Collapse Analysis Research Articles

Introduction: Crediting Stiegler

The opening contribution to this special edition on “The Truth of Stiegler” tests the claim that the more Bernard Stiegler develops his analysis of the catastrophic collapse of society, the further he risks departure from the philosophical rigor of his earliest ideas on the technical constitution of “intermittently not-inhuman” (“noetic”) life. His diagnoses of the collapse of trust revolve around a critique of misplaced faith () in computational capitalism’s pursuit of certainty, but are arguably themselves undermined by Stiegler’s dogmatic certainty in his own arguments. We can make more sense of the apparent inconsistency by extending Stiegler’s ideas on exhaustion and the disintegration of the public sphere to show how a surfeit of certainty gives rise to a defensive posture that complicates his insistence on the therapeutic value of truth and openness.

Failure of expandable lumbar interbody cages – critical analysis of secondary collapse, pseudarthrosis & surgical revision during follow-up

Failure of expandable lumbar interbody cages – critical analysis of secondary collapse, pseudarthrosis & surgical revision during follow-up

The dynamic analysis of the Troja footbridge – the analysis of the possibility of the early warning before the collapse

The subject of this paper is to summarize the results of the analysis of the Troja footbridge collapse. The analysis included the remains inspection, creation of the numerical models, and analysis of the measurement, done on the bridge. The analysis included the impact of variable influences, including the defect of the tendons. Based on variable methods, the conclusions are given, if the failure could have been detected by used methods.

Progressive Collapse Analysis of the Champlain Towers South in Surfside, Florida

Progressive Collapse Analysis of the Champlain Towers South in Surfside, Florida

Progressive Collapse Analysis of RC building due to Fire load

Fire hazard is perceived to be one of the most destructive hazards faced by mankind in any urban environment as a primary or a secondary consequential event. In recent decades there has been substantial increase in adaptation of RC buildings for residential, commercial & office purposes. Therefore, the building fire appears as a more frequent hazard in comparison with other natural or man-made events. The occurrence of fire is unpredictable and high frequent event, that has potential to create a disaster (resulting in huge loss of property and life). Therefore, there is an imminent need for its consideration during analysis, design of new buildings and in assessment of structural integrity for existing buildings. This aids in providing a safe and functional fire-resistant building during its design life. The recent incidents that have occurred in Hyderabad city (Deccan Mall & Swapnalok complex etc), Telangana state, India, in particular is an epitome of this disaster. However, the existing codes of practice for Indian code designed buildings (BIS) in particular do not address assessment of the building structural behaviour subjected to fire load. Moreover, progressive collapse mechanism of any building can initiate due to loss of critical structural components due to any unforeseen event like explosion, accident, etc. Further, there are more likelihood of triggering of a fire hazard, eventually resulting in cascading failure of a structure. Hence, an attempt has been made to assess the structural integrity of structure during initiation of progressive collapse subjected to fire load. The hypothetical G+3(ground + three floors) reinforced concrete building designed as per IS456:2000, modelled and analysed using the structural finite element software (SAP2000). Progressive collapse analysis of the building is performed as per the GSA guidelines and subjected to simultaneous application of fire load (as per ISO 834 standard fire curve as the input fire load) on all its structural components. Further the performance of the building under fire scenarios were assessed in terms of its resistance duration using the Structural fire software (SAFIR). The outcomes of the study clearly pronounce the structural vulnerability of the building components in resisting the fire exposure for certain duration of time, quantified in terms of response parameters (Bending moments, Shear forces, Demand Capacity Ratio (DCR), etc).

Progressive Collapse Resistance Assessment of a Multi-Column Frame Tube Structure with an Assembled Truss Beam Composite Floor under Different Column Removal Conditions

To estimate the progressive collapse resistance capacity of a multi-column frame tube structure with an assembled truss beam composite floor (ATBCF), pushdown analysis and nonlinear dynamic analysis are conducted for such a structure using the alternate load path (ALP) method. The bearing capacities of the remaining structures under three different work conditions, which are the side middle column removal, the edge middle column removal, and the corner column removal, are individually studied, and the collapse mechanism of the remaining structures is analyzed based on the aspects of the internal force redistribution and the failure mode of the second defense line. Simultaneously, the influence of the column failure time on the dynamic response of the remaining structure and the dynamic amplification coefficient is discussed. The results indicate that the residual bearing capacity of the remaining structure following the bottom corner column removal is higher than that of the one following the side or edge middle column removal, while the latter has a stronger plastic deformation capacity. When the ALP method is adopted to operate the progressive collapse analysis, it is reasonable to take the column failure time as 0.1 times the period of the first-order vertical vibration mode of the remaining structure, and it is suitable to set the dynamic amplification coefficient as 2.0, which is the ratio of the maximum dynamic displacement to the static displacement of the remaining structure under the transient loading condition.

Seismic performance and collapse analysis of RC framed-wall structure excited with Turkey/Syria destructive earthquake

Due to the increasingly serious threat of natural disasters, it is crucial to examine the ability of buildings to withstand such catastrophes. The damaged structures observed in the recent Turkey/Syria destructive earthquake on February 6th, 2023, attracted the attention of experts and stirred controversy regarding the main causes of this extensive damage. Since numerical simulation is widely utilized as a powerful tool to investigate the buildings’ seismic response, an efficient simulation procedure is presented to investigate the structural response and capture the damage induced in RC framed-wall structure excited by the Turkey/Syria earthquake and aims to present valuable remarks to avoid or even mitigate the damage that may occur in future events. Moreover, the ground motion vertical component is typically neglected in structural design/analysis, and the recent seismic codes did not consider it adequately, leading to a lack of general understanding of the structural response and threatening the structures’ safety. However, the results revealed that considering vertical components substantially impacts the structural response where significant amplification is recorded. A comprehensive comparison between the two cases (excitation with HL component and combined HL and VL components), when the building is excited with two records of this event, is presented in terms of displacement time history, inter-story drift, and straining actions. For instance, the amplification index AISR for the shear forces ranges between 13% to 387% and 35% to 47% for the axial compression force at the first record and ranges between 13% to 62% for the shear forces and 12% to 50% for the axial compression force at the second record. Furthermore, the collapse analysis is performed to explore the structural collapse pattern under this earthquake, which affects the adjacent road network resilience and evacuation plans. This study is crucial for implementing effective risk mitigation measures, enhancing the buildings’ resilience, and is of great importance for the performance-based design concept since damage anticipation and domination are the main objectives of this design concept.

Correction: Comparative Analysis of Code-Based Dynamic Column Removal and Impact-Induced Progressive Collapse in Steel Moment-Resisting Frames

Correction: Comparative Analysis of Code-Based Dynamic Column Removal and Impact-Induced Progressive Collapse in Steel Moment-Resisting Frames

Reconstruction coefficient analysis of honeybee collapse due to pesticide contamination

In this paper we consider the inverse problems of identifying space-dependent coefficients of the mortality rate of the bees and the rate of contamination of the forager bees by pesticides. The model is described by a weakly coupled system of two reaction-diffusion equations for the spatial distribution of uncontaminated and contaminated foraging bees. Final time t = T observations of the density of uncontaminant and contaminant forager bees are used. We propose two approaches for studying the problems. The first one uses the overspecified information to transform the problems into non-linear parabolic equations involving the solution values at the final time. This allows us to prove, using fixed-point arguments, existence of solution to the inverse problems. The second study employs the concept of the quasi-solution to establish existence of solution to the inverse problems as minimizers of least-square cost functionals.

A simplified method for the dynamic analysis of structures under column loss

The progressive collapse of buildings as a dynamic phenomenon can be fully understood only within a transient dynamic analysis context considering for damping and inertia effects. The response of a typical beam-column substructure is usually dominated by a single mode of deformation, thus the single-degree-of-freedom (SDOF) modelling assumption provides an accurate representation of the problem. In this study, the dynamic response of an inelastic SDOF system with damping was investigated analytically. Closed form analytical equations of the model were derived that describe the complete dynamic response in the time domain. Moreover, simplified formulae to estimate peak responses and Dynamic Increase Factors (DIFs) were provided. Numerical dynamic analyses in OpenSees were performed to verify the accuracy of the analytical model. The results indicate that the analytical model can trace the full dynamic response accurately while peak displacements can be accurately estimated with the proposed formulas. The estimated DIFs were in agreement with available from the literature results and demonstrate the significant effect of damping and hardening. Application of the analytical methodology on the progressive collapse analysis of a 10-storey steel frame demonstrated the effectiveness and potential of the proposed SDOF system.

Progressive collapse analysis and retrofit of a steel-RC building considering catenary effect

Despite their low probability of occurrence, the consequences of abnormal loads may be very important, both in economic terms and in terms of human lives. This has stimulated the development of strengthening and retrofitting techniques to mitigate the risk of progressive collapse of buildings. However, their application to real-scale buildings is still lacking. This paper describes the progressive collapse analysis and retrofit of a steel-reinforced concrete hospital building. The progressive collapse performance under different column removal scenarios is investigated using both nonlinear static and dynamic analyses. A two-step pushdown analysis procedure is developed to estimate the dynamic amplification factor (DIF) to partially compensate for the dynamic effects. The results have revealed the vulnerability of the building due to the low tensile axial resistance of the beam-to-column connections. Both the hypothesis of DIF = 2 and the almost inversely proportional relationship between DIF and vertical deflection have proven to be ineffective due to the catenary effect. A retrofit solution is proposed based on an outrigger-belt truss system on the rooftop level. The results show the effectiveness of the retrofit strategy. The displacement dynamic response of the retrofitted structure is significantly reduced if compared to the original structure since it goes from about 20 cm to less than 1 cm. However, the tensile strength of column-to-column connections of the top three floors is inadequate and should be increased. To this aim, a strengthening intervention is developed to increase the tensile strength from 565 kN to 965 kN, thus allowing the tensile axial forces caused by the column removed to be resisted.

A pharmacogenetic study of perampanel: association between rare variants of glutamate receptor genes and outcomes

Introduction: The selection of antiseizure medication usually requires a trial-and-error process. Our goal is to investigate whether genetic markers can predict the outcome of perampanel (PER) use in patients with epilepsy.Method: The studied participants were selected from our previous epilepsy genetics studies where whole exome sequencing was available. We reviewed the medical records of epilepsy patients older than 20 years old treated with PER. The outcome of PER treatment included the response to PER, the occurrence of any adverse drug reaction (ADR), the presence of behavior ADR, and the ability to adhere to PER for more than 1 year. We investigated the association between the rare variants of the glutamate receptor genes and the outcomes of PER use.Result: A total of 83 patients were collected. The gene group burden analysis showed that enriched genetic variants of the glutamate receptor gene group were statistically significantly associated with the occurrence of ADR, while the glutamate ionotropic receptor delta type subunit had a nominal association with the occurrence of ADR. The gene collapse analysis found that GRID1 had a nominal association with the occurrence of ADR and GRIN3A had a nominal association with the occurrence of behavior ADR. However, these nominal associations did not remain statistically significant once adjusted for multiple testing.Discussion: We found that enriched rare genetic variants of the glutamate receptor genes were associated with the occurrence of ADR in patients taking PER. In the future, combining the results of various pharmacogenetic studies may lead to the development of prediction tools for the outcome of antiseizure medications.

Cold-formed steel strength predictions for torsion and bending–torsion interaction

Locally slender cross-section members, such as cold-formed steel open sections, are susceptible to significant twisting and high warping torsion stresses. Torsion considerations are complicated by whether it is derived as a first-order effect from loading or a second-order effect from instability. Previous direct torsion experiments on lipped Cee sections have shown significant inelastic reserve. Furthermore, the current design for combined bending–torsion interaction has limitations, including only considering the first yield and ignoring the cross-section slenderness in torsion. Two parametric studies were conducted to predict both the torsion capacity and the combined bending–torsion interaction in locally slender cross-sections. Shell finite element analysis of lipped Cee and Zee sections for both the torsion only and the combined bending–torsion cases were created using a validated model. For the torsion-only study, various cross-section geometries, steel grades, and member lengths covering the range of practically expected torsional slenderness were investigated. A set of bimoment parameters, including yield, buckling, and plastic bimoments, were calculated and the ultimate bimoment was determined by shell finite element collapse analyses. A simple uniform equation predicting the bimoment capacity was adopted and two bimoment strength curves are proposed for local and distortional buckling-controlled cases respectively. For the combined bending–torsion case, various practical cross-sections and bracing conditions were investigated with various ratios of applied torsion and bending. Shell finite element buckling and collapse analyses were performed to determine the critical and ultimate moments and bimoments. It was found that the current AISI standard is conservative under most scenarios. Updated torsion–bending interaction equations incorporating bimoment and bending moments are proposed. The interaction equations are dependent on the cross-section, the direction of the applied torsion, and the bracing condition.

Back analysis of a building collapse under snow and rain loads in a Mediterranean area

Abstract. At the end of February 2018 the Mediterranean area of Montpellier in France was struck by a significant snowfall that turned into an intense rain event caused by an exceptional atmospheric situation. This rain-on-snow event produced pronounced damage to many buildings of different types. In this study, we report a detailed back analysis of the roof collapse of a large building, namely Irstea Cévennes. Attention is paid to the dynamics of the climatic event, on the one hand, and the mechanical response of the metal roof structure to different snow and rain loads, on the other hand. The former aspect relies on multiple sources of information that provide reliable estimates of snow heights in the area before the rain came into play and substantially modified the load on the roof. The latter aspect relies on detailed finite-element simulations of the mechanical behavior of the roof structure in order to assess the pressure due to snow and rain loading, which could theoretically lead to failure. By combining the two approaches, it is possible to reconstruct the most probable scenario for the roof failure before its full collapse. As an example of building behavior and vulnerability to an atypical rain-on-snow event in the Mediterranean area of France, this detailed case study provides useful key points to be considered in the future for a better mitigation of such events in non-mountainous areas.

Metagenomic analysis of ecological niche overlap and community collapse in microbiome dynamics.

Species utilizing the same resources often fail to coexist for extended periods of time. Such competitive exclusion mechanisms potentially underly microbiome dynamics, causing breakdowns of communities composed of species with similar genetic backgrounds of resource utilization. Although genes responsible for competitive exclusion among a small number of species have been investigated in pioneering studies, it remains a major challenge to integrate genomics and ecology for understanding stable coexistence in species-rich communities. Here, we examine whether community-scale analyses of functional gene redundancy can provide a useful platform for interpreting and predicting collapse of bacterial communities. Through 110-day time-series of experimental microbiome dynamics, we analyzed the metagenome-assembled genomes of co-occurring bacterial species. We then inferred ecological niche space based on the multivariate analysis of the genome compositions. The analysis allowed us to evaluate potential shifts in the level of niche overlap between species through time. We hypothesized that community-scale pressure of competitive exclusion could be evaluated by quantifying overlap of genetically determined resource-use profiles (metabolic pathway profiles) among coexisting species. We found that the degree of community compositional changes observed in the experimental microbiome was correlated with the magnitude of gene-repertoire overlaps among bacterial species, although the causation between the two variables deserves future extensive research. The metagenome-based analysis of genetic potential for competitive exclusion will help us forecast major events in microbiome dynamics such as sudden community collapse (i.e., dysbiosis).

Pragmatic seismic collapse meso‐scale analysis of old Dutch masonry churches

AbstractThe demand for advanced nonlinear time‐history and seismic collapse simulations of old unreinforced masonry (URM) constructions to support informed risk evaluation and mitigation plans is rapidly increasing in the structural engineering profession. On one hand, offering cutting‐edge solutions based on the latest advances is challenging for practitioners, given the reduced timeframe usually available for projects and the specialized knowledge required. On the other hand, researchers frequently face difficulties in accessing old buildings and gathering key data required in complex numerical collapse analysis strategies. In this work, a pragmatic approach for evaluation of the earthquake collapse response of vulnerable old URM churches typical of the Northern Netherlands, now exposed to low‐magnitude induced seismicity due to gas extraction, is presented. To bridge the gap between academic and industry applications, an integrated framework is proposed that combines archival and onsite research, code‐based prescriptions, geometrical characterization and simplified discrete element modeling. Main outcomes include the identification of recurrent damage patterns for five old URM churches erected during the 11th, 13th, 14th, and 19th centuries, representative of key traditional multi‐leaf and cavity‐wall structural types, as well as relevant failure mechanisms and collapsed debris distributions for seismic signals of varying intensities. Produced results constitute a solid foundation of data on which to base the design of ad‐hoc retrofits and development of tailored risk assessment models. This study opens a new line of inquiry while discussing practical challenges and research questions which arose, to be of interest to both applied researchers and structural engineering professionals.

Simplified numerical model for the collapse analysis of RC frame under oblique impact

The objective of this study is to develop a simplified numerical model that can be used to accurately and quickly conduct collapse analysis of a reinforced concrete (RC) frame impacted by a vehicle obliquely at 45°. The simplified numerical model included introduces a simplified RC frame and a simplified vehicle. For the simplified RC frame, a mixed modelling technique was used, in which structural components that experienced serious damage were simulated using detailed elements, while the retained structural components were simulated by larger elements. A constraint algorithm of nodal rigid body in LS-DYNA was adopted to guarantee the displacement compatibility of two kinds of element. For the simplified vehicle model, the spring–mass system was improved on the basis of the energy conservation principle to represent the vehicle in a 45° impact. Combining the simplified RC frame model and vehicle model, the impact response of an RC frame subjected to vehicle impact was studied and compared with the results of a detailed RC frame model impacted by a detailed vehicle. The validation confirmed that these introduced simplifications could significantly improve the computational efficiency and ensure the computational accuracy for the collapse analysis of an RC frame subjected to vehicle impact.

Comparative Analysis of Code-Based Dynamic Column Removal and Impact-Induced Progressive Collapse in Steel Moment-Resisting Frames

Comparative Analysis of Code-Based Dynamic Column Removal and Impact-Induced Progressive Collapse in Steel Moment-Resisting Frames

Comparison of risk-based robustness indices in progressive collapse analysis of building structures

A current challenge in Structural Engineering is the identification of a robustness index for the design of structures subject to low-probability high-consequence load events. Robustness indices proposed in the literature have not been subject to comprehensive scrutiny. Few comparisons presented so far have been limited to simple academic examples involving idealized systems, which cannot suggest robustness values for practical design. In this paper a comprehensive evaluation of two risk-based robustness indices is presented, addressing progressive collapse of regular frame structures subject to damage by abnormal loads. Herein frames of different aspect ratios are considered, subject to local damage of different size, in hazard-independent and hazard-dependent (blast loading) scenarios. System damage states include plastic bending failure of beams, as well as local and global column crushing. Moreover, robustness indices are compared for structures conventionally designed, for structures strengthened following the codified Alternate Path Method (APM), and for structures resulting from risk-based optimization, for different hazard probability levels. Results suggest that the robustness index of Baker, Schubert and Faber performs better when comparing conventional to APM-strengthened codified designs. The Praxedes, Yuan and He robustness index is less sensitive but appears to be more appropriate to describe structures resulting from risk-based optimization.

Discrete element analysis of dynamic characteristics and earthquake collapse of solid structure ancient masonry pagoda

In order to investigate the seismic damage and collapse mechanism of ancient masonry pagodas, a numerical model of the Tang Dynasty masonry pagoda (Xuanzang Pagoda) located at Xingjiao Temple was established using the discrete element software 3DEC, and non-linear mechanical parameters of the contact surfaces between rigid blocks were defined. Dynamic characteristics were analyzed, and the seismic response of the ancient pagoda was calculated by inputting El-Centro waves, Tianjin waves, and Lanzhou artificial waves with different intensities in three directions. The study analyzed the damage failure process of the pagoda, identified vulnerable areas, and obtained its collapse.The results show that the ancient pagoda behaves as an elastic–plastic system at intensity 7 degree seismic action. The acceleration response of the floors increases along the height, and the displacement angle between floors appears as an inflection point at the second floor. The middle floors are especially vulnerable to damage due to low cohesion and strong movements of the internal soil fill. As the intensity increases, significant damage occurs, with rapid floor displacement response and upward extension of cracks. The top floor of the ancient pagoda collapses first with stair-shaped oblique cracks, followed by a floor-by-floor destruction from top to bottom. The collapse of floors with different hole locations also vary. These findings provide valuable insights for predicting the vulnerable areas and collapse of Xuanzang Pagoda under seismic action.