scholarly journals Assessing the Seismic Behavior of Rammed Earth Walls with an L-Form Cross-Section

2019 ◽  
Vol 11 (5) ◽  
pp. 1296 ◽  
Author(s):  
Quoc-Bao Bui ◽  
Tan-Trung Bui ◽  
Mai-Phuong Tran ◽  
Thi-Loan Bui ◽  
Hoang-An Le
Keyword(s):  
Cross Section ◽  
Seismic Performance ◽  
Seismic Behavior ◽  
Rectangular Cross Section ◽  
Construction Material ◽  
Numerical Approach ◽  
Rammed Earth ◽  
3D Fem ◽  
Earthquake Performance ◽  
Earth Walls

Rammed earth (RE) is a construction material which is made by compacting the soil in a formwork. This material is attracting the attention of the scientific community due to its sustainable characteristics. Among different aspects to be investigated, the seismic performance remains an important topic which needs advanced investigations. The existing studies in the literature have mainly adopted simplified approaches to investigate the seismic performance of RE structures. The present paper adopts a numerical approach to investigate the seismic behavior of RE walls with an L-form cross-section. The 3D FEM model used can take into account the plasticity and damage of RE layers and the interfaces. The model was first validated by an experimental test presented in the literature. Then, the model was employed to assess the seismic performance of a L-form wall of a RE house at different amplitudes of earthquake excitations. Influences of the cross-section form on the earthquake performance of RE walls were also investigated. The results show that the L-form cross-section wall has a better seismic performance than a simple rectangular cross-section wall with similar dimensions. For the L-form cross-section wall, the damage observed concentrates essentially on the connection between two flanges of the wall.

scholarly journals Design Optimisation Strategies for Solid Rammed Earth Walls in Mediterranean Climates

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 325
Author(s):  
Giada Giuffrida ◽  
Maurizio Detommaso ◽  
Francesco Nocera ◽  
Rosa Caponetto
Keyword(s):  
Energy Demand ◽  
Construction Material ◽  
Base Material ◽  
Energy Performance ◽  
Embodied Energy ◽  
Rammed Earth ◽  
Earth Construction ◽  
Material Choice ◽  
Earth Walls ◽  
Raw Earth

The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.

scholarly journals Flow through a helical pipe with rectangular cross-section

1970 ◽  
Vol 4 (2) ◽  
pp. 99-110
Author(s):  
Md Mahmud Alam ◽  
Delowara Begum ◽  
K Yamamoto
Keyword(s):  
Aspect Ratio ◽  
Iterative Method ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Main Tool ◽  
Numerical Approach ◽  
Dean Number ◽  
Helical Pipe ◽  
Flow Through ◽  
Marine Engineering

The effects of torsion, aspect ratio and curvature on the flow in a helical pipe of rectangular cross- section are studied by introducing a non-orthogonal helical coordinate system. Spectral method is applied as main tool for numerical approach where Chebyshev polynomial is used. The numerical calculations are obtained by the iterative method. The calculations are carried out for 0≤ δ ≤0.02, 1≤ λ ≤ 2.85, 1≤ γ ≤2.4, at Dn = 50 & 100 respectively, where d is the non-dimensional curvature, l the torsion parameter, g the aspect ratio and  Dn the pressure driven parameter (Dean number).DOI: http://dx.doi.org/10.3329/jname.v4i2.991 Journal of Naval Architecture and Marine Engineering Vol.4(2) 2007 p.99-110

scholarly journals Current State of Modern Rammed Construction: A Case Study of First Peoples House after Seven Years Exposure

2015 ◽  
Vol 666 ◽  
pp. 63-76 ◽  
Author(s):  
Allan Kailey ◽  
Gupta Rishi
Keyword(s):  
Construction Material ◽  
Surface Condition ◽  
Infrared Camera ◽  
Rammed Earth ◽  
Destructive Testing ◽  
Current State ◽  
First Peoples ◽  
Wet Climate ◽  
The University ◽  
Earth Walls

This paper presents a study on the current condition of the First Peoples House, located at the University of Victoria in British Columbia. The building houses two rammed earth walls that exemplify the use of stabilized rammed earth as a modern construction material. These rammed earth walls have been exposed to 7 years of natural weathering in a wet climate. A rebound hammer, infrared camera, and a new method developed to quantify surface deterioration were used in Non-Destructive Testing (NDT). The results provided insight into the compressive strength, thermal envelope and surface condition of the walls. Relationships between wind direction and wind speed are presented. It is postulated that the wall that is most exposed to a combination of both effects will exhibit the largest forms of deterioration. This hypothesis was addressed using results from NDT and local wind data.

scholarly journals Vertical Rods as a Seismic Reinforcement Technique for Rammed Earth Walls: An Assessment

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Q.-B. Bui ◽  
T.-T. Bui ◽  
R. El-Nabouch ◽  
D.-K. Thai
Keyword(s):  
Compressive Strength ◽  
Numerical Study ◽  
Construction Material ◽  
Thermal Inertia ◽  
Embodied Energy ◽  
Rammed Earth ◽  
Seismic Action ◽  
Horizontal Force ◽  
The Subject ◽  
Earth Walls

Rammed earth (RE) is a construction material which is manufactured by compacting soil by layers within a formwork to build a monolithic wall. RE material is the subject of numerous scientific researches during the last decade because of the significant heritage of RE buildings and the sustainable properties of this material: low embodied energy, substantial thermal inertia, and natural regulator of moisture. The seismic performance of RE buildings is an interesting topic which needs to be thoroughly investigated. This paper presents a numerical study which assesses the relevancy of a seismic reinforcement technique for RE walls by using two vertical steel rods installed at two extremities of the walls. The discrete element method (DEM) was used to model unreinforced and reinforced RE walls. These walls were first loaded with a vertical stress on the top to simulate the vertical loads and then submitted to a horizontal loading on the top to simulate the seismic action. Two current cases of RE buildings were investigated: one-storey and two-storey buildings. The results showed that the reinforcement technique enhanced the maximum horizontal force about 25% and 10%, respectively, for the cases of one- and two-storey buildings. Higher effectiveness of this reinforcement technique is expected for RE materials having higher compressive strength, for example, stabilized RE.

scholarly journals Shear Parameters of Rammed Earth Material: Results from Different Approaches

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
R. El-Nabouch ◽  
Q.-B. Bui ◽  
P. Perrotin ◽  
O. Plé
Keyword(s):  
Numerical Model ◽  
Seismic Performance ◽  
Numerical Models ◽  
Construction Material ◽  
Experimental Studies ◽  
Friction Angle ◽  
Rammed Earth ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Experimental Values

Rammed earth (RE) is a construction material which is manufactured by compacting the soil in a formwork, in different layers. Several recent studies have investigated this material. The seismic performance of RE buildings is an important topic which needs to be carefully investigated. The complex numerical model seems a performant approach to investigate the seismic performance of a whole building. To correctly establish the model, the shear parameters of the material, which are the cohesion and the friction angle, should be identified. This paper first presents experimental studies on the shear parameters of RE through the direct shear tests, at two different scales. The differences of the results at different scales are analyzed. Then, the obtained experimental values are used in a numerical model to simulate the shear behavior of RE walls which are loaded by a constant vertical stress and pushed horizontally on the top. From the obtained results, the values for numerical models are recommended.

scholarly journals Seismic Behavior of Rammed Earth Walls with Precast Concrete Tie Columns

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xinlei Yang ◽  
Hailiang Wang
Keyword(s):  
Rural Areas ◽  
Seismic Behavior ◽  
Precast Concrete ◽  
Rammed Earth ◽  
Deformation Capacity ◽  
Test Results ◽  
Load Bearing ◽  
Displacement Ductility ◽  
Reversed Cyclic ◽  
Earth Walls

Rammed earth (RE) constructions are widespread in underdeveloped rural areas in developing countries. However, these RE constructions are often susceptible to earthquake damage due to their poor seismic performance. Precast concrete tie columns and ring beam (tie bars) were proposed to improve the seismic behavior of RE constructions. Four RE walls, including a traditional RE wall and three RE walls with precast concrete tie columns and ring beam (tie bars), were tested under reversed cyclic loading, and the seismic behavior of these tested specimens was evaluated in terms of failure pattern, energy dissipation, displacement ductility, and stiffness degradation. The results showed that a significant increase of the load-bearing and deformation capacity could be achieved with the application of precast concrete tie columns in combination with RE. The load-bearing capacity and deformation capacity of traditional RE wall were increased by an average of 113% and 417%, respectively. These test results could provide reference to the design and construction of the environmental-friendly structures in rural areas.

Seismic performance of stabilised/unstabilised rammed earth walls

2021 ◽  
Vol 245 ◽  
pp. 112982
Author(s):  
Moein Ramezanpour ◽  
Abolfazl Eslami ◽  
Hamid Ronagh
Keyword(s):  
Seismic Performance ◽  
Rammed Earth ◽  
Earth Walls

Experimental testing of the in-plane behavior of bearing modern rammed earth walls

2018 ◽  
Vol 21 (13) ◽  
pp. 2045-2055 ◽  
Author(s):  
Tiegang Zhou ◽  
Bo Liu ◽  
Xiang Zhao ◽  
Jun Mu
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Failure Modes ◽  
Experimental Testing ◽  
Mainland China ◽  
Shear Capacity ◽  
Rammed Earth ◽  
Seismic Belt ◽  
China Mainland ◽  
Earth Walls

With the introduction of the modern rammed earth technique, a large number of modern rammed earth buildings were constructed in China Mainland. China has a vast territory, which faces the Circum-Pacific seismic belt on the east and the Eurasian seismic belt on the south; earthquake has constantly threatened the safety of people’s lives and property. Consequently, it is necessary to probe in the seismic performance of rammed earth buildings. Two un-stabilized rammed earth specimens, one un-stabilized rammed earth reinforced with geogrid sheets’ specimens, and four stabilized rammed earth specimens were built for obtaining a better insight on the behavior of un-stabilized rammed earth/stabilized rammed earth walls under cyclic in-plane loads. Testing results are discussed in terms of failure mode, shear capacity, hysteretic curve, stiffness degradation, and total energy dissipation to provide comparisons of the seismic performance between un-stabilized rammed earth and stabilized rammed earth specimens. Different failure modes indicated that the cohesion between particles and the bond strength between layers are the two key parameters for the shear capacity of rammed earth buildings. It is also demonstrated that stabilized rammed earth specimens have higher shear and energy dissipation capacity but weaker deformation capacity than un-stabilized rammed earth.

Assessing the in-plane seismic performance of rammed earth walls by using horizontal loading tests

2017 ◽  
Vol 145 ◽  
pp. 153-161 ◽  
Author(s):  
Ranime El-Nabouch ◽  
Quoc-Bao Bui ◽  
Olivier Plé ◽  
Pascal Perrotin
Keyword(s):  
Seismic Performance ◽  
Rammed Earth ◽  
Horizontal Loading ◽  
Loading Tests ◽  
Earth Walls
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