Investigation of the structural response through simple numerical models derived automatically from LiDAR scanning: The case of masonry vaults in historical buildings

2020 ◽  
pp. 610-616
Author(s):  
G. Angjeliu ◽  
G. Cardani
Keyword(s):  
Numerical Models ◽  
Structural Response ◽  
Historical Buildings ◽  
Masonry Vaults

scholarly journals Research on Hydroelastic Response of an FMRC Hexagon Enclosed Platform

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1110
Author(s):  
Wei-Qin Liu ◽  
Luo-Nan Xiong ◽  
Guo-Wei Zhang ◽  
Meng Yang ◽  
Wei-Guo Wu ◽  
...  
Keyword(s):  
Time Domain ◽  
Numerical Models ◽  
Structural Response ◽  
Deep Ocean ◽  
Surface Model ◽  
Large Area ◽  
Floating Structure ◽  
Small Depth ◽  
Response Amplitude Operators ◽  
Hydroelastic Response

The numerical hydroelastic method is used to study the structural response of a hexagon enclosed platform (HEP) of flexible module rigid connector (FMRC) structure that can provide life accommodation, ship berthing and marine supply for ships sailing in the deep ocean. Six trapezoidal floating structures constitute the HEP structure so that it is a symmetrical very large floating structure (VLFS). The HEP has the characteristics of large area and small depth, so its hydroelastic response is significant. Therefore, this paper studies the structural responses of a hexagon enclosed platform of FMRC structure in waves by means of a 3D potential-flow hydroelastic method based on modal superposition. Numerical models, including the hydrodynamic model, wet surface model and finite element method (FEM) model, are established, a rigid connection is simulated by many-point-contraction (MPC) and the number of wave cases is determined. The load and structural response of HEP are obtained and analyzed in all wave cases, and frequency-domain hydroelastic calculation and time-domain hydroelastic calculation are carried out. After obtaining a number of response amplitude operators (RAOs) for stress and time-domain stress histories, the mechanism of the HEP structure is compared and analyzed. This study is used to guide engineering design for enclosed-type ocean platforms.

scholarly journals Performance of a bridge deck as solar collector in a thermal energy storage system

2020 ◽  
Vol 205 ◽  
pp. 07009
Author(s):  
Di Wu ◽  
Gangqiang Kong ◽  
Hanlong Liu ◽  
Xi Zhu ◽  
Hefu Pu
Keyword(s):  
Wind Speed ◽  
Solar Energy ◽  
Solar Collector ◽  
Bridge Deck ◽  
Collection Efficiency ◽  
Numerical Models ◽  
Storage System ◽  
Structural Response ◽  
Radiation Energy ◽  
Heat Element

Solar energy can be stored in subsurface and extracted to melt snow and deice in winter. In summer, the bridge deck heat element in a bridge deicing system could serve as a solar energy collector without additional cost. Numerical models were developed in this study to investigate the performance of a bridge deck solar collector. The effects of radiation intensity and wind speed on the solar energy collection efficiency of a bridge deck solar energy collector were discussed and analyzed. The results show that the temperature of the slab was decreased during the solar collection process, and the solar energy collection efficiency of the bridge deck solar collector was about 26~47%. The collection efficiency of solar energy at a given wind speed was increased with the decreasing of the radiation energy, and this effect was more pronounced when the wind speed was higher. The solar energy collection was beneficial to the durability of the top asphalt layer as well as the structural response of the bridge because the magnitude and gradient of the slab temperature were much lower when the bridge deck served as a solar energy collector.

Modelling the response of structure-tuned liquid damper systems under large amplitude excitation using SPH

2021 ◽  
pp. 1-31
Author(s):  
Kevin P. McNamara ◽  
Michael J. Tait
Keyword(s):  
Experimental Data ◽  
Large Amplitude ◽  
Numerical Models ◽  
Model Performance ◽  
Structural Response ◽  
System Response ◽  
Tuned Liquid Damper ◽  
Tall Structures ◽  
Incompressible Sph ◽  
Lower Excitation

Abstract The tuned liquid damper (TLD) is a system used to reduce the response of tall structures. Numerical modelling is a very important tool when designing TLDs. Many existing numerical models are capable of accurately capturing the structure-TLD system response at serviceability levels, covering the range where TLDs are primarily intended to perform. However, these models often have convergence issues when considering more extreme structural excitations. The goal of this study is to develop a structure-TLD model without convergence limitations at large amplitude excitations. A structure-TLD numerical model where the TLD is represented by a 2D incompressible SPH scheme is presented. The TLD contains damping screens which are represented by a force term based on the Morison equation. The performance of the model is assessed by comparing to experimental data for a structure-TLD system undergoing large amplitude excitations consisting of four-hour random signals and shorter transient signals. The model shows very good agreement with the experimental data for the structural response. The free surface response of the TLD is captured accurately by the model for the lower excitation forces considered, however as the excitation force is increased there are some discrepancies. The large amplitude excitations also result in SPH fluid particles penetrating the boundaries, resulting in degradation of the model performance over the four-hour simulations. Overall, the model is shown to capture the response of a structure-TLD system undergoing large amplitude excitations well.

Damage Assessment of a Building Subjected to a Terrorist Attack

2014 ◽  
Vol 17 (11) ◽  
pp. 1693-1704 ◽  
Author(s):  
E.L. Eskew ◽  
S. Jang
Keyword(s):  
Damage Detection ◽  
Damage Assessment ◽  
Structural Damage ◽  
Numerical Models ◽  
Terrorist Attack ◽  
Structural Response ◽  
Structural Condition ◽  
Condition Assessment ◽  
Detection Methods ◽  
Specific Element

An increasing threat of global terrorism has led to concerns about bombings of buildings, which could cause minor to severe structural damage. After such an event, it is important to rapidly assess the damage to the building to ensure safe and efficient emergency response. Current methods of visual inspection and non-destructive testing are expensive, subjective, and time consuming for emergency responders' usage immediately after an attack. On the other hand, vibration-based damage detection methods with wireless smart sensors could provide rapid assessment of structural characteristics with low cost. For blast analysis, structural response is usually determined using a simplified SDOF version of the undamaged structure, such as used in a Pressure-Impulse (P-I) Diagram, or using more complex FEM (finite element method) models. However, the simplified models cannot take into account damage caused by blast focus at a specific location or on a specific element, which may induce local failure leading to potential progressive collapse, and the more complex FEM models take too long to derive applicable results to be effective for a rapid structural assessment. In this paper, a new method to incorporate vibration-based damage detection methods to calculate the multi degree of freedom structural stiffness for determining structural condition is provided to create a framework for the rapid structural condition assessment of buildings after a terrorist attack. The stiffness parameters are generated from the modal analysis of the measured vibration on the building, which are then used in a numerical simulation to determine its structural response from the blast. The calculated structural response is then compared to limit conditions that have been developed from ASCE blast design codes to determine the damage assessment. A laboratory-scale building frame has been employed to validate the developed use of experimentally determined stiffness by comparing the P-I diagram using the experimental stiffness with that from numerical models. The reasonable match between the P-I diagrams from the numerical models and the experiments shows the positive potential of the method. The framework and examples of how to develop a rapid condition assessment are presented.

Experimental Determination of the Static Equivalent Pressures of Gas Phase Detonations in Pipes and Comparison With Numerical Models

2013 ◽  
Author(s):  
Hans-Peter Schildberg ◽  
Jan P. M. Smeulers ◽  
Gersom Pape
Keyword(s):  
Gas Phase ◽  
Numerical Models ◽  
Pressure Ratio ◽  
Structural Response ◽  
Propagation Speed ◽  
Time Profile ◽  
Design Guidelines ◽  
Outer Diameter ◽  
Detonation Pressure ◽  
Auto Ignition

In order to determine the effective load of gas phase detonations on pipe walls (“static equivalent pressure”), comprehensive experiments have been conducted in 48.3×2.6 and 114.3×3.6 pipes (outer diameter [mm] × wall thickness [mm]), in which deflagrative explosions of stoichiometric C2H4/O2/N2-mixtures at 20 °C underwent the transition to detonation. Initial pressures were chosen high enough to produce detonation pressures that caused significant bulging of the pipe walls. All 8 different pressure scenarios that can be distinguished for gas phase detonations in pipes were addressed by the experiments, even the extremely rare case of having the deflagration to detonation transition occurring within about 1 pipe diameter a head of blind flange which yields the largest static equivalent pressure of all scenarios. By these tests it was possible to (1) validate the predictions of recently developed numerical models for predicting the structural response of the pipe wall and to (2) determine the static equivalent pressure of gas phase detonations in pipes even for those detonative pressure scenarios for which a reliable pressure/space/time profile required as input for the numerical models is at present not yet available. Once the static equivalent pressure is known, the well-established pressure vessel design guidelines, which can only cope with static loads, can be applied for detonation pressure proof pipe design in all those cases where the detonation speed is not close to the propagation speed of the flexural waves in the pipe. Furthermore, preliminary information was obtained about which of the 8 detonative pressure scenarios only depends on the Chapman-Jouguet pressure ratio of the involved mixture and which scenarios will also depend on other characteristic parameters of the involved mixture (difference between initial temperature and auto ignition temperature, ignition delay time).

scholarly journals Structural analisys of concrete pre-stressed reservoirs for sludge fermentation – water waste treatment plant bucharest – glina. numerical fem assessment of the structural response for static in-duty loads

2013 ◽  
Vol 9 (1) ◽  
pp. 42-58
Author(s):  
Tudor Bugnariu
Keyword(s):  
Waste Treatment ◽  
Numerical Models ◽  
Limit State ◽  
Treatment Plant ◽  
Structural Response ◽  
Soil Mass ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Waste Treatment Plant ◽  
Water Waste

Abstract The paper refers to a structural finite element analysis on the reservoirs for sludge fermentation subjected to static in-duty loads, at Glina Water Waste Treatment Plant. The purpose was to assess the stress and deformation states in subsequent erection and service conditions, to verify the design provisions and to emphasize the sensitivities, for a structure which was designed in the ‘80s based on analytical procedures. The results obtained on the numerical models highlight the importance of the soil-structure interaction, in peculiar the one influenced by the soil mass deformability, on the overall structural response. Based on the calculated stresses, all structural components were verified according to the actual design codes at the ultimate limit state and the service limit state (water tightness/crack emergence).

Pounding between Inelastic Three-Storey Buildings under Seismic Excitations

2015 ◽  
Vol 665 ◽  
pp. 121-124 ◽  
Author(s):  
Robert Jankowski
Keyword(s):  
Numerical Analysis ◽  
Numerical Models ◽  
Ground Motions ◽  
Permanent Deformation ◽  
Structural Response ◽  
The Other ◽  
Lumped Mass ◽  
Seismic Excitations ◽  
Structural Interactions ◽  
Inelastic Behaviour

Structural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations. The discrete lumped-mass numerical models of two building have been used in the analysis. The results of the study indicate that the response of the lighter and more flexible inelastic building can be substantially influenced by structural interactions, and collisions may even lead to the permanent deformation of the structure. On the other hand, the behaviour of the heavier and stiffer building does not really change considerably during the earthquake. The results of the study also indicate that incorporation of the inelastic behaviour of colliding buildings with different dynamic characteristics is very important for the purposes of accurate numerical modelling of pounding-involved structural response under damaging seismic excitations.

scholarly journals Structural Response Estimation Using Gated Recurrent Unit

2021 ◽  
Vol 21 (3) ◽  
pp. 171-179
Author(s):  
Geonyeol Jeon ◽  
Jaehyung Park ◽  
Jongwon Jung ◽  
Hyungchul Yoon
Keyword(s):  
Model Updating ◽  
Numerical Models ◽  
Structural Response ◽  
Mean Square ◽  
Actual Structure ◽  
Current State ◽  
Simulation Based ◽  
Learning Technique ◽  
Validation Tests ◽  
Gated Recurrent Unit

Recent tragedies have demonstrated that natural disasters, such as earthquakes and typhoons, can wreak havoc on society. Numerical models and simulations are used for predicting the structural response and damage caused by disasters. However, some structures do not have any design drawings or numerical models, and thus, problems are encountered when conducting numerical simulations. Furthermore, even if the model exists, the response predicted through numerical simulation may be different from the response of the actual structure. Although effort has been made to resolve this issue using model-updating techniques, these methods are laborious for developing a new model that reflects the current state of the structure. Therefore, the aim of this study is to develop a new method that automatically predicts the time-series response of structures using a deep learning technique. The gated recurrent unit), based on the recurrent neural network, was used to predict the structural response. Simulation-based validation tests were conducted to verify the performance of the proposed method. The proposed method could estimate the response of the structure with a root-mean-square error of 13.59%.

scholarly journals On the statics of curved masonry structures via numerical models

2018 ◽  
Vol 2 (2) ◽  
pp. 181-188
Author(s):  
Valentino Paolo Berardi ◽  
Mariella De Piano
Keyword(s):  
Numerical Models ◽  
Static Problem ◽  
Variational Approximation ◽  
Content Type ◽  
Existing Structures ◽  
Tension And Compression ◽  
Definition Of ◽  
Masonry Vaults ◽  
Minimal Mass ◽  
Numerical Approaches

PurposeThis paper aims to review recent literature results on the equilibrium problem and the strengthening design of masonry vaults. Design/methodology/approachA Lumped Stress Method (LSM) is considered within the Heyman’s safe theorem, based on the definition of thrust surface of a masonry curved structure. In particular, the static problem of the vault is formulated by introducing a membrane continuous of the studied masonry structure to associate with a spatial truss through a nonconforming variational approximation of the thrust surface and membrane stress potential. A tensegrity approach based on a minimal mass design strategy, different strengths in tension and compression of the material is discussed within the strengthening strategy of masonry vaults. FindingsThe numerical results have highlighted the efficacy of the two numerical approaches to assess the vulnerability of existing structures and design optimal strengthening interventions of these structures. Originality/valueThe presented models can represent fast and useful tools to assess the vulnerability of existing structures and design optimal strengthening interventions with composite materials of these structures.

scholarly journals Assessing the Main Frequencies of Modern and Historical Buildings Using Ambient Noise Recordings: Case Studies in the Historical Cities of Crete (Greece)

Heritage ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 171-188 ◽  
Author(s):  
Margarita Moisidi ◽  
Filippos Vallianatos ◽  
Maria Rosaria Gallipoli
Keyword(s):  
Ambient Noise ◽  
Structural Response ◽  
Risk Assessments ◽  
Earthquake Risk ◽  
Historical Buildings ◽  
Earthquake Disaster ◽  
Local Site ◽  
Resonance Phenomena ◽  
Operational Decision Making ◽  
Planning Development

Monitoring seismic structural response is an essential issue in earthquake risk assessments and mitigation studies for monumental buildings in order to undertake earthquake disaster management. This study aims at identifying the resonant frequency of soil and modern and historical buildings in three major municipalities of Crete (Heraklion, Chania, and Rethymno) using ambient noise recordings (microtremors) considering the importance of soil–structure interaction to seismic structural response, particularly for historical buildings and monumental structures. In this study, ambient noise recordings have been processed through Horizontal to Vertical Spectral Ratios (H/V) to preliminarily examine the main frequencies and to examine whether the building has its main frequency close to that of the soil in order to identify potential resonance phenomena. Numerous ambient noise recordings were recorded on the soil, in the basement, and at each n-floor of the buildings. The incorporation of local site conditions and soil-building resonance phenomena into the urban planning development of Crete regarding earthquake risk assessments is necessary. In this direction, microtremors can be used as an effective tool to support civil protection preparation and operational decision-making in terms of earthquake disaster, specifically in the area of Crete, which is characterized by high seismic activity and a high cultural monuments capacity.

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