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1.
Many surviving ancient monuments are freestanding stone masonry structures, which appear to be vulnerable to horizontal dynamic loads such as earthquakes. However, such structures have stood for thousands of years despite numerous historic earthquakes. This study proposes a scaled-down dynamic centrifuge modelling test to study how these masonry structures resist seismic loading. The test is proposed for seismic risk assessments to evaluate risk of damage from a future seismic event. The seismic behaviour of a 3-storey, freestanding stone block structure has been modelled and tested within a centrifuge. Models were made at 3 different scales and dynamic tests were conducted using different centrifugal acceleration fields so that the behaviours could be transformed to an equivalent full-scale prototype and compared. Data from 2 earthquakes and a sweeping signal were used to simulate the effects of earthquake ground motion within the centrifuge. The acceleration and frequency responses at each storey height of the model were recorded in different centrifugal acceleration fields. Similar behaviours appeared when the results of the small-scale models were transformed to a full-size prototype scale. This confirms that the seismic behaviour of stone masonry structures can be predicted using scaled-down models. 相似文献
2.
Bruno Silva Jo?o M. Guedes António Arêde Aníbal Costa 《Bulletin of Earthquake Engineering》2012,10(1):211-234
The conservation and rehabilitation of monuments is a matter of important investigation, and the need for accurate structural
analysis, capable of effectively predicting the structural behaviour of this type of constructions, under static and dynamic
loads, is increasing. Currently there are numerous computational methods and tools, supported by different theories and strategies
with different levels of complexity, computation time and cost which are available to perform such analyses. A complex analysis
is not always synonym of a better result and the choice of a method over another depends mostly on the purpose of the analysis.
This work aims at evaluating the capacity of a non linear continuum damage model (Faria et al. in Int J Solids Struct 35(14):1533–1558,
1998), originally developed for concrete structures, to simulate the behaviour of stone masonry structures. In particular, the
seismic response of an old stone masonry construction, the Gondar church, is analysed considering different levels of geometrical
and material complexity. The verification and calibration procedures use the experimental results from tests performed on
stone masonry walls at the Laboratory for Earthquake and Structural Engineering of the Faculty of Engineering of Porto University
and from other tests found in the bibliography (Vasconcelos in Experimental investigations on the mechanics of stone masonry:
Characterization of granites and behaviour of ancient masonry shear walls. PhD Thesis, Universidade do Minho, Guimar?es, Portugal,
2005). The results are compared, assessing the differences and the importance of using complex tools, such as the continuum damage
model, to better simulate and understand the global behaviour of such constructions. 相似文献
3.
Jorge Proen?a António Sousa Gago Joaquim Cardoso Vítor Cóias Raquel Paula 《Bulletin of Earthquake Engineering》2012,10(1):113-133
Traditional non-reinforced masonry walls are particularly prone to failure when subjected to out-of-plane loads and displacements
caused by earthquakes. Moreover, singularities such as openings in fa?ades may trigger local collapse, for either in-plane
or out-of plane motion. Bearing in mind all the former limitations, STAP, with the scientific support of ICIST and LNEC, has
been developing a reduced intrusiveness seismic strengthening methodology for traditional masonry structures. The technique
consists in externally applying Glass Fibre Reinforced Polymer (GFRP) composite strips to one or both faces of walls. Connection
between GFRP composite strips and masonry substrate is enhanced through specifically detailed anchorages or confinement connectors.
This technique has been developed and studied through an extensive series of experimental tests, which are briefly reviewed.
This paper focuses more deeply on the latest experimental program, aimed at the characterization of the masonry-GFRP composite
interface behaviour. This testing program comprised 29 masonry specimens, strengthened with externally bonded GFRP composite
strips with anchorages. The testing variables were the number and spacing of anchorages as well as the loading history type:
monotonic or repeated. Results clearly show that the use of anchorages dramatically enhances bond behaviour and that its number
and spacing have a significant effect on deformation capacity and a less pronounced effect on strength. Based on experimental
evidence, this paper also provides a calculation model and ULS safety assessment procedure for out-of-plane strength of reinforced
masonry walls. This calculation model leads to interaction curves on strengthened masonry walls subjected to compression and
out-of-plane flexure. 相似文献
4.
This study attempts to propose dynamic centrifuge model tests as a method of seismic risk assessment in order to discover how stone architectural heritages with masonry structures have endured seismic load, and whether there is any possibility of future earthquake damage. Dynamic centrifuge tests have been conducted for one fifteenth scale models of Seok-ga-tap and the five-storey stone pagoda of Jeongnimsa temple site, which are Korean representative stone pagodas. In order to make input motions of the earthquake simulator, site investigation and site-specific response analysis have been performed. The models of two stone pagodas, which have the same number of pieces with the real structures, have been produced and the dynamic centrifuge tests have been conducted for the model pagodas. Accelerometers were attached at different heights of the pagoda. The measured acceleration records and frequency responses were analysed during dynamic centrifuge test. Two real earthquake records, Hachinohe and Ofunato earthquakes and a sweeping signal with ranged frequency were utilised for input motions of dynamic centrifuge tests to evaluate the behaviour of the stone pagodas. For Seok-ga-tap models, it was observed that acceleration tends to be amplified with height. The third floor body shows at most 2.5 amplification of acceleration in comparison to the surface ground. The amplification was at a frequency of 3.83 Hz and it was considered as the natural frequency of the pagoda. For the five-storey stone pagoda, the seismic wave energy significantly reduced while it passed the first body floor, and then the peak acceleration was gradually amplified upwards. It was found that the pagodas did not collapse when the peak acceleration of ground surface was raised to 0.4 g. Given that the maximum design seismic acceleration specified in Korean seismic design guide is 0.22 g and the amplification ratio of peak acceleration in the supporting ground of the pagodas ranges from 1.45 to 1.74, it can be shown that the two pagodas are stable against 2400-year return period earthquake level, and have excellent seismic performance. 相似文献
5.
Charalambos Mouzakis Chrissy-Elpida Adami Lucia Karapitta Elizabeth Vintzileou 《Bulletin of Earthquake Engineering》2018,16(2):803-829
The present work focuses on the seismic behaviour of timber-laced masonry buildings with timber floors, before and after the application of intervention techniques. A two-storey building with timber ties (scale 1:2) was subjected to biaxial seismic actions. Prior to the execution of shaking table tests, the dynamic characteristics of the model were identified. The base acceleration was increased step-wise until the occurrence of significant but repairable damages. Afterwards, the masonry was strengthened by means of grouting, whereas the diaphragm action of the top floor of the building was enhanced and the model was re-tested. The tests on the timber reinforced model before strengthening show that the presence of timber ties within the masonry elements contributes to improved seismic behaviour. The performance of the model after strengthening shows that the selected intervention techniques led to a significant improvement of the seismic behaviour of the building model. 相似文献
6.
Norio Hori Norio Inoue Dangol Purushotam Tetsuya Nishida Jun Kobayashi 《地震工程与结构动力学》2006,35(13):1699-1719
To improve the seismic performance of masonry structures, confined masonry that improves the seismic resistance of masonry structures by the confining effect of surrounding bond beams and tie columns is constructed. This study investigated the earthquake resisting behaviour of confined masonry structures that are being studied and constructed in China. The structural system consists of unreinforced block masonry walls with surrounding reinforced concrete bond beams and tie columns. The characteristics of the structure include: (1) damage to blocks is reduced and brittle failure is avoided by the comparatively lower strength of the joint mortar than that of the blocks, (2) the masonry walls and surrounding reinforced concrete bond beams and tie columns are securely jointed by the shear keys of the tie columns. In this study, wall specimens made of concrete blocks were tested under a cyclic lateral load and simulated by a rigid body spring model that models non‐linear behaviour by rigid bodies and boundary springs. The results of studies outline the resisting mechanism, indicating that a rigid body spring model is considered appropriate for analysing this type of structure. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
7.
Seismic behaviour of masonry buildings, built of low compressive strength units, is discussed. Although such materials have already been tested and approved for use from mechanical and thermal insulation point of view, the knowledge regarding their structural behaviour is still lacking. In order to investigate the resistance and deformation capacity of this particular type of masonry construction in seismic conditions, a series of eight walls and model of a two-storey full scale confined masonry building have been tested by subjecting the specimens to cyclic shear loads. All tests were conducted under a combination of constant vertical load and quasi static, cyclically imposed horizontal load. The behaviour of tested specimens was of typical shear type. Compared with the behaviour of plain masonry walls, the presence of tie-columns resulted into higher resistance and displacement capacity, as well as smaller lateral resistance degradation. The response of the model was determined by storey mechanism with predominant shear behaviour of the walls and failure mechanism of the same type as in the case of individual confined masonry walls. Adequate seismic behaviour of this particular masonry structural type can be expected under the condition that the buildings are built as confined masonry system with limited number of stories. 相似文献
8.
Cheomseongdae is known to be the oldest astronomical observatory in Asia. According to historical records, the Gyeongju area, where Cheomseongdae is located, suffered from numerous medium‐scale earthquakes. Cheomseongdae has a masonry structure, which is apparently vulnerable to horizontal dynamic loads such as earthquakes. However, despite its appearance, features such as the filler of the lower half, inner irregular‐shaped stones which can induce high frictional resistance, eight long horizontal tie stones inside the artefact, and a grid of interlocking headstones increase its resistance to horizontal dynamic loads. Dynamic centrifuge model tests were performed on Cheomseongdae in order to evaluate the seismic response characteristics of this architectural heritage structure. Model tests were executed on two 1/15‐scale models: one which was an exact duplicate of the original Cheomseongdae and the other without the long horizontal tie stones and grid of interlocking headstones. On the basis of the amplification patterns in the time and frequency domains, the differences in seismic behaviour between the two Cheomseongdae models, and a broken stone at the 19th layer during tests, the long horizontal tie stones and headstones were found to increase the seismic resistance within Cheomseongdae and provide a glimpse of the ‘seismic design’ of our ancestors. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Seismic upgrading of old masonry buildings by seismic isolation and CFRP laminates: a shaking-table study of reduced scale models 总被引：2，自引：2，他引：0
The efficiency of improving the seismic resistance of old masonry buildings by means of seismic isolation and confining the
structure with CFRP laminate strips has been investigated. Five models of a simple two-story brick masonry building with wooden
floors without wall ties have been tested on the shaking table. The control model has been built directly on the foundation
slab. The second model has been separated from it by a damp-proof course in the form of a PVC sheet placed in the bed-joint
between the second and the third course, whereas the third model has been isolated by rubber isolators placed between the
foundation slab and structural walls. Models four and five have been confined with CFRP laminate strips, simulating the wall
ties placed horizontally and vertically at floor levels and corners of the building, respectively. One of the CFRP strengthened
models has been placed on seismic isolators. Tests have shown that a simple PVC sheet damp-proof course cannot be considered
as seismic isolator unless adequately designed. Tests have also shown that the isolators alone did not prevent the separation
of the walls. However, both models confined with CFRP strips exhibited significantly improved seismic behavior. The models
did not collapse even when subjected to significantly stronger shaking table motion than that resisted by the control model
without wall ties. 相似文献
10.
Historic masonry buildings in seismically active regions are severely damaged by earthquakes, since they certainly have not been explicitly designed by the original builders to withstand seismic effects, at least not in a ‘scientific’ way from today’s point of view. The assessment of their seismic safety is an important first step in planning the appropriate interventions for improving their pertinent resistance. This paper presents a procedure for assessing the seismic safety of historic masonry buildings based on measurements of their natural frequencies and numerical simulations. The modelling of the brittle nonlinear behaviour of masonry is carried out on the macro-level. As an example, a recently completed investigation of the seismic behaviour of the Aachen Cathedral is given, this being the first German cultural monument to be included in the UNESCO cultural heritage list in 1978. Its construction goes back to the 9th century a.d. and it is considered as one of the finest examples of religious architecture in Central Europe. The investigation is based on measurements of the natural frequencies at different positions and numerical simulations using a detailed finite element model of the Cathedral. 相似文献
11.
2017年5月11日新疆塔什库尔干5.5级地震给震区建筑结构造成了不同程度破坏。选择震区钢筋混凝土（RC）框架结构、砖混结构以及土石木结构等3类典型建筑结构,介绍了各类建筑结构地震破坏特点,分析了震害特征与破坏机理。结果表明:RC框架结构在地震中表现出了优异的抗震性能,即使在震中区,破坏也仅仅表现为非结构性破坏,如填充墙开裂和吊顶脱落等;砖混结构绝大多数抗震性能优良,仅震中区的少数建筑物发生了承重墙墙体开裂情况;土石木结构房屋抗震性能最差,地震破坏最为严重,是导致该次地震人员伤亡主要原因。建议地震高烈度设防区房屋建筑应采用抗震性能较好的RC框架结构和砖混结构,而抗震性能差的土石木建筑房屋应尽量避免继续建设和使用。结果可供类似地区房屋建设和建筑结构抗震设计等工作参考。 相似文献
12.
建筑砌体结构抗震性能评估,对建筑结构安全的稳定性至关重要。本文从四个方面分析建筑砌体结构抗震性能提升的条件,根据建筑结构的抗震性影响因素,评估抗震能力。构建建筑砌体结构抗震性能的评估BIM指标体系;利用BIM模型中的三角模糊数,定量计算建筑砌体结构抗震性能指标的模糊判断矩阵,得到建筑砌体结构的三角模糊数值,分析筑砌体结构抗震性能指标的单排序情况,结合对建筑砌体结构抗震性能评估体系指标权重系数和单项得分的计算,实现基于BIM的建筑砌体结构抗震性能评估。结合模拟建筑实例分析,利用建筑结构倒塌概率测试建筑砌体结构的抗震性能,并利用评估结果与实际评估结果的拟合度测试提出方法的准确性。实例结果证明,能够准确的得到抗震性能的评估结果。 相似文献
13.
A non-linear finite element model for plain masonry structures under lateral static loads and seismic base inputs is presented. Three super-imposed elasto-plastic shear elements are used in order to approximate the typical force-displacement curve for masonry. Material properties are identified with respect to results of shear tests on single piers. Modelling of entire structures is then performed and the numerical results are satisfactorily checked against the experimental outputs of static and shaking table tests of simple 1 and 2 storey buildings. The out of plane behaviour of walls is accounted for by means of a simplified method. 相似文献
14.
Recent seismic events have caused damage or collapse of invaluable historical buildings, further proving the vulnerability of unreinforced masonry (URM) structures to earthquakes. This study aims to understand failure of masonry arches—typical components of URM historic structures—subjected to horizontal ground acceleration impulses. An analytical model is developed to describe the dynamic behaviour of the arch and is used to predict the combinations of impulse magnitudes and durations which lead to its collapse. The model considers impact of the rigid blocks through several cycles of motion, illustrating that failure can occur at lower ground accelerations than previously believed. The resulting failure domains are of potential use for design and assessment purposes. Predictions of the analytical model are compared with results of numerical modelling by the distinct element method, and the good agreement between results validates the analytical model and at the same time confirms the potential of the distinct element framework as a method of evaluating complex URM structures under dynamic loading. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
15.
Gianni Blasi Daniele Perrone Maria Antonietta Aiello 《Bulletin of Earthquake Engineering》2018,16(12):6105-6130
A wide number of experimental studies conducted in latest years pointed out the high influence of the mechanical properties of masonry units and mortar bed joints on lateral strength and stiffness of masonry panels. This feature significantly modifies the global response of infilled frames under seismic actions as well as the local interaction phenomena. Despite a wide investigation on the influence of the infills on global behaviour of reinforced concrete (RC) frames has already been provided, different features characterizing the seismic performances of buildings suggest the need of accurately evaluating local interaction phenomena as well as the influence of the panel on specific and relevant aspects, as the accelerations transferred to non-structural components. This study provides a parametrical analysis of the influence of shear strength and elastic modulus of masonry infills on the seismic behaviour of RC frames originally designed for gravity loads. Regular buildings with different height were analysed using the Incremental Dynamic Analysis in order to provide fragility curves, investigate on the collapse mechanisms and define the floor spectra depending on the properties of the infills. Results obtained pointed out the high influence of the considered parameters on the fragility of existing RC frames, often characterized by inadequate transversal reinforcement of columns, which may lead to brittle failure due to the interaction with the infills. Floor response spectra are also significantly affected by the influence of masonry infills both in terms of shape and maximum spectral accelerations. Lastly, on the basis of the observed failure mechanisms, a parameter defining the ductility of the frames depending on the properties of the infills was also provided (Capacity Design Factor). The correlation between the mechanical properties of the infills and this parameter suggests its reliability in the simplified vulnerability analysis of existing buildings as well as for the design of new buildings. 相似文献
16.
17.
Giulio Castori Marco Corradi Alessandro De Maria Romina Sisti Antonio Borri 《Bulletin of Earthquake Engineering》2018,16(10):4561-4580
Studies oriented to restoration and conservation of historical monumental buildings have recourse to structural analysis as a way to investigate the genuine structural features of the construction, to better understand its present condition and actual causes of existing damage, to estimate its safety conditions and to determine necessary remedial measures. Based on this background, this paper discusses on the seismic vulnerability of masonry fortresses by means of an analysis methodology based on three different analytical procedures, according to an increased knowledge of the structure. As a relevant case study the Albornoz fortress, a 14th stone masonry construction located in central Italy, was selected. Initially, the strategy proposed to perform this task was aimed at testing and developing an expeditious and non-destructive procedure to evaluate both the seismic vulnerability and the main mechanical properties of the different masonry typologies. The macroscale structural behavior of the fortress was then evaluated through a nonlinear static analysis (pushover) and a more simple approach based on the kinematic theorems of the limit analysis. From this point of view, by comparing the capacity of the construction to withstand lateral loads with the expected demands resulting from seismic actions, these methods provided a highly effective means of verifying the safety of the masonry structure and its vulnerability to extensive damage and collapse. 相似文献
18.
Seismic assessment of existing unreinforced masonry buildings represents a current challenge in structural engineering. Many historical masonry buildings in earthquake regions were not designed to withstand seismic loading; thus, these structures often do not meet the basic safety requirements recommended by current seismic codes and need to be strengthened considering the results from realistic structural analysis. This paper presents an efficient modelling strategy for representing the nonlinear response of unreinforced masonry components under in‐plane cyclic loading, which can be used for practical and accurate seismic assessment of masonry buildings. According to the proposed strategy, generic masonry perforated walls are modelled using an equivalent frame approach, where each masonry component is described utilising multi‐spring nonlinear elements connected by rigid links. When modelling piers and spandrels, nonlinear springs are placed at the two ends of the masonry element for describing the flexural behaviour and in the middle for representing the response in shear. Specific hysteretic rules allowing for degradation of stiffness and strength are then used for modelling the member response under cyclic loading. The accuracy and the significant potential of the proposed modelling approach are shown in several numerical examples, including comparisons against experimental results and the nonlinear dynamic analysis of a building structure. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
19.
Dipendra Gautam 《Bulletin of Earthquake Engineering》2018,16(10):4661-4673
This paper outlines the seismic vulnerability of rural stone masonry buildings affected by the 2015 Gorkha earthquake sequence. Summary of field observation is presented first and empirical fragility curves are developed from the detailed damage assessment data from 603 villages in central, eastern and western Nepal. Fragility curves are developed on the basis of 665,515 building damage cases collected during the post-earthquake detailed damage assessment campaign conducted by Government of Nepal. Two sets of fragility functions are derived using peak ground acceleration and spectral acceleration at 0.3 s as the intensity measures. The sum of the results highlights that stone masonry buildings in Nepal are highly vulnerable even in the case of low to moderate ground shaking. The results further indicate that in the case of strong to major earthquakes, most of the stone masonry buildings in Nepal would sustain severe damage or collapse. 相似文献