Lakhta Center: Automated Structural and Geotechnical Health Monitoring

"Lakhta Center" became a large scale public and office project in Primorskiy district of Saint-Petersburg, Russia. The Complex is comprised of supertall Tower, Multifunctional Building and the Arch with long span structures integrated with stylobate part. A number of innovation technologies and design solutions have been applied during the construction of the project. According to the Building Codes and Regulations, to improve structural safety during the construction and maintenance periods, permanent structural health monitoring (SHM) program has been developed. The main objective of SHM is to minimize structural failure risks due to uncertainties in soil and structural materials behavior. General information about design and organizational arrangements for deploying automated structural and geotechnical health monitoring system of the "Lakhta Tower" is provided in the following paper. SHM architecture and topology, applied instrumentation, measurement methodology, software and monitoring parameters of the structure are described. The article presents the results of the Tower structural behavior monitoring during the construction period. The correlation between the measured and the predicted Tower structure performance was analyzed and found in good agreement. A few anomalies were identified and investigated. The focus is made to the informational value of the monitoring data for the increasing of soil, foundation and structure FE-modelling quality for construction accompaniment purposes

Recent dynamic of hydro-ecosystems of thermokarst depressions in the Central Siberia from satellite and in situ observations : importance for agriculture and human life

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Remote sensing of Siberian wetlands and peatlands

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Imaging permafrost active layer thickness under forest for climate model improvement

(IF 7.67; Q1)International audiencePermafrost is an important but poorly known carbon reservoir which is vulnerable to the high latitude accelerated warming. The projected thickening of its superficial seasonally thawed active layer and its induced spatial reorganization will hasten Carbon release in the atmosphere while impacting hydrology, geochemical transfers, vegetation repartition and ground stability. Active layer thickness (ALT) is only assessed by northern stations, therefore, its spatial distribution remains unknown and lacks for model evaluation, especially under the boreal forest. The all-weather spaceborne InSAR technique has shown only partial sensitivity to ALT through ground movements and remained restricted to non-forested areas. To overcome these limitations, we generalized the ground movement estimation under the omnipresent forest by exploiting the SAR polarimetric information, on the one side, and we isolated the thermodynamical component from the hydrological one during freezeback using a land surface model, on the other side, to extract ALT. Based on a one year TerraSAR-X time serie acquired over the region of Yakustk, we obtained a first high resolution ALT image which reveals unexpected short scale spatial heterogeneity, arranged along anisotrotopic patterns. Its poor comparison with the ALT simulated by the ISBA land surface model, currently used in climate modeling, highlights that climate models, and thus their simulations of greenhouse gas emissions, remain very uncertain over northern high latitudes in absence of regionalized ALT information under the boreal forest. This novel approach, operable using current and future sensors over wide areas, offers a new way forward to improve modeling as well as to optimally monitor global warming from the high latitudes

Organic carbon and total nitrogen stocks in soils of the Lena River Delta

The Lena River Delta, which is the largest delta in the Arctic, extends over an area of 32 000 km(2) and likely holds more than half of the entire soil organic carbon (SOC) mass stored in the seven major deltas in the northern permafrost regions. The geomorphic units of the Lena River Delta which were formed by true deltaic sedimentation processes are a Holocene river terrace and the active floodplains. Their mean SOC stocks for the upper 1m of soils were estimated at 29 kgm(-2) +/- 10 kgm(-2) and at 14 kgm(-2) +/- 7 kgm(-2), respectively. For the depth of 1 m, the total SOC pool of the Holocene river terrace was estimated at 121 Tg +/- 43 Tg, and the SOC pool of the active floodplains was estimated at 120 Tg +/- 66 Tg. The mass of SOC stored within the observed seasonally thawed active layer was estimated at about 127 Tg assuming an average maximum active layer depth of 50 cm. The SOC mass which is stored in the perennially frozen ground at the increment 50-100 cm soil depth, which is currently excluded from intense biogeochemical exchange with the atmosphere, was estimated at 113 Tg. The mean nitrogen (N) stocks for the upper 1m of soils were estimated at 1.2 kgm(-2) +/- 0.4 kgm(-2) for the Holocene river terrace and at 0.9 kgm(-2) +/- 0.4 kgm(-2) for the active floodplain levels, respectively. For the depth of 1 m, the total N pool of the river terrace was estimated at 4.8 Tg +/- 1.5 Tg, and the total N pool of the floodplains was estimated at 7.7 Tg +/- 3.6 Tg. Considering the projections for deepening of the seasonally thawed active layer up to 120 cm in the Lena River Delta region within the 21st century, these large carbon and nitrogen stocks could become increasingly available for decomposition and mineralization processes

Ground movement estimation in Yakutia using Dual-Pol InSAR TerraSAR-X data

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Following deformation over permafrost environment during a whole freeze/thaw cycle using Pol-D-InSAR

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