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Investigation on the Structural Behavior of Rammed Earth Structures

Kianfar, Ehsan | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 54764 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Toufigh, Vahab
  7. Abstract:
  8. Nowadays, construction with earthen materials has become more widespread due to their advantages: low construction cost, low embodied energy, application of green materials, and recyclability. Rammed earth (RE) as a sustainable construction has been used worldwide for decades. They are built in many countries such as Australia, China, India, and many parts of Africa and Europe. The rammed earth materials are cheap, accessible, and green and provide good thermal buffering. Stabilizers such as cement and lime with high embodied energy are frequently used in rammed earth construction to enhance materials' mechanical properties and durability. Stabilizers in RE materials could affect the energy consumption and output of carbon emissions of buildings. Therefore, studies shall be executed to apply proper additives as a replacement for the industrial stabilizers to reduce the environmental impacts of commonly used materials.Investigations on the behavior of rammed earth structures due to the variability of materials worldwide are limited. Due to a lack of design standards, guides, and provisions for the design and construction of rammed earth materials, the engineering decisions often rely on the rule-of-thumb method, leading to quite conservative procedures. In addition, not considering the different environmental conditions can cause damage and unsafe design of this type of construction. Furthermore, the studies on the nonlinear behavior of RE structures as a result of mentioned limitations are still rare and not comprehensive. RE materials are brittle and have high mass. The collapse and damage of many rammed earth structures have been reported in past earthquakes. Therefore, to reduce the risk of human and economic losses in the unavoidable environmental loads and possible earthquakes, finding a reliable solution to analyze and design these structures and rehabilitate the existing ones.The main objective of this research is to investigate the overall behavior of rammed structures. The investigations would be performed in two phases. In the experimental phase, small-scale samples will be tested to assess the applicability of different green and waste stabilizers and additives. In the analytical phase, the reliability analysis would first be done unstabilized, and cement stabilized rammed earth structures under non-seismic loads under relatively severe and moderate loads. Then, the probabilistic approach dealing with uncertainties is used to check the general recommendations on the wall thickness and compressive strength of materials. Then, the seismic behavior of rammed earth structures will be investigated by nonlinear modeling, and the uncertainty of earthquake load will be considered in the assessment of RE structures. Finally, the endurance time method will be used to compare different types of rammed earth structures, and results will be used for seismic analysis.
    Keywords
  9. Keywords:
  10. Rammed Earth Structures ; Reliability Analysis ; Seismic Analysis ; Endurance Time Method ; Green Construction Materials ; Sustainable Structures

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