The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including real-time monitoring, providing wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are the next big revolution in the UAV technology promising to provide new opportunities in different applications, especially in civil infrastructure in terms of reduced risks and lower cost. Civil infrastructure is expected to dominate more than $45 Billion market value of UAV usage. In this paper, we present UAV civil applications and their challenges. We also discuss the current research trends and provide future insights for potential UAV uses. Furthermore, we present the key challenges for UAV civil applications, including charging challenges, collision avoidance and swarming challenges, and networking and security-related challenges. Based on our review of the recent literature, we discuss open research challenges and draw high-level insights on how these challenges might be approached.

Unmanned Aerial Vehicles: A Survey on Civil Applications and Key Research Challenges

Seismic Rehabilitation of Existing Buildings

This paper presents a summary of current practice and recent developments in the application of passive energy dissipation systems for seismic protection of structures. The emphasis is on the application of passive energy dissipation systems within the framing of building structures. Major topics that are presented include basic principles of energy dissipation systems, descriptions of the mechanical behavior and mathematical modeling of selected passive energy dissipation devices, advantages and disadvantages of these devices, development of guidelines and design philosophy for analysis and design of structures employing energy dissipation devices, and design considerations that are unique to structures with energy dissipation devices. A selection of recent applications of passive energy dissipation systems is also presented.

Energy dissipation systems for seismic applications: Current practice and recent developments

Over the past few years, the application of camera-equipped Unmanned Aerial Vehicles (UAVs) for visually monitoring construction and operation of buildings, bridges, and other types of civil infrastructure systems has exponentially grown. These platforms can frequently survey construction sites, monitor work-in-progress, create documents for safety, and inspect existing structures, particularly for hard-to-reach areas. The purpose of this paper is to provide a concise review of the most recent methods that streamline collection, analysis, visualization, and communication of the visual data captured from these platforms, with and without using Building Information Models (BIM) as a priori information. Specifically, the most relevant works from Civil Engineering, Computer Vision, and Robotics communities are presented and compared in terms of their potential to lead to automatic construction monitoring and civil infrastructure condition assessment.

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Visual monitoring of civil infrastructure systems via camera-equipped Unmanned Aerial Vehicles (UAVs): a review of related works

New measures of spectral intensity based on the horizontal components of ground shaking are introduced. These new measures are independent of the in situ orientation of the recordings and encompass the full range of spectral amplitudes over all possible rotation angles. Unlike previously introduced measures that are also orientation independent, no geometric means are used in the computation of the new measures. The new measures based on fiftieth percentile values of the response spectra show small but systematic increases (to a factor of about 1.07 at a 10 sec period) compared to the comparable geometric-mean measure.

Orientation-independent, nongeometric-mean measures of seismic intensity from two horizontal components of motion

Civil engineers always face the challenge of uncertainty in planning, building, and maintaining infrastructure. These works rely heavily on a variety of surveying and monitoring techniques. Unmanned aerial vehicles (UAVs) are an effective approach to obtain information from an additional view, and potentially bring significant benefits to civil engineering. This paper gives an overview of the state of UAV developments and their possible applications in civil engineering. The paper begins with an introduction to
UAV hardware, software, and control methodologies. It also reviews the latest developments in technologies
related to UAVs, such as control theories, navigation methods, and image processing. Finally, the paper
concludes with a summary of the potential applications of UAV to seismic risk assessment, transportation,
disaster response, construction management, surveying and mapping, and flood monitoring and assessment.

A review of rotorcraft Unmanned Aerial Vehicle (UAV) developments and applications in civil engineering

The Next Generation Attenuation (NGA) relationships for shallow crustal earthquakes in the western United States predict a rotated geometric mean of horizontal spectral demand, termed GMRotI50, and not maximum spectral demand. Differences between strike-normal, strike-parallel, geometric-mean, and maximum spectral demands in the near-fault region are investigated using 147 pairs of records selected from the NGA strong motion database. The selected records are for earthquakes with moment magnitude greater than 6.5 and for closest site-to-fault distance less than 15 km. Ratios of maximum spectral demand to NGA-predicted GMRotI50 for each pair of ground motions are presented. The ratio shows a clear dependence on period and the Somerville directivity parameters. Maximum demands can substantially exceed NGA-predicted GMRotI50 demands in the near-fault region, which has significant implications for seismic design, seismic performance assessment, and the next-generation seismic design maps. Strike-norm...

Maximum Spectral Demands in the Near-Fault Region:

Performance assessment of conventional and base-isolated nuclear power plants for earthquake and blast loadings

SUMMARY Seismic or base isolation is a proven technology for reducing the effects of earthquake shaking on buildings, bridges and infrastructure. The benefit of base isolation has been presented in terms of reduced accelerations and drifts on superstructure components but never quantified in terms of either a percentage reduction in seismic loss (or percentage increase in safety) or the probability of an unacceptable performance. Herein, we quantify the benefits of base isolation in terms of increased safety (or smaller loss) by comparing the safety of a sample conventional and base-isolated nuclear power plant (NPP) located in the Eastern U.S. Scenario- and time-based assessments are performed using a new methodology. Three base isolation systems are considered, namely, (1) Friction Pendulum TM bearings, (2) lead–rubber bearings and (3) low-damping rubber bearings together with linear viscous dampers. Unacceptable performance is defined by the failure of key secondary systems because these systems represent much of the investment in a new build power plant and ensure the safe operation of the plant. For the scenario-based assessments, the probability of unacceptable performance is computed for an earthquake with a magnitude of 5.3 at a distance 7.5km from the plant. For the time-based assessments, the annual frequency of unacceptable performance is computed considering all potential earthquakes that may occur. For both assessments, the implementation of base isolation reduces the probability of unacceptable performance by approximately four orders of magnitude for the same NPP superstructure and secondary systems. The increase in NPP construction cost associated with the installation of seismic isolators can be offset by substantially reducing the required seismic strength of secondary components and systems and potentially eliminating the need to seismically qualify many secondary components and systems. Copyright q 2010 John Wiley & Sons, Ltd.

Seismic performance assessment of base-isolated safety-related nuclear structures

The existing design formulas such as those provided by FEMA 273 (or FEMA 356) and other research reports have provided significantly convenient tools to practical engineers in determining the damping coefficients of the supplemental viscous dampers corresponding to an expected added damping ratio to the structure. However, the relative vertical deformation between the ends of the damper was not considered when the formulas were derived. This has resulted into the lack of accuracy for predicting the added damping ratio of medium-rise to high-rise buildings compared with low-rise buildings. This is primarily due to the fact that, for the medium-rise and high-rise buildings, the flexural deformation is as significant as the shear deformation of the building when subjected to earthquake loading, and thus the vertical relative deformation may be comparable with the horizontal relative displacement between the ends of the damper. In this study, new design formulas are derived for commonly used installation schemes of viscous dampers. Numerical verifications have indicated that the new design formulas predict a more accurate viscous damping ratio contributed by linear viscous dampers and ensure a more conservative design for the structure with nonlinear viscous dampers.

Yin-Nan Huang

Papers

A review of rotorcraft Unmanned Aerial Vehicle (UAV) developments and applications in civil engineering

Maximum Spectral Demands in the Near-Fault Region:

Performance assessment of conventional and base-isolated nuclear power plants for earthquake and blast loadings

Seismic performance assessment of base-isolated safety-related nuclear structures

Design Formulations for Supplemental Viscous Dampers to Building Structures