scholarly journals The Failure of Masonry Walls by Disaggregation and the Masonry Quality Index

Heritage ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 1162-1198
Author(s):  
Antonio Borri ◽  
Marco Corradi ◽  
Alessandro De Maria
Keyword(s):  
Quality Index ◽  
Failure Modes ◽  
Structural Response ◽  
Theoretical Models ◽  
Masonry Walls ◽  
Wall Panel ◽  
Seismic Capacity ◽  
Structural Behaviour ◽  
Historic Masonry ◽  
Type Of Failure

The visual method for assessment of the structural behaviour of historic masonry walls, known by the acronym MQI (Masonry Quality Index) was introduced in 2002 by a team of researchers from the University of Perugia, Italy. This is based on a visual survey of the faces and the cross section of a wall panel, and it aims at verifying if a wall complies with the “rules of the art”. Based on this analysis, it is possible to calculate a numerical index: numerous tests, carried out on site by the authors to validate the method, have demonstrated that the index is able to provide useful information about the mechanical characteristics and structural response, in general, of the analysed wall panel. The failure mode of a wall panel under the action of an earthquake is a critical aspect. In general, the failure modes can be categorized in two classes: masonry disaggregation and the development of a local or global mechanism of wall elements (macroelements). Several theoretical models and numerical simulations only consider the latter. In this paper, application of the MQI method is further investigated, with particular emphasis to those masonry typologies which are more prone to collapse by disaggregation during a seismic event. Under the action of an earthquake, some types of masonry are typically unable to deform and to split in macroelements, and another type of failure occurs: this is the so-called “masonry disaggregation” or “masonry crumbling”. This type of failure anticipates the ones resulting from macroelement methods or stress analysis. As a conclusion, these latter methods become completely inappropriate and potentially hazardous, as they overestimate the seismic capacity of the building under investigation. The MQI method has been adapted to assess the structural response of different types of masonry under the action of an earthquake. In detail, the aim was to verify when the phenomenon of masonry disaggregation is likely to occur.

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 Force-Based Seismic Evaluation of Retrofitting Interventions of Historic Masonry Castles by 3D Rigid Block Limit Analysis

2020 ◽  
Vol 10 (15) ◽  
pp. 5035
Author(s):  
Lucrezia Cascini ◽  
Giuseppe Brando ◽  
Francesco P. A. Portioli ◽  
Morena Rita Forgione ◽  
Claudio Mazzanti ◽  
...  
Keyword(s):  
Limit Analysis ◽  
Failure Modes ◽  
Three Dimensional ◽  
Historical Analysis ◽  
Quantitative Measure ◽  
Rigid Block ◽  
Seismic Evaluation ◽  
Seismic Capacity ◽  
Seismic Safety ◽  
Historic Masonry

This paper deals with the force-based assessment of collapse mechanisms and strengthening interventions of the historic masonry castle “Bussi sul Tirino” (Abruzzi, Italy) using rigid block limit analysis (RBLA). The structure, which is a fortified palace dating back to the 11th century, has experienced severe earthquakes over the centuries and was hit once again in 2009 by the L’Aquila earthquake. Based on the historical analysis and the results of in situ investigations, a spatial rigid block model of an entire structural unit was generated using the in-house software LiABlock_3D. The software is a MATLAB® based tool for three-dimensional RBLA, which provides as outputs collapse failure modes and collapse load multipliers. In addition, a specific routine was developed for the purpose of the study to compute the participating mass ratio and the spectral acceleration that activated the failure mechanisms. The results of the numerical analysis were used to address three different retrofitting interventions, based on the use of connection elements and ties that, according to the minimum intervention principle, progressively enhanced the seismic capacity. Comparisons in terms of seismic safety indices are finally provided in order to give a quantitative measure of the effectiveness of the adopted retrofitting strategies.

scholarly journals Analytical and numerical seismic assessment of heritage masonry towers

2019 ◽  
Vol 18 (3) ◽  
pp. 969-1008 ◽  
Author(s):  
Giacomo Torelli ◽  
Dina D’Ayala ◽  
Michele Betti ◽  
Gianni Bartoli
Keyword(s):  
Seismic Risk ◽  
Failure Modes ◽  
Local Stress ◽  
Masonry Structures ◽  
Stress Concentrations ◽  
Seismic Capacity ◽  
Historic Masonry ◽  
Existing Structures ◽  
Masonry Towers ◽  
Kinematic Analyses

Abstract The new Italian building code, published in 2018 [MIT in NTC 2018: D.M. del Ministero delle Infrastrutture e dei trasporti del 17/01/2018. Aggiornamento delle Norme Tecniche per le Costruzioni (in Italian), 2018], explicitly refers to the Italian “Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage” [PCM in DPCM 2011: Direttiva del Presidente del Consiglio dei Ministri per valutazione e riduzione del rischio sismico del patrimonio culturale con riferimento alle norme tecniche per le costruzioni, G.U. n. 47 (in Italian), 2011] as a reliable source of guidance that can be employed for the vulnerability assessment of heritage buildings under seismic loads. According to these guidelines, three evaluation levels are introduced to analyse and assess the seismic capacity of historic masonry structures, namely: (1) simplified global static analyses; (2) kinematic analyses based on local collapse mechanisms, (3) detailed global analyses. Because of the complexity and the large variety of existing masonry typologies, which makes it particularly problematic to adopt a unique procedure for all existing structures, the guidelines provide different simplified analysis approaches for different structural configurations, e.g. churches, palaces, towers. Among the existing typologies of masonry structures there considered, this work aims to deepen validity, effectiveness and scope of application of the Italian guidelines with respect to heritage masonry towers. The three evaluation levels proposed by the guidelines are here compared by discussing the seismic risk assessment of a representative masonry tower: the Cugnanesi tower located in San Gimignano (Italy). The results show that global failure modes due to local stress concentrations cannot be identified if only simplified static and kinematic analyses are performed. Detailed global analyses are in fact generally needed for a reliable prediction of the seismic performance of such structures.

scholarly journals Strength Enhancement of Interlocking Hollow Brick Masonry Walls with Low-Cost Mortar and Wire Mesh

2021 ◽  
Vol 6 (12) ◽  
pp. 166
Author(s):  
Panuwat Joyklad ◽  
Nazam Ali ◽  
Muhammad Usman Rashid ◽  
Qudeer Hussain ◽  
Hassan M. Magbool ◽  
...  
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Cement Mortar ◽  
Low Cost ◽  
Brick Masonry ◽  
Wire Mesh ◽  
Masonry Walls ◽  
Structural Behaviour ◽  
Hollow Brick ◽  
Strength And Ductility

Cement–clay Interlocking Hollow Brick Masonry (CCIHBM) walls are characterized by poor mechanical properties of bricks and mortar. Their performance is observed to be unsatisfactory under both gravity and seismic loads. There is an urgent need to develop sustainable, environmentally friendly, and low-cost strengthening materials to alter the structural behaviour of brick masonry walls in terms of strength and ductility. The results of an experimental investigation conducted on the diagonal compressive response of CCIHBM walls are presented in this study. In this experimental study, a total of six CCIHBM walls were constructed using cement–clay interlocking hollow bricks. One was tested as a control or reference wall, whereas the remaining walls were strengthened using cement mortar. In some walls, the cement mortar was also combined with the wire mesh. The research parameters included the type of Ordinary Portland Cement (OPC) (Type 1 and Type 2), thickness of cement mortar (10 mm and 20 mm), and layers of wire mesh (one and three layers). The experimental results indicate that control or unstrengthened CCIHBM walls failed in a very brittle manner at a very low ultimate load and deformation. The control CCIHBM wall, i.e., W-CON, failed at an ultimate load of 247 kN, and corresponding deflection was 1.8 mm. The strength and ductility of cement mortar and wire mesh-strengthened walls were found to be higher than the reference CCIHBM wall. For example, the ultimate load and deformation of cement-mortar-strengthened wall were found to be 143% and 233% higher than the control wall, respectively. Additionally, the ultimate failure modes of cement mortar and wire mesh strengthened were observed as ductile as compared to the brittle failure of reference wall or unstrengthened CCIHBM wall, which increased by 66% and 150% as compared with the control wall.

scholarly journals Quasi-Static Nonlinear Seismic Assessment of a Fourth Century A.D. Roman Aqueduct in Istanbul, Turkey

Heritage ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 401-421
Author(s):  
Semih Gonen ◽  
Bora Pulatsu ◽  
Ece Erdogmus ◽  
Engin Karaesmen ◽  
Erhan Karaesmen
Keyword(s):  
Contact Stiffness ◽  
Point Contact ◽  
Structural Response ◽  
Fourth Century ◽  
Friction Angle ◽  
Stone Masonry ◽  
Seismic Capacity ◽  
Historic Masonry ◽  
Joint Friction ◽  
Modeling Approach

The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises distinct rigid blocks interacting along their boundaries based on the point-contact hypothesis. Thus, the discontinuous stone skeleton of the masonry aqueduct is represented explicitly in the computational model. First, a validation study was conducted on the laboratory experiment to demonstrate the capabilities of the adopted modeling approach. Then, a discontinuum model representing the Valens Aqueduct was used to assess the seismic capacity of the structure under gradually increasing lateral forces. The numerical simulations gave insight into the structural response of the aqueduct from the elastic range to total collapse. Additionally, parametric research was performed considering joint properties, namely the joint tensile strength, contact stiffness, joint friction angle, and compressive strength of the masonry, to quantify the effects of contact parameters on the displacement response of the DEM model. Further inferences were made regarding the modeling parameters, and practical conclusions were derived.

Innovative seismic strengthening of historic masonry walls using polymer mortar and steel strips

2021 ◽  
Vol 228 ◽  
pp. 111507
Author(s):  
Xianhua Yao ◽  
Zi-Xiong Guo ◽  
Syed Humayun Basha ◽  
Qunxian Huang
Keyword(s):  
Masonry Walls ◽  
Seismic Strengthening ◽  
Historic Masonry ◽  
Steel Strips ◽  
Polymer Mortar

Resistance of Reinforced Concrete Frames with Masonry Infill Walls to In-Plane Vertical Loading

2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Progressive Collapse ◽  
Lateral Loading ◽  
Masonry Walls ◽  
Reinforced Concrete Frame ◽  
Masonry Infill ◽  
Concrete Frame ◽  
Vertical Loading ◽  
Infill Masonry

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.

scholarly journals PULL-OUT RESISTANCE OF SELF-TAPPING SCREWS IN CROSS-LAMINATED TIMBER MADE FROM RADIATA PINE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Xin Li ◽  
Mahmud Ashraf ◽  
Mahbube Subhani ◽  
Paul Kremer
Keyword(s):  
Failure Modes ◽  
Construction Materials ◽  
Structural Response ◽  
Radiata Pine ◽  
Raw Material ◽  
Fibrous Materials ◽  
Cross Laminated Timber ◽  
Pull Out ◽  
Traditional Construction ◽  
Penetration Depths

Cross-laminated timber (CLT) is now considered a viable alternative to traditional construction materials both in mid-rise and high-rise structures. The structural response of CLT heavily relies on the type of timber used in manufacturing, and this can vary significantly based on the original source for this naturally grown raw material. Spruce has been widely used in Europe for CLT production, but in Australia, locally available radiata pine is used by XLam for the manufacturing of their CLT panels. Self-tapping screws (STS) are typically recommended by CLT manufacturers and are most commonly used in relevant construction due to their high load carrying capacities and easy installation process. VGS STSs produced by Rothoblaas were used to investigate their composite actions when pulled-out from three-layer XLam CLT panels with thicknesses of 105 mm and 135 mm. VGS screws with 11 mm in diameter were inserted both parallel-to-grain and perpendicular-to-grain on the narrow face of the CLT panels as part of the current study. Typical failure modes as well as critical penetration depths were carefully recorded. Obtained results showed significant increase of pull-out capacity as penetration depths were increased for considered cases. However, experimental results also showed some obvious inconsistencies. These observations clearly demonstrate the challenges associated with working naturally grown fibrous materials and highlights the importance of major research on this field.

A Theoretical and Experimental Analysis of the Bending Behavior of Unbonded Flexible Pipes

2014 ◽  
Author(s):  
Tatiana Vargas-Londoño ◽  
José Renato M. de Sousa ◽  
Carlos Magluta ◽  
Ney Roitman
Keyword(s):  
Internal Pressure ◽  
Cross Section ◽  
Structural Response ◽  
Experimental Tests ◽  
Theoretical Models ◽  
External Pressure ◽  
Local Behavior ◽  
Flexible Pipes ◽  
Floating System ◽  
Bending Loads

Due to its compound cross-section, the prediction of the structural response of flexible pipes to loads such as their self-weight, internal and external pressure, movements imposed by the floating system and environmental loads such as currents, waves and wind is quite complex. All these loads generate stresses and strains in the cross section of the pipe that have to be properly evaluated in order to ensure integrity of the line. Research has been done on the local behavior of flexible pipes under combined axisymmetric loads as well as under bending loads. However, there is a lack of research combining both axisymmetric and bending loads, as also in the study of the strains in the tensile amour layers of the pipes, aspects which are important for the calibration of theoretical models to predict such behavior. Based on that, this study aims to evaluate the local behavior of flexible pipes under combinations of axisymmetric (tension, and internal pressure) and bending loads via a series of experimental tests in a 9.13″ I.D pipe. In the experimental tests, the behavior of the pipe was studied for three load combinations: i) bending combined with tension; ii) bending combined with internal pressure; and iii) bending combined with tension and internal pressure. Based on these tests, the authors obtained the strains in the tensile armor layer, axial elongation due to tension, axial reaction forces due to internal pressure, and deflection due to bending. These measurements were used to calibrate a theoretical model devoted to simulate the pipe’s response, getting accurate results for stiffness and stresses of the pipe in each scenario.

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