors of the mode shapes, and the eigenvalue matrix that contains the associated natural frequencies. By taking advantage of the characteristic of the AR model with ERA (ARMERA), civil engineering can address problems related to damage detection. Operational modal analysis using ARMERA is applied to three experiments. One experiment is coupled with an artificial neural network algorithm and it can detect damage locations and extension. The neural network uses a specific number of ARCs as input and multiple submatrix scaling factors of the structural stiffness matrix as output to represent the damage.