Urban areas increasingly suffer from subsurface heat islands: an underground climate change responsible for environmental, public health, and transportation issues. Soils, rocks, and construction materials deform under the influence of temperature variations and excessive deformations can affect the performance of civil infrastructure. Here I explore if ground deformations caused by subsurface heat islands might affect civil infrastructure. The Chicago Loop district is used as a case study. A 3-D computer model informed by data collected via a network of temperature sensors is used to characterize the ground temperature variations, deformations, and displacements caused by underground climate change. These deformations and displacements are significant and, on a case-by-case basis, may be incompatible with the operational requirements of civil structures. Therefore, the impact of underground climate change on civil infrastructure should be considered in future urban planning strategies to avoid possible structural damage and malfunction. Overall, this work suggests that underground climate change can represent a silent hazard for civil infrastructure in the Chicago Loop and other urban areas worldwide, but also an opportunity to reutilize or minimize waste heat in the ground.
Photogrammetry and Augmented Reality for Underground Infrastructure Sensing, Mapping and Assessment
Digital three-dimensional (3-D) information concerning the location and condition of subsurface urban infrastructure is emerging as a potential new paradigm for aiding in the assessment, construction, emergency response, management, and planning of these vital assets. Subsurface infrastructure encompasses utilities (water, stormwater, wastewater, gas, electricity, telecommunications, steam, etc.), geotechnical formations, and the built underground (including tunnels, subways, garages and subsurface buildings). Traditional approaches for collecting location information include merging as-built drawings, historical records, and dead reckoning; and combining with information gathered by above-ground geophysical instruments, such as ground penetrating radars, magnetometers and acoustic sensors. This paper presents results of efforts aimed at using photogrammetric and augmented reality (AR) techniques to aid collecting, processing, and presenting 3-D location information.
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- NSF-PAR ID:
- 10128860
- Date Published:
- Journal Name:
- International Conference on Smart Infrastructure and Construction 2019 (ICSIC): Driving data-informed decision-making
- Page Range / eLocation ID:
- 169 to 175
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract -
The ground beneath many urban areas worldwide is warming up due to so-called subsurface urban heat islands. Resulting from localized and large-scale drivers of heat in the underground, subsurface heat islands cause thermally induced deformations of key materials constituting civil infrastructure: soils, rocks, concrete, and systems thereof. Currently, the effects of thermally induced deformations driven by subsurface heat islands on the performance and durability of civil infrastructure remain poorly understood. This paper presents the results of a numerical and experimental study to shed light on the impacts of subsurface urban heat islands on civil infrastructure. The study is based on the first 3-D model of the subsurface characterizing the central business district of Chicago, called the Loop, which is affected by an underground climate change. This numerical model is used in combination with temperature data gathered through a sensing network deployed across the Loop district to run thermo-hydro-mechanical simulations of the current subsurface conditions, highlighting satisfactory capabilities to model reality. Based on the analysis of the current subsurface conditions, numerical predictions are run over fifty years to reproduce the influence of heat flows on the deformation of the subsurface. The obtained results indicate that subsurface urban heat islands can involve noteworthy and potentially detrimental effects on the performance and durability of civil infrastructure, requiring consideration in the design of such structures or mitigation through appropriate strategies. An analysis of such strategies is proposed and perspectives to hamper this silent hazard for urban areas are provided.more » « less
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Abstract The Húsavík‐Flatey Fault Zone (HFFZ) is the largest strike‐slip fault in Iceland and poses a high seismic risk to coastal communities. To investigate physics‐based constraints on earthquake hazards, we construct three fault system models of varying geometric complexity and model 79 3‐D multi‐fault dynamic rupture scenarios in the HFFZ. By assuming a simple regional prestress and varying hypocenter locations, we analyze the rupture dynamics, fault interactions, and the associated ground motions up to 2.5 Hz. All models account for regional seismotectonics, topo‐bathymetry, 3‐D subsurface velocity, viscoelastic attenuation, and off‐fault plasticity, and we explore the effect of fault roughness. The rupture scenarios obey earthquake scaling relations and predict magnitudes comparable to those of historical events. We show how fault system geometry and segmentation, hypocenter location, and prestress can affect the potential for rupture cascading, leading to varying slip distributions across different portions of the fault system. Our earthquake scenarios yield spatially heterogeneous near‐field ground motions modulated by geometric complexities, topography, and rupture directivity, particularly in the near‐field. The average ground motion attenuation characteristics of dynamic rupture scenarios of comparable magnitudes and mean stress drop are independent of variations in source complexity, magnitude‐consistent and in good agreement with the latest regional empirical ground motion models. However, physics‐based ground motion variability changes considerably with fault‐distance and increases for unilateral compared to bilateral ruptures. Systematic variations in physics‐based near‐fault ground motions provide important insights into the mechanics and potential earthquake hazard of large strike‐slip fault systems, such as the HFFZ.
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1680/icsic.64669.169
