Keywords

1 Introduction

URM buildings are weak to failure in an earthquake. Un-reinforced masonry (URM) is widely used in the world. Mortar is a weak part of masonry. Two types of collapse are commonly noticed during seismic prone areas. In-plane and out-of-plane collapses are noticed in URM structures [1]. The in-plane collapse mode is vitally significant in URM walls under seismic action. Past investigator shows that throughout an earthquake, the principal collapse mode is shear [2,3,4]. The vital in-plane collapse strategies of URM walls exposed to seismic actions are presented in Fig. 1 [5, 6].

Fig. 1
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In-plane failure techniques of un-reinforced brick walls a Shear failure, b Sliding failure, c Rocking failure, d Toe-crushing failure

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Application of geosynthetic products has been utilized widely in numerous civil engineering construction viz. retaining walls, embankments, soil backfill [7]. Geosynthetic enhances the execution of roads inside the base course [8, 9]. Geosynthetic, as a form of base isolation, has been investigated by Yegian and Kadakal [10]. There is an expansion to develop new applications to resolve different civil engineering problems [11,12]. In-plane strength is significantly enhanced by using Geosynthetic products [13].

This aim of this study to calculate the in-plane shear behaviour of un-strengthened and strengthened brick walls by application of geotextile with various patterns numerically using ANSYS [14]. To get a diagonal shear collapse mode of a masonry wall, a force can be applied along diagonal of masonry panel as per ASTM E519 [15].

2 Numerical Model

2.1 Introduction

Masonry is an anisotropic component found by the assemblage of bricks and mortar. Numerical models of un-strengthened and strengthened masonry have been formed by finite element analysis in ANSYS. Therefore, numerical models of masonry habitually display a reasonable level of complexity. Generally, three different methods are implemented for the modelling of masonry. The modelling approaches are complete micro-modelling, simplified micro-modelling and macro-modelling [16–18]. In this research, a macro nonlinear 3D model has been formed to determine the in-plane performance of un-strengthened and geotextile strengthened brick masonry specimen.

2.2 Parameters Utilized in Masonry

The parameters utilized in masonry are determined experimentally. The material utilized in the research is illustrated in Table 1. The parameters of the nonwoven geotextiles utilized in the present study are presented in Table 2.

Table 1 Composition of the masonry constituents [13]
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Table 2 Composition of nonwoven polypropylene geotextile [13]
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2.3 Model Description

To determine the in-plane performance of masonry panel under the diagonal compression test, a 3D macro model is analysed. The masonry is assumed as a homogenous considered. The mechanical parameters of the whole structure being homogeneous elements. The dimensions of the masonry panel are 600 mm × 600 mm × 125 mm. Figure 2 illustrates the detail description of the setup and boundary limitations. The compressive loads are applied simultaneously along one diagonal. Therefore, one diagonal gets contracted, and other gets extended.

Fig. 2
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Masonry specimen loaded diagonally

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In this model, masonry specimen is modelled with a higher-order 3D, 10 nodes of SOLID187 tetrahedron elements Fig. 3a.

Fig. 3
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Elements taken of model a SOLID 187 b CONTA174 c SHELL63

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Geotextile is utilized with SHELL 63 element due to its bending and membrane capacities in the ANSYS, and the detail description is depicted in Fig. 3b. The interface between masonry and geotextile is modelled with CONTA174 element Fig. 3c. The Drucker–Prager formulation is considered for the masonry specimen [13]. Nonlinear behaviour is investigated.

Figure 4a–c depicts finite element mesh utilized for the masonry panel before and after strengthening correspondingly. Nonlinear static analyses are adopted by using the Newton–Raphson iteration method.

Fig. 4
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Mesh details of a UR, b RHSS, c RXSS

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3 Results and Discussion

The strengthening of masonry specimen was evaluated. Figure 5 depicts the distribution of shear stress. Shear capability is enhanced from UR to RHSS and RHSS to RXSS correspondingly.

Fig. 5
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Shear stress distribution for a UR, b RHSS, c RXSS at collapse

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The load-deformation graphs evaluated along the compressed diagonal is investigated. The load-deformation capacities increase with strengthening giving maximum in case of the diagonal pattern. Figure 6 depicts the graphs of comparative load-deformation performances for masonry specimen. The comparison indicates almost equal before and after strengthening in collapse load and the stiffness correspondingly.

Fig. 6
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Diagonal compression of masonry specimen

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As per ASTM E 519, the distribution of shear stress for masonry specimen is evaluated and shown in Table 3 and Fig. 7.

Table 3 Evaluated diagonal strength
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Fig. 7
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Comparison of the Diagonal shear strength of one-side strengthened specimen

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The Diagonal shear strength enhanced from 36 to 39%. Furthermore, it was also illustrated that the panel with diagonal strengthening gives better performance.

Figure 7 illustrates the comparisons of the diagonal shear strength of the one-side strengthened specimen. RXSS indicates the highest stiffness and deformation capability.

4 Conclusions

The numerical observation was investigated under diagonal compression tests to develop the diagonal shear strength of masonry specimen. Based on the analysis, the following findings are pointed out:

  • The strengthened specimen enhanced the failure load and deformation from UR to RHSS and RHSS to RXSS correspondingly.

  • The diagonal shear strength enhanced from 0.3128 to 0.3197 MPa.

  • Furthermore, diagonal strengthening has more stiffness than others.

  • Brittle failure noticed for un-strengthened panel while strengthening enhanced its deformation capability.

  • It is also pointed out that load-carrying capability, deformation capability, diagonal shear strength and stiffness are significantly increased from parallel to diagonal, respectively.