In-Plane Cyclic Response of New Urm Systems with Thin Web and Shell Clay Units

Morandi, Paolo; Albanesi, L.; Magenes, Guido

doi:10.1080/13632469.2019.1586801

Cited by 16 publications

(6 citation statements)

References 13 publications

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“…Here, an approach derived from the interpretation of shear‐compression tests on load‐bearing masonry walls has been used (e.g., see Morandi et al.) 33 . Since three loading cycles at each target displacement were carried out in this experimental campaign on TA1 to TA5, three envelopes are obtained.…”

Section: Interpretation Of Out‐of‐plane Experimental Resultsmentioning

confidence: 99%

In‐plane/out‐of‐plane interaction of strong masonry infills: From cyclic tests to out‐of‐plane verifications

Morandi

Hak

Milanesi

et al. 2021

Earthq Engng Struct Dyn

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The construction of RC frame structures with masonry infills is part of the traditional building practice in many European countries and worldwide. Several studies have been recently conducted to improve further the understanding of the seismic response of masonry infills, which are mainly focused on weak/slender clay masonry panels representing a common typology of the past, whereas very limited research has been devoted to stronger/thicker masonry infills, which nowadays are being adopted with increasing frequency in newly designed RC structures for their excellent thermal and acoustic performance. In order to fill this gap, within a systematic experimental and numerical research program, the in‐plane and out‐of‐plane experimental response of ‘strong’ masonry infills has been investigated at the Eucentre and the University of Pavia. In particular, this paper presents the framework and discusses the results of out‐of‐plane static cyclic tests on full‐scale, single‐storey, single‐bay RC frame specimens infilled with 35 cm thick tongue and groove clay unit walls, the related damage propagation and the failure mechanisms. The in‐plane/out‐of‐plane experimental interaction evaluated in terms of stiffness and strength reduction and period increase in function of previous in‐plane damage is also introduced, with the aim of providing a simplified out‐of‐plane strength verification within the European codified design procedures.

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Section: Interpretation Of Out‐of‐plane Experimental Resultsmentioning

confidence: 99%

In‐plane/out‐of‐plane interaction of strong masonry infills: From cyclic tests to out‐of‐plane verifications

Morandi

Hak

Milanesi

et al. 2021

Earthq Engng Struct Dyn

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“…However, demolishing and reconstruction of the entire infills is a more convenient solution because repairment could be too expensive. At the maximum attained in-plane drifts, the damage level is much higher and it should be classified as a near collapse limit state (NCLS), in which the cracking in mortar joints is extensive and crushing and spalling of bricks are widespread, but the collapse still does not occur, as described by Morandi et al (2022). Table 13 shows a concentration of the damage in the middle row of the infill in test T2 and next to columns in test T3 in final in-plane load stages, that might be attributed to the effect of simultaneously applied in-and out-ofplane loads in test T3.…”

Section: Fully Infilled Rc Frames (T2 T3)mentioning

confidence: 99%

Experimental results of reinforced concrete frames with masonry infills with and without openings under combined quasi-static in-plane and out-of-plane seismic loading

Milijaš

Marinković

Butenweg

et al. 2023

Bull Earthquake Eng

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Reinforced concrete (RC) frames with masonry infills can be encountered all over the world, especially in earthquake prone regions. Although masonry infills are usually not considered in the design process, in the case of seismic loading they are subjected to in-plane and out-of-plane forces that can act separately or simultaneously. In recent earthquakes it was observed that seismic loads can severely damage masonry infills or even cause their complete collapse, especially when the loads act simultaneously. Due to this, effects of interaction of in-plane and out-of-plane loads on seismic performance of masonry infills have received more attention recently. However, most of studies focus only on fully infilled frames, even though openings, such as windows and doors are essential parts of infills that substantially affect the seismic response of masonry infills. Therefore, this article presents the results of a comprehensive experimental study on nine full-scale traditional masonry RC frames infilled with modern hollow clay bricks for configurations with and without window and door openings under separate, sequential and combined in-plane and out-of-plane loading. Based on the results, a detailed comparison and interpretation for the different infill and loading configurations is presented. The test results clearly show the unfavourable influence of openings and combined loading conditions as well as the importance of the quality of execution of the circumferential mortar joint between infill and frame. The new findings can be used as a basis for the required development of innovative solutions to improve significantly the seismic performance of RC frames with masonry infills.

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“…The definition of proper limits at SD and NC on the post-peak experimental envelope is still controversial, since the in-plane response of the walls is strongly affected by several parameters and may be characterized, for weak failure modes, either by post-peak branches with gradual force degradation or by sudden decays after the peak. For example, vertically hollowed clay masonry piers tested by Morandi et al, 2019b (typology "MA"), failed by shear, provided strength reduction up to more than 50%, with drift values significantly larger than those at 20% of degradation (from about 2 to 4 times larger), still guaranteeing some reserve capacity against vertical loads; on the other hand, some other types of masonry showed a sudden decay after the peak force with limited increment of deformation capacity after 20% of drop (see, e.g., Petry and Beyer, 2014). Although wider investigation on this topic is surely still needed, the Severe Damage limit state is here associated to the value of deformation corresponding to a strength degradation of 20% after the peak, considering also that in the vast majority of experimental tests, the development of visible shear cracking corresponds just about to the attainment of the peak shear force capacity.…”

Section: Evaluation Of Q*: Considerations On Drift Limits For Shear M...mentioning

confidence: 99%

Latest findings on the behaviour factor q for the seismic design of URM buildings

Morandi

Butenweg

Breis³

et al. 2022

Bull Earthquake Eng

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Recent earthquakes as the 2012 Emilia earthquake sequence showed that recently built unreinforced masonry (URM) buildings behaved much better than expected and sustained, despite the maximum PGA values ranged between 0.20 -0.30g, either minor damage or structural damage that is deemed repairable. Especially low-rise residential and commercial masonry buildings with a code-conforming seismic design and detailing behaved in general very well without substantial damages. The low damage grades of modern masonry buildings that was observed during this earthquake series highlighted again that codified design procedures based on linear analysis can be rather conservative. Although advances in simulation tools make nonlinear calculation methods more readily accessible to designers, linear analyses will still be the standard design method for years to come. The present paper aims to improve the linear seismic design method by providing a proper definition of the qfactor of URM buildings. These q-factors are derived for low-rise URM buildings with rigid diaphragms which represent recent construction practise in low to moderate seismic areas of Italy and Germany. The behaviour factor components for deformation and energy dissipation capacity and for overstrength due to the redistribution of forces are derived by means of pushover analyses. Furthermore, considerations on the behaviour factor component due to other sources of overstrength in masonry buildings are presented. As a result of the investigations, rationally based values of the behaviour factor q to be used in linear analyses in the range of 2.0 to 3.0 are proposed.

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In-Plane Cyclic Response of New Urm Systems with Thin Web and Shell Clay Units

Cited by 16 publications

References 13 publications

In‐plane/out‐of‐plane interaction of strong masonry infills: From cyclic tests to out‐of‐plane verifications

In‐plane/out‐of‐plane interaction of strong masonry infills: From cyclic tests to out‐of‐plane verifications

Experimental results of reinforced concrete frames with masonry infills with and without openings under combined quasi-static in-plane and out-of-plane seismic loading

Latest findings on the behaviour factor q for the seismic design of URM buildings

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