Experimental Evaluation of Unreinforced Adobe Wall Made of Adobe Units of Historical City of Yazd

Document Type : Original Research

Author
A. Jahanmohammadi
BHRC (Building and Housing Research Center)
10.22034.24.3.45
Abstract
Regarding the decisions made in the 41st world heritage committee for the nomination of historic city of Yazd, Iran has to maintain the buildings located in the core and buffer zone of historic district of the city and construct new buildings as well. With respect to new buildings, natural and cultural issues must be considered and architectural details must be followed in compatible with district’s specifications. In addition, new methods must be adopted to improve the behavior of the buildings; the methods must be compatible with the structural essence. Based on the reports, most of the buildings located in the historic core and buffer zone of Yazd are typically one- or two-story adobe masonry buildings, especially ancient, traditional or historic ones. Therefore, for constructing new buildings, using adobe as the main material is required. This will result in investigating the properties of adobe as the material, adobe masonry building for detecting the load-bearing system and the constructional features that may help the whole response of the building to the earthquake forces. In this regard and with respect to the architectural aspects of historic buildings in a historic district, the structural performance in response to imposed forces is evaluated and participation of adobe walls in bearing the vertical and horizontal forces is determined. Based on the existing information resulted from the evaluation of characteristics of adobe, the main specifications of adobe as the main material in before mentioned construction is presented. These results are mainly focused on the adobe units made in Yazd and by using the soil of the district. Using this information, the common expected values for compressive, tensile and flexural strength of adobe units and clay mortar are presented. To evaluate the performance of adobe walls which are built in a historic building with natural material and by experts, previous investigations are reviewed. These investigations usually cover the experiments on adobe units and adobe prisms made by natural materials of Yazd city. To complete the overall investigation in this regard, complementary tests are followed in this research. Specimens of the test have been prepared by using the adobe units and clay mortars made in the city of Yazd. The preliminary tests have been conducted on the adobe units, clay mortars and adobe prisms. After that, performance of a full-scale adobe wall under the simultaneous horizontal and vertical loads is evaluated. Regarding the results, behavior of an unreinforced adobe wall is detected and its defeats are reported. Based on the experimental results and previous studies performed on studying the architectural features of the historic district of Yazd, recommendations for common values of the strength in adobe units and prisms are presented. In addition, special issues are raised. These issues must be considered in constructing the adobe masonry buildings in order to fulfill the architectural requirements and help the whole structure to bear the gravity and seismic forces. It is expected that these issues be considered in any upcoming guidelines that will be provided for constructing new adobe buildings in Yazd and any other historic districts.

Keywords

Subjects

[1] ICHHTO, 2017. Nomination of historic city of Yazd, Nomination detailed text for the world heritage committee.
[2] Technical committee, 2017. Decisions adopted during the 41st session of the world heritage committee, WHC/17/41.COM/18.
[3] Technical committee, 2018. Design and construction of masonry buildings, Chapter 8 of National Building Regulations of Iran (NBRI).
[4] Mansouri, F., 2018. An Enquiry into the Principles and Codes of Earthen Architecture (Emphasizing on Earthen Architecture Building Codes in Countries with the Same Seismic Zoning as Iran). MSc. Thesis, 2018. Yazd University.
[5] Omidvari, F., 2018. Comparative analysis of Adobe Building codes from different countries prone to seismic hazards. Post-Doctoral research. University of Grenoble.
[6] Faghih Khorasani, F., 2019. Effects of using natural short fibers reinforcing in clay adobe units on the behavior of masonry walls. PhD. Dissertation. Amirkabir University.
[7] Mohammadi, H., Eslami, A., Morshed, R., 2022. Experimental evaluation into improving the mechanical properties of adobe using palm fibers. Amirkabir J. Civil Eng., 54(6) 2321-2342.
[8] Mirjalili, A., Eslami, A., Morshed, R., 2020. Experimental investigation into the effect of vertical loading on in-plane cyclic behavior of adobe walls. Construction and Building Materials, 264, 120706.
[9] Meybodian, H., Eslami, A., Morshed, R., 2020. Sustainable lateral strengthening of traditional adobe walls using natural reinforcements. Construction and Building Materials 260, 119892.
[10] Mirabi Banadaki, H., Morshed, R., Eslami, A., 2019. In-plane cyclic performance of adobe walls retrofitted with near-surface-mounted steel rebars. Engineering Structures 194, 106–119.
[11] Mirabi Banadaki, H., Eslami, A., Ronagh, H., 2020. Near-surface-mounted retrofitting of damaged/undamaged adobe walls using steel bars: Analytical evaluation of experimental results. Structures 28, 2111–2121.
[12] HajiSadeghi, N., 2018. Conservation and Safety Assessment of Vaulted Adobe Architecture in Yazd, Iran. Doctoral Thesis, University of Minho.
[13] Maserrat, H., 2015. From soil to adobe, architectural and anthropology aspects. Yazda publication.
[14] Dormohammadi, M., Rahimnia, R., 2017. Soil mechanical stabilization and determination of its position in vernacular materials of hot and dry climate, Journal of Architecture Hot and dry climate, 5 (6), 29-49.
[15] Bakhshi A., Ghannad, M., Masaeli, H., Yekrangnia, M., 2011. Assessment of seismic Behavior of Domed-roof Adobe Buildings - existing and reinforced cases, Bonyad Maskan Publication.
[16] Veiseh, S., Mazloomi sani, M., 2023. Utilization of stabilized adobe for restoration of old buildings and construction of new buildings in the historical context of Yazd, G1039, BHRC publications.
[17] Esmaeili, A., Ghalenoi, M., 2013. Effect of palm fibers and lime as natural stabilizer on the mechanical properties of adobe. Maskan-o-mohit roosta, 138, 53-62.
[18] ASTM C109/C109M-20a, 2020. Standard test method for compressive strength of hydraulic cement mortars (using 2-in. or [50-mm] cube specimens), West Conshohocken, PA, ASTM International.
[19] ASTM C307–18, 2018. Standard test method for tensile strength of chemical resistant mortar, grouts, and monolithic surfacings, West Conshohocken, PA, ASTM International.
[20] ASTM C348–19, 2019. Standard test method for flexural strength of hydraulic cement mortars, West Conshohocken, PA, ASTM International.
[21] ASTM C1552-16, 2016. Standard practice for capping concrete masonry units and masonry prisms for testing, West Conshohocken, PA, ASTM International.
[22] ASTM C 1314-07, 2007. Test Method for Compressive Strength of Masonry Prism, West Conshohocken, PA, ASTM International.
[23] ASTM C1531-16, 2016. Standard Test Methods for In Situ Measurement of Masonry Mortar Joint Shear Strength Index, West Conshohocken, PA, ASTM International.
Modares Civil Engineering journal
Volume 24, Issue 3
July and August 2024
Pages 45-58