Masonry walls subjected to out-of-plane loading, such as in a seismic event, require reinforcement to improve the ductility of the system. In current masonry construction practice, reinforcement is placed internally and fully grouted. For new construction this can make the wall unjustifiably heavy by not taking advantage of its light, hollow structure. For existing construction, it is difficult to retrofit using this technique. Additionally, the reinforcement is located close to the neutral axis which reduces its effectiveness. Fiber-Reinforced Polymer (FRP) bars, strips and sheets are becoming increasingly popular in construction applications due to their noncorrosive nature and ease of installation. Also, stainless steel bars are used where the structure is exposed to a corrosive environment but have not found wider application for masonry structures. This study is an experimental investigation of the structural performance of masonry walls reinforced with Near-Surface-Mounted (NSM) FRP and stainless steel reinforcement under out-of-plane bending. Additionally, walls with Externally Bonded (EB) FRP sheets were tested. The study simulates retrofitting applications and also proposes the NSM technique for new wall construction, using pre-grooved blocks, in lieu of the conventional method of internal reinforcing and grouting. To accommodate the NSM reinforcement, the grooves in the masonry blocks were aligned with ducts used to anchor the NSM reinforcement in the concrete footing. Seven wall specimens were tested, including walls reinforced with conventional and stainless steel bars, glass-fibre reinforced polymer (GFRP), and carbon-FRP (CFRP) reinforcement. The study demonstrated the feasibility and effectiveness of the NSM technique for new construction. Walls with NSM reinforcement showed a superior performance to those with EB reinforcement. It was shown that increasing the FRP reinforcement ratio may result in a change of failure mode, and as such, the increase in strength may not be proportional to the increase in reinforcement ratio. NSM steel-reinforced walls showed a superior performance in terms of strength, stiffness and the ductility associated with the formation of a plastic hinge at the base. / Thesis (Master, Civil Engineering) -- Queen's University, 2010-05-31 06:24:20.976

The primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.

Lime mortar and plaster have been investigated with the aim to improve the knowledge on how to make them as durable as before the cement technology was developed. The background was the durability problems experienced for newly produced lime plaster on the medieval churches on the island of Gotland, Sweden. In some cases the new lime plaster façades showed severe frost damages after only one winter. Although the lime was burnt and produced according to old local traditions, the lime mortar was still mixed and worked onaccording to methods developed for lime-cement mortar. This often led to a very porous lime plaster with a lime shell in the surface and such a plaster has been shown to be sensitive to frost expansion. Field studies were combined with laboratory studies of thin section specimens. Optical microscopy and scanning electron microscopy have been important analytical methods showing the porosity and the structure of the binder and aggregate materials. The investigations have been carried out on both historic and on newly made reference mortar and plaster. The field studies were carried out mainly on Gotland, using local materials. The influence of the raw materials, i.e. lime, aggregate and blending ratio was investigated. The focus has been on the workability of the fresh mortars as well as the pore structure of the carbonated plaster. The craftsmanship, meaning mixing and application of mortar and working the plaster surface, was studied in order to clarify its final pore structure. The pore structure in a material determines many of its technical properties, such as moisture transportation, compressive strength, permeability and frost resistance. All these properties are closely connected to the durability of the mortar and plaster. The permeability of the plaster has an impact also on the durability of the covered construction materials. Behind low-permeable plasters made with hydraulic binder, examples of extensive damages of rotten wood and leached lime have been shown. The investigations have shown the importance of choosing a mortar adjusted to the building construction. They also showed the importance of choosing a blending ratio adjusted to the specific binder and sand used in order to get a mortar with a suitable pore structure and good durability. It has also shown the importance of knowing when and how to work on the plaster surface in order to obtain a homogenous material that is well receptive for lime wash and has a good frost resistance. The combination of all the investigations has led to a method for reconstructing historic mortar and plaster with good durability.

The primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.

Out-of-plane laterally loaded masonry wall panels are still much used in modem structures. However due to their anisotropic and highly composite nature, it is extremely difficult to understand their behaviour and to date there is no analytical method that is capable of accurately predicting the response of masonry panels to the applied loadings. This is one of the major obstacles in analysing and designing masonry structures. This research studied a new method that accurately predicts the response of laterally loaded masonry wall panels. In this dissertation, the method of using corrector factors developed by previous researchers was further studied using model updating and artificial intelligence (AI) techniques based on previous experimental results of full scale wall panels tested in the University of Plymouth. A specialised non-linear finite element analysis (FEA) program was used to implement the method developed in this study. The analytical response was compared with other experimental results from different laboratories. Initially, it was found that there was some obvious noise in the experimental load deflection data, which made comparison between FEA and the experimental results very difficult. The research therefore proposed a methodology for minimising the experimental noise based on 3D surface fitting and regression analyses applied to lateral deflection experimental data. The next step was the detailed study of corrector factors using the numerical model updating procedure. Corrector factors were determined for various zones within a masonry panel (the Base Panel) by minimising the discrepancy between the experimental load deflection data and those obtained from non-linear FE analysis. A detailed model updating procedure was studied including the model analysis, the objective function and the constraint function for the genetic algorithm (GA). A uniqueness study to corrector factors was also carried out. The following step was undertaken to analyse general masonry wall panels using the findings of this study. The concept of zone similarities proposed by previous researcher, which was based on the relative distance of each zone from similar boundaries, was used for applying correctors from the base panel to the new panel to be analysed. A modified cellular automata (CA) model was used to match the similar zones between the new panel and the base panel. The generality and robustness of this method was validated using a number of masonry wall panels tested by various organizations. These walls were single leaf masonry wall panels of clay bricks with different boundary types, dimensions, with and without openings. The main finding in this research are that the boundary effects have a major influence on the response of masonry panels subjected to lateral loading, improperly defined boundary conditions in FEA are the main source of error in the past numerical analysis. Using the corrector factors that are able to properly quantify the actual boundary effects and make appropriate revisions, more accurate analysis is achieved and the predicted response of masonry walls match with their experimental results very well.

About half of the building stock in Turkey is masonry type and one fourth of the building stock is one-storey brick type masonry buildings. Especially the rural masonry houses are commonly constructed by their own residents without any engineering knowledge. Traditional masonry houses usually have heavy roofs which generate large lateral forces on walls during earthquakes. Readily available retrofitting techniques are mostly complicated and costly making it not feasible for uneducated poor residents to strengthen their own houses. The aim of this thesis is to develop a new alternative strengthening technique using scrap tires that is economic and easy to apply on the walls of one-story masonry houses. In order to investigate the usage of scrap tires for masonry wall post-tensioning, forty three scrap tire rings (STRs) from nine different brands and nine rim-rings direct tension experiments were conducted. The average tensile load capacities of STRs and rim-rings were found as 132.6 kN and 53 kN, respectively. Six strip walls (i.e., four brick- and two briquette-walls) strengthened by applying post-tensioning loads with STCs and hybrid system were tested in out-of-plane bending direction. The out-of-plane capacity of the brick and briquette walls increased up to about 9 times and 5 times with respect to their nominal capacities, respectively. Finally, two-full scale traditional masonries were tested by the tilting table. The capacity of strengthened house increased 75% with respect to the unstrengthened one. The results obtained form the conducted tests are highly promising and suggest that the method can be used as a low-cost and simple strengthening technique for seismically deficient single storey, masonry type houses.

In Turkey, in most of the reinforced concrete buildings, hallow masonry infill walls are used as a non-structural element, during design stage, their contribution to overall building behavior is not well known. Observations made after the earthquakes revealed that these non-structural elements had beneficial effects on the lateral capacity of the building. In this study, the contribution of the hallow masonry infill walls to the lateral behavior of reinforced concrete buildings was investigated. For this purpose, two different buildings were chosen as case studies. Three and six story symmetric buildings are modeled as bare and infilled frames. The parameters that were investigated are column area, infill wall area, distribution of masonry infill walls throughout the story. To determine the effect of each parameter, global drift ratios are computed and are compared for each case.

Despite their poor performance, non-standard clay bricks are commonly used in construction of low-rise buildings and rural houses in Indonesia. These clay bricks are produced traditionally in home industries. Indonesia is located in an active seismic region and many masonry buildings were badly damaged or collapsed during recent earthquakes. Such buildings are classified as non-engineered structures as they are built without using any proper design standard. Lateral load response of un-reinforced masonry walls is investigated in this research project, with the aim of better understanding the behaviour of these masonry walls using low quality local bricks. A comprehensive experimental program was undertaken with masonry wall elements of 600 mm x 600 mm x 110 mm constructed from local bricks from Cikarang in West Java - Indonesia. Wall specimens were constructed and tested under a combination of constant vertical compression load and increasing horizontal or lateral in-plane loads, of monotonic, repeated and cyclical nature. The vertical compressive loading was limited to 4% of maximum brick compressive strength. Masonry mortar mix used to construct the specimens was prepared according to Indonesian National Standard. Three different types of masonry wall panels were considered, (i) (normal) brick masonry walls, (ii) surface mortared brick masonry walls and (iii) comforted surface mortared brick masonry walls. The results indicated that the lateral load bearing capacity of masonry wall is usually lower than that of mortared and comforted walls. Despite this, the lateral load capacity under cyclic loads decreased 50 % of the average capacity of the walls under monotonic and repeated lateral loads. Using the results from the experimental program, a simplified model for the equivalent diagonal spring stiffness of local clay brick walls was developed. This stiffness model derived from experimental results in then used to simplify the structural analysis of clay brick wall panels in Indonesia. The design guideline for brick masonry houses and low-rise buildings in six Indonesian seismic zones was developed, as a contribution towards the development of design guidance for constructing brick masonry houses in Indonesia.

Amendments pasted onto front end-cover. / Bibliography: p. 221-240. / xvi, 354 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Documents the experimental and analytical research undertaken aimed at providing the fundamental tools required to succesfully avoid the identified brittle "weak link" in the design of new and the assessment of existing unreinforced masonary buildings. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000?

"November 2004" / Bibliography: p.167-179. / xi, 333 p. : ill., photos (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Focuses on behavioural models of masonry walls with a view to improving their accuracy and extending their application. Results include a numerical model and mathematical expressions capable of predicting the key stages of the non-linear load-deflection behaviour of walls subjected to vertical bending and axial loading; new mathematical expressions for horizontal and diagonal bending moment capacities that are dimensionally consistent and account for the beneficial effects of compressive stress; and. Experimental test data for masonry sections subjected to horizontal and diagonal bending, which were used in the development and verification of the new mathematical expressions. / Thesis (Ph.D.)--University of Adelaide, School of Civil and Environmental Engineering, 2004