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.

Bond of Steel Bars to Masonry Mortar Joints: Test Results and Analytical Modelling

2017 ◽  
Vol 747 ◽  
pp. 319-325 ◽  
Author(s):  
Matteo Maragna ◽  
Cristina Gentilini ◽  
Giovanni Castellazzi ◽  
Christian Carloni
Keyword(s):  
High Strength ◽  
Experimental Tests ◽  
Analytical Investigation ◽  
Masonry Walls ◽  
Test Results ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bars ◽  
Masonry Mortar

In this paper, the preliminary results of a series of pull-out tests conducted on mortar cylinders with embedded bars are presented. The bars are made of high strength stainless steel and are of helical shape to increase mechanical interlocking with the surrounding mortar. Usually, such bars are employed in situ to realize structural repointing in the case of fair-faced masonry walls. To this aim, they are inserted in the mortar bed joints of masonry for providing tensile strength to the walls and with the function of crack stitching. The aim of the present experimental tests is to determine the bond-slip relationship for bars embedded in masonry. Firstly, pull-out tests are conducted on mortar cylinders considering different embedded lengths of the bars. Further tests are on-going on masonry specimens with bars embedded in the mortar joints. An analytical investigation is also carried out for the interpretation of the pull-out test results.

scholarly journals EFFECT OF IMPACT LOAD ON THE PERFORMANCE OF CONCRETE SLABS REINFORCED BY CFRP BARS

2021 ◽  
Vol 25 (01) ◽  
pp. 68-79
Author(s):  
Hind T. Khamies ◽  
◽  
Mu’taz K. Medhlom ◽  
Keyword(s):  
Impact Load ◽  
High Strength ◽  
Shear Capacity ◽  
Experimental Results ◽  
Slab Thickness ◽  
Empirical Formulas ◽  
Steel Bars ◽  
Rc Slabs ◽  
The Cost ◽  
Frp Bars

Using FRP bars in the concrete structures under harsh environment produces extension of those service life and dropping of the cost of their lifecycle. This study investigated the influence of slab thickness, material of rebar, arrangement of reinforcement and mass’s dropped on the dynamic behavior of RC slabs by using laboratory experiments. Seven specimens 1550×1550 mm dimension with two thickness 120 and 150mm, single control specimen reinforced with steel bars and six specimens reinforced by CFRP bars were experimentally investigated under sequential dropping-weight ranged from 50 to 150kg, it was a rigid steel projectile, used to apply impacting load. 2.5m was the height of dropping. For estimated penetration depth, three empirical formulas have been used, ACE formulae was preferable predictor than other formulas. Different codes were used to calculation punching shear capacity and critical velocity of perforation and compared the experimental results with these codes. The experimental results showed that the shear properties of slabs have a significant effect in their general behavior. And preferable performance in FRP slabs than slabs reinforced with steel can be achieved which considering high strength and corrosion resistance of this material, which makes it a suitable choice for reinforcing materials.

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.

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.

Crack Propagation in Compression and Mounted Arrestors

2014 ◽  
Vol 624 ◽  
pp. 595-602 ◽  
Author(s):  
Susanna Casacci ◽  
Angelo Di Tommaso ◽  
Cristina Gentilini
Keyword(s):  
Tensile Strength ◽  
Numerical Model ◽  
Crack Propagation ◽  
Three Dimensional ◽  
Masonry Walls ◽  
Masonry Structures ◽  
High Tensile Strength ◽  
Steel Bars ◽  
Out Of Plane ◽  
Compressive Loads

Strengthening of masonry walls is a key aspect during building retrofitting operations having conservation goals. “Reinforced repointing technique” involves the application of materials having high tensile strength such as steel bars, steel textile sheets or composites thin pultruded laminae with cracks arrestors function, to reduce the vulnerability of masonry structures against in-plane and out-of-plane actions. In this paper, a three-dimensional numerical model is developed to evaluate the efficiency of reinforcing steel bars facing crack propagation phenomenon under increasing compressive loads.

scholarly journals Sustainable Brick Masonry Bond Design and Analysis: An Application of a Decision-Making Technique

2019 ◽  
Vol 9 (20) ◽  
pp. 4313
Author(s):  
Shah ◽  
Arshad ◽  
Farhan ◽  
Raza ◽  
Khan ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Cement Mortar ◽  
Bond Formation ◽  
Maximum Level ◽  
Brick Masonry ◽  
Masonry Structures ◽  
Strength Tests ◽  
The Relationship ◽  
Interface Behaviour ◽  
Selection Of

This research intends to explore the sustainable masonry bond formation and interface behaviour of brick masonry bonds with different cement mortar ratios. To test the sustainable behaviour of different brick bonds, different tests were applied to evaluate the performance of the developed five brick masonry structures with the help of four mortar ratios. Following that pattern, the methodologies of a prism triplet test, a bond wrench test, a shear bond test and strength tests for brick masonry were applied. The prism triplet test explained the bonding behaviour of mortar by producing a maximum strength (0.21 MPa) with a 1:3 mix ratio, and the minimum strength (0.095 MPa) with a 1:8 mix ratio. The bond wrench test showed a bond strength of maximum 0.0685 MPa with a mortar ratio of 1:3 and a minimum of 0.035 MPa with a mortar ratio of 1:8. The strength tests for masonry structures expressed that compressive strength (0.786 MPa) and flexural strength (0.352 MPa) were found to be at maximum level with a mortar ratio (1:3) with an English bond formation. For predictions of compressive and flexural strength, artificial neural networks (ANNs) were deployed, and successful predictions of these values along with the relationships between different properties of the material, mortar combinations and bond combinations are presented to complete the exploration of the relationship. This pattern can be helpful for the selection of sustainable brick masonry formations for housing development.

Strengthening of RC-Brick Masonry Walls with Opening Using Basalt Fiber Reinforced Polymer

2014 ◽  
Vol 1021 ◽  
pp. 63-67 ◽  
Author(s):  
Zhen Lei ◽  
Jun Tong Qu ◽  
Yong Wang
Keyword(s):  
Basalt Fiber ◽  
Brick Masonry ◽  
Fiber Reinforced Polymer ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Fiber Reinforced ◽  
Promising Alternative ◽  
Reinforced Polymer ◽  
Strengthening Technique ◽  
Basalt Fiber Reinforced Polymer

FRP strengthening technique provides a promising alternative for masonry structures. This paper presents research results of quasi-static tests investigating the in-plane mechanical behavior of RC-brick masonry walls with opening strengthened with basalt fiber reinforced polymer (BFRP). Two half scale RC-brick walls were constructed, one without any strengthening scheme served as the reference specimen, another one was directly strengthened with BFRP in mixed strengthening configuration. All specimens were tested under low frequency cyclic loading. BFRP can effectively improve the lateral strength of the wall by a factor of 0.16, and the improvement in the lateral deformation capacity was much significant. The seismic performance of the composite wall strengthened with BFRP can exceed the unreinforced reference, which verifies the effectiveness of BFRP strengthening technique to strengthening RC-brick composite masonry structures in seismically endangered regions.

scholarly journals Experimental Research on Seismic Performance of Damaged Brick Walls Strengthened with Embedded Horizontal Steel Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Liu Tingbin ◽  
Jia Rubo ◽  
Pei Xianke ◽  
Zhang Jiawei ◽  
Zhao Jianchang
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Masonry Wall ◽  
Shear Capacity ◽  
Brick Masonry ◽  
Reconstruction Process ◽  
Skeleton Curve ◽  
Aspect Ratios ◽  
Steel Bars ◽  
Energy Dissipation Capacity

Six brick masonry specimens (two unreinforced specimens, two reinforced specimens, and two specimens reinforced after being damaged), which have different aspect ratios, were tested under low-frequency cyclic loading. The seismic performances of these specimens, including failure characteristics, deformation capacity, carrying capacity, energy dissipation capacity, hysteresis characteristics, and stiffness degradation, were analyzed. The following results were obtained: the ductility of the damaged walls could be significantly improved after they were reinforced with embedded horizontal steel bars; the ultimate shear capacity of the damaged brick masonry walls with the aspect ratios of 1.8 and 0.5 was improved by 6.8% and 4.7%, respectively; the displacement corresponding to the ultimate bearing capacity was close to that of the unreinforced brick masonry wall; the hysteresis loop of the reinforced wall became plumper and encompassed a larger area; after the ultimate load was reached, a clear yielding platform appeared in the skeleton curve of the reinforced wall; the reinforced wall exhibited good ductility, after entering plastic stage; the energy dissipation capacity of the reinforced wall was significantly greater than that of the unreinforced wall. In conclusion, the seismic performance of the damaged brick masonry wall can be improved by embedding horizontal steel bars, and this reinforcing method can be applied in the postseismic reconstruction process.

Shear Capacity of Hexagonal Masonry Walls with Hollow and Solid Blocks

2013 ◽  
Vol 432 ◽  
pp. 144-151
Author(s):  
Kug Kwan Chang ◽  
Dae Won Seo
Keyword(s):  
Residential Buildings ◽  
Shear Walls ◽  
Shear Capacity ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Reinforcing Bar ◽  
Masonry Construction ◽  
Different Types ◽  
Masonry Material ◽  
Reversed Cyclic

Masonry structures are used throughout the world for the construction of residential buildings. However, from a structural viewpoint, the masonry material is characterized by a very low tensile strength; thus, masonry construction often present diffuse fracture patterns. Moreover, masonry bearing and shear walls have been found to be vulnerable to earthquakes. In this study, to improve the seismic performance of masonry structures, hexagonal blocks were developed and six masonry walls used in hexagonal block were tested to failure under reversed cyclic lateral loading. This paper focuses on an experimental investigation of different types of wall used in hexagonal blocks, i.e. walls with different hexagonal blocks and with different reinforcing bar arrangements, subjected to applied cyclic loads. The cracking and damage patterns and hysteretic feature are evaluated. Results showed that damage to blocks in reduced and brittle failure is avoided by the comparatively hexagonal block walls than the existing masonry walls.

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