Reinforced Masonry Structures Research Articles

Feasibility Study of UHPC Reinforced Masonry Structure

With the increase of service life of masonry structure and the damage of masonry structure caused by external environment, the structure will be difficult to meet the design requirements. It is necessary to repair and reinforce the existing structure or replace the original structure with a new type of composite structure. ultra-high performance concrete (UHPC) is a kind of high strength, high ductility, high durability material, which has the advantages of almost impermeability, almost no carbonization, and almost zero chloride ion penetration and sulfate penetration. UHPC has been widely used in the field of concrete structure reinforcement, whether the masonry structure can be better strengthened has become the research content of this paper. Basic mechanics of UHPC materials at home and abroad By systematically combing and summarizing the research progress of performance and reinforcement design, the feasibility of UHPC reinforced masonry structure is obtained.

Development of Fragility and Vulnerability Functions for Reinforced Masonry Structures in Mexico: A Case Study

The north of the state of Baja California (BC) is located in one of the regions of Mexico with a high seismic risk. The predominant infrastructure in the city of Tijuana consists of reinforced masonry housing structures, making it crucial to understand the dynamic behavior of this type of structure. Using the “Vulnerability Modeller’sToolKit” (VMTK), fragility functions were obtained for low, medium, and high levels of seismic design. It was found that the probability of achieving or surpassing the different damage states (light, moderate, extensive, and complete) is high in low-height housing (1–3 floors) for an expected value of 0.50 g of PGA and in medium-height housing (4–7 floors) for an expected value of 0.5 g of SA (T = 0.5 s).Vulnerability functions were derived, and it was determined that, for a low seismic design level, low-height and medium-height structures, respectively presented loss probability rates of 30% and 44% for an expected value of 0.50 g of PGA and SA (T = 0.5 s). These fragility and vulnerability functions can be used to estimate damage and losses in future risk scenarios, thereby reducing uncertainty in the risk analysis calculations for the city of Tijuana.

Vibration Signal Diagnostic Information of Reinforced Masonry Elements Destruction

Reinforced masonry constructions and their elements must meet strength and stability requirements. These conditions determine wall structure safety during construction and operation. Safety depends on diagnostically aimed tests that check the objects’ quality or locate damages to structural elements that arise during operation. This article is focused on the experimental modal analysis research of reinforcement ceramic masonry elements. The aim of the research was to check whether it is possible to observe the damage in reinforced masonry structures and the accompanying vibration of signal transition functions by conducting pilot studies and using different types of reinforcements. The experiment was conducted on three samples of various types of reinforced brick walls. During the vibration tests, the segments were subjected to various loads, and it was observed how the increasing cracks and damage changed the courses of the measured functions of the vibration process, reflecting the damage to the segments. This made it possible to assess the variability of the vibration characteristics of the tested reinforced wall elements and the usefulness of the applied test method. The aim of the study was to check the assessed effectiveness by testing the degradation of the reinforced wall elements. The research confirmed the usefulness of the SISO methodology in identifying damages, which has been implemented in selected precast factories in Poland.

An effective numerical modelling strategy for FRCM strengthened curved masonry structures

Fabric Reinforced Cementitious Matrix (FRCM) composites are currently considered a very effective solution for strengthening masonry constructions. However, the mechanical interactions governing the response and the strength of FRCM reinforced masonry structures are very complex, especially in the case of curved structures. Moreover, these interactions involve several interfaces between different materials. Thus, the development of accurate numerical models for curved FRCM reinforced masonry structures comes up against several difficulties, and models too complex for practical applications can be obtained. In addition, several mechanical parameters needed for the calculations are generally inaccessible by conventional experimental tests.Here, a suitable numerical modelling strategy for FRCM strengthened curved masonry structures is proposed to combine the accuracy in simulating the actual behaviour in terms of stiffness, strength and collapse mechanisms with a reasonable simplicity, making the proposed approach usable also by practitioners, by adopting commercial codes and at a moderate computational effort. The relatively small number of mechanical parameters characterizing the model can be determined by ordinary experimental tests on materials or by literature formulations.The proposed modelling strategy is validated with respect to experimental data found in literature concerning a FRCM reinforced masonry barrel vault, and then is employed for studying the seismic capacity of the vault through a pushover analysis. A broad sensitivity analysis sheds light on the effect of variations of the mechanical parameters on the predicted overall behaviour, showing the robustness of the results obtainable through the proposed approach concerning inaccuracies in the determination of the parameters often very difficult to determine by ordinary experimental tests on masonry structures.

Seismic Behavior of Reinforced Masonry Structure: Relation between the Behavior Factor and the Ductility

The present work concerns a numerical study of the behavior of reinforced masonry (RM) structures under seismic loading. These structures are made of small hollow elements with reinforcements embedded in the horizontal joints. They were dimensioned according to the rules and codes commonly used. They are subject to vertical loads due to their own weight, and to horizontal loads due to seismic forces introduced by the accelerograms. The software used is the non-linear analysis program Drain2D, based on the finite element method, where the shear panel element was introduced. A series of calculations was performed on a number of structures at different levels, excited by three major accelerograms (El Centro, Cherchell, and Kobe). Throughout the study, our main interest is to evaluate the behaviour factor, the ductility, and the failure mode of these structures while increasing the intensity of earthquakes introduced. The results of this present study indicate that the average values of the behaviour factor and the global ductility are of the order of q≈μ≈3.00. The reinforced masonry structures studied have been broken by interstage displacement. The results given by the study are comparable to those given in the literature and in Eurocode 8. The behavior of reinforced masonry under a seismic load is similar to the behavior of reinforced concrete; it is a ductile behavior that allows the dissipation of the energy transmitted by the earthquake. These numerical studies confirm and complete the experimental work carried out by other researchers. Doi: 10.28991/CEJ-2022-08-10-012 Full Text: PDF

Natural Vibration Characteristics Analysis of a High-Rise Reinforced Masonry Structure Based on Field Test Data

In structural response array observation, the vibration response of a structure during an earthquake or from the natural environment is recorded and stored using high-sensitivity strong motion seismographs, and the dynamic characteristics of the structure are analyzed and determined using random signal data processing technology. Due to the use of field test data for analysis, this may be the most accurate and effective way to obtain the actual characteristics of the structure, which can be further used to verify the accuracy of theoretical analysis, experimental results, and numerical simulations. Therefore, this technique plays an important role in earthquake prevention and disaster reduction, with the application of strong motion observation data. In this paper, field vibration tests were performed on the highest reinforced masonry structure in China. With the test environmental vibration data, the natural vibration frequency values and mode shapes of the structure were identified using the peak picking method. A numerical modal analysis was then performed to verify the accuracy of the field test results. In addition, the structural response records obtained during an earthquakes in Songyuan were also used to identify the natural vibration frequency of the structure and the changes in the natural vibration frequency before, during, and after the earthquake. The results showed that the structure was not damaged during the earthquake and remained in an elastic state.

A Comprehensive Review on Unreinforced and Reinforced Masonry Structures Modeling Strategies

A Comprehensive Review on Unreinforced and Reinforced Masonry Structures Modeling Strategies

Batma Derinliği Ve Çapları Farklı Olan Zıvanaların Deneysel Olarak İncelenmesi

Shelter is one of the basic needs of human beings. Masonry structures have met this need since ancient times. Masonry structures have an important place among the building types. It is also under construction in many rural areas. Since protecting historical structures is among our most important duties, we need to know the repair and strengthening methods and methods of such masonry structures, and to be able to apply the best to that structure. Metal fasteners (clamp and tenon) are used in the repair and reinforcement of masonry structures. 
 Although it is known that these metal fasteners will contribute positively to the structures, it is not known how to use them in the most effective way. This study presents experimental studies aiming to find the most effective use of tenons, which are metal fasteners connecting vertical units in historical buildings. Variables in the experimental study were the tenon diameter and the tenon penetration depth into the stone. In the experimental study, it will be tried to determine which variables will be used in order to obtain more positive results with anchorage (tensile) experiments. It is exciting that this experimental study, which aims to find the most effective use of fasteners that have been used for centuries and still continues to be used, is the first of its kind. In addition, due to the subject of this study, it is thought that it will be an example for future studies.

Effects of basalt and glass fiber composites usage for strengthening on the cyclic behavior of brick infill walls

In the current study, the effects of 10 mm bilaterally applied basalt fiber reinforced concrete (BRC) and glass fiber reinforced concrete (GRC) plasters with different fiber content (1.0%, 2.0% and 3.0%) on the behavior of the brick infill walls were investigated. For this purpose, strengthened brick infill walls placed in a hinged steel frame on all four corners were examined comparatively with their non-plastered and ordinary cement plastered conditions under cyclic loading. The load carrying capacities, displacement ductility, stiffness degradation and energy dissipation capacities of infill walls were determined using obtained results. The test results showed that brick walls with 1.0% glass fiber and 2.0% basalt fiber content showed the best performance in terms of load carrying and energy dissipation capacity. Also brick wall with 1.0% glass fiber content has the lowest stiffness degradation decrease at the ultimate drift ratio. In addition to all these, it has been observed that the mechanical behavior of the walls strengthened with plasters containing different percentages of fiber has improved considerably compered to non-plastered and ordinary cement plastered brick walls. This situation reveals that basalt and glass fiber plasters can be used to strengthen the walls. It is recommended that this method can be used quickly and effectively in the reinforcement of masonry structures, which have a large amount in the existing building stock.

АНАЛИЗ ПРОЧНОСТИ ПРИ ОСЕВОМ РАСТЯЖЕНИИ КЛАДКИ ИЗ ЯЧЕИСТОБЕТОННЫХ БЛОКОВ АВТОКЛАВНОГО ТВЕРДЕНИЯ НА РАЗЛИЧНЫХ РАСТВОРАХ И КЛЕЕВЫХ СОСТАВАХ

The article presents the results of a comparative analysis of the axial tensile strength of masonry made of autoclaved cellular concrete blocks with cement mortars of various grades and polyurethane adhesive compositions of various manufacturers. The tests were carried out on prototypes made of two cubes of 150x150x150 mm glued together. As cellular concrete, blocks of autoclaved hardening of the compressive strength class B1.5, B2.5, B3.5 were used. M200 and M300 cement mortars, "Tytan Professional”, "Technonicol", "Bonolit" and “KUDO” foamed polyurethane glues were used as a binder. The experiment was performed in the Laboratory of the Department of Reinforced Concrete and Masonry Structures of the Moscow State University of Civil Engineering. On the basis of the experiment, the values of the increase in the strength of the masonry under axial tension were obtained depending on the binder.

Investigation of the adherence between clay blocks and grouts

Abstract This study aims to evaluate the adherence between clay blocks and grouts. For this purpose, push-out and pull-out tests were performed to assess the adherence presented by different combinations of five types of clay blocks and two types of grouts. The results demonstrated that the geometry of the cells of the clay blocks has a preponderant role in their adherence with grout, as the extent of the contact area between grout and block depends on the geometry of the cell. The shrinkage of the grout can cause the formation of cracks at the interface between block and grout, reducing the adherence between the materials. The shrinkage formed inside each type of block can be estimated based on the testing procedure developed in this research and used in conjunction with the geometric characteristics of the cells of the blocks to estimate the maximum load in the push-out tests. The test procedure developed to estimate the percentage of contact area lost due to grouts shrinkage shows to be promising, since its results were used in the equation to estimate the bond strength between blocks and grouts and shown good correlation. However, more study must be done because there are other variables that can affect the results. These results show that it is possible to use different characteristics of blocks and grouts to increase the adherence between these materials and provide a better behavior for reinforced masonry structures. However, it looks like if block types with a grooved hollow cell are used, a bigger contact surface is produced, and a higher bond strength appears to be assured.

Analysis of flood impacts on masonry structures and mitigation measures

The impact of floods can be devastating to buildings, especially in countries and villages in mountainous areas. Based on the flood impact risk analysis results, two methods are suggested by authors to improve the flood impact defense capability of rural buildings in this paper: increasing the strength of the mortar used in masonry structures, as well as adding reinforced concrete (RC) columns and circle beams to masonry structures. The impact of floods on the reinforced masonry structures is simulated numerically, and the failure process, stress, and deformation behaviors of masonry structures are analyzed. Compared to the computational results of normal masonry structures, the advantages of the two methods proposed in this manuscript are studied. Increasing the mortar strength slows the rate of damage to the masonry structure but does not improve the deformation or the failure behaviors. Increasing the mortar strength slightly decreases the first principal stress on the mortar and brick elements but has no effect on the third principal stress. Adding the RC frames not only delays the damage to the building and improves the failure behavior of the masonry structure but also decreases the first and third principle stresses of the brick and mortar elements.

Assessment of groundwater depletion–induced land subsidence and characterisation of damaging cracks on houses: a case study in Mohali-Chandigarh area, India

The present study identified groundwater depletion–induced land subsidence by spaceborne differential interferometric SAR (DInSAR) technique and assessed the damaging impacts of land subsidence by characterising the cracks on houses in Mohali-Chandigarh area of India. First, we identified groundwater depletion hot spots using pre-monsoon and post-monsoon groundwater-level (GWL) data of Central Ground Water Board (CGWB), India, for the period of 2005–2018. Both conventional and advanced DInSAR techniques were used to identify temporally consistent subsiding areas and measure precise rates of subsidence in and around groundwater depletion hot spots. We studied the damaging impacts of land surface deformation by characterising the damaging cracks on houses in affected areas. Groundwater depletion and resulting aquifer-system compaction increase effective stress on confining clay layer which leads to stress build-up at the soil-structure interface and causes damaging cracks on houses. A variety of damaging cracks on houses were observed at the affected areas such as Sohana, Landran, Kharar and Kurali localities. We attempted to characterise the damaging cracks on the basis of shape, size, orientation, surface morphology and texture of the cracks; sense of ground movement; and nature of stress build-up at the interface. We identified tensional cracks, compressional cracks and shear cracks with diverse orientations and separation widths. Finally, a comparative assessment of groundwater depletion, land subsidence and damaging impacts on houses has been made. Using DInSAR technique, we identified land subsidence in and around the groundwater depletion areas in Sohana and Landran (both in Mohali City area), Kharar and Kurali (in Mohali district outside Mohali City area) and Sectors 27–28 in Chandigarh with radar line-of-sight subsidence rates of ~6–7.5 cm/year, ~5.5–6.5 cm/year, and ~ 4 cm/year respectively. We observed that the houses in and around Landran appears to be worst affected followed by Kharar, Sohana and Kurali. From this study, it appears that the type of construction of the houses, e.g. prevalence of masonry and reinforced masonry structures, is primarily responsible for the worst damaging impacts of the houses in Landran and Kurali areas besides the magnitude of land subsidence.

A study of bearing capacity of reinforced masonry beams with GFRP reinforcement

This article presents the results of experimental researches of bearing capacity and deformability of reinforced masonry beams with combined reinforcement. This study was carried out in the zone of maximum bending moment. The reinforcement A400C and A1000 were used for experimental samples. The combined action of ceramic masonry and reinforcement was ensured at the expense of a cement-sand grout in the joints of masonry and vertical reinforcing meshes in support zones of beams, which were welded to angle bars. Besides that, there was carried out a comparison of the results of experimental researches with calculated values by the active standards of Ukraine. This comparison permits to determine the expediency of the use of the existing design procedure of bearing capacity of reinforced masonry structures with combined double reinforcement. Finally, this scientific work has also presented the conclusions about the possibility of the efficient design of reinforced masonry structures in the effective area of normal forces.

Finite element analysis of UHPC reinforced masonry structure

Based on the existing UHPC material parameters, masonry parameters and the application of reinforcement projects on the market, ABAQUS's unique concrete plastic damage (CDP) constitutive model can be used for concrete and other brittle materials. The constitutive parameters are obtained by curve fitting experiments by other scholars, and this paper has carried out appropriate calibrations. Numerical analysis is the pseudo-static loading form of UHPC reinforced low-strength masonry walls. Through the analysis and simulation of the hysteresis curve, skeleton curve, equivalent plastic strain Moire diagram, peak stress, strain and other parameters, the changes in shear resistance before and after UHPC reinforced masonry walls are evaluated.

Vulnerability of Florida residential structures to hurricane induced coastal flood

This paper presents a methodology to develop hurricane induced coastal flood vulnerability functions for residential construction based on empirical tsunami fragility functions. A force equivalency mapping procedure first transforms the tsunami fragility functions into coastal flood fragility functions. Following the quantification of the damage states and the incorporation of repair costs, the coastal flood fragility functions translate into coastal flood vulnerability functions. Insurance claims data from the National Flood Insurance Program and vulnerability functions independently derived by the US Army Corps of Engineers are employed to validate single-story on-grade timber and reinforced masonry structure model outputs. The limitations of the model and future developments are discussed.

Seismic behavior of a partially grouted reinforced masonry structure: Shake‐table testing and numerical analyses

SummaryIn regions of low to moderate seismicity in North America, reinforced masonry structures are mostly partially grouted. The behavior of such structures under lateral seismic loads is complicated because of the interaction of the grouted and ungrouted masonry. As revealed in past experimental studies, the performance of partially grouted masonry (PGM) walls under in‐plane cyclic lateral loading is inferior to that of fully grouted walls. However, the dynamic behavior of a PGM wall system under severe seismic loads is not well understood. In this study, a full‐scale, one‐story, PGM building designed for a moderate seismic zone according to current code provisions was tested on a shake table. It was shown that the structure was able to develop an adequate base shear capacity and withstand two earthquake motions that had an effective intensity of two times the maximum considered earthquake with only moderate cracking in mortar joints. However, the structure eventually failed in a brittle manner in a subsequent motion that had a slightly lower effective intensity. A detailed finite element model of the test structure has been developed and validated. The model has been used to understand the distribution of the lateral force resistance among the wall components and to evaluate the shear‐strength equation given in the design code. The code equation has been found to be adequate for this structure. Furthermore, a parametric study conducted with the finite element model has shown that the introduction of a continuous bond beam right below a window opening is highly beneficial.

Determination of physico-mechanical characteristics of concrete for 3D printing building designs

Problem statement. Currently, methods of manufacturing building structures and products using a 3D printer are becoming increasingly popular. In 3D printing technology one of the main factors that affects the quality of the final product is the composition of the concrete mix used. Moreover, for each type of product, it is important to develop a separate composition of the mixture, which has certain physical and mechanical properties. Analysis of the current state of development and research of concrete for 3D printing of structures showed that the choice of materials for printing depends on the functional purpose of the created object and its scope. At the same time, a distinctive feature of concrete used in the practice of modern construction is that each developer of a 3D printer presents its mixture without revealing its composition. Analysis of publications. The main material used in 3D-construction is concrete-an artificial stone building material obtained as a result of the formation and solidification of a rationally selected and compacted mixture. Such a mixture consists of a binder-cement, large and small aggregates, water, and in some cases with the addition of various modifying additives. One of the main directions of modification of concrete mix is the use of special additives, which significantly affect the characteristics of concrete. Examples of such additives are kaolin clay, silica fume, air lime, fly ash, superplasticizers, hardening accelerators, and mixture strength set. In world practice, for 3D printing of structures for concrete reinforcement, a variety of fibers, fiberglass and other fillers are introduced into the mixture, which can significantly increase the strength of concrete. Currently, in Dnipropetrovsk region in Bratskoe village there is a production room, where the production of small piece concrete products with the help of 3D printing has been established. Department of Reinforced Concrete and Masonry Structures, State Higher Education Institution “Pridniprovska State Academy of Civil Engineering and Architecture” established cooperation with this production facility, engaged in the improvement of manufacturing technology and the application of mixtures, as well as the development of optimal concrete compositions. The first step of such cooperation is the development of mixtures with various binders and hardening accelerators, which significantly affect the reduction of the setting time of mixtures. Purpose of the work was to identify physico-mechanical characteristics of concrete,which is used to manufacture the structures at the production plant in Bratskoe. At the same time the goal was also to compare the characteristics of concrete made using 3D printing by extruding the mixture through a nozzle and molded by manually sealing the mixture. Conclusions. It is found out that in modern construction it is quite efficient and technologically simple to implement the advantages of 3D printing technology for the manufacture of individual structural elements of buildings and structures. As a result of tests of concrete compositions for 3D printing of structures, it was found that the closest concrete grade in terms of strength of basic samples-cubes that were made in molds is M300, and samples-cubes that were selected from structures is M250. Scale factors were established for the samples-cubes with ribs of 100, 70, and 50 mm, which were determined with respect to the strength of standard specimens with a 150-mm rib size.

Experimental investigation of effect of section configuration on seismic performance of an innovative integrated concrete masonry wall system

Abstract In this study, an innovative integrated concrete masonry wall (ICMW) system is proposed to improve the seismic behavior of infill masonry in reinforced masonry structures. The ICMW system consists of a load-bearing component comprising two reinforced concrete masonry walls and a partition component comprising one ungrouted masonry wall and autoclaved aerated concrete blocks. Four ICMW specimens were designed for cyclic loading test and the effects of the section type of the load-bearing component and infill on the seismic performance of the specimens were investigated. An obvious pinching effect was observed on the load-displacement curves of all specimens. Different flexural and shear failure modes occurred in the specimens due to the section type of the load-bearing components, whereas the infill heightened the crack propagation. The results indicated that the stiffness degradation, displacement ductility, energy dissipation, and equivalent viscous damping ratio of the specimens were obviously influenced by the section type owing to different failure modes. Moreover, it was observed that the infill had a beneficial influence on the ductility coefficient of the specimens because of its timely separation. Based on these results, it is concluded that the ICMW is an effective construction system in which the partition component participates in the specimen loading process at the initial stage and separates from the specimen to protect it and prevent out-of-plane damage at the final stage.

Comprehensive approach to the restoration of historical and cultural monuments (example of the mansion of A. A. Polovtsov)

The article deals with the problems of restoration design and study of cultural heritage objects that have a long history of existence and operation since the first half of the 19th century. The main aspects faced by researchers of monuments in our time are listed. The list of problems that designers face when studying such objects in St. Petersburg is given. A small dive into the technology of historical development for 250-300 years in St. Petersburg is made. The features of historic masonry and reinforced masonry structures are discussed. In particular, the problems of the state of brickwork walls of cultural heritage monuments of the early 19th century are listed. As a result, it can be stated that the technical and technological difficulties of restoration and the most problematic objects in the design were left to the current generation. We can also say that the current community of restoration designers, to a greater extent, does not take into account many factors that affect the integrity and load-bearing capacity of masonry historical walls. Using the example of a cultural heritage object - the building of the mansion of A. A. Polovtsov, the stages of design of restoration work and analysis of the result obtained and forced corrections after detailed restoration implementation in the structure during its restoration and conservation are given.