The Vulnerability Assessment of Historical Masonry Buildings Against Earthquakes by the Modified Equivalent Frame Method

2010 ◽  
Vol 133-134 ◽  
pp. 735-740
Author(s):  
Faramarz Alemi ◽  
Peyman Homami ◽  
Mahmood Golabchi ◽  
Mohsen Akbarian

Insufficient ductility and lack of integrity have caused extensive damages and undesirable responses in masonry buildings in past earthquakes. These types of structures are distributed all over Iran and the vulnerability assessment of such structure is one of the main concerns between structural engineers. Developing an advance finite element model to simulate the behaviour of a masonry structure is a very complicated procedure which may not be practical and applicable in most cases, so many attempts have been performed to find simple methods for analysing these structures. The Equivalent Frame Method is one of the well-known methods which is rather simple and could be used for vulnerability assessment of some historical structures like Iranian caravanserais. The architectural configurations of Iranian caravanserais were regular and symmetric. When the arrangement of walls and openings are modular it is convenient to model the piers and spandrels as a frame type columns and beams. The simplicity of the conventional Equivalent Frame Method sometime leads to an inaccuracy of the assessment, therefore some modification for the upgrading of this method has been proposed. Using the shell elements beside the frame elements in a modelling procedure may eliminate some disadvantages of the conventional Equivalent Frame Method. In this study a modification has been proposed to improve the upgraded Equivalent Frame Method ability in predicting the failure modes of the masonry walls such as, toe crashing. The proposed modification has been used in the static nonlinear analysing of a masonry structure by the Equivalent Frame Method. The given results have acceptable reconciliation with practical reality and it seems to be useful, especially in a rapid assessments.

2021 ◽  
Author(s):  
C. Marano ◽  
M. Petracca ◽  
G. Camata ◽  
E. Spacone

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 205
Author(s):  
Igor Tomić ◽  
Francesco Vanin ◽  
Ivana Božulić ◽  
Katrin Beyer

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.


2014 ◽  
Vol 1008-1009 ◽  
pp. 1209-1212
Author(s):  
Wen Qi Niu ◽  
Wen Fang Zhang

Masonry structure, the number of large, wide area distribution, and earthquake damage survey, masonry structure severely damaged. In this paper, using the finite element tool ABAQUS, combined with an equivalent volume element simulation technology, the establishment of spatial finite element model to study the loading height of the brick wall failure modes and effects of seismic performance issues in depth analysis of its constant vertical pressure, different loading height seismic performance and failure modes under. The results show that: the greater the load height, the wall more prone to bending failure, otherwise prone to shear failure; loading height bigger, better ductility of the wall, the ultimate bearing capacity is smaller.


2021 ◽  
pp. 136943322110073
Author(s):  
Yu Cheng ◽  
Yuanlong Yang ◽  
Binyang Li ◽  
Jiepeng Liu

To investigate the seismic behavior of joint between special-shaped concrete-filled steel tubular (CFST) column and H-section steel beam, a pseudo-static test was carried out on five specimens with scale ratio of 1:2. The investigated factors include stiffening types of steel tube (multi-cell and tensile bar) and connection types (exterior diaphragm and vertical rib). The failure modes, hysteresis curves, skeleton curves, stress distribution, and joint shear deformation of specimens were analyzed to investigate the seismic behaviors of joints. The test results showed the connections of exterior diaphragm and vertical rib have good seismic behavior and can be identified as rigid joint in the frames with bracing system according to Eurocode 3. The joint of special-shaped column with tensile bars have better seismic performance by using through vertical rib connection. Furthermore, a finite element model was established and a parametric analysis with the finite element model was conducted to investigate the influences of following parameters on the joint stiffness: width-to-thickness ratio of column steel tube, beam-to-column linear stiffness ratio, vertical rib dimensions, and axial load ratio of column. Lastly, preliminary design suggestions were proposed.


2020 ◽  
Vol 4 (4) ◽  
pp. 182
Author(s):  
Luciano Ombres ◽  
Salvatore Verre

In the paper, the bond between a composite strengthening system consisting of steel textiles embedded into an inorganic matrix (steel reinforced grout, SRG) and the concrete substrate, is investigated. An experimental investigation was carried out on medium density SRG specimens; direct shear tests were conducted on 20 specimens to analyze the effect of the bond length, and the age of the composite strip on the SRG-to-concrete bond behavior. In particular, the tests were conducted considering five bond length (100, 200, 250, 330, and 450 mm), and the composite strip’s age 14th, 21st, and 28th day after the bonding. Test results in the form of peak load, failure modes and, bond-slip diagrams were presented and discussed. A finite element model developed through commercial software to replicate the behavior of SRG strips, is also proposed. The effectiveness of the proposed numerical model was validated by the comparison between its predictions and experimental results.


2014 ◽  
Vol 919-921 ◽  
pp. 401-405
Author(s):  
Zuo Yun Mei ◽  
Chuan Qing Liu ◽  
Xing Mi ◽  
Ping Wu

A new reinforcement measure with no-fire operation is presented, which is very suitable for space trusses which are located in gas stations. A finite element model (FEM) is presented with shell elements and multipoint constraint elements. With this FEM, nonlinear analyses are carried out. Analytical results show that integral failure of reinforced pipe is caused by yielding of original pipe inside. So it is not necessary to reinforce original pipe using steel pipe bonded outside with high yield strength. With the increase of length of bonded pipe outside, loading according to elastic stage and ultimate bearing loading increase, it is clear that the length of bonded pipe outside is an important factor which influences the bearing capacity.


2013 ◽  
Vol 554-557 ◽  
pp. 484-491 ◽  
Author(s):  
Alexander S. Petrov ◽  
James A. Sherwood ◽  
Konstantine A. Fetfatsidis ◽  
Cynthia J. Mitchell

A hybrid finite element discrete mesoscopic approach is used to model the forming of composite parts using a unidirectional glass prepreg non-crimp fabric (NCF). The tensile behavior of the fabric is represented using 1-D beam elements, and the shearing behavior is captured using 2-D shell elements into an ABAQUS/Explicit finite element model via a user-defined material subroutine. The forming of a hemisphere is simulated using a finite element model of the fabric, and the results are compared to a thermostamped part as a demonstration of the capabilities of the used methodology. Forming simulations using a double-dome geometry, which has been used in an international benchmarking program, were then performed with the validated finite element model to explore the ability of the unidirectional fabric to accommodate the presence of interlaminate cabling.


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