scholarly journals Equivalent frame modelling of an unreinforced masonry building with flexible diaphragms

2016 ◽  
Vol 49 (3) ◽  
pp. 234-244 ◽  
Author(s):  
Yasuto Nakamura ◽  
Hossein Derakhshan ◽  
Abdul H. Sheikh ◽  
Jason M. Ingham ◽  
Michael C. Griffith
Keyword(s):  
Global Analysis ◽  
Time History ◽  
Unreinforced Masonry ◽  
Dynamic Responses ◽  
Nonlinear Time History Analysis ◽  
Stone Masonry ◽  
Masonry Building ◽  
Flexible Diaphragms ◽  
Equivalent Frame ◽  
Modelling Approach

A case study was conducted to investigate the applicability of the equivalent frame modelling for the nonlinear time-history analysis of unreinforced masonry buildings with flexible diaphragms. The dynamic responses calculated from the equivalent frame models were compared against shake table test results of a full-scale two-storey stone masonry building. The investigated modelling approach reflected the simplifications commonly assumed for the global analysis of buildings; namely, considering the diaphragms to behave elastically and neglecting the stiffness and strength contributions of the out-of-plane responding walls. The sensitivity of the analysis to different idealisations of the equivalent frame, as well as to the diaphragm stiffness values, were also investigated. Discussions are provided on the accuracies and limitations of the investigated modelling approach, which may serve as a useful guidance for practical application.

Probabilistic Peak Displacement Analysis of Bridge Structures with P-Δ Effect

2013 ◽  
Vol 405-408 ◽  
pp. 1674-1677
Author(s):  
Bo Yu ◽  
Di Liu ◽  
Lu Feng Yang
Keyword(s):  
Time History ◽  
Dynamic Responses ◽  
Nonlinear Time History Analysis ◽  
Bridge Structure ◽  
Vibration Period ◽  
Peak Displacement ◽  
Sdof System ◽  
Bridge Structures ◽  
Performance Based Seismic Design ◽  
Nonlinear Time History

Peak displacement is one of the most important parameters for the performance based seismic design of bridge structure, while the peak displacement is often significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the statistics of peak displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single degree of freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the mean and dispersion of peak displacement of bridge structures, especially if the normalized yield strength and the natural vibration period are small.

Shaking Table Test of a Strengthened Full-Scale Stone Masonry Building with Flexible Diaphragms

2013 ◽  
Vol 8 (3) ◽  
pp. 349-375 ◽  
Author(s):  
Guido Magenes ◽  
Andrea Penna ◽  
Ilaria Enrica Senaldi ◽  
Maria Rota ◽  
Alessandro Galasco
Keyword(s):  
Shaking Table Test ◽  
Full Scale ◽  
Shaking Table ◽  
Stone Masonry ◽  
Masonry Building ◽  
Flexible Diaphragms

scholarly journals A comparative study on a complex URM building: part I—sensitivity of the seismic response to different modelling options in the equivalent frame models

2021 ◽  
Author(s):  
Daria Ottonelli ◽  
Carlo Filippo Manzini ◽  
Corrado Marano ◽  
Emilia Angela Cordasco ◽  
Serena Cattari
Keyword(s):  
Seismic Response ◽  
Dynamic Properties ◽  
Limit State ◽  
Central Italy ◽  
Structural Safety ◽  
Stone Masonry ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Maximum Acceleration ◽  
Equivalent Frame

AbstractThe paper presents the comparison of the results of nonlinear static analyses carried out using six software packages (SWs) available at professional level and operating in the field of the equivalent frame (EF) approach on a model representative of a complex masonry building. The structure is inspired by the school “P. Capuzi” in Visso (MC, Italy), proposed as one of the benchmark structures in the “URM nonlinear modelling—Benchmark project” funded by the Italian Department of Civil Protection within the context of the ReLUIS projects. The 2-stories building is characterized by an irregular T-shaped plan and load-bearing walls consisting of two-leaf stone masonry with a rather regular bond scheme. The school was severely damaged by the seismic sequence that hit Central Italy in 2016/2017 and essentially exhibited a global in-plane box-type response, with a clear evidence of cracks concentrated in piers and spandrels. The availability of an accurate survey of the crack extension represents a precious and rare reference to firstly address in the paper the rules to be adopted in the EF models for the definition of the structural elements geometry. Then, the comparison of results is made with a twofold aim: firstly, by setting the models adopting shared and consistent modelling assumptions across the SWs; secondly, by investigating the sensitivity of the seismic response to some common epistemic and modelling uncertainties (namely: the adoption of various EF idealization rules for walls, the out-of-plane contribution of piers, the flange effect). In both cases, results are post-processed to define reference values of the achievable dispersion. The comparison is carried out in relation to a wide set of parameters, namely: global parameters (e.g. dynamic properties, pushover curves and equivalent bilinear curves); synthetic parameters of the structural safety (i.e. the maximum acceleration compatible with the ultimate limit state); the damage pattern simulated by SWs.

scholarly journals Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 205
Author(s):  
Igor Tomić ◽  
Francesco Vanin ◽  
Ivana Božulić ◽  
Katrin Beyer
Keyword(s):  
Failure Modes ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Plane Failure ◽  
Friction Resistance ◽  
Flexible Diaphragms ◽  
Out Of Plane ◽  
Equivalent Frame

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexible diaphragms are most commonly timber floors made of planks and beams, which are supported on recesses in the masonry walls and can slide when the friction resistance is reached. Using equivalent frame models, we capture the effects of both the diaphragm stiffness and the finite strength of wall-to-diaphragm connections on the seismic behaviour of unreinforced masonry buildings. To do this, we use a newly developed macro-element able to simulate both in-plane and out-of-plane behaviour of the masonry walls and non-linear springs to simulate wall-to-wall and wall-to-diaphragm connections. As an unretrofitted case study, we model a building on a shake table, which developed large in-plane and out-of-plane displacements. We then simulate three retrofit interventions: Retrofitted diaphragms, connections, and diaphragms and connections. We show that strengthening the diaphragm alone is ineffective when the friction capacity of the wall-to-diaphragm connection is exceeded. This also means that modelling an unstrengthened wall-to-diaphragm connection as having infinite stiffness and strength leads to unrealistic box-type behaviour. This is particularly important if the equivalent frame model should capture both global in-plane and local out-of-plane failure modes.

Shake-Table Test of a Strengthened Stone Masonry Building Aggregate with Flexible Diaphragms

2019 ◽  
Vol 13 (7) ◽  
pp. 1078-1097 ◽  
Author(s):  
Gabriele Guerrini ◽  
Ilaria Senaldi ◽  
Francesco Graziotti ◽  
Guido Magenes ◽  
Katrin Beyer ◽  
...  
Keyword(s):  
Shake Table Test ◽  
Stone Masonry ◽  
Masonry Building ◽  
Shake Table ◽  
Flexible Diaphragms

Study on Earthquake Response Analysis of Reinforced Concrete Masonry Structure

2011 ◽  
Vol 295-297 ◽  
pp. 244-248 ◽  
Author(s):  
Hai Xu Yang ◽  
Tong Shen ◽  
Jian Gang Yao
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Time History ◽  
Concrete Block ◽  
Nonlinear Time History Analysis ◽  
Response Analysis ◽  
Elastic Model ◽  
Masonry Building ◽  
Analysis Model ◽  
Concrete Masonry

According to the analysis of a six-story reinforced concrete masonry building model with the methods of nonlinear time history analysis, the seismic performance of structure has been studied in this paper. The interstory shear-deformation and stiffness of linear elastic model is established. The availability of the analysis model, hysteretic model and relevant parameters adopted and the computation program developed are verified. The longitudinal deformation of structure is bigger than the lateral deformation under different earthquake waves, from this it can be showed that longitudinal seismic performance is smaller than lateral wall; for seven-story concrete block building with core-and tie-columns, the requirement of the seismic fortification intensity can be met. The analysis of this paper provides a reference for reinforced concrete block buildings.

Dynamic P-Δ Effect on Probabilistic Residual Displacement of Bridge Structures

2013 ◽  
Vol 405-408 ◽  
pp. 1678-1681
Author(s):  
Bo Yu ◽  
Di Liu ◽  
Lu Feng Yang
Keyword(s):  
Time History ◽  
Dynamic Responses ◽  
Nonlinear Time History Analysis ◽  
Stability Factor ◽  
Bridge Structure ◽  
Residual Displacement ◽  
Sdof System ◽  
History Analysis ◽  
Bridge Structures ◽  
Nonlinear Time History

Residual displacement has been identified as one of the most important parameter to assess the reparability and usability of bridge structures after strong earthquake, which is significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the probabilistic characteristics of residual displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single-degree-of-freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the residual displacement, especially for systems with large stability factor and/or small post-yield stiffness ratio and yield strength.

Study on Rational Ratios of Lateral Stiffness for Masonry Building with Frame Structure at First Two Stories

2012 ◽  
Vol 174-177 ◽  
pp. 2012-2015
Author(s):  
Xiao Long Zhou ◽  
Ying Min Li ◽  
Lin Bo Song ◽  
Qian Tan
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Shear Wall ◽  
Calculation Model ◽  
Frame Structure ◽  
Wall Structure ◽  
Masonry Building ◽  
Lateral Stiffness ◽  
Stiffness Ratio ◽  
Lateral Stiffness Ratio

There are two typical seismic damage characteristics to the masonry building with frame shear wall structure at first two stories, and the lateral stiffness ratio of the third storey to the second storey is one of the key factors mostly affecting the seismic performance of this kind of building. However, some factors are not considered sufficiently in current Chinese seismic codes. According to the theory of performance-based seismic design, the seismic performance of this kind of structure is analyzed in this paper by taking time-history analysis on models which with different storey stiffness ratios. The results show that when the lateral stiffness ratio controlled in a reasonable range, the upper masonry deformation can be ensured in a range of elastic roughly, and the bottom frame can be guaranteed to have sufficient deformation and energy dissipation capacity. Finally, according to the seismic performance characteristics of masonry building with frame shear wall structure at first two stories, especially the characteristics under strong earthquakes, a method of simplified calculation model for the upper masonry is discussed in this paper.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

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