Staff members at Los Alamos National Laboratory (LANL) produced a summary of the structural health monitoring literature in 1995. This presentation will summarize the outcome of an updated review covering the years 1996 2001. The updated review follows the LANL statistical pattern recognition paradigm for SHM, which addresses four topics: 1. Operational Evaluation; 2. Data Acquisition and Cleansing; 3. Feature Extraction; and 4. Statistical Modeling for Feature Discrimination. The literature has been reviewed based on how a particular study addresses these four topics. A significant observation from this review is that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition. As such, the discrimination procedures employed are often lacking the appropriate rigor necessary for this technology to evolve beyond demonstration problems carried out in laboratory setting.

A review of structural health monitoring literature 1996-2001

Technology developments in structural health monitoring of large-scale bridges

Structural health monitoring (SHM) is a term increasingly used in the last decade to describe a range of systems implemented on full-scale civil infrastructures and whose purposes are to assist and inform operators about continued 'fitness for purpose' of structures under gradual or sudden changes to their state, to learn about either or both of the load and response mechanisms. Arguably, various forms of SHM have been employed in civil infrastructure for at least half a century, but it is only in the last decade or two that computer-based systems are being designed for the purpose of assisting owners/operators of ageing infrastructure with timely information for their continued safe and economic operation. This paper describes the motivations for and recent history of SHM applications to various forms of civil infrastructure and provides case studies on specific types of structure. It ends with a discussion of the present state-of-the-art and future developments in terms of instrumentation, data acquisition, communication systems and data mining and presentation procedures for diagnosis of infrastructural 'health'.

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Structural health monitoring of civil infrastructure

Seismic Rehabilitation of Existing Buildings

A review of vibration-based damage detection in civil structures : from traditional methods to Machine Learning and Deep Learning applications

The semi‐analytical solution of the dynamic behavior of vertical pile groups is presented. The solution accounts for the pile‐soil‐pile dynamic interaction and is based on modeling the soil as a plane strain continuum and the piles as a set of finite elements. The method is generally enough to model any pile group geometry in a layered soil. The proposed method is simple since it needs no special soil modeling, accurate since its results compared well with the results of finite elements method, and cheaper to use than the finite element method. Some case studies are presented which show that the dynamic pile‐soil‐pile interaction is important for longer distances between the piles than the static case. It is shown also that correction factors due to dynamic pile‐soil‐pile interaction is frequency dependent.

Dynamic Behavior of Pile Groups

Numerous terrorist events during the last decade, including the 2001 attack on the World Trade Center, have heightened concern about the safety of bridges during intentional/unintentional blast load effects. Analysis of highway bridges under blast loads requires accurate generation and application of blast loads and good understanding of the behavior of components of a bridge during high strain rate loading encountered during blast loads. In this paper, a new approach for the application of blast loads on bridge components has been presented. This approach can apply realistic loads and can simulate both reflection and diffraction of blast loads. Using this approach, verification of simulation of blast loads in LS-DYNA has been carried out by using available blast tests on two types of beams. A high fidelity model of a typical three-span highway bridge has been developed for investigation of blast load effects on a three-span reinforced concrete bridge. It is observed that the range of demands impo...

Blast Load Effects on Highway Bridges. I: Modeling and Blast Load Effects

One of the most frequently used approaches for minimizing the potential for progressive collapse in buildings is the alternate path method. The appeal of this method is primarily due to its relative simplicity and threat independent specification. Applications of the alternate path method typically employ a component design strategy in which the adequacy of the system is based on individual structural components successfully satisfying the acceptance criteria. This design philosophy is also used in evaluating other extreme loading conditions such as seismic loads and direct blast loads. However, the adequacy of the global structural system is not usually investigated during this component design process. This paper details the importance of investigating global effects when evaluating the potential for progressive collapse in buildings. There are two types of frames that will be evaluated: moment-resisting (sway) frames and nonsway frames that include lateral-force resisting elements, such as shear walls. The necessity for considering the global response of a damaged structure becomes apparent following the evaluation of the overall stability of these systems. In addition, the conclusions concerning progressive collapse investigations will be generalized for application to seismic and direct blast hazards. A simple design and analysis method will be introduced, along with the associated acceptance criteria.

Global System Considerations for Progressive Collapse with Extensions to Other Natural and Man-Made Hazards

高速道路橋への発破荷重の効果 ii:破壊モードおよび多ハザード相関関係

Bridges with different seismic design levels and concrete compressive strengths have been analyzed for three levels of underdeck blast loads. It is observed that there are several other damage modes besides failure of bridge columns that may contribute to a complete collapse of the bridge. In general, it is demonstrated that an increased seismic resistance leads to improved performance during blast loads. Both concrete strength and seismic capacity are equally effective for bridges designed with higher seismic resistance. Extensive simulations have been performed to establish a correlation between the ratio of ductility and strength reduction factor, μ/R, and pier top displacement for concrete with different compressive strengths. It has been observed that the pier top displacement decreases drastically for μ/R>6. Moreover, it is observed from results of 27 simulations that bridge piers with μ/R>6 survive high levels of blast loads (without failure of piers).

Mohammed M. Ettouney

Papers

Dynamic Behavior of Pile Groups

Blast Load Effects on Highway Bridges. I: Modeling and Blast Load Effects

Global System Considerations for Progressive Collapse with Extensions to Other Natural and Man-Made Hazards

高速道路橋への発破荷重の効果 ii:破壊モードおよび多ハザード相関関係

Blast Load Effects on Highway Bridges. II: Failure Modes and Multihazard Correlations