Experimental Shear Behaviour of Rammed Earth Strengthened with a TRM-Based Compatible Technique

Abstract:

Earthen constructions are spread worldwide, not only as architectural heritage but also as new buildings, in which a total of around one fourth of the global population is estimated to live in. Among the different raw earth techniques, rammed earth was widely used to build vernacular dwellings in different regions. Despite the raising awareness for the high seismic hazard, recognized seismic vulnerability and high seismic exposure associated with earthen structures, the reduction of their seismic risk has been a topic insufficiently addressed. In general, the seismic vulnerability of rammed earth structures is due to poor connections between structural elements (walls and floors), high self-weight and low strength of the material. Hence, a TRM-based strengthening technique is proposed to improve their seismic capacity. To estimate the enhancement of the in-plane performance achieved with the TRM, an experimental program was conducted. Rammed earth wallets were tested under diagonal compression considering their unstrengthened and strengthened condition. The TRM strengthening was performed by embedding a glass fibre mesh (GRE) or a nylon mesh (NRE) in a compatible earth-based mortar. In general, the proposed TRM-based strengthening seems to improve the shear behaviour of rammed earth by enhancing the shear strength and promoting stress distribution after cracking, while no significant influence on the shear modulus of rammed earth seems to occur.

• Periodical: Key Engineering Materials (Volume 817)
• Pages: 544-551
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.817.544
• Online since: August 2019
• Authors: Antonio Romanazzi*, Michiel Van Gorp, Daniel V. Oliveira, Rui A. Silva, Els Verstrynge
• Keywords: Diagonal Compression Test, Digital Image Correlation (DIC), Shear Strength, Textile Reinforced Mortar

References

[1] H. Houben, H. Guillaud, Earth construction: a comprehensive guide. London, Intermediate Technology Publication, (2008).

[2] R.A. Silva, D.V. Oliveira, T. Miranda, N. Cristelo, M.C. Escobar, E. Soares, Rammed earth construction with granitic residual soils: The case study of northern Portugal, Construction and Building Materials, 47 (2013) 181-191.

DOI: 10.1016/j.conbuildmat.2013.05.047

[3] R.A. Silva, N. Mendes, D.V. Oliveira, A. Romanazzi, O. Domínguez-Martínez, T. Miranda, Evaluating the seismic behaviour of rammed earth buildings from Portugal: from simple tools to advanced approaches. Engineering Structures, 157 (2018) 144-156.

DOI: 10.1016/j.engstruct.2017.12.021

[4] M. Correia, Rammed earth in Alentejo. Lisbon, Argumentum, (2007).

[5] T.T. Bui, Q.B. Bui, A. Limam, S. Maximilien, Failure of rammed earth walls: From observations to quantifications. Construction and Building Materials, 51 (2014) 295-302.

DOI: 10.1016/j.conbuildmat.2013.10.053

[6] K. Liu, M. Wang, Y. Wang, Seismic retrofitting of rural rammed earth buildings using eternally bonded fibers. Construction and Building Materials, 100 (2015) 91-101.

DOI: 10.1016/j.conbuildmat.2015.09.048

[7] A.A. Costa, H. Varum, H. Rodrigues, G. Vasconcelos, Seismic behaviour analysis and retrofitting of a row building. In Correia M., Lourenço P.B., Varum H., Seismic Retrofitting: Learning from vernacular architecture. London, Taylor and Francis Group, (2015).

DOI: 10.1201/b18856-39

[8] G. De Felice, S. De Santis, L. Garmendia, B. Ghiassi, P. Larringa, P.B. Lourenço, D.V. Oliveira, F. Paolacci, C.G. Papanicolaou, Mortar-based systems for externally bonded strengthening of masonry. Materials and Structures, 47 (2014) 2021-2037.

DOI: 10.1617/s11527-014-0360-1

[9] B. Ghiassi, G. Marcari, D.V. Oliveira, P.B. Lourenço, Numerical analysis of bond behavior between masonry bricks and composite materials. Engineering Structures, 43 (2012) 210- 220.

DOI: 10.1016/j.engstruct.2012.05.022

[10] L. Righetti, V. Edmondson, M. Corradi, A. Borri, Fiberglass grids as sustainable reinforcement of historic masonry. Materials, 9 (2016) 1-17.

DOI: 10.3390/ma9070603

[11] J. Vargas, M. Blondet, F. Ginocchio, G. García, 35 Años de investigaciones en sismo adobe: la tierra armada, International Conference SismoAdobe 2005: architecture, construction and conservation of earthen buildings in seismic areas, Lima, (2005).

[12] T.L.G. Michiels, Seismic retrofitting techniques for historic adobe buildings. International Journal of Architectural Heritage, 9 (2014) 1059-1068.

DOI: 10.1080/15583058.2014.924604

[13] A. Figueiredo, H. Varum, A. Costa, D. Silveira, C. Oliveira, Seismic retrofitting solution of an adobe masonry wall. Materials and Structures, 46 (2013) 203-219.

DOI: 10.1617/s11527-012-9895-1

[14] Y. Wang, M. Wang, K. Liu, W. Pan, X. Yang, Shaking table tests on seismic retrofitting of rammed earth structures. Bulletin of Earthquake Engineering, 3 (2017) 1037-155.

DOI: 10.1007/s10518-016-9996-2

[15] M. Fagone, F. Loccarini, G. Ranocchiai, Strength evaluation of jute fabric for the reinforcement of rammed earth structures. Composites Part B: Engineering, 133 (2017) 1-13.

DOI: 10.1016/j.compositesb.2016.12.054

[16] K. Van Balen, I. Papayianni, R. Van Hees, L. Binda, A. Waldum, Introduction to requirements for and functions and properties of repair mortars. RILEM TC 167-COM: Characterisation of Old Mortars with Respect to their Repair,. Materials and Structures, 38 (2005) 781-785.

DOI: 10.1617/14319

[17] L. Miccoli, D.V. Oliveira, R.A. Silva, U. Müller, L. Schueremans, Static behaviour of rammed earth: experimental testing and finite element modelling. Materials and Structures, 48 (2015) 3443-3456.

DOI: 10.1617/s11527-014-0411-7

[18] D.V. Oliveira, R.A. Silva, C. Barroso, P.B. Lourenco, Characterization of a compatible low cost strengthening solution based on the TRM Technique for Rammed Earth. Key Engineering Materials, 747 (2018) 150-157.

DOI: 10.4028/www.scientific.net/kem.747.150

[19] A. Romanazzi, D.V. Oliveira, R.A. Silva, A TRM-based compatible strengthening solution for rammed earth heritage: investigation of the bond behavior. In proc. of SAHC2018, International Conference of Structural Analysis of historical Construction, Cusco, Peru, (2018).

DOI: 10.1007/978-3-319-99441-3_171

[20] M. Van Gorp, Experimental study of in-plane behaviour of rammed earth strengthened with TRM. MsC thesis, KU Leuven, (2018).

[21] GOM Correlate 2018 Software Digital Image Correlation.

[22] ASTM E519, Standard test method for diagonal tension (shear) in masonry assemblages, (2002).