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.

scholarly journals Experimental and Numerical Study of Polymer-Retrofitted Masonry Walls under Gas Explosions

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 863
Author(s):  
Meng Gu ◽  
Xiaodong Ling ◽  
Hanxiang Wang ◽  
Anfeng Yu ◽  
Guoxin Chen
Keyword(s):  
Coating Thickness ◽  
Failure Modes ◽  
Numerical Study ◽  
Field Tests ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Economic Losses ◽  
Masonry Walls ◽  
Spray Pattern ◽  
Gas Explosions

Unreinforced masonry walls are extensively used in the petrochemical industry and they are one of the most vulnerable components to blast loads. To investigate the failure modes and improve the blast resistances of masonry walls, four full-scale field tests were conducted using unreinforced and spray-on polyurea-reinforced masonry walls subjected to gas explosions. The results suggested that the primary damage of the unreinforced masonry wall was flexural deformation and the wall collapsed at the latter stage of gas explosion. The presence of polyurea coatings could effectively improve the anti-explosion abilities of masonry walls, prevent wall collapses, and retain the flying fragments, which would reduce the casualties and economic losses caused by petrochemical explosion accidents. The bond between the polymer and masonry wall was critical, and premature debonding resulted in a failure of the coating to exert the maximum energy absorption effect. A numerical model for masonry walls was developed in ANSYS/LS-Dyna and validated with the test data. Parametric studies were conducted to explore the influences of the polyurea-coating thickness and spray pattern on the performances of masonry walls. The polyurea-coating thickness and spray pattern affected the resistance capacities of masonry walls significantly.

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.

INFLUENCE OF NEAR-SURFACE MOUNTED FRP WITH CEMENTITIOUS MATERIAL ON OUT-OF-PLANE BEHAVIOR OF REINFORCED MASONRY WALLS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Zuhair Aljaberi ◽  
John J. Myers
Keyword(s):  
Concrete Block ◽  
Cementitious Material ◽  
Masonry Walls ◽  
Near Surface ◽  
Modes Of Failure ◽  
Reinforced Walls ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Near Surface Mounted ◽  
Frp Bars

Eight medium scale reinforced masonry walls were built as a part of this study. These reinforced walls were strengthened using carbon fiber reinforced polymer [FRP] (bars and tapes) and glass FRP (bars) using a near surface mounted technique (NSM) with cementitious material; constant mild steel reinforcement ratio (ρ) was used. These strengthened walls were supported as a simply supported wall under an out-of-plane cyclic load applied along two line loads. This study presented the effect of different parameters, these parameters related to FRP (type and amount), bond pattern (stack and running), and existing of FRP in compression face of the walls. This paper reveals the relation between these factors and the out-of-plane capacity of the reinforced wall strengthened with FRP. Different modes of failure occurred in the strengthened reinforced walls, including a punching shear failure through the concrete block, crushing of concrete block and debonding of FRP reinforcement from the masonry substrate.

scholarly journals Activated Ductile CFRP NSMR Strengthening

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2821
Author(s):  
Jacob Wittrup Schmidt ◽  
Christian Overgaard Christensen ◽  
Per Goltermann ◽  
José Sena-Cruz
Keyword(s):  
Failure Modes ◽  
Elastic Response ◽  
Applied Theory ◽  
Strengthening Effect ◽  
The Novel ◽  
Near Surface ◽  
Linear Elastic ◽  
Near Surface Mounted ◽  
High Elongation ◽  
Strengthened Beam

Significant strengthening of concrete structures can be obtained when using adhesively-bonded carbon fiber-reinforced polymer (CFRP) systems. Challenges related to such strengthening methods are; however, the brittle concrete delamination failure, reduced warning, and the consequent inefficient use of the CFRP. A novel ductile near-surface mounted reinforcement (NSMR) CFRP strengthening system with a high CFRP utilization is introduced in this paper. It is hypothesized that the tailored ductile enclosure wedge (EW) end anchors, in combination with low E-modulus and high elongation adhesive, can provide significant strengthening and ductility control. Five concrete T-beams were strengthened using the novel system with a CFRP rod activation stress of approximately 980 MPa. The beam responses were compared to identical epoxy-bonded NSMR strengthened and un-strengthened beams. The linear elastic response was identical to the epoxy-bonded NSMR strengthened beam. In addition, the average deflection and yielding regimes were improved by 220% and 300% (average values), respectively, with an ultimate capacity comparable to the epoxy-bonded NSMR strengthened beam. Reproducible and predictable strengthening effect seems obtainable, where a good correlation between the results and applied theory was reached. The brittle failure modes were prevented, where concrete compression failure and frontal overload anchor failure were experienced when failure was initiated.

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.

scholarly journals Inclusion of CFRP-Epoxy Composite for End Anchorage in NSM-Epoxy Strengthened Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Md. Akter Hosen ◽  
Mohd Zamin Jumaat ◽  
A. B. M. Saiful Islam
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Cover ◽  
Structural Members ◽  
Premature Failure ◽  
Near Surface ◽  
Steel Bars ◽  
Near Surface Mounted ◽  
Separation Failure ◽  
Concrete Cover Separation

Nowadays, the use of near surface mounted (NSM) technique strengthening reinforced concrete (RC) structural members is going very popular. The failure modes of NSM strengthened reinforced concrete (RC) beams have been shown to be largely due to premature failure such as concrete cover separation. In this study, CFRP U-wrap end anchorage with CFRP fabrics was used to eliminate the concrete cover separation failure. A total of eight RC rectangular beam specimens of 125 mm width, 250 mm depth, and 2300 mm length were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM steel bars and the remaining four specimens were strengthened with NSM steel bars together with the U-wrap end anchorage. The experimental results showed that wrapped strengthened beams had higher flexural strength and superior ductility performance. The results also show that these beams had less deflection, strain, crack width, and spacing.

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