• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.13-20
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• 2017

Unreinforced masonry buildings are vulnerable to lateral forces, such as earthquakes, owing to the nature of the building materials, yet numerous masonry buildings remain in South Korea. Since the majority of the existing masonry buildings were constructed more than 20 years ago, it is necessary to develop economical reinforcement methods for disaster reduction. In this study, external reinforcement of masonry walls using adhesive stiffeners was proposed as a reinforcement method for such age-old masonry buildings. Six specimens were fabricated with different aspect ratios (L/H = 1.0, 1.3, and 2.0) and used in static load tests to verify the reinforcement effect. The experimental results showed that the masonry walls before and after reinforcement were ruptured by rigid body rotation and slip. In addition, the maximum strength, maximum displacement, and dissipated energy of the walls were shown to increase after applying the adhesive stiffeners, thereby verifying the excellent reinforcement effect. Furthermore, an adhesive stiffener design for unreinforced masonry walls was proposed based on the increased shear strength achieved by using conventional glass fibers. The proposed design can be used as a basis for the application of adhesive stiffeners for unreinforced masonry walls.

• Advances in Computational Design
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• v.7 no.3
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• pp.229-251
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• 2022

In 2017, an intraplate earthquake of Mw 7.1 occurred 120 km from Mexico City (CDMX). Most collapsed structural buildings stroked by the earthquake were flat slab systems joined to reinforced concrete (RC) columns, unreinforced masonry, confined masonry, and dual systems. This article presents the simulated response of an actual six-story RC frame building with masonry infill walls that did not collapse during the 2017 earthquake. It has a structural system similar to that of many of the collapsed buildings and is located in a high seismic amplification zone. Five 3D numerical models were used in the study to model the seismic response of the building. The building dynamic properties were identified using an ambient vibration test (AVT), enabling validation of the building's finite element models. Several assumptions were made to calibrate the numerical model to the properties identified from the AVT, such as the presence of adjacent buildings, variations in masonry properties, soil-foundation-structure interaction, and the contribution of non-structural elements. The results showed that the infill masonry wall would act as a compression strut and crack along the transverse direction because the shear stresses in the original model (0.85 MPa) exceeded the shear strength (0.38 MPa). In compression, the strut presents lower stresses (3.42 MPa) well below its capacity (6.8 MPa). Although the non-structural elements were not considered to be part of the lateral resistant system, the results showed that these elements could contribute by resisting part of the base shear force, reaching a force of 82 kN.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.51-58
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• 2013

This study Masonry Buildings in rural areas, due to the lateral load resistance for seismic reinforcement method is proposed. Some of the proposed methods for reinforcement directly through finite element analysis to evaluate the change in frequency. The results for the following: This paper has the object of investigating natural frequencies of opening thick plates on Pasternak foundation by means of finite element method and providing Kinematic design data for mat of building structures. In this paper, vibration analysis of rectangular opening thick plate is done by use of Serendipity finite element with 8 nodes by considering shearing strain of plate. It is shown that natrural frequencies depend on not only Winkler foundation parameter but also shear foundation parameter, opening position.

• Structural Engineering and Mechanics
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• v.47 no.1
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• pp.99-118
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• 2013

Earthquakes, which are unavoidable natural phenomena in Turkey, have often produced economic and social disaster. The latest destructive earthquakes happened in Van city. Van, Turkey, earthquakes with M = 7.2 occurred on 23 October 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanlivillage) and M = 5.6 on 9 November 2011 epicentered near the town of Edremit south of Van in eastern Turkey and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 4000 buildings collapsed or were seriously damaged. The majority of the damaged structures were seismically insufficient, unreinforced masonry and adobe buildings in rural areas. In this paper, site surveys of the damaged masonry and adobe buildings are presented and the reasons for the caused damages are discussed in detail.

• Earthquakes and Structures
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• v.4 no.3
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• pp.241-264
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• 2013

Since the beginning of the twentieth century, the progressive and rapid spread of reinforced concrete (RC) has led to the adoption of mixed masonry-RC solutions, such as the confined masonry. However, together with structures conceived with a definite role for earthquake behaviour, the spreading of RC technology has caused the birth of mixed solutions inspired more by functional aspects than by structural ones, such as: internal masonry walls replaced by RC frames, RC walls inserted to build staircases or raising made from RC frames. Usually, since these interventions rise from a spontaneous build-up, any capacity design or ductility concepts are neglected being designed only to bear vertical loads: thus, the vulnerability assessment of this class becomes crucial. To investigate the non-linear seismic response of these structures, suitable models and effective numerical tools are needed. Among the various modelling approaches proposed in the literature and codes, the authors focus their attention on the equivalent frame model. After a brief description of the adopted model and its numerical validation, the authors aim to point out some specific peculiarities of the seismic response of mixed masonry-RC structures and their repercussions on safety verification procedures (referring in particular way to the non-linear static ones). In particular, the results of non-linear static analyses performed parametrically to various configurations representative of different interventions are discussed.

• Earthquakes and Structures
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• v.25 no.3
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• pp.209-221
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• 2023

The Mw=7.7 (Pazarcık-Kahramanmaraş) and Mw=7.6 (Elbistan-Kahramanmaraş) earthquakes that occurred in Türkiye on 06.02.2023 with 9 hours' intervals, caused great losses of life and property as the biggest catastrophe in the instrumental period. The earthquakes affecting an area of 14% of the country were enormous and caused a great deal of loss of life and damage. Numerous buildings have collapsed or damaged at different levels, both in the city centers and in rural areas. Within the scope of this study, masonry structure damage built from different types of materials in the earthquake region was taken into consideration. In this study, the damage and causes of such masonry structures that do not generally receive engineering services were examined and explained in detail. Insufficient interlocking between wall-wall and wall-roof, inadequate masonry, lack of horizontal and vertical bond beams, usage of low-strength materials, poor workmanship, and heavy earthen roof are commonly caused to structural damages. Separation at the corner point and out-of-plane mechanism in structural walls, and heavy earthen roof damages are common types of damage in masonry structures.

• Earthquakes and Structures
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• v.9 no.1
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• pp.257-279
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• 2015

The primary objective of this study is to summarize results from previous experimental tests on laboratory specimens of RC/steel frames with masonry infills, in order to develop fragility functions that permit the estimation of damage in typical non-structural components of RC frame buildings, as a function of attained peak interstory drift. The secondary objective is to derive loss functions for such non-structural components, which provide information on the probability of experiencing a certain level of monetary loss when a given damage state is attained. Fragility curves and loss function developed in this study can be directly used within the FEMA P-58 framework for the seismic performance assessment of RC frame buildings with masonry infills.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.101-110
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• 2005

In Seoul, structural deterioration is severe in the private masonry buildings which have been built since 1906s. But most of these structures remain without any repair works. As a result, the rate of deterioration is getting faster and these dangerous structures may cause hazardous circumstances to the adjacent structures and neighborhood. The purpose of this study is to investigate the actual conditions of wall cracks among the defect types which occur in private masonry buildings and to analyze the correlation between safety grades and wall cracks for offering the fundamental data. Using these date we can establish basic criteria for safety grades of structures and improve the quality of masonry buildings. The result of this study indicate that there are high correlations between safety grades and the width of crack but much less so with the length. Furthermore, with regard to crack patterns, vertical cracks much more negatively effected the safety grades.

• Earthquakes and Structures
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• v.1 no.4
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• pp.371-390
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• 2010

Historical buildings in seismically active regions are severely damaged by earthquakes, since they certainly were not designed by the original builders to withstand seismic effects. In particular the reports after major ground motions indicate that earthquake-induced pounding between buildings may lead to substantial damage or even collapse of colliding structures. The research on structural pounding during earthquakes has been recently much advanced, although most of the studies are conducted on simplified single degree of freedom systems. In this paper a detailed pounding-involved response analysis of three adjacent structures is performed, concerning the main bodies of the "Quinto Orazio Flacco" school. The construction includes a main masonry building, with an M-shaped plan, and a reinforced concrete building, separated from the masonry one and realized along its free perimeter. By the analysis of the capacity curves obtained by suitable pushover procedures performed separately for each building, it emerges that masonry and reinforced concrete buildings are vulnerable to earthquake-induced structural pounding in the longitudinal direction. In particular, due to the geometric configuration of the school, a special case of impact between the reinforced concrete structure and two parts of the masonry building occurs. In order to evaluate the pounding-involved response of three adjacent structures, in this paper a numerical procedure is proposed, programmed using MATLAB software. Both a non-linear viscoelastic model to simulate impact and an elastic-perfectly plastic approximation of the storey shear force-drift relation are assumed, differently from many commercial softwares which admit just one non-linearity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.5 s.57
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• pp.133-141
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• 2009

50 year-old masonry buildings which had been constructed using lime mortar have caused lots of problems because of using different material, cement mortar, when they repair them. Also, there is little information on structural capacities and details of masonry buildings built using lime mortar. In addition, it is difficult to evaluate the structural capacities of the buildings which were often constructed by untrained labors. To preserve the original masonry construction, the study on their construction materials and methodologies has to be carried out. This paper provides basic information for establishing standard details of masonry works using lime mortar in order to overcome these problems when cultural properties are repaired or retrofitted. To do this, compression tests of lime mortar were preformed with the parameters of mixing ratios, mixing material, curing time and curing conditions etc. Based on the test results, the differences between lime mortar and cement mortar were specified and the structural characteristics of lime mortar were also presented in this paper.