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 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.

scholarly journals Experimental and Numerical Study of Behaviour of Reinforced Masonry Walls with NSM CFRP Strips Subjected to Combined Loads

Buildings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 103
Author(s):  
Houria Hernoune ◽  
Benchaa Benabed ◽  
Antonios Kanellopoulos ◽  
Alaa Hussein Al-Zuhairi ◽  
Abdelhamid Guettala
Keyword(s):  
Failure Modes ◽  
Numerical Study ◽  
Masonry Wall ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Near Surface ◽  
Combined Loads ◽  
Reinforced Masonry ◽  
Brick And Mortar ◽  
Near Surface Mounted

Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) walls using the detailed micro-modelling approach (DMM) by means of ABAQUS software. In this analysis, the non-linearity behavior of brick and mortar was simulated using the concrete damaged plasticity (CDP) constitutive laws. The results proved that the application of the NSM-CFRP strips on the masonry wall influences significantly strength, ductility, and post-peak behavior, as well as changing the failure modes. The adopted DMM model provides a good interface to predict the post peak behavior and failure mode of unreinforced brick masonry walls.

Numerical Evaluation of Mechanical Parameters Role in GFRP Strengthened Cobblestone Masonry Walls

2017 ◽  
Vol 747 ◽  
pp. 504-511
Author(s):  
Natalino Gattesco ◽  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Parametric Study ◽  
Peak Load ◽  
Element Model ◽  
Masonry Wall ◽  
Fiber Reinforced Polymers ◽  
Masonry Walls ◽  
Glass Fiber Reinforced ◽  
Reinforced Masonry ◽  
Smeared Crack Approach ◽  
Smeared Crack

The use of a GFRP (Glass Fiber Reinforced Polymers) mesh, embedded as a reinforcement in a mortar coating on both wall sides, proved to be effective and reliable in increasing the masonry wall resistance and the plastic deformation capacity.In this study, a NL finite element model, developed to predict the in-plane behaviour of masonry walls strengthened by means of this technique, is refined and used in an extensive parametric study. Numerical results were compared with diagonal compression test data on URM and RM cobblestone masonry samples, showing good agreement. The masonry panel and the mortar coating were modelled as isotropic homogeneous materials with a smeared crack approach, whereas the GFRP reinforcement was modelled as a mesh of truss elements. Properties assigned to materials were derived from experimental tests.The parametric study performed before on some involved mechanical properties, considering a standard range of variation, is now extended to other parameters. Moreover, the combined variation of different properties is considered. The actual contribute of each component (masonry, GFRP mesh, mortar) on some macroscopic parameters (strength and ductility of the specimen) is evaluated.The parametric analysis highlights the important role of the GFRP mesh not only on the peak load increment but also on the post-peak behavior and, in particularly, on the ductility increment of the reinforced masonry panel. These results can address the optimization of the intervention technique and the deliverable of operative guidelines for practitioners.

Analysis of safety of slender concrete masonry walls in relation to CSA S304-14

2019 ◽  
Vol 46 (5) ◽  
pp. 424-438
Author(s):  
Andrea C. Isfeld ◽  
Anna Louisa Müller ◽  
Mark Hagel ◽  
Nigel G. Shrive
Keyword(s):  
Concrete Block ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Effective Height ◽  
Design Standard ◽  
Euler Buckling ◽  
Concrete Masonry ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Support Conditions

The Canadian masonry design standard appears to be overly conservative in determining the capacity of concrete block walls with slenderness ratios greater than 30. When assessing the potential for buckling of a masonry wall according to Euler buckling criteria, the effective height is determined in part from the end supports. In Euler theory only pinned, fixed and free support conditions are considered, and the Canadian standard considers the support conditions to be hinged, elastic or stiff. For a partially reinforced masonry wall a true hinged base support is expected to be difficult to achieve, as the width of the concrete block restrains rotation. The effect of the base support conditions on the deflected shape of partially grouted block walls was investigated under axial and out-of-plane loading. The results of this testing were compared with calculations based on the Canadian masonry standard. It becomes clear that the standard is overly conservative in many cases and the design of slender walls needs to be re-examined.

Out-of-Plane Behavior of Masonry Walls Strengthened with Ferrocement

2010 ◽  
Vol 163-167 ◽  
pp. 3545-3550 ◽  
Author(s):  
Sheng Ping Chen
Keyword(s):  
Volume Fraction ◽  
Load Capacity ◽  
Experimental Studies ◽  
Material Model ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Ultimate Load Capacity ◽  
Softening Behavior ◽  
Reinforced Masonry ◽  
Out Of Plane

Un-reinforced masonry (URM) structures may fail and collapse under out-of-plane loads generated by seismic forces or explosions. Adding a ferrocement overlay onto the URM walls is an effective solution in increasing the ultimate load capacity and ductility. This paper deals with the numerical and experimental studies on the out-of-plane behavior of un-reinforced masonry walls strengthened with ferrocement. The material parameters considered are the volume fraction of reinforcement and the loading area. A numerical model was proposed to simulate the experimental results. The employed material model for masonry wall is based on the theory of Drucker-Prager plasticity taking into account the tension softening behavior, while the ferrocement is modeled as a composite material with linear strain hardening followed by ideal plasticity. The proposed model simulates the load-deflection behavior of the strengthened wall well.

scholarly journals Experimental Examination of Hollow Brick Masonry Wall with Reinforcement

2019 ◽  
Vol 8 (4) ◽  
pp. 4680-4684 ◽  
Keyword(s):  
Shear Walls ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Masonry Building ◽  
Brick Wall ◽  
High Wind ◽  
Load Bearing ◽  
Reinforced Masonry ◽  
Hollow Brick

The research aims at conducting a quality research with Reinforcement of a hollow brick wall. The empty internal sections significantly lower the dead load. With a better surface finish, the side of the block was cast, minimizing the cost of plastering. Several sample mixes are tested to achieve a finished surface. The respective frames were cast with and without reinforcement and the test results were compared. The blocks were used to build masonry walls and ' load-bearing strength ' of the walls was tested. It is possible to use the reinforced hollow block as a load-bearing wall. Nearly 75 percent of the deaths related to the earthquake in the last century,Buildings have collapsed, the majority of which (more than 70 percent)is due to the collapse of buildings made of masonry. Most of the properties in India are Unreinforced Masonry (URM) buildings that are weak and vulnerable even under moderate earthquakes and that function on the wall due to high wind forces, causing severe damage to high wind loads and it is recognized that Reinforced Masonry Building has many advantages over unreinforced masonry building.The use was very limited in Indian building practices and there are still no approved codes and shear walls were used in most constructions, even in mild earthquakes, instead of reinforced masonry walls

Experimental study of reinforced masonry walls subjected to combined axial load and out-of-plane bendingThis article is one of a selection of papers published in this Special Issue on Masonry.

2007 ◽  
Vol 34 (11) ◽  
pp. 1486-1494 ◽  
Author(s):  
Y. Liu ◽  
K. Hu
Keyword(s):  
Slenderness Ratio ◽  
Compressive Loading ◽  
Masonry Wall ◽  
Test Results ◽  
Secondary Effects ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Support Conditions ◽  
The Moment ◽  
Type Of Failure

Twelve reinforced masonry wall specimens with nominal dimensions of 2400 mm × 800 mm × 150 mm were tested under eccentric compressive loading with varying eccentricity to thickness ratios, e/t, and end eccentricity ratios, e1/e2. Pinned-pinned support conditions resulted in a slenderness ratio of 17.1 for all specimens. Test results showed that the variation of ultimate load, Pu, and effective modulus of rigidity values, EIeff, at failure depended on the type of failure mode, which was influenced by e/t and e1/e2 ratios and their interaction. Comparing ultimate loads obtained by test against those calculated using the EIeff values from the Canadian standard CSA S304.1-04 and against the ones calculated using the EIeff values proposed herein indicates that, while the moment magnifier method used in the current Canadian design standard to account for secondary effects is effective, the standard underestimates EIeff values, especially in regions where compression-controlled failure tends to predominate and, thus, leads to a conservative design. However, the use of proposed EIeff values in combination with the moment magnifier method provides estimations of ultimate loads in reasonably good agreement with test results.

Experimental determination of masonry beam-column behaviour

2001 ◽  
Vol 28 (5) ◽  
pp. 794-803 ◽  
Author(s):  
Yi Liu ◽  
J L Dawe
Keyword(s):  
Single Layer ◽  
Masonry Wall ◽  
Experimental Program ◽  
Masonry Walls ◽  
Test Results ◽  
Eccentricity Ratio ◽  
Design Code ◽  
Concrete Masonry ◽  
Wall Stiffness

An experimental program consisting of 36 reinforced concrete masonry wall specimens comprised of 400 × 200 × 150 mm standard units in two series of tests was carried out to investigate the behaviour of masonry walls under combined axial and lateral loading. W2R series specimens had a single layer of vertical steel, and W4R series specimens had a double layer of vertical steel. Test results show that the effective wall stiffness, (EI)eff, differs from currently specified code values in regions where compression failure tends to predominate. Overall test results presented graphically in the form of lateral load versus deflection, axial load versus moment, and (EI)eff versus eccentricity ratio, e/t, indicate that the current Canadian masonry design code underestimates the effective stiffness of walls with eccentricity ratios e/t < 0.4.Key words: beam–column, masonry, reinforcement, experimental, rigidity, moment magnifier.

scholarly journals Seismic resistance of brick masonry walls

1974 ◽  
Vol 7 (4) ◽  
pp. 167-187
Author(s):  
M. J. N. Priestley ◽  
D. O. Bridgeman
Keyword(s):  
Cyclic Loading ◽  
Cell Types ◽  
Masonry Wall ◽  
Brick Masonry ◽  
Seismic Resistance ◽  
Masonry Walls ◽  
Shear Load ◽  
Reinforced Masonry ◽  
Wall Panels

This paper summarises the results obtained from testing 18 reinforced masonry wall panels under racking load. The programme included tests on both RBM and Hollow Cell types of brick construction under slow cyclic loading. It is shown that satisfactory ductility can be obtained from brick masonry walls if sufficient horizontal steel is provided to carry the full shear load, and if the critical compression zones at the bottom corners of the wall are confined by the use of thin reinforcing plates in the bottom few mortar courses. Without these precautions severe load degradation occurs under successive load reversals.

Numerical study of composite material (FRP/TRC)-reinforced masonry walls under in-plane loading

2021 ◽  
pp. 002199832110152
Author(s):  
Thi-Loan Bui ◽  
Zakaria Ilyes Djamai ◽  
A Si Larbi ◽  
N Reboul ◽  
E Ferrier
Keyword(s):  
Numerical Study ◽  
Concrete Block ◽  
Masonry Wall ◽  
Efficiency Factor ◽  
Elastic Behaviour ◽  
Uniaxial Tensile ◽  
Axial Stiffness ◽  
Masonry Walls ◽  
Global Factor ◽  
Reinforced Masonry

Fibre-reinforced polymers (FRPs) and textile-reinforced concretes (TRCs) are becoming increasingly common solutions for strengthening masonry walls. This study focuses on different approaches for modelling the behaviour of hollow concrete block masonry walls strengthened with FRPs and a TRC subjected to in-plane loading. Specifically, the masonry is modelled using the heterogeneous approach, wherein the damage post-peak softening behaviours of both bricks and mortar are considered, as this approach is appropriate for material and structure scales. To model the FRP/TRC-reinforced masonry walls, the reinforcements (FRPs/TRC) are perfectly connected to the substrate. Although the homogeneous approach is proposed to model the FRPs with linear elastic behaviour and is shown to be appropriate for modelling the FRP-reinforced masonry walls, the TRC is modelled using the heterogeneous approach, allowing for the real contribution of the filaments to be expressed through an ‘efficiency factor’. The numerical results show that this factor has a significant influence on the behaviour of the TRC and therefore, on the overall behaviour of the TRC-reinforced walls. However, the ‘efficiency factor’ of the TRC sample is significantly higher than that of the TRC in the strengthened wall. This result confirms that the choice of the heterogeneous approach to model the TRC in our case is appropriate. Moreover, it verifies that it is impossible to transpose this global factor from the material scale (uniaxial tensile stress) to the structure scale when the application target is a masonry wall (multi-axiality, and therefore, complexity of the stress). Consequently, the constitutive laws of the TRC composite obtained through only direct uniaxial tensile characterization procedures are insufficient to enable a suitable restitution of the overall behaviour of the masonry reinforced with the TRC. In addition, regardless of the nature of the reinforcement, the overall behaviours of the masonry walls reinforced with the FRPs/TRC are governed by both the axial stiffness of the reinforcement and the compressive strength of the masonry substrate.

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