scholarly journals Monitoring of Thermal and Moisture Processes in Various Types of External Historical Walls

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 505 ◽  
Author(s):  
Dariusz Bajno ◽  
Lukasz Bednarz ◽  
Zygmunt Matkowski ◽  
Krzysztof Raszczuk
Keyword(s):  
Masonry Wall ◽  
Design Guidelines ◽  
Masonry Walls ◽  
Historical Buildings ◽  
Wall Structures ◽  
Mutual Comparison ◽  
Energy Audits ◽  
Biological Corrosion ◽  
Comfort Parameters ◽  
The Impact

In order to create and make available the following: Design guidelines, recommendations for energy audits, data for analysis and simulation of the condition of masonry walls susceptible to biological corrosion, deterioration of comfort parameters in rooms, or deterioration of thermal resistance, the article analyzes various types of masonry wall structures occurring in and commonly used in historical buildings over the last 200 years. The summary is a list of results of particular types of masonry walls and their mutual comparison. On this basis, a procedure path has been proposed which is useful for monitoring heat loss, monitoring the moisture content of building partitions, and improving the hygrothermal comfort of rooms. The durability of such constructions has also been estimated and the impact on the condition of the buildings that have been preserved and are still in use today was assessed.

Study on the explosion-proof performance of polyurea-reinforced masonry walls with different spraying methods

2019 ◽  
Author(s):  
Wei Shang ◽  
Xu-dong Zu ◽  
Zheng-xiang Huang ◽  
Wen-ni Shen
Keyword(s):  
Masonry Wall ◽  
Blast Waves ◽  
Impact Fracture ◽  
Back Surface ◽  
Masonry Walls ◽  
Test Results ◽  
Contact Explosion ◽  
Reinforced Masonry ◽  
Theoretical Predictions ◽  
The Impact

Abstract Based on the propagation theory of blast waves and the strain rate effect of polyurea, the explosion-proof performance of polyurea-reinforced masonry walls with different spraying methods is discussed in this paper. The impact fracture of masonry walls after contact explosion was analyzed, and the fracture results of a blast wave on polyurea-reinforced masonry walls with different spraying methods were predicted. Furthermore, explosion-proof experiments of a standard masonry wall (2m×1.2m×0.37m) under three conditions including non-sprayed, back surface sprayed polyurea and double-sided sprayed polyurea were carried out to verify the theoretical predictions. Finally, the impact fracture results of standard masonry walls after a 1 kg TNT contact explosion under the three conditions were obtained. The test results were in good agreement with the theoretical predictions. It clearly demonstrated that polyurea coating can significantly improve the explosion-proof performance of masonry walls, and double-sided sprayed showed better explosion-proof performance than back surface sprayed at the same coating thickness.

scholarly journals Multi-Leaf Masonry Walls with Full, Damaged and Consolidated Infill: Experimental and Numerical Analyses

2017 ◽  
Vol 747 ◽  
pp. 488-495 ◽  
Author(s):  
Ivano Aldreghetti ◽  
Daniele Baraldi ◽  
Giosuè Boscato ◽  
Antonella Cecchi ◽  
Lorenzo Massaria ◽  
...  
Keyword(s):  
Finite Element ◽  
Comparative Analysis ◽  
Structural Complexity ◽  
Experimental Tests ◽  
Masonry Wall ◽  
Research Community ◽  
Masonry Walls ◽  
Historic Buildings ◽  
Structural Elements ◽  
Historical Buildings

Multi-leaf masonry walls constitute the construction typology most widely adopted in historic buildings. This aspect, together with the intrinsic structural complexity, heterogeneity and irregularity, directs the present research towards a topic not yet sufficiently investigated by the research community of architects and civil engineers. In this paper, the case of multi-leaf masonry wall has been investigated, and with the aim of reproducing historical buildings structural elements, three different typologies of multi-leaf masonry walls have been considered: (i) full infill, (ii) damaged infill, (iii) consolidated infill. A comparative analysis has been performed and results of experimental tests have been compared with numerical ones obtained by means of Finite Element (FE) models.

Non Linear Response of Masonry Wall Structures Subjected to Cyclic and Dynamic Loading

2010 ◽  
Vol 133-134 ◽  
pp. 747-752
Author(s):  
Fernando Sima ◽  
Pere Roca ◽  
Climent Molins
Keyword(s):  
Masonry Wall ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Matrix Formulation ◽  
Wall Structures ◽  
Non Linear ◽  
Equivalent Frame ◽  
Generalized Matrix ◽  
Frame Systems ◽  
Solid Walls

A method for non-linear dynamic analysis of wall masonry structures is presented. The method takes advantage of a Generalized Matrix Formulation (GMF) for the serviceability and ultimate analysis of structures composed of arches and/or masonry walls, in which open and solid walls are described as equivalent frame systems. This formulation has been complemented with a cyclic constitutive model and an algorithm for the integration of the equation of motion, resulting in a numerically efficient method for non-linear analysis in time domain of complex masonry systems.

The Effect of Biaxial Interlocking Block to the Masonry Wall Properties under Uniaxial Compression Load

2021 ◽  
Vol 1041 ◽  
pp. 107-114
Author(s):  
Fauziah Aziz ◽  
Mohd Fadzil Arshad ◽  
Hazrina Mansor
Keyword(s):  
Compressive Strength ◽  
Slenderness Ratio ◽  
Research Work ◽  
Compressive Load ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Masonry Unit ◽  
Compression Load ◽  
The Individual ◽  
The Impact

Biaxial Interlocking Block (BIB) is a new interlocking block system introduced in this research work. BIB was designed and expected to have the capacity to resist the biaxial load. In this research, the production of BIB was introduced, and the properties of BIB as the individual and walling unit was identified. The features of BIB in terms of density, compressive strength and MOE was identified. To define the impact BIB to the masonry wall capacity, nine walls panel and nine prisms including Solid Block (SB) and cement sand brick (CSB) have been constructed and tested under concentric compressive load. From the data obtained, the BIB walling system was calculated and identified. All the properties values of BIB masonry obtained compared with SB and CSB masonry values. The relationship of masonry properties by different types of masonry unit was also identified and discuss. From all the data and analysis carried out, it is found that the features of masonry unit have influenced the walling properties of the constructed wall. The higher compressive strength of masonry unit will enhance the capacity of the masonry walls. From this research, it is also found that BIB is having excellent properties as a walling unit as compare to SB and CSB wall. A linear relationship between the compressive strength of the samples regardless of the changing in masonry unit compressive strength has been found appropriate with the same slenderness ratio. This work offers valuable data of BIB to the masonry walls properties under compressive load.

scholarly journals Improving the usability of climate indicator visualizations through diagnostic design principles

2021 ◽  
Vol 166 (3-4) ◽  
Author(s):  
Michael D. Gerst ◽  
Melissa A. Kenney ◽  
Irina Feygina
Keyword(s):  
Design Guidelines ◽  
Party Affiliation ◽  
Abstract Concepts ◽  
Design Modification ◽  
Climate Indicators ◽  
Present Complex ◽  
Control Versus ◽  
Climate Indicator ◽  
Political Party Affiliation ◽  
The Impact

AbstractVisual climate indicators have become a popular way to communicate trends in important climate phenomena. Producing accessible visualizations for a general audience is challenging, especially when many are based on graphics designed for scientists, present complex and abstract concepts, and utilize suboptimal design choices. This study tests whether diagnostic visualization guidelines can be used to identify communication shortcomings for climate indicators and to specify effective design modifications. Design guidelines were used to diagnose problems in three hard-to-understand indicators, and to create three improved modifications per indicator. Using online surveys, the efficacy of the modifications was tested in a control versus treatment setup that measured the degree to which respondents understood, found accessible, liked, and trusted the graphics. Furthermore, we assessed whether respondents’ numeracy, climate attitudes, and political party affiliation affected the impact of design improvements. Results showed that simplifying modifications had a large positive effect on understanding, ease of understanding, and liking, but not trust. Better designs improved understanding similarly for people with different degrees of numerical capacity. Moreover, while climate skepticism was associated with less positive subjective responses and greater mistrust toward climate communication, design modification improved understanding equally for people across the climate attitude and ideological spectrum. These findings point to diagnostic design guidelines as a useful tool for creating more accessible, engaging climate graphics for the public.

scholarly journals Use of the AE Effect to Determine the Stresses State in AAC Masonry Walls under Compression

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3459
Author(s):  
Radosław Jasiński ◽  
Krzysztof Stebel ◽  
Paweł Kielan
Keyword(s):  
Ultrasonic Waves ◽  
Image Correlation ◽  
Masonry Walls ◽  
Acceptable Error ◽  
Compressive Stresses ◽  
Deformation State ◽  
Hydrostatic Stresses ◽  
Stress States ◽  
The Impact ◽  
Masonry Units

Safety and reliability of constructions operated are predicted using the known mechanical properties of materials and geometry of cross-sections, and also the known internal forces. The extensometry technique (electro-resistant tensometers, wire gauges, sensor systems) is a common method applied under laboratory conditions to determine the deformation state of a material. The construction sector rarely uses ultrasonic extensometry with the acoustoelastic (AE) method which is based on the relation between the direction of ultrasonic waves and the direction of normal stresses. It is generally used to identify stress states of machine or vehicles parts, mainly made of steel, characterized by high homogeneity and a lack of inherent internal defects. The AE effect was detected in autoclaved aerated concrete (AAC), which is usually used in masonry units. The acoustoelastic effect was used in the tests described to identify the complex stress state in masonry walls (masonry units) made of AAC. At first, the relationships were determined for mean hydrostatic stresses P and mean compressive stresses σ3 with relation to velocities of the longitudinal ultrasonic wave cp. These stresses were used to determine stresses σ3. The discrete approach was used which consists in analyzing single masonry units. Changes in velocity of longitudinal waves were identified at a test stand to control the stress states of an element tested by the digital image correlation (DIC) technique. The analyses involved density and the impact of moisture content of AAC. Then, the method was verified on nine walls subjected to axial compression and the model was validated with the FEM micromodel. It was demonstrated that mean compressive stresses σ3 and hydrostatic stresses, which were determined for the masonry using the method considered, could be determined even up to ca. 75% of failure stresses at the acceptable error level of 15%. Stresses σ1 parallel to bed joints were calculated using the known mean hydrostatic stresses and mean compressive stresses σ3.

scholarly journals Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2961
Author(s):  
Moein Rezapour ◽  
Mehdi Ghassemieh ◽  
Masoud Motavalli ◽  
Moslem Shahverdi
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Vertical Strip ◽  
Maximum Resistance ◽  
The Cross ◽  
Post Tensioning

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

Influence of Sulphate on the Moisture Movement of Calcium Silicate Brick Masonry Wall

2010 ◽  
Vol 133-134 ◽  
pp. 201-204
Author(s):  
Ibrahim Mohamad H. Wan ◽  
B.H. Abu Bakar ◽  
M.A. Megat Johari ◽  
P.J. Ramadhansyah
Keyword(s):  
Relative Humidity ◽  
Calcium Silicate ◽  
Masonry Wall ◽  
Sodium Sulphate ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Moisture Movement ◽  
Moisture Expansion ◽  
Curing Period ◽  
Wet Condition

This paper presents the behaviour of moisture movement of calcium silicate brick masonry walls exposed to sodium sulphate environment. The walls were exposed to three sodium sulphate conditions with sulphate concentrations of5%, 10% and 15%. For comparison, some walls were also exposed to dry and wet condition which acts as a control conditions. All specimens were prepared and cured under polythene sheet for 14 days in a controlled environmental room and maintained at relative humidity and temperature of 80 ± 5% and 25 ± 2°C, respectively. After the curing period, the specimens were exposed to sodium sulphate as well as drying and water exposures, during which moisture movement was measured and monitored for a period of up to 7 months. As a result, the moisture expansion was observed and recorded for all masonry wall specimens after exposed to the sulphate condition.

Mechanical Properties of Various Models of Interlocking Concrete Blocks under In-Plane and Out-of-Plane Loads

2021 ◽  
Vol 881 ◽  
pp. 149-156
Author(s):  
Mochamad Teguh ◽  
Novi Rahmayanti ◽  
Zakki Rizal
Keyword(s):  
Mechanical Properties ◽  
Building Material ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Plane Shear ◽  
Out Of Plane ◽  
Concrete Blocks ◽  
Local Materials

Building material innovations in various interlocking concrete block masonry from local materials to withstand lateral earthquake forces is an exciting issue in masonry wall research. The block hook has an advantage in the interlocking system's invention to withstand loads in the in-plane and out-of-plane orientations commonly required by the masonry walls against earthquake forces. Reviews of the investigation of in-plane and out-of-plane masonry walls have rarely been found in previous studies. In this paper, the results of a series of experimental tests with different interlocking models in resisting the simultaneous in-plane shear and out-of-plane bending actions on concrete blocks are presented. This paper presents a research investigation of various interlocking concrete blocks' mechanical properties with different hook thicknesses. Discussion of the trends mentioned above and their implications towards interlocking concrete block mechanical properties is provided.

Implementation of electrical impedance tomography for analysis of building moisture conditions

2018 ◽  
Vol 37 (5) ◽  
pp. 1837-1861 ◽  
Author(s):  
Tomasz Rymarczyk ◽  
Jan Sikora ◽  
Paweł Tchórzewski
Keyword(s):  
Distribution Pattern ◽  
Evaluation Study ◽  
Moisture Distribution ◽  
Historical Buildings ◽  
Reconstruction Algorithms ◽  
Electrical Tomography ◽  
Impedance Tomography ◽  
Measuring Device ◽  
Content Type ◽  
The Impact

Purpose The paper aims to present an innovative solution for evaluation study of the dampness level of walls and historical buildings. Design/methodology/approach Electrical tomography enables one to obtain a distribution pattern of wall dampness. The application of modern tomographic techniques in conjunction with topological algorithms will allow one to perform very accurate spatial assessment of the dampness levels of buildings. The proposed application uses the total variation, Gauss–Newton and level set method to solve the inverse problem in electrical tomography. Findings Research shows that electrical tomography can provide effective results in damp buildings. This method can provide 2D/3D moisture distribution pattern. Research limitations/implications The impact of this technique will be limited to inspection of the facility after floods or assessment of historical buildings. Practical implications The presented method could eventually lead to a much more effective evaluation of moisture in the walls. Social implications The solution has commercial potential and could result in more cost-effective monitoring of historical buildings, which have an economic impact on society. Originality/value The authors propose a system for imaging spatial moistness of walls and historic buildings based on electrical tomography and consisting of a measuring device, sensors and image reconstruction algorithms.

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