Seismic Behaviour of Rocking Elements Reinforced with Composite Materials

2017 ◽  
Vol 747 ◽  
pp. 604-611
Author(s):  
Simona Coccia ◽  
Fabio di Carlo ◽  
Stefania Imperatore
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Dynamic Equation ◽  
Masonry Wall ◽  
Rigid Bodies ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Gfrp Bars ◽  
Out Of Plane ◽  
Vertical Walls

Seismic behaviour and vulnerability of existing masonry structures are typically characterized by out-of-plane response of vertical walls. The dynamic response of such elements can be analytically assessed considering the dynamic equation of rigid bodies not resistant to tensile stresses. Many studies available in literature have highlighted the vulnerability of this type of structures against out-of-plane movements. In order to withstand horizontal seismic actions, appropriate and effective retrofitting interventions have to be properly designed. In this paper, the rocking response of a masonry wall retrofitted with elastic GFRP bars is investigated. A parametric survey is also carried out, to evaluate the increase in strength of the masonry wall, due to the presence of the composite material.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Side Walls ◽  
Seismic Forces

Abstract The seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. An in-plane strengthening intervention is often needed on traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effect of un-stiffened and stiffened timber floors on the seismic behaviour of an existing listed masonry building is investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be followed in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is here applied in the DEM models of the masonry building. Different seismic ground accelerations, different floor types and different wall-to-diaphragm connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear resistant walls up to the shear-sliding collapse of the side walls of the structure. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipating part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for seismic resistant walls.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Seismic Forces

AbstractThe seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. A strengthening intervention is often needed for traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effects of unreinforced and reinforced timber floors on the seismic behaviour of an existing listed masonry building are investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be captured in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is applied herein to DEM models of the masonry building. Different seismic ground accelerations, different floor types and different floor-to-wall connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear-resistant walls up to the shear-sliding collapse of the structural sidewalls. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipate part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for shear-resistant walls.

Out-of-Plane Strengthening of Masonry Walls with FRCM Composite Materials

2017 ◽  
Vol 747 ◽  
pp. 158-165 ◽  
Author(s):  
Alessandro Bellini ◽  
Andrea Incerti ◽  
Claudio Mazzotti
Keyword(s):  
Composite Materials ◽  
Failure Modes ◽  
Theoretical Models ◽  
Masonry Wall ◽  
Image Correlation ◽  
Vertical Position ◽  
Masonry Walls ◽  
Out Of Plane ◽  
Set Up ◽  
Innovative Techniques

Structural strengthening by using composite materials proved to be one of the most suitable solutions for reinforcing masonry buildings. In this framework, the focus point of the presented experimental study is to evaluate the out-of-plane behaviour of masonry walls strengthened with Fiber Reinforced Cementitious Matrix (FRCM) composites when subjected to horizontal actions, by analyzing and discussing failure modes and their out-of-plane capacity. To this purpose, a new experimental set-up was developed, capable of applying an axial force and out-of-plane horizontal actions on full-scale masonry panels, placed in vertical position and subjected to a stress state similar to that present on a real masonry wall. Experimental results, obtained by using traditional and innovative techniques (such as Digital Image Correlation), will be compared with those coming from more conventional tensile and bond tests performed on FRCM coupons applied on masonry substrates, making use of simple theoretical models.

scholarly journals FEM-DEM Modeling for Out-of-plane Loaded Masonry Panels: A Limit Analysis Approach

2012 ◽  
Vol 6 (1) ◽  
pp. 231-238 ◽  
Author(s):  
Emanuele Reccia ◽  
Antonio Cazzani ◽  
Antonella Cecchi
Keyword(s):  
Discrete Element ◽  
Masonry Wall ◽  
Rigid Bodies ◽  
Masonry Walls ◽  
Lateral Loads ◽  
Kinematic Limit ◽  
Wall Panels ◽  
Out Of Plane ◽  
Coulomb Type ◽  
Historical Masonry

In this work the performances of the Discrete Element Method (DEM) applied to kinematic limit analyses of the out-of-plane behavior of masonry wall panels (with different textures) are investigated. A discrete model of masonry is proposed, which assumes that rigid blocks are connected by a mortar interface: this is ap-propriate for historical masonry, where mortar is much more deformable than blocks and joints thickness is negligible. Therefore blocks can be modeled as rigid bodies connected by zero thickness Mohr-Coulomb-type interfaces. The applied method is known as FEM/DEM, which combines finite and discrete element models. A comparison with well-known and meaningful examples presented by Giuffrè has been carried out in order to validate this method for studying the behavior of masonry. For this purpose, 2D DEM models reproducing walls sections have been considered: they reproduce masonry walls with different staggered blocks, in particular stack bond and running bond patterns, subjected to lateral loads.

scholarly journals Masonry Walls Retrofitted with Vertical FRP Rebars

Buildings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 72
Author(s):  
Simona Coccia ◽  
Fabio Di Carlo ◽  
Stefania Imperatore
Keyword(s):  
Ad Hoc ◽  
Masonry Wall ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Seismic Capacity ◽  
Seismic Behaviour ◽  
Safety Level ◽  
Dynamic Analyses ◽  
Out Of Plane ◽  
Vertical Bars

The out-of-plane behaviour of the walls as a consequence of an earthquake is the main vulnerability of existing masonry structures. In the case of rigid in compression not tensile resistant material, incremental dynamic analyses may be employed to evaluate the effective strength of a rocking element. When the seismic capacity of the wall is inadequate, retrofit interventions are required to assure an acceptable safety level. Conventional seismic retrofitting techniques on masonry walls influence the seismic performance of the element, which typically is modified in an out-of-plane bending behaviour. In this paper, analytical investigations are presented to investigate the possibility of a seismic retrofitting intervention able to increase the seismic strength of the wall without modifying its seismic behaviour. The analysed retrofitting technique consists in the application of composite vertical bars either in the middle section of the wall or at its external surfaces. The seismic behaviour of the retrofitted masonry wall is analytically evaluated by means of a parametric incremental dynamic analysis, carried out with an ad hoc in-house software. The effectiveness of the intervention is analysed in terms of level of seismic improvement, defined as the ratio between the seismic capacity of the reinforced and unreinforced walls.

scholarly journals A Multi-Scale Analysis Based on a Map-Oriented Database for the Out-of-Plane Seismic Behaviour of Masonry Structures

2021 ◽  
Author(s):  
Chenjie Yu ◽  
Sander Meijers
Keyword(s):  
Kinematic Analysis ◽  
Linear Time ◽  
Time History ◽  
Unreinforced Masonry ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Accurate Analysis ◽  
Multi Scale ◽  
Non Linear ◽  
Out Of Plane

Abstract Since 1986, earthquakes have occurred in East Groningen , but most houses, schools and are made of unreinforced masonry, which must now withstand magnitude 4 earthquakes. This has created an urgent need to assess large amounts of buildings in a fast but reliable manner. The out-of-plane behaviour is important for seismic assessments of unreinforced masonry buildings. Although the most accurate analysis method to determine the out-of-plane response of such walls is non-linear time-history analysis ( NLTH ), non-linear kinematic analysis ( NLKA ) provides a simple, fast but still reliable solution due to the computational difficulties of NLTH for structures constructed of unreinforced masonry. In this paper, the out-of-plane behaviours of masonry structures are up-scaled from a component scale to a provincial scale in a multi-scale manner. A map-oriented database is established to describe both local behaviours of walls and global behaviours of a province. The out-of-plane assessment by non-linear kinematic analysis ( NLKA ) is automated via the database without further calculations after the static analysis. The database provides a solid guidance to determine which detailed assessment methods will be adopted with limited data before a FEM model is built

scholarly journals Application Research of New Cementitious Composite Materials in Saline Soil Subgrade Aseismic Strengthening

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Shuai Huang ◽  
Yuejun Lyu ◽  
Yanju Peng
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Pore Water Pressure ◽  
Saline Soil ◽  
Water Pressure ◽  
Research Result ◽  
Engineering Application ◽  
Cementitious Composite ◽  
Seismic Behaviour ◽  
Damage Degree

Saline soil affected by earthquakes and groundwater can lead to subgrade subsidence and collapse in highway construction. Consequently, considering the potential activity of the waste slag and magnesia, new cementitious composite materials used in solid saline soil were developed in our study. The unconfined compressive strengths of the saline soil solidified by the new cementitious composite materials with a combination of magnesium oxide, calcium oxide, gypsum, and mineral powder and cement were investigated, and the optimum dosage proportion of the new cementitious composite material for solidifying saline soil was determined; then the SEM, EDS, and XRD of the saline soil solidified by the new cementitious composite materials and cement were analysed. The research result showed that the saline soil solidified by our newly developed cementitious composite material showed compact internal structure and uniformly distributed soil particles; moreover, the new cementitious composite material exhibited a favourable solidifying effect on harmful ions in saline soil, and the Cl− trapping capacity of the new cementitious composite materials was stronger than that of cement. Finally, our developed cementitious composite material was applied to saline soil subgrade strengthening, and the displacement, acceleration, excess pore water pressure, and damage degree of the subgrade strengthening by our newly developed cementitious composite materials decreased remarkably; therefore, our newly developed cementitious composite material can improve the seismic behaviour of the saline soil subgrade and show potential future engineering application value.

Study of the Composite Materials Optimal Structure Containing a Hollow Aluminum and Silica Microsphere Dependence on Humidity

2020 ◽  
Vol 12 ◽  
Author(s):  
Alexandra Atyaksheva ◽  
Yermek Sarsikeyev ◽  
Anastasia Atyaksheva ◽  
Olga Galtseva ◽  
Alexander Rogachev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Strength Function ◽  
Theory And Practice ◽  
Optimal Structure ◽  
Optimal Size ◽  
Structure And Properties ◽  
Power Functions ◽  
Silica Microsphere ◽  
Heat Engineering

Aims:: The main goals of this research are exploration of energy-efficient building materials when replacing natural materials with industrial waste and development of the theory and practice of obtaining light and ultra-light gravel materials based on mineral binders and waste dump ash and slag mixtures of hydraulic removal. Background.: Experimental data on the conditions of formation of gravel materials containing hollow aluminum and silica microsphere with opportunity of receipt of optimum structure and properties depending on humidity with the using of various binders are presented in this article. This article dwells on the scientific study of opportunity physical-mechanical properties of composite materials optimization are considered. Objective.: Composite material contains hollow aluminum and silica microsphere. Method.: The study is based on the application of the method of separation of power and heat engineering functions. The method is based on the use of the factor structure optimality, which takes into account the primary and secondary stress fields of the structural gravel material. This indicates the possibility of obtaining gravel material with the most uniform distribution of nano - and microparticles in the gravel material and the formation of stable matrices with minimization of stress concentrations. Experiments show that the thickness of the cement shell, which performs power functions, is directly related to the size of the raw granules. At the same time, the thickness of the cement crust, regardless of the type of binder, with increasing moisture content has a higher rate of formation for granules of larger diameter. Results.: The conditions for the formation of gravel composite materials containing a hollow aluminosilicate microsphere are studied. The optimal structure and properties of the gravel composite material were obtained. The dependence of the strength function on humidity and the type of binder has been investigated. The optimal size and shape of binary form of gravel material containing a hollow aluminosilicate microsphere with a minimum thickness of a cement shell and a maximum strength function was obtained. Conclusion.: Received structure allows to separate power and heat engineering functions in material and to minimize the content of the excited environment centers.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

Hierarchical ZSM-22/PHTS composite material and its hydro-isomerization performance in hydro-upgrading of gasoline

2021 ◽  
Author(s):  
Jiyuan Fan ◽  
Chengkun Xiao ◽  
Jinlin Mei ◽  
Cong Liu ◽  
Aijun Duan ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Impregnation Method ◽  
Molar Ratios

CoMo series catalysts based on ZSM-22/PHTS (ZP) composite materials with different SiO2/Al2O3 molar ratios were prepared via the impregnation method. The properties of the ZP material and the corresponding catalysts...

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