scholarly journals Evaluation Of Shear Capacity For Brick Masonry Walls

2015 ◽  
Vol 5 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Eva Partene ◽  
Luminita Fekete-Nagy ◽  
V. Stoian
Keyword(s):  
Residential Buildings ◽  
Concrete Columns ◽  
Unreinforced Masonry ◽  
Shear Capacity ◽  
Experimental Program ◽  
Masonry Walls ◽  
Common System ◽  
Vertical Loading ◽  
Reinforced Masonry ◽  
Ceramic Blocks

Abstract The papers presents the results of an experimental program and provides valuable information regarding the behaviour of structural masonry walls built up using ceramic blocks with hollows, which represents a very common system for low-rise residential buildings, up to 4 stories, depending on the seismic acceleration on site. A number of six masonry walls where tested in bear state being subjected to constant vertical loading and to cyclic in-plane horizontal loads. The main objective was to determine the shear capacity for unreinforced masonry walls and reinforced masonry walls. The experimental results were also useful to determine the contribution of the reinforcing of the masonry walls with concrete columns. The comparison between unreinforced masonry and reinforced masonry has a great importance due to the fact that the Romanian Seismic Standards have imposed the reinforcement in seismic areas for building with more than 1 storey. Further studies will be conducted on strengthening the masonry walls using FRP materials.

scholarly journals A Study on Finite Element Modelling and Analysis with respect to Experimental Results of Strengthened Unreinforced Masonry Walls With and Without Kevlar-FRP

2021 ◽  
Vol 23 (2) ◽  
pp. 67-77
Author(s):  
Sugeng Wijanto ◽  
Takim Andriono ◽  
Jovita Tanudjaja
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Three Dimensional ◽  
Unreinforced Masonry ◽  
Shear Capacity ◽  
Masonry Walls ◽  
Test Results ◽  
Element Modelling ◽  
Laboratory Test Results ◽  
Set Up

Unreinforced masonry (URM) walls, found in most historical buildings in Indonesia, are relatively brittle with wide variety of material properties. The behaviour of URM walls is very complex, especially when subjected to seismic excitation. In this research, a finite element modelling was set up in order to analyse the seismic performance of URM wall experimental test units, with and without strengthening material. The analysis was conducted using SAP2000 computer program. Three dimensional solids and springs as link connectors were assigned to represent the masonry behaviour. This research aims to compare results obtained from the computer analysis and the previously conducted laboratory experiments. The effectiveness of Kevlar fibre material, which was installed on both wall surfaces and modelled as truss element was also investigated. It was found that the failure mechanisms shown by the SAP2000 model was similar to the laboratory test results. The use of Kevlar Fibre as strengthening material was found able to significantly increase the stiffness and shear capacity of the URM wall.

scholarly journals Experimental Examination of Hollow Brick Masonry Wall with Reinforcement

2019 ◽  
Vol 8 (4) ◽  
pp. 4680-4684 ◽  
Keyword(s):  
Shear Walls ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Masonry Building ◽  
Brick Wall ◽  
High Wind ◽  
Load Bearing ◽  
Reinforced Masonry ◽  
Hollow Brick

The research aims at conducting a quality research with Reinforcement of a hollow brick wall. The empty internal sections significantly lower the dead load. With a better surface finish, the side of the block was cast, minimizing the cost of plastering. Several sample mixes are tested to achieve a finished surface. The respective frames were cast with and without reinforcement and the test results were compared. The blocks were used to build masonry walls and ' load-bearing strength ' of the walls was tested. It is possible to use the reinforced hollow block as a load-bearing wall. Nearly 75 percent of the deaths related to the earthquake in the last century,Buildings have collapsed, the majority of which (more than 70 percent)is due to the collapse of buildings made of masonry. Most of the properties in India are Unreinforced Masonry (URM) buildings that are weak and vulnerable even under moderate earthquakes and that function on the wall due to high wind forces, causing severe damage to high wind loads and it is recognized that Reinforced Masonry Building has many advantages over unreinforced masonry building.The use was very limited in Indian building practices and there are still no approved codes and shear walls were used in most constructions, even in mild earthquakes, instead of reinforced masonry walls

Strengthening of Masonry Walls Using Fiber Reinforced Polymer (FRP) Materials

2015 ◽  
Vol 660 ◽  
pp. 198-201 ◽  
Author(s):  
Eva Partene ◽  
Valeriu Stoian ◽  
Andrei Bindean ◽  
Luminita Fekete-Nagy
Keyword(s):  
Failure Modes ◽  
Shear Resistance ◽  
Fiber Reinforced Polymer ◽  
Experimental Program ◽  
Masonry Walls ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Earthquake Resistant ◽  
Ceramic Blocks

The paper presents the behavior of masonry walls built up using ceramic blocks with hollows tested in bear state and then strengthened using FRP materials. A number of two masonry walls are subjected to cyclic in-plane horizontal loads and constant vertical loads, in order to determine the efficiency of the strengthening solutions compared with the shear resistance of the walls in bear state. Also, the experimental program is useful to observe the failure modes of the strengthened walls and also to determine if such strengthening solutions is earthquake-resistant.

scholarly journals Experimental Study on Seismic Behavior of Masonry Walls Strengthened by Reinforced Mortar Cross Strips

2019 ◽  
Vol 11 (18) ◽  
pp. 4866 ◽  
Author(s):  
Dong ◽  
Sui ◽  
Jiang ◽  
Zhou
Keyword(s):  
Seismic Performance ◽  
Cyclic Load ◽  
Failure Modes ◽  
Shear Failure ◽  
Constant Load ◽  
Shear Capacity ◽  
Experimental Program ◽  
Test Results ◽  
Reinforced Masonry ◽  
Key Factor

Due to the poor seismic performance, strengthening of masonry structures is always a significant problem worthy to study. It has been proven that the bearing capacity of existing masonry buildings can be enhanced greatly with efficient strengthening measures. An experimental program was conducted to investigate seismic performance of un-reinforced masonry (URM) walls strengthened b,y reinforced mortar (RM) cross strips. Eleven walls were tested under horizontal low-cyclic load, simultaneously with a vertical constant load on the top face. Three URM walls were tested as reference. The other eight walls were externally strengthened with 40 and 60 mm thick of RM cross strips on one or both faces. Test results showed that externally strengthening with RM cross strips was an efficient way to enhance the seismic performance of URM walls. The failure modes were divided into shear failure and shear-compression failure. All the tested walls did not collapse until the test ended, while many diagonal cracks and few vertical cracks appeared on mortar strips. After strengthening, the shear capacity of the strengthened walls increased by at least 38.2%, and the reinforcement ratio was noted to be the key factor to influence the shear capacity with positive correlation. Besides, RM cross strips did improve deformation capacity greatly.

Improving in-plane seismic response of unreinforced masonry walls using steel strips

2020 ◽  
Vol 23 (12) ◽  
pp. 2709-2723 ◽  
Author(s):  
Abbas Darbhanzi ◽  
Mohammad S Marefat ◽  
Mohammad Khanmohammadi
Keyword(s):  
Seismic Response ◽  
Failure Modes ◽  
Unreinforced Masonry ◽  
Linear Displacement ◽  
Experimental Program ◽  
Masonry Walls ◽  
Displacement Capacity ◽  
Steel Strips ◽  
Lateral Strength ◽  
Low Costs

This article discusses the results of an experimental program to retrofit unreinforced masonry walls by means of diagonal and vertical steel strips. The technique has several advantages such as simplicity to apply, relatively low costs, and insignificant disruption of service functions during the repair. The tests were conducted on three specimens: two with both diagonal and vertical steel strips and one with only diagonal steel strips, and all attached to one face of the walls. The tests showed that the steel strips improved lateral strength, increased non-linear displacement capacity, and changed the nature of the failure modes.

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.

Pull-Out Behavior of Adhesive Connections in Unreinforced Masonry Walls

2016 ◽  
Vol 32 (4) ◽  
pp. 2357-2375 ◽  
Author(s):  
Dmytro Dizhur ◽  
Arturo Schultz ◽  
Jason Ingham
Keyword(s):  
Failure Modes ◽  
Unreinforced Masonry ◽  
Experimental Program ◽  
Masonry Walls ◽  
Embedment Depth ◽  
Clay Brick ◽  
Metal Mesh ◽  
Comparative Performance ◽  
Pull Out ◽  
Adhesive Anchors

The connections between walls of unreinforced masonry (URM) buildings and flexible timber diaphragms are critical building components that must perform adequately before desirable earthquake response of URM buildings may be achieved. Field observations made during the initial reconnaissance and the subsequent damage surveys of clay brick URM buildings following the 2010/2011 Canterbury, New Zealand, earthquakes revealed numerous cases where anchor connections joining masonry walls or parapets with roof or floor diaphragms appeared to have failed prematurely. These observations were more frequent for adhesive anchor connections than for through-bolt connections (i.e., anchorages having plates on the exterior facade of the masonry walls). Subsequently, an in-field test program was undertaken in an attempt to evaluate the performance of adhesive anchor connections between unreinforced clay brick URM walls and roof or floor diaphragm. The study consisted of a total of almost 400 anchor tests conducted in eleven existing URM buildings located in Christchurch, Whanganui and Auckland. Specific objectives of the study included the identification of failure modes of adhesive anchors in existing URM walls and the influence of the following variables on anchor load-displacement response: adhesive type, strength of the masonry materials (brick and mortar), anchor embedment depth, anchor rod diameter, overburden level, anchor rod type, quality of installation, and the use of metal mesh sleeves. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5° to the perpendicular projection from the wall surface) and anchors positioned horizontally was investigated. Observations on the performance of wall-to-diaphragm connections in the 2010/2011 Canterbury earthquakes, a summary of the performed experimental program and test results, and a proposed pull-out capacity relationship for adhesive anchors installed into multi-leaf clay brick masonry are presented herein.

Assessing vibration induced damage in unreinforced masonry walls subject to vehicular impact – A numerical study

2021 ◽  
Vol 245 ◽  
pp. 112843
Author(s):  
Mohammad Asad ◽  
Tatheer Zahra ◽  
David P Thambiratnam ◽  
Tommy H.T. Chan ◽  
Yan Zhuge
Keyword(s):  
Numerical Study ◽  
Unreinforced Masonry ◽  
Masonry Walls

Full‐scale shake‐table tests on two unreinforced masonry cavity‐wall buildings: effect of an innovative timber retrofit

2021 ◽  
Author(s):  
Marco Miglietta ◽  
Nicolò Damiani ◽  
Gabriele Guerrini ◽  
Francesco Graziotti
Keyword(s):  
Seismic Vulnerability ◽  
Concrete Slab ◽  
Cost Effective ◽  
Unreinforced Masonry ◽  
Full Scale ◽  
Cavity Wall ◽  
Masonry Walls ◽  
Shake Table ◽  
Earthquake Excitation ◽  
Reinforced Concrete Slab

AbstractTwo full-scale building specimens were tested on the shake-table at the EUCENTRE Foundation laboratories in Pavia (Italy), to assess the effectiveness of an innovative timber retrofit solution, within a comprehensive research campaign on the seismic vulnerability of existing Dutch unreinforced masonry structures. The buildings represented the end-unit of a two-storey terraced house typical of the North-Eastern Netherlands, a region affected by induced seismicity over the last few decades. This building typology is particularly vulnerable to earthquake excitation due to lack of seismic details and irregular distribution of large openings in masonry walls. Both specimens were built with the same geometry. Their structural system consisted of cavity walls, with interior load-bearing calcium-silicate leaf and exterior clay veneer, and included a first-floor reinforced concrete slab, a second-floor timber framing, and a roof timber structure supported by masonry gables. A timber retrofit was designed and installed inside the second specimen, providing an innovative sustainable, light-weight, reversible, and cost-effective technique, which could be extensively applied to actual buildings. Timber frames were connected to the interior surface of the masonry walls and completed by oriented strands boards nailed to them. The second-floor timber diaphragm was stiffened and strengthened by a layer of oriented-strand boards, nailed to the existing joists and to additional blocking elements through the existing planks. These interventions resulted also in improved wall-to-diaphragm connections with the inner leaf at both floors, while steel ties were added between the cavity-wall leaves. The application of the retrofit system favored a global response of the building with increased lateral capacities of the masonry walls. This paper describes in detail the bare and retrofitted specimens, compares the experimental results obtained through similar incremental dynamic shake-table test protocols up to near-collapse conditions, and identifies damage states and damage limits associated with displacements and deformations.

scholarly journals Experimental Investigation into the Seismic Performance of Prefabricated Reinforced Masonry Shear Walls with Vertical Joint Connections

2021 ◽  
Vol 11 (10) ◽  
pp. 4421
Author(s):  
Zhiming Zhang ◽  
Fenglai Wang
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Shear Walls ◽  
Construction Method ◽  
Shear Capacity ◽  
Initial Stiffness ◽  
Equivalent Viscous Damping ◽  
Displacement Ductility ◽  
Reinforced Masonry ◽  
Cracking Performance

In this study, four single-story reinforced masonry shear walls (RMSWs) (two prefabricated and two cast-in-place) under reversed cyclic loading were tested to evaluate their seismic performance. The aim of the study was to evaluate the shear behavior of RMSWs with flanges at the wall ends as well as the effect of construction method. The test results showed that all specimens had a similar failure mode with diagonal cracking. However, the crack distribution was strongly influenced by the construction method. The lateral capacity of the prefabricated walls was 12% and 27% higher than that of the corresponding cast-in-place walls with respect to the rectangular and T-shaped cross sections. The prefabricated walls showed better post-cracking performance than did the cast-in-place wall. The secant stiffness of all the walls decreased rapidly to approximately 63% of the initial stiffness when the first major diagonal crack was observed. The idealized equivalent elastic-plastic system showed that the prefabricated walls had a greater displacement ductility of 3.2–4.8 than that of the cast-in-place walls with a displacement ductility value of 2.3–2.7. This proved that the vertical joints in prefabricated RMSWs enhanced the seismic performance of walls in shear capacity and ductility. In addition, the equivalent viscous damping of the specimens ranged from 0.13 to 0.26 for prefabricated and cast-in-place walls, respectively.

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