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.

Behaviour of adhesive steel anchors under impulse-type loading

2009 ◽  
Vol 36 (11) ◽  
pp. 1835-1847 ◽  
Author(s):  
Abass Braimah ◽  
Ettore Contestabile ◽  
Rick Guilbeault
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Dynamic Behaviour ◽  
Stone Masonry ◽  
Experimental Program ◽  
Embedment Depth ◽  
Test Results ◽  
Dynamic Increase Factor ◽  
Adhesive Anchors

The dynamic behaviour of adhesive anchors embedded in concrete is not well established, neither is their behaviour in stone masonry. This paper presents an experimental program designed to study the dynamic behaviour of adhesive anchor – substrate systems under impulse-type loading. The adhesive anchor – substrate systems consisted of steel rods bonded to concrete and limestone with an epoxy-based adhesive. Two steel anchor diameters (6.4 and 9.5 mm), two embedment depths (89 and 114 mm), and two angles of substrate penetration (90° and 45°) were investigated. The predominant failure mode observed for the steel anchor – concrete substrate samples was steel fracture, whereas for the steel anchor – limestone substrate samples, both steel fracture and limestone substrate failure modes were observed. The test results show that in most cases the dynamic increase factor (DIF) of adhesive anchors decreases with an increase in the embedment depth. Also, a substrate penetration angle of 45° increases the DIF in comparison with samples with 90° penetration angle. The DIFs of 1.2 and 2.5 are recommended for adhesive anchors with normal and 45° limestone substrate penetrations, respectively, while for concrete substrate, the recommended DIFs are 1.2 and 3.2 for normal and 45° substrate penetrations, respectively.

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.

PULL OUT STRENGTH FOR DIFFERENT SIZE OF DOWEL AND GRAIN DIRECTION OF GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Mohamad Iswandi Jinne ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Maximum Load ◽  
Experimental Program ◽  
Drilling Process ◽  
Test Results ◽  
Bond Behaviour ◽  
Pull Out ◽  
Timber Joints ◽  
Different Thickness ◽  
Pull Out Strength

This paper presents an experimental program for testing glued-in dowel glulam timber joints. Hundred thirty glulam specimens, each with a single glued-in rebar parallel to the grain and perpendicular to grain with different size of dowels 12mm, 16mm and 20mm were tested to evaluate the effects of anchorage length and different dowel diameter for parallel and perpendicular to the grain on pull-out strength and bond behaviour of glued-in rebar timber joints. The test results showed that the maximum load for specimen with dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction. Failure modes were characterized by pull out failure in the mode of adhesive-dowel, yet one sample failed in timber-adhesive mode. This might happened because the surface of the timber was burned by drilling machine during the drilling process. The pull-out was tested with different thickness grain direction with different dowel size with a rate of 2mm/min and the failure modes were observed after the testing of pull-out test. PRF is the adhesive used for the strengthening purposes. Resistance to the withdrawal of dowels glued-in perpendicularly was 44.2% to 53.5 % lower than that obtained for dowels glued-in parallel to the grain direction. The result shows that the dowel glued-in parallel to the grain given the higher maximum load than dowel glued-in perpendicular to the grain direction.

A Numerical Study on the Pull-Out Strengths of Anchor Bolts Embedded in Concrete Using the Smoothed Particle Hydrodynamics Method

2016 ◽  
Vol 711 ◽  
pp. 1111-1117 ◽  
Author(s):  
Yoshimi Sonoda
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Failure Modes ◽  
Numerical Study ◽  
Failure Process ◽  
Embedment Depth ◽  
Anchor Bolt ◽  
Pull Out ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Anchor Bolts

The strength of an anchor bolt in concrete structure under pull-out load is usually designed by three possible failure modes such as fracture of anchor bolt, cone failure of concrete and bond failure between anchor bolt and concrete. In general, the design load is considered the smallest load corresponding to the aforementioned failure mechanisms. However, unexpected failure often occurs in the anchorage zone due to the complex failure or the change of failure condition. Therefore, it is important to develop the accurate analysis method of ultimate load bearing capacity of the anchor bolt. In this study, we conducted an analytical study using Adaptive Smoothed Particle Hydrodynamics (ASPH) in order to simulate the failure process of anchorage zone and discussed the effect of embedment depth of anchor bolts on their ultimate strength.

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.

Shake Table Testing of Seismically Restrained Clay-Brick Masonry Parapets

2018 ◽  
Vol 34 (1) ◽  
pp. 99-119 ◽  
Author(s):  
Marta Giaretton ◽  
Dmytro Dizhur ◽  
Jason Ingham
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Unreinforced Masonry ◽  
Brick Masonry ◽  
Seismic Events ◽  
Shake Table ◽  
Northridge Earthquake ◽  
Clay Brick ◽  
Seismic Capacity ◽  
Shake Table Testing

Past seismic events, such as the 1994 Northridge earthquake, the 2001 Nis-qually earthquake, and the 2010/2011 Canterbury earthquakes, have repeatedly served as reminders of the hazards posed by unreinforced masonry parapets. Observed failure modes have included several cases where adopted retrofit techniques were inadequate to effectively secure parapets during earthquake-induced shaking. In response, this paper investigates, by means of shake table testing, the dynamic behavior of nine clay-brick masonry parapets with commonly used bracing systems and alternative securing techniques, such as post-tensioning and combined braces and vertical strong-backs. Seismic capacity was improved 6 to 8 times compared to the as-built postcracked condition. The addition of vertical strong-backs further improved the performance of braced parapets, with capacity increased 12 times compared to as-built parapets. Parapet construction and retrofit procedures are presented, followed by a discussion of the developed failure modes as well as the response of the retrofitted parapets.

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 and Numerical Study of Polymer-Retrofitted Masonry Walls under Gas Explosions

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 863
Author(s):  
Meng Gu ◽  
Xiaodong Ling ◽  
Hanxiang Wang ◽  
Anfeng Yu ◽  
Guoxin Chen
Keyword(s):  
Coating Thickness ◽  
Failure Modes ◽  
Numerical Study ◽  
Field Tests ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Economic Losses ◽  
Masonry Walls ◽  
Spray Pattern ◽  
Gas Explosions

Unreinforced masonry walls are extensively used in the petrochemical industry and they are one of the most vulnerable components to blast loads. To investigate the failure modes and improve the blast resistances of masonry walls, four full-scale field tests were conducted using unreinforced and spray-on polyurea-reinforced masonry walls subjected to gas explosions. The results suggested that the primary damage of the unreinforced masonry wall was flexural deformation and the wall collapsed at the latter stage of gas explosion. The presence of polyurea coatings could effectively improve the anti-explosion abilities of masonry walls, prevent wall collapses, and retain the flying fragments, which would reduce the casualties and economic losses caused by petrochemical explosion accidents. The bond between the polymer and masonry wall was critical, and premature debonding resulted in a failure of the coating to exert the maximum energy absorption effect. A numerical model for masonry walls was developed in ANSYS/LS-Dyna and validated with the test data. Parametric studies were conducted to explore the influences of the polyurea-coating thickness and spray pattern on the performances of masonry walls. The polyurea-coating thickness and spray pattern affected the resistance capacities of masonry walls significantly.

scholarly journals Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 205
Author(s):  
Igor Tomić ◽  
Francesco Vanin ◽  
Ivana Božulić ◽  
Katrin Beyer
Keyword(s):  
Failure Modes ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Plane Failure ◽  
Friction Resistance ◽  
Flexible Diaphragms ◽  
Out Of Plane ◽  
Equivalent Frame

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexible diaphragms are most commonly timber floors made of planks and beams, which are supported on recesses in the masonry walls and can slide when the friction resistance is reached. Using equivalent frame models, we capture the effects of both the diaphragm stiffness and the finite strength of wall-to-diaphragm connections on the seismic behaviour of unreinforced masonry buildings. To do this, we use a newly developed macro-element able to simulate both in-plane and out-of-plane behaviour of the masonry walls and non-linear springs to simulate wall-to-wall and wall-to-diaphragm connections. As an unretrofitted case study, we model a building on a shake table, which developed large in-plane and out-of-plane displacements. We then simulate three retrofit interventions: Retrofitted diaphragms, connections, and diaphragms and connections. We show that strengthening the diaphragm alone is ineffective when the friction capacity of the wall-to-diaphragm connection is exceeded. This also means that modelling an unstrengthened wall-to-diaphragm connection as having infinite stiffness and strength leads to unrealistic box-type behaviour. This is particularly important if the equivalent frame model should capture both global in-plane and local out-of-plane failure modes.

scholarly journals Design Recommendations for Bonded Anchors under Fire Conditions Using the Resistance Integration Method

2021 ◽  
Vol 11 (17) ◽  
pp. 7810
Author(s):  
Omar Al-Mansouri ◽  
Romain Mège ◽  
Nicolas Pinoteau ◽  
Thierry Guillet ◽  
Roberto Piccinin ◽  
...  
Keyword(s):  
Failure Modes ◽  
Integration Method ◽  
Temperature Profiles ◽  
Test Results ◽  
Pull Out ◽  
Epoxy Adhesives ◽  
Assessment Procedures ◽  
Adhesive Anchors ◽  
Recommendations For Assessment ◽  
Fire Conditions

Fire design of cast-in place and post-installed anchors in concrete under fire is covered by EN 1992-4, Annex D, allowing steel- and concrete-related failure modes of anchors to be calculated. This informative annex of EN 1992-4 is limited to cast-in place or mechanical anchors, whereas post-installed adhesive anchors remain out of its scope. This paper presents a study of the applicability of the more flexible resistance integration method (RIM), proposed originally for the design of the pull-out resistance of post-installed reinforcement (PIR) by Pinoteau, on bonded anchors in uncracked concrete. This method is validated from a comparison of test results obtained from two research projects conducted at CSTB and TU Kaiserslautern on bonded anchors in uncracked concrete under ISO 834-1 fire conditions. The data considered include tests conducted on anchor sizes from M8-M30 using three different adhesives (two epoxy adhesives and one cementitious mortar). Design of the pull-out resistance under fire using RIM requires numerical calculation of temperature profiles considering models of concrete and steel elements; different assumptions about modeling these elements can produce vastly different end results. Finally, recommendations for assessment procedures for bonded anchors under fire conditions are provided as entry data for design.

Sign in / Sign up

Export Citation Format

Share Document