Seismic strengthening of masonry walls using bamboo components

2019 ◽  
Vol 22 (14) ◽  
pp. 2982-2997 ◽  
Author(s):  
Qingfeng Xu ◽  
Xi Chen ◽  
Jian-Fei Chen ◽  
Kent A Harries ◽  
Lingzhu Chen ◽  
...  
Keyword(s):  
Construction Industry ◽  
Cement Mortar ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Limit States ◽  
Green Material ◽  
Remote Areas ◽  
Externally Bonded ◽  
Reinforced Cement ◽  
Energy Dissipation Capacity

Bamboo is a sustainable green material and has been gradually applied in the construction industry; however, little research on strengthening masonry structures with bamboo has been carried out. In this article, strengthening methods using bamboo were developed including bamboo grid reinforced cement mortar layer, externally bonded bamboo mats, additional confining horizontal bamboo reinforced concrete band beams, and bamboo strips placed in mortar joints. Ten masonry walls were designed including two reference walls. Experimental results showed that all the strengthening methods can improve certain aspects of the seismic performance of masonry walls. The shear strength, deformability, and energy dissipation capacity of masonry walls strengthened with bamboo grid reinforced cement mortar and externally bonded bamboo mats were the most improved. The limit states of tested walls were discussed. Strengthened masonry structures with bamboo components are promising methods and can be used especially in remote areas.

Mechanical in-plane behaviour of masonry walls reinforced by composite materials: Experimental and analytical approaches

2017 ◽  
Vol 51 (30) ◽  
pp. 4231-4249 ◽  
Author(s):  
L Bui ◽  
N Reboul ◽  
A Si Larbi ◽  
E Ferrier
Keyword(s):  
Reinforced Concrete ◽  
Composite Materials ◽  
Experimental Tests ◽  
Analytical Models ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Textile Reinforced Concrete ◽  
Reinforced Polymers ◽  
Externally Bonded ◽  
Analytical Approaches

Masonry is a traditional building system in most countries of the world, including France. However, in recent decades, earthquakes have caused significant damage to masonry structures. The possibility of using textile-reinforced concrete or fibre-reinforced polymers to strengthen masonry structures has been recently assessed. This article addresses the effectiveness of externally bonded composite materials, particularly those based on newly developed cementitious matrices, to strengthen masonry structures. Experimental tests were performed in a previous study on six masonry walls, five of which were strengthened on both sides with either textile-reinforced concrete or fibre-reinforced polymers. This experimental campaign has been supplemented to determine the mechanical properties of the materials involved in design models, and it is used to check the potential of analytical models to predict lateral strength. This study identifies the interests and the restrictions governing the use of traditional empirical design approaches (employed for fibre-reinforced polymer-strengthened walls) when next-generation textile-reinforced concrete composites are used as strengthening materials. Adjustments taking into account the specificities of textile-reinforced concrete behaviour have been introduced, and their impact on the relevance of the models has been quantified.

Sub-Paneling of Masonry Walls Using Precast Reinforced Concrete Elements for Earthquake Resistance

2014 ◽  
Vol 30 (2) ◽  
pp. 913-937 ◽  
Author(s):  
Durgesh C. Rai ◽  
Vaibhav Singhal ◽  
Samaresh Paikara ◽  
Debashis Mukherjee
Keyword(s):  
Earthquake Resistance ◽  
Structural Performance ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Lateral Loads ◽  
Cyclic Tests ◽  
Energy Dissipation Capacity ◽  
Element Density ◽  
Strength And Stiffness ◽  
Concrete Elements

Some traditional designs of masonry structures have shown acceptable structural performance during past earthquakes. In these structures, a grid of horizontal, vertical, and/or diagonal elements divide a large wall into smaller wall areas and provide confinement to masonry panels. In addition, grid elements provide a definite shearing plane along which masonry blocks can slide adding to deformability and energy-dissipation capacity. Inclined elements significantly add to lateral stiffness and strength depending on whether they can develop a complete truss action for lateral loads. Cyclic tests were conducted on five half-scaled wall specimens with different sub-paneling schemes using RC precast grid elements. Experimental results and finite element studies were used to develop simplified predictive relations for strength and stiffness response based on a confinement factor representing the grid element density. These relations can be used to configure the grid elements for desired performance levels with additional inputs about the global behavior.

Typical brick masonry walls reinforced with high-strength mortar and steel bars in the horizontal joints

2021 ◽  
pp. 136943322110122
Author(s):  
Xinqiang Yao ◽  
Bin Liang ◽  
Hai Zhang ◽  
Ziliang Zhang ◽  
Zheng He
Keyword(s):  
Cement Mortar ◽  
High Strength ◽  
Shear Capacity ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Test Plan ◽  
Static Tests ◽  
Rural Buildings ◽  
Steel Bars

Based on investigation of rural buildings in china, there are more than 20% of the masonry structures constructed in 1970s. Thus, the old blue bricks (OBB) and old red bricks (ORB), which demolished from the typical brick masonry structures was built in 1970s, was chosen in the test. During demolishing the OBB and ORB, the original mortar was destroyed. Thus, the 1:7.8 cement mortar was chosen instead of original mortars and the 1:5 cement mortar was chosen as the reinforcement mortar. In order to know the performant of the reinforcement methods, there are three-level test plan was put forward in the study. Firstly, the mechanical properties of OBB and ORB and mortars was tested; Secondly, the experiment tested the shear strength of the reinforced and unreinforced masonry specimens along mortar joints; Thirdly, there are four walls (OBB reinforced wall and unreinforced wall, ORB reinforced wall and unreinforced wall) have been made for the pseudo-static tests. This research conducted physical performance tests on masonry bricks, masonry components, and masonry walls of typical masonry structures. Through experiments, the shear capacity of the masonry structure reinforced by high-strength mortar and steel bars can be obtained.

scholarly journals In-Plane Seismic Response of Unreinforced and Jacketed Masonry Walls

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 472
Author(s):  
Senad Medić ◽  
Mustafa Hrasnica
Keyword(s):  
World War Ii ◽  
Cement Mortar ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Recent Past ◽  
Southeast Europe ◽  
World War ◽  
Lateral Strength ◽  
The University ◽  
Diagonal Crack

Low-rise residential and public masonry structures constitute a large portion of the building patrimony, yet they were erected during the massive reconstruction of Southeast Europe after World War II before any design rules existed in the engineering praxis. Unreinforced unconfined masonry buildings (URM) were proven rather vulnerable during stronger earthquake motions in the recent past. To determine lateral strength, stiffness, and capacity of energy dissipation of the URM walls, in-plane tests were performed at the University of Sarajevo. Two full-scale plain walls (233 × 241 × 25 cm) built with solid clay brick and lime-cement mortar and two walls strengthened with RC jacketing on both sides were subjected to cyclic lateral loading under constant vertical precompression. Plain walls failed in shear with a typical cross-diagonal crack pattern. Jacketed walls exhibited rocking with characteristic S-shaped hysteretic curves and significantly larger ductility compared with plain walls. Wallets were tested for modulus of elasticity and compressive strength of masonry and the results showed considerable variations.

scholarly journals Preparation and piezoresistivity of carbon nanotube-coated sand reinforced cement mortar

2020 ◽  
Vol 9 (1) ◽  
pp. 1445-1455
Author(s):  
Song Gao ◽  
Jianlin Luo ◽  
Jigang Zhang ◽  
Fei Teng ◽  
Chao Liu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Cement Mortar ◽  
Aqueous Suspension ◽  
Ac Impedance ◽  
Stress Sensitivity ◽  
Multiwall Carbon Nanotube ◽  
Impedance Technique ◽  
Reinforced Cement ◽  
Coated Sand ◽  
Mechanical Strengths

Abstract Water and sand were used as the medium of multiwall carbon nanotube (MCNT) and prepared MCNT aqueous suspension and MCNT suspension-coated sand, respectively; afterwards, they were introduced into cement mortar (MNT/CM, MNTSM), respectively. Next, mechanical strengths and piezoresistive properties (DC resistivities (ρ v), AC impedances (Z r)) under cyclic loadings (σ c) of two types of MNT/CM and MNTSM nanocomposites were investigated to explore the intrinsic and self-sensing behaviors. Results reveal that MCNT can be evenly and well-coated on sand, which favors to achieve its intrinsic self-sensing property. Although the fraction changes in ρ v and Z r under the same σ c of MNTSM are both lower than those of MNT/CM, the stress sensitivity of MNTSM is only −1.16%/MPa (DC resistivity), −1.55%/MPa (AC impedance); its sensing linearity and stability (2.53, 2.45%; 2.73, 2.67%) are superior to those of MNT/CM (4.94, 2.57%; 3.78, 2.96%). Piezoresistivity using AC impedance technique is helpful to acquire balanced sensing sensitivity and stability while applied as intrinsic sensors in infrastructure.

Multifunctional Textiles for Protection against Natural Hazards

2008 ◽  
Vol 56 ◽  
pp. 601-608 ◽  
Author(s):  
Donato Zangani
Keyword(s):  
Health Monitoring ◽  
Structural Damage ◽  
Monitoring Systems ◽  
Masonry Walls ◽  
Historic Buildings ◽  
Masonry Structures ◽  
Strong Earthquakes ◽  
Soil Structures ◽  
Earthquake Protection ◽  
Heavy Rainfalls

Textile structures are extensively used in construction in forms of geotextiles. The retrofitting of existing masonry walls and soil structures is particularly important for earthquake protection of historic buildings and protection of earthworks against landslides. Unreinforced masonry structures are highly vulnerable because being originally designed mainly for gravity loads they often cannot withstand the dynamic horizontal loads in case of strong earthquakes. Soil structures, such as embankments, are subjected to landslides after heavy rainfalls or during earthquakes. Hence the necessity to develop efficient methods for the retrofitting of existing masonry buildings and earthworks and of related monitoring systems to possibly prevent the structural damage. To solve the above issues new multifunctional textile structures are being developed for application in construction for the retrofitting of masonry structures and earthworks, integrating a combination of different functions, including structural health monitoring.

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