Snow Load Research Articles

Fragility analysis of long-span lightweight steel structures subjected to combined earthquake and non-uniform snow loads

Lightweight steel structures are commonly used in industrial facilities due to their low weight, high strength, and excellent performance. The design of these structures for cold regions not only has to consider the effects of earthquakes but also the negative impact of snow loads. Industrial structures often have long spans, and the effects of uneven snow loads cannot be underestimated. However, relatively few studies have focused on the performance of lightweight steel structures under the influence of combined earthquake and non-uniform snow loads. Therefore, this study assessed the seismic fragility of a typical single-span, double-sloped lightweight steel factory under combined earthquake and non-uniform snow loads using incremental dynamic analysis. Non-uniform snow loads, as compared to uniform snow loads, substantially increase the structural displacement responses, thereby increasing the structural failure risk. The improved structural design developed in this study effectively decreases the impact of adverse loading scenarios and enhances the multi-hazard resilience of the structure. Accordingly, these results can serve as an important theoretical guide for enhancing the safety of lightweight steel structures subjected to multiple hazards in cold regions.

Operation, Expansion, and Improvement of the Snow Load Alert System “YukioroSignal”

The “YukioroSignal” system, which provides snow load alerts, was developed to inform decision-making regarding snow removal from house roofs. It was launched in Niigata Prefecture in 2018 and expanded to cover all special heavy snowfall areas in Japan, including the Hokkaido, Tohoku, and Hokuriku regions in 2024. The system uses the SNOWPACK model to estimate high-accuracy snow weight from real-time snow depth data published online at observation points. At locations where snow depth gauges are not installed, such as in mountainous areas, snow weight is estimated using inverse distance-weighted interpolation, but accuracy is reduced. To overcome this problem, this study attempted to integrate this information with the snow water equivalent distribution calculated using the simple-layer snow distribution model. To validate this improvement, manual observations of snow weight were performed at 98 sites and compared with simulation results. The accuracy of snow weight estimation at distances far away from snow depth stations was improved. The six-year operation of YukioroSignal showed the additional required information that is vulnerable to damage even with less snowfall, such as vacant houses, and caution of changes in hazard levels by an increase in snowburst in a short period.

Numerical investigation on the behavior of thin concrete shells subjected to nonuniform and asymmetrical loads

AbstractConcrete shells, designed with near optimal shapes for uniform gravity loads, can be subjected to nonmembrane effects caused by nonuniform and asymmetrical loads. In this paper, a numerical study on the effect of normative loads on a thin triangular concrete shell with three supports is presented. Two actions were considered, wind and snow, which present high spatial variability in both intensity and direction, assuming the values established in Eurocode 1 for the worst possible location, in Portugal. Linear, nonlinear and stability analyses were performed using the ABAQUS software. Results suggest that the wind action, but especially the exceptional snow load in drifted arrangement, produce significant bending moments, leading to decompression, and eventually to the development of stresses above the tensile strength of current concrete classes. Therefore, the production of these shells by assembling prefabricated un‐reinforced modules, requires the use of ultrahigh‐performance fiber reinforced concrete, combined with prestressing.

Research on probabilistic analysis of trapezoidal triangle truss

As a region affected by the Mongolian Siberian high-pressure system, the Northeast area of China faces extreme low temperatures and snowy weather in winter, which poses a high demand for local energy. As a relatively mature sustainable energy source, laying solar photovoltaic panels on the roofs of residential buildings relied on sufficient local sunlight resources has become a feasible measure. From the perspective of engineering safety, this paper studies the stability of a single span double slope roof steel truss with added solar photovoltaic panels under snow loads. First, the types of loads on the truss are analyzed, assuming the distribution of the load and capacity of any member in the truss structure. Then, Monte Carlo algorithm is used to simulate the failure probability, and finally the failure probability of the member as well as the overall structure is obtained. As a conclusion, this paper finds that the stability of this structure is basically not affected by the above factors, and this provides certain reference significance for balancing safety and economic benefits in practical engineering design.

Numerical simulation of wind–snow flow on a roof considering time-varying snow phase boundaries

Large-span roofs can be damaged by uneven snow loads caused by snow drifting. To predict wind-induced snow loads more accurately, this paper proposes a numerical simulation method. The method considers the interaction of wind and snow, the changing characteristics of snow phase boundaries over time, and corrects for snow deposition and erosion flux. The effectiveness of the method was confirmed by simulating wind–snow flow on a three-centered cylindrical shell and comparing the results with wind tunnel measurements. The simulation considered different snowfall conditions and time-varying snow phase boundaries on a large-span shell-shaped roof. The study investigated the influence of snowfall conditions and dynamic changes in snow phase boundaries on snow cover distribution by comparing simulation results.

Numerical investigation of wind-induced snowdrift on a long-span saddle-shaped roof based on the k-kl-ω model

Long-span structures are more vulnerable to the imbalanced distribution of snow loads, which is a primary factor contributing to structural failure. The development of snowdrifts is directly related to the shape of buildings, as it significantly affects turbulent characteristics and the process of snow drifting. This study explores the evolution of snowdrifts on a long-span saddle-shaped roof under various wind conditions. The numerical k-kl-ω model is validated against observation data by testing the flow field and snow distribution features of a stepped flat roof and a wind tunnel test. The snowdrift on a long-span saddle-shaped roof is simulated using the proven method, and the snowdrift's properties are studied at different wind speeds, wind angles, and threshold friction speeds. A comparative analysis of wind-induced snowdrift development on open and closed roofs is given, and the snow shape coefficients for each roof partition of the prototype roof are also provided. The findings indicate that the characteristics of snowdrifts on the roof vary with changing wind environmental factors, and the adverse inflow velocity and wind angle are identified. Snow morphology variation is more subject to an influence on changing inflow velocities compared to an alternation in wind-blowing time. The study reveals differences in how wind-driven fresh snow and long-deposited snow distribute themselves, with fresh snow producing more unevenness, potentially affecting roofs' load-bearing capacity.

Machine learning and traditional approaches in shear reliability of steel fiber reinforced concrete beams

In the field of structural engineering, the exploration of steel fibre reinforced concrete (SFRC) beams has recently intensified, particularly due to their improved tension and shear performance of structure. This study pioneers a novel reliability analysis of shear capacity predictions for SFRC beams, distinctively classifying the datasets into high-strength (HSFRC) and normal-strength (NSFRC) categories. A comprehensive database of 142 HSFRC and 265 NSFRC beams serves as the foundation for this analysis, which critically examines the standard Gaussian distribution in shear design models and proposes the Lognormal and Weibull distributions as more precise alternatives. Employing advanced First-order (FORM) and Second-order Reliability Methods (SORM), the study covers a broad spectrum of load conditions, including dead, live, snow, wind, and seismic loads, to evaluate various empirical, semi-empirical and machine learning proposed shear capacity prediction formulas. One of the key innovations of this research is the development of differentiated resistance coefficients for various risk levels in the reliability analysis, allowing future structural designers to tailor their designs according to specific risk profiles. This approach significantly enhances the balance between economic efficiency and structural safety based on the evolution of different target reliability indexes. The study reveals that existing design equations for SFRC beams generally lean towards conservatism. This study found that formulas derived from machine learning exhibited superior prediction ability compared to traditional theoretically derived regression formulas. When compared the proposed machine learning formulas, the Tarawneh's formula demonstrated better prediction ability than the Kara's formula when applied to larger datasets. However, high predictive power does not necessarily equate to high reliability. Machine learning formulas prioritise predictive accuracy, often at the expense of insufficient redundancy for ensuring safety. Overall, it introduces Kara's formula for NSFRC beams, which stands out with its superior predictive performance, offering an optimal balance of safety and cost-efficiency. Ashour's formula is also identified as a more effective and safer option for HSFRC beams. Complementing these findings, the extensive sensitivity analysis of the collected data not only confirms the robustness of the conclusions but also prepares for the integration of broader datasets in the future.

ВАРИАНТЫ РЕКОНСТРУКЦИИ БОЛЬШОЙ СПОРТИВНОЙ АРЕНЫ СТАДИОНА «ЛУЖНИКИ» К КУБКУ МИРА ПО ФУТБОЛУ В 2018 ГОДУ

The article presents the results of comparing the options for choosing the type of console part, which is additionally mounted to increase the coverage area, which is necessary to meet the strict requirements of the International Football Federation (FIFA) for the possibility of holding the opening and final matches of the FIFA World Cup at the stadium. Based on the results of comparing the options, the type of cantilever part and the roof material were selected, the process of determining snow loads obtained by blowing the frame model in a wind tunnel is presented. The paper presents the main results of the calculation, as well as the first values of the natural shapes and frequencies of vibrations. The surface was reconstructed for the 2018 FIFA World Cup in Russia, which made it possible to successfully host the opening and final matches of the championship and increase the prestige of our country in the world.

Construction Disaster Hazard Caused by a Defective Building Structural Survey

The present paper encompasses an analysis of a production hall reinforced concrete roof structure in terms of its limiting snow load. Errors which were made at the survey and thermal retrofitting design stages for the structure in question have been identified. These contributed to a construction disaster hazard which could occur in the event of intensive snowfall. Reinforced concrete roofing structures are least prone to failures caused by the impact of the weather, however they do occur. This results from both structural wear and also often from the addition of extra loads. These loads may be caused by thermal retrofitting as well as installation of additional equipment on the roof, including the currently popular photovoltaic systems. Using the structure subject to the analysis as an example, the authors have proposed a procedure for diagnosing and analysing reinforced concrete roofing structures in terms of upgrades and installation of additional equipment thereon.

Seasonal crustal movements in Northeast Japan revisited

Seasonal movements of global navigation satellite system (GNSS) stations in Northeast (NE) Japan are mainly driven by elastic loading of snow, reaching a few meters deep along the western flank of the backbone range. Here we study them in a comprehensive manner to solve remaining problems. GNSS stations in the inland area show sharp and strong subsidence peaks in winter and remain flat in other seasons, a response consistent with the snow loading. On the other hand, those close to coasts show broad and weak winter subsidence peaks. This needs additional loads in spring to retard the rapid decay of snow loading. We propose that rice fields work as natural reservoirs until early summer and evaluate quantitative consistency of the hypothesis. We also found that some stations show abnormally large winter subsidence that cannot be explained by snow loading alone. Here we examine two factors, i.e., groundwater extraction in winter for melting snow on roads, and snow accretion onto GNSS antenna radomes. We also evaluate seasonal ocean water mass changes in the Japan Sea using GRACE satellite gravimetry data. We found its role in seasonal crustal movements in NE Japan quite small.

Numerical Simulation of Structural Performance in a Single-Tube Frame for 12 m-Span Chinese Solar Greenhouses Subjected to Snow Loads

To address the structural concerns of a 12.0 m-span landing assembled single-tube frame (LASF) for Chinese solar greenhouses subjected to snow loads, the internal forces and deformations of LASF and its reinforced counterpart (RLASF) were numerically simulated to determine the ultimate bearing capacities (Lu) and the failure loads (Lf). During the simulations, steel tubes were modeled as beam188 elements and cables as link180 elements. The frame constraints and the connections were assumed to be fixed supports and rigid, respectively. The loads were determined according to the Chinese standard (GB51183-2016). Simulations revealed that the LASF and RLASF primarily withstand bending moments and are prone to strength failures under snow loads. Both exhibited lower Lu and Lf under non-uniform snow loads than under uniform snow loads. The results also indicated that crop loads could deteriorate the structural safety of the LASF and RLASF. Lu and Lf were found to be proportional to the section modulus of the tubes. The effects of wind loads and initial geometry imperfections on Lf of the LASF and RLASF can be neglected. Furthermore, the RLASF exhibited higher Lf compared to the LASF. Steel usage of the RLASF could be further reduced by replacing circular tubes with rectangular tubes, making the RLASF a feasible option for constructing Chinese solar greenhouses.

Performance Optimization Design Study of Box-Type Substations Subjected to the Combined Effects of Wind, Snow, and Seismic Loads

As a pivotal node in both urban and rural power grids, the box-type substation not only serves the functions of power conversion and distribution but also need to provide structural support and environmental adaptability. However, deficiencies in strength, stiffness, or vibration characteristics may lead to vibration and noise issues, and extreme environmental changes can pose risks of structural damage. This study aims to verify and optimize the seismic resistance and environmental adaptability of box-type substations through finite element simulation methods. Using SOLIDWORKS, a three-dimensional model of the box-type substation was constructed, and static and dynamic analyses were conducted using Ansys Workbench to comprehensively evaluate the dynamic response of the box-type substation under wind, snow loads, and seismic action. Through iterative simulations and a comparison of multiple design solutions, the structural optimization of the substation was achieved. The optimized structure balances strength and stiffness, significantly reducing the weight of the substation body, with the wall thickness reduced by 60%. Additionally, the phenomenon of stress concentration on the side walls was eliminated, ensuring that the equivalent stress is below the material yield strength. This research provides methods and empirical results for enhancing the performance and reliability of box-type substations under seismic conditions, confirming the feasibility of a lightweight design, while ensuring structural safety.

Simulation of roof snow loads based on a multi-layer snowmelt model: Impact of building heat transfer

Simulation of roof snow loads based on a multi-layer snowmelt model: Impact of building heat transfer

Experimental Study on Shear Strength of Roof–Snow Interfaces for Prediction of Roof Snow Sliding

The sliding of roof snow may result in surcharges of snow load on lower roofs or the injury of pedestrians on the ground. It is therefore of great significance to study the mechanism of roof snow sliding, such that prevention or control measures can be developed to manage the risk. Considering four commonly used roofing materials, glass, steel, membrane, and concrete, two types of experiments were carried out in this study to possibly reveal the influence of roofing materials on the shear strength of the roof–snow interface: one is the critical angle tests where the angle at which the snow starts to slide off from the roof is tested, and the other is the shearing tests which aim to test the shear strength of the roof–snow interfaces at specific temperatures. The results showed that the critical angle for roof snow sliding, as well as the shear strength of the roof–snow interface for the four considered roofing materials, show a U-shape trend with the increase in surface roughness and that the shear strength of the roof–snow surface ranges from 0.15 kPa to 2 kPa for the cases considered, while the strength reaches its maximum at certain temperatures near −5 °C for a specific roofing material and snow thickness. These findings could be a useful reference for future experimental or simulation studies on roof snow sliding.

Snowfall Replenishes Groundwater Loss in the Great Basin of the Western United States, but Cannot Compensate for Increasing Aridification

AbstractThere has been an acceleration of groundwater loss in the Great Basin (GB) of the western U.S. as determined from total water storage (TWS) measurements from the GRACE/FO satellite missions. From 2002 to 2023, there was a loss of TWS in the GB of ∼68.7 km3 which is more than six times the current volume of the Lake Mead Reservoir. In this arid/semi‐arid region, groundwater is the primary factor contributing to the decade‐scale decline in TWS. Stronger declining trends are found in the western versus the eastern GB. Snow loading is the major cause of seasonal fluctuations of TWS in the GB. Despite annual replenishment of groundwater by snow, the downward trend persists even in notable snow years. Likely causes include declining snow mass, upstream water diversions and increased evaporation/sublimation due to increasing temperatures. Dire consequences for humans and wildlife are associated with this large loss of groundwater.

Behavior of Metal Frame of Ribbed-ring Dome with Decrease in Number of Supporting Columns

Investigation of the stress state of the metal frame of a ribbed-ring dome, when the number of supporting columns under it is gradually reduced. With that, the same distances or steps between the columns are maintained along the entire contour of the support ring. The main elements of the dome frame and columns are made of steel I-beams. Frames, the domes of which are supported by a different number of cyclically symmetrical columns, were considered as subjects of research. All the domes are characterized by the same geometric structure and size, the same cross sections of the same type of frame elements and are exposed to the same loads. The research was carried out on computer models by calculating the combined effect of the load from the weight of load-bearing and enclosing structures and an asymmetric snow load. The models with a reduced number of columns are obtained by regularly removing them from the original computer model. During the analysis, the stresses in the elements of the frames of all models were determined, which were compared with each other. Deformation graphs and comparative diagrams of the stress state relationships of the frame elements of the original and transformed models are obtained. An assessment of the change in the stress state of the ribbed-ring dome frame with a decrease in the number of columns is given. Significant changes in the stress state of the support ring were noted.

Changes to the Regulatory Definition of Climatic Loads and Impacts on Building Structures

Purpose. The main purpose of the publication is a qualitative and quantitative analysis of changes in climate loads associated with the introduction of the DBN V.1.2–2:2006 standard in the national regulatory framework, compared to the previous standard, as well as further changes to this standard. Methodology. To achieve this goal, both the standards for determining loads and impacts on building structures and the Amendments introduced, which provided for a number of innovations, were considered. The main emphasis is placed on the methodology for determining various types of climatic loads, including loads from the self-weight of soils, snow and wind loads, ice and wind loads, as well as the system for compiling combinations of these loads. The issue of terminology for the process of determining loads is covered. Findings. Based on the comparative analysis, it has been established that the approach to load combinations proposed in the Amendments allows obtaining higher values than all previously used approaches. The methodology for determining the load from the self-weight of soils remained unchanged. The methodology for determining snow and wind loads has been fundamentally changed. The final values of the loads are 2.5–3 times higher than the values in the previous standard. This is most evident in Sumy and Chernihiv regions of Ukraine. The methodology for determining the ice and wind load was supplemented in terms of taking into account the wind pressure in the presence of ice deposits. At the same time, the correlation with wind pressure in the absence of ice deposits is not clear enough. Originality. Changes in the methodology for determining the main types of climatic loads on building structures for the conditions of Ukraine, in particular, loads from the self-weight of soils, snow and wind loads, ice and wind loads, as well as the system for compiling combinations of these loads, were qualitatively and quantitatively assessed. Practical value. The data obtained make it possible to determine the ways and directions for further improvement and refinement of the existing methods for calculating the main climatic loads for the conditions of Ukraine.

ANALYSIS AND ALGORITHM FOR STRENGTHENING ARCHED STRUCTURES OF END-TO-END COMPOSITE CROSS-SECTION

As a result of the increase in snow load, which affects the reliability of arched structures, in accordance with changes No. 2, 3, 4 SP20.13330.2016 (russ. Set of rules), there is a need to strengthen these structures.The aim of the work is to develop reinforcement of arched structures and to develop a typical technical solution to increase the margin of safety for the most common type of structure.

Extreme snowfalls and atmospheric circulation patterns in the Cantabrian Mountains (NW Spain)

This research examines the atmospheric patterns associated with damages caused by extreme snowfalls during a 115-year period, using newspapers as the source to document the events and performing then a synthetic damage index. Between 1900 and 2015 there was 180 days with personal and material damages due to snowfalls (without considering associated hazards as snow avalanches or landslides): Apart from the numerous material damages recorded, 60 people were killed and 254 injured. Advections from the north represented a 30% of damaging days (followed by cyclonic and northeastern) accumulating the greatest number of days in the highest deciles of damage, although cyclonic days were the most damaging ones on average. The analysis of data from five weather stations in the area, allowed to relate weather types with temperature and precipitation extremes, showing that northern and cyclonic types led to the lowest temperature and the highest precipitation. Both the number of events and the damage index decreased throughout the study period, with the most serious events (those that caused deaths and injuries) highly concentrated in the first half of the 20th century. This decrease trend is parallel to that observed in the frequency of two of the most damaging advections, northern and northeastern (responsible for a 46.7% of damage), which have gone from representing 7.3% of days before 1930 to 5.8% after 1990. Futhermore, the relationship between the NAO phases and the days of damage has been examined, noting that damages are less frequent and les intense during the NAO's positive phase. Finally, non-atmospheric drivers such as land-use intensity decline in rural areas and Spanish regulations on roof snow loads standards (initiated in the 1960s and refined subsequently, thus mitigating roof collapses and associated casualties), could have partially contributed to the decline in snowfall damage in the area.

Seasonal Modulation of Crustal Seismicity in Northeastern Japan Driven by Snow Load

AbstractNumerous studies have reported that surface hydrological loading can seasonally modulate seismicity rates at crustal depths. For example, substantial winter snow accumulation occurs across the Japanese Islands, and these snowy regions appear to have seasonally modulated the occurrence of previous large inland earthquakes. Therefore, it is important to investigate the impact of seasonal stress changes on crustal seismicity to deepen our understanding of earthquake generation. Here we constrain seasonal changes in the surface load across northeastern Japan using Global Navigation Satellite System surface displacements and evaluate the potential relationship between temporal trends in inland seismicity and estimated seasonal stress changes. The spatial distribution of the seasonal surface load is consistent with snow depth along the Sea of Japan. The inland seismicity beneath northeastern Japan is modestly modulated by the seasonal stress changes that are induced by the annual snow load. However, this seasonal response is weaker than that in other regions. This weak modulation may be due to the small surface‐load‐induced stress perturbation relative to the long‐term‐averaged stressing rate and/or the limited presence of crustal fluids to trigger seismicity in Japan.