Experimental Evaluation of Unreinforced Brick Masonry Mechanical Properties by the Flat-Jack Method – an Extensive Campaign in Croatia

Stepinac, Mislav; Lulić, Luka; Damjanović, Domagoj; Duvnjak, Ivan; Bartolac, Marko; Lourenço, Paulo B.

doi:10.1080/15583058.2023.2208542

Cited by 5 publications

(4 citation statements)

References 33 publications

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“…The flat-jack test is not the main focus of this paper and, therefore, will not be explained in detail. For more specific information about the test itself and its application, see [53,54].…”

Section: Case Study Informationmentioning

confidence: 99%

Assessment of Existing Masonry Resistance Using Partial Factors Approaches and Field Measurements

Lulić,

Lukačević,

Skejić

et al. 2023

Buildings

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The vast majority of existing structures in Croatia, as well as in other European countries, are made of unreinforced masonry. The seemingly ideal building material presents a great challenge for engineers in earthquake-prone zones. Given that structural failure can have significant consequences in terms of loss of human lives as well as financial losses, a comprehensive structural reliability assessment is needed. Old existing masonry structures often do not have design documentation, and even when they do, the initial mechanical properties have almost certainly degraded over time. That is why in situ testing is of great importance, but masonry is also characterized by a large scattering of results. After recent severe earthquakes in Croatia, more than ever, there is a need for a more reliable assessment of existing masonry structures. This paper presents reliability approaches for resistance evaluation of existing masonry in a real case study where basic failure modes of the masonry were observed. First, the data recommended in standards were used, followed by the updated data obtained from the flat-jack test. Finally, the design value method (DVM) and the adjusted partial factor method (APFM) were used. These methods align with Eurocode standards for new structures but are also adaptable for the assessment of existing structures. Differences in the results between the existing and the new version of the standard were observed, as well as an increase in the obtained resistances with an increase in the complexity of the methods used. Also, the influence of in situ testing proved to be an important factor in the analysis.

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Section: Case Study Informationmentioning

confidence: 99%

Assessment of Existing Masonry Resistance Using Partial Factors Approaches and Field Measurements

Lulić,

Lukačević,

Skejić

et al. 2023

Buildings

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Section: In-situ Testsmentioning

confidence: 99%

“…Experiences from an extensive test campaign conducted after the recent devastating earthquakes in 2020 in Croatia are presented in [27]. The results from that campaign are presented in [28]. The principle of the single flat-jack test is to partially relieve the compressive stress in the wall by removing the mortar from the horizontal bed joint.…”

Section: In-situ Testsmentioning

confidence: 99%

The Assessment and Retrofitting of Cultural Heritage—A Case Study of a Residential Building in Glina

Ožić

Markić²,

Moretić

et al. 2023

Buildings

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The focus of the study is on the renovation of a specific case study, which is a 19th century building under cultural heritage protection. It highlights the particular challenges faced by civil engineers in the structural renovation of buildings that are under heritage protection. Preserving the identity of these buildings limits the available methods for strengthening their seismic capacity. At the beginning, information about the seismic activity and the different post-earthquake evaluation procedures are presented to identify the damage and take appropriate further steps. Then, basic information about the building is given and supported by graphic attachments. In the following, the methods and materials are explained, focusing on in situ testing with the semi-destructive flat-jack method and the analysis of the structure with the nonlinear method implemented in the software. Subsequently, the obtained results are presented and discussed, accompanied by graphics. An approach for strengthening the structure is presented, which includes a combination of traditional methods and innovative solutions suitable for the preservation of cultural heritage. The discussion and conclusions emphasize the importance of assessing and retrofitting existing masonry structures due to their vulnerability, especially in earthquake-prone areas. Finally, this article also provides insights into the local context, cultural significance, and historical background of the building, along with the specific retrofitting solutions employed to address its unique requirements.

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“…Detaljniji opis flat-jack metode, njene provedbe te određenih poteškoća za vrijeme provedbe ispitivanja dane su u [12]. Također, prikaz rezultata opsežne flat-jack studije provedene na postojećim nearmiranim zidanim konstrukcijama u Hrvatskoj može se pronaći u [13].…”

Section: Slika 3 Određivanje Početne Posmične čVrstoćeunclassified

Flat-jack method for testing masonry

Lulić,

Stepinac

2023

Zajednički Temelji 2023. - uniSTem : Deseti Skup Mladih Istraživača Iz Područja Građevinarstva I Srodnih Tehničkih Znanosti, Sp

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The recent seismic events that shook Croatia made it clear that there is a great need for the renovation of a significant number of existing buildings. A large portion of these are vulnerable buildings made of unreinforced masonry. In order to make the renovation and strengthening of such structures efficient and sustainable, detailed investigations must be conducted to assess the existing condition of the structure. Various methods are used for this purpose. The flat-jack method has been proven to be a very useful semi-destructive testing method. Flat-jacks are used to apply stress to the masonry, causing it to deform. An insight into the mechanical properties of the masonry is acquired by measuring the aforementioned stresses and deformations and processing the measured data. The vertical stress state, the modulus of elasticity, and the initial shear strength of the masonry can be determined during the three test phases.

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Experimental Evaluation of Unreinforced Brick Masonry Mechanical Properties by the Flat-Jack Method – an Extensive Campaign in Croatia

Cited by 5 publications

References 33 publications

Assessment of Existing Masonry Resistance Using Partial Factors Approaches and Field Measurements

Assessment of Existing Masonry Resistance Using Partial Factors Approaches and Field Measurements

The Assessment and Retrofitting of Cultural Heritage—A Case Study of a Residential Building in Glina

Flat-jack method for testing masonry

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