Mechanical Properties of Tibetan Rubble Stone Masonry Under Uniaxial Compression

: Basic mechanical properties of Tibetan rubble stone masonry, a unique 10 architectural structure in western China, may affect the bearing capacity of architectural 11 structures. In this study, a compression test was carried out on a Tibetan rubble prism to 12 investigate its failure mechanism and stress-strain characteristics under uniaxial 13 compression. Based on the experimental results, we obtained two simple compression 14 constitutive models for Tibetan rubble stone masonry, established equations applicable to 15 predicting the compressive strength of Tibetan rubble stone masonry, and obtained a 16 relationship between compressive strength and the elasticity modulus through a regression 17 analysis.


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Tibetan rubble stone masonry, a unique architectural structure in western China, refers to 23 a masonry composed of natural rubble, clay, and waste materials. Yellow clay caulking and 24 gravel caulking masonry form the most common types of Tibetan walls. The defects of natural 25 materials (e.g., irregular shapes of stones, low flexural strength, poor bonding performance of 26 clay, and poor resistance to rain wash) significantly reduce the stress performance and 27 durability of Tibetan rubble stone masonry walls, resulting in poor compression performance 28 of Tibetan rubble stone masonry. Currently, there are few research results available due to the 29 regional characteristics of Tibetan rubble stone masonry. In Equation (5) -20] 75 indicated that test costs and periods can be reduced by obtaining the compressive strength 76 and elasticity modulus of specimens based on tests of prismatic specimens built with the same 77 materials. Moreover, Eurocode 6 [21] also analyzed the mechanical properties of rubble stone 78 masonry by testing prismatic specimens.

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In summary, many scholars have investigated mechanical properties of traditional 80 masonry structures, but the mechanical properties of Tibetan rubble stone masonry structures 81 have rarely been explored. The failure mechanism of Tibetan rubble stone masonry structures 82 greatly differs from that of conventional masonry structures [22]. In this study, by fully 83 considering the characteristics of Tibetan rubble stone masonry (i.e., relative size, internal 84 composition, geometric shape, and structural characteristics), representative prismatic      Table 3.

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The two layers of rubble, i.e., inner and outer, bear the primary portion of the load in 123 Tibetan stone masonry. To simplify the compression test, the middle inter-layer was removed, 124 and a basic study was performed on the Tibetan rubble stone masonry, as shown in Figure   125 2(a). According to the European standard EN1052-1 [24], prismatic specimens should contain 126 at least three layers and at least one joint. Based on the characteristics of Tibetan walls and 127 experimental conditions, when the height to thickness ratio (h/t) is greater than 2, the 128 boundary effect will be insignificant [22].   148 Figure 4 shows the measured compressive stress-strain curves of rubble prisms 149 constructed using two different masonry processes, i.e., clay caulking and gravel caulking.

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The stress was obtained by dividing the compressive load by the cross-sectional area (F/A),  Table 5 155 shows the parameters of the masonry, e.g., the compressive strength and the elasticity modulus, which were derived from the measured results

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The stress-strain curves in Figure 4 show that although the two different types of prisms   (Table 6), as well as failure processes and morphologies similar to those described above.

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In Equation (15), parameter a denotes the ratio of the secant modulus corresponding to 248 the peak point of prismatic specimens to the initial tangent modulus.

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The failure of Tibetan rubble stone masonry was assumed to obey the Weibull statistical Strain( mm/mm) where a and m are the parameters of the Weibull distribution.

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The macro-damage of the masonry is a conglomeration of the damage and deterioration 287 of meso-elements. The development of the masonry structure from an undamaged state to a 288 completely damaged state is a continuous process where the damage increases over time.

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Therefore, a damage variable, D, was defined: The values of a and m in Equation (19) were determined by the uniaxial compression tests.

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According to the characteristics and boundary conditions of stress-strain curves for masonry 294 under uniaxial compression, a constitutive model for Tibetan rubble stone masonry under 295 uniaxial compression was developed:    Table 7.    Table 2). The comparison is provided in Table 8.