The equilibrium of spherical domes is a fundamental topic in structural engineering, particularly for masonry structures, where the material’s inability to resist tension influences the force distribution. This study proposes an integral formulation for the equilibrium of a spherical dome, incorporating normal stresses and shear stresses, explicitly considering their spatial variations. The formulation extends classical membrane and bending theories by integrating the effects of stress gradients and torsional moments, providing a more detailed understanding of force equilibrium. The proposed approach aligns with and extends the concept of thrust surfaces, as discussed by Sajtos et al. (2020), introducing a framework that accommodates general force distributions and possible cracking patterns. The results suggest that the inclusion of moment equilibrium considerations leads to a more precise determination of the structural safety of cracked domes. This study contributes to the ongoing research on the stability and failure mechanisms of domes by offering a more comprehensive analytical framework.
Abstract The equilibrium of spherical domes is a fundamental topic in structural engineering, particularly for masonry structures, where the material’s inability to resist tension [...]
This paper addresses the concept of structural robustness in buildings, particularly focusing on progressive collapse, a phenomenon where localized damage leads to widespread structural failure. Resilient buildings are designed to maintain adequate performance during unexpected extraordinary events, such as explosions, impacts, or earthquakes, yet defining "adequate" performance remains complex. Design codes often refer to the "proportion" between accidental events and their consequences, highlighting the need for a deeper understanding of progressive collapse. This collapse occurs through a series of failures in structural elements, such as beams and columns, which trigger a dynamic load redistribution and result in a catastrophic domino effect. Examples of progressive collapse, such as the Ronan Point Building collapse in 1968 and the World Trade Center collapse in 2001, have driven research and regulatory efforts in this field.
While strengthening all structural elements could improve a building's damage tolerance, this approach is costly. Alternative strategies, such as redundancy and compartmentalization, are commonly used, but their effectiveness is still debated. Similarly, although anti-seismic design enhances progressive collapse resistance, it does not represent the optimal strategy for maximizing resistance. This study emphasizes the limitations of current design codes and the need for improved analytical models of progressive collapse.
The paper introduces a new simulation method based on the Discrete Element Method (DEM) to conduct large-scale parametric studies. This approach is used to identify collapse mechanisms and develop kinematic models to analyze and generalize simulation results. By extending the P-Δ method to both intact and damaged structures, simplified formulas are derived for calculating collapse loads and progressive collapse resistance. The methodology is applied to investigate the progressive collapse of 2D reinforced concrete frames subjected to the sudden removal of beams and columns. The findings highlight the importance of designing structures that can redistribute and dissipate loads, utilizing the ductility of components to avoid fragile failure behavior.
Robustness Interpretation of Intact and Damaged Framed Structures
EUR ING Alessandro Calvi
Abstract This paper addresses the concept of structural robustness in buildings, particularly focusing on progressive collapse, a phenomenon where localized damage leads to widespread [...]
This paper deals with the issue of structural collapse considering an analogy between ductilebrittle transition of materials, taking into account the current literature which also considers the number of fragility and the stress intensification factor in the presence of crack, with extension on a larger scale involving framed structures subjected to increasing vertical loads. It is evaluated the ductile-fragile transition in relation to concrete frames with different structural hierarchy (2x2, 5x5, 11x11).
Abstract This paper deals with the issue of structural collapse considering an analogy between ductilebrittle transition of materials, taking into account the current literature which [...]
Hydropower plant future production estimation is based on hydrological-hydraulic data. The present metholodogy validates the median as the reference parameter to be used for a better interpretation of statistical series, because it is a centered value where duration curves and their complementary curves intersect. Then, it is not affected by extreme events, providing a well representation of the whole dataset.
Abstract Hydropower plant future production estimation is based on hydrological-hydraulic data. The present metholodogy validates the median as the reference parameter to be used for [...]
The Himalayan region, characterized by complex geological formations and high tectonic activity, presents significant challenges for tunnel construction. This paper examines geomechanical issues such as tunnel squeezing, stress-induced instability, and rock bursting, with a focus on hydropower and railway tunnel projects in Nepal and India. Case studies, including the Chameliya Hydroelectric Project, Parbati II Hydroelectric Project, Nilgirikhola Hydroelectric Project, and railway tunnels in the Garhwal Himalaya, highlight the impact of weak, schistose rock masses and extreme overburden pressures. Various engineering methodologies, including empirical, semianalytical, analytical, and numerical modeling approaches, are discussed to assess stress states and deformation behavior. The study underscores the need for adaptive excavation techniques, such as the New Austrian Tunneling Method (NATM) and rock mass classification systems, to ensure tunnel stability. By integrating probabilistic analysis and advanced support systems, this research contributes to optimizing underground construction strategies in geologically challenging terrains.
Abstract The Himalayan region, characterized by complex geological formations and high tectonic activity, presents significant challenges for tunnel construction. This paper examines [...]
Tunnel collapse is a critical issue in geotechnical engineering, affecting the safety, functionality, and economic viability of underground structures. This study examines the primary failure mechanisms of tunnels, including roof instability, shear failure of sidewalls, base heave, wedge failure, and progressive collapse, with a particular focus on hydropower tunnels. The role of principal stress directions and stress redistribution in failure processes is analyzed, highlighting the effects of excavation-induced unloading, in situ stress concentration, and external influences such as groundwater infiltration and seismic activity. Special attention is given to hydropower tunnels, where transient hydrostatic pressure variations, mineralogical degradation, and high in situ stresses increase the likelihood of collapse. The study integrates limit analysis and fracture mechanics to model tunnel failure mechanisms, emphasizing how plastic deformation and crack propagation contribute to instability. Numerical simulations and real-world case studies illustrate the interaction between stress conditions and structural response. The findings suggest that tunnel stability is rarely governed by a single factor but rather by a combination of geological, structural, and environmental influences that evolve over time. Future research should focus on the development of real-time monitoring systems using artificial
Abstract Tunnel collapse is a critical issue in geotechnical engineering, affecting the safety, functionality, and economic viability of underground structures. This study examines [...]
In this paper, a number of innovative technologies are presented that have the potential to improve the efficiency and utilization of hydropower. These technologies include new turbine designs, improved efficiency, small hydro.
Abstract In this paper, a number of innovative technologies are presented that have the potential to improve the efficiency and utilization of hydropower. These technologies include [...]
Collection of Energy Science & Engineering (2024).
Abstract
In this paper, a number of innovative technologies are presented that have the potential to improve the efficiency and utilization of
hydropower. These technologies include new turbine designs, improved efficiency, small hydro.
Abstract In this paper, a number of innovative technologies are presented that have the potential to improve the efficiency and utilization of
hydropower. These technologies include [...]
Dam Engineering Conference Proceedings 
Advanced Equilibrium Analysis of Spherical Masonry Domes: An Integral Formulation 
