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Shake table testing and computational investigation of the seismic performance of modularized suspended building systems

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Zhihang Ye at Shantou University
Zhihang Ye
Gang Wu
Gang Wu
Gang Wu
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De-Cheng Feng at Southeast University
De-Cheng Feng
  • Southeast University
Abdollah Shafieezadeh at The Ohio State University
Abdollah Shafieezadeh
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Abstract and Figures

Suspended building structures have inherent architectural aesthetics and are able to achieve low seismic-induced displacements of the primary structure and accelerations of the suspended segments. A recently proposed subtype of suspended building structures harnesses discrete prefabricated modules to overcome the fragility originating from inter-story drift within the suspended segment and to enhance the overall attenuation. This paper presents the first shake table experimental study of this subtype to directly evaluate its aseismic performance and develop a physics-based modeling strategy that is validated and therefore is reliable. For this purpose, 1:15 scaled shake table experiments of modularized suspended structures were conducted with three fundamental configurations. Each model in each configuration was subjected to at least five ground motions. Results indicate that displacements at the top of the primary structure are reduced by around 50%; in the structure with discrete modules and inter-story dampers, quicker decay was shown, accompanied by lower accelerations of the modules. The inter-story drift ratio of the suspended segment reached 3.75% under 0.12 g PGA excitation, indicating the potential of drift-induced fragility if a regular structure is adopted and proving the benefit of modularization. Numerical models of the tested structural systems have been developed in OpenSees platform. Simulated responses show satisfactory agreement with the measured ones. Subsequent parametric analyses reveal that the performance is sensitive to both the stiffness and damping values especially when the damper is of viscous type. Optimal stiffness facilitates tuning between the primary and secondary structures while optimal damping enhances dissipation notably. Moreover, it is observed that the inherent friction handicaps dissipation instead of facilitating it.
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Vol.:(0123456789)
Bulletin of Earthquake Engineering (2020) 18:5247–5279
https://doi.org/10.1007/s10518-020-00902-3
1 3
ORIGINAL RESEARCH
Shake table testing andcomputational investigation
oftheseismic performance ofmodularized suspended
building systems
ZhihangYe1,2· GangWu1,3 · De‑ChengFeng1,3· AbdollahShaeezadeh2
Received: 2 August 2019 / Accepted: 4 July 2020 / Published online: 15 July 2020
© Springer Nature B.V. 2020
Abstract
Suspended building structures have inherent architectural aesthetics and are able to achieve
low seismic-induced displacements of the primary structure and accelerations of the sus-
pended segments. A recently proposed subtype of suspended building structures harnesses
discrete prefabricated modules to overcome the fragility originating from inter-story drift
within the suspended segment and to enhance the overall attenuation. This paper presents
the first shake table experimental study of this subtype to directly evaluate its aseismic
performance and develop a physics-based modeling strategy that is validated and there-
fore is reliable. For this purpose, 1:15 scaled shake table experiments of modularized sus-
pended structures were conducted with three fundamental configurations. Each model in
each configuration was subjected to at least five ground motions. Results indicate that dis-
placements at the top of the primary structure are reduced by around 50%; in the structure
with discrete modules and inter-story dampers, quicker decay was shown, accompanied by
lower accelerations of the modules. The inter-story drift ratio of the suspended segment
reached 3.75% under 0.12g PGA excitation, indicating the potential of drift-induced fra-
gility if a regular structure is adopted and proving the benefit of modularization. Numerical
models of the tested structural systems have been developed in OpenSees platform. Sim-
ulated responses show satisfactory agreement with the measured ones. Subsequent para-
metric analyses reveal that the performance is sensitive to both the stiffness and damping
values especially when the damper is of viscous type. Optimal stiffness facilitates tuning
between the primary and secondary structures while optimal damping enhances dissipation
notably. Moreover, it is observed that the inherent friction handicaps dissipation instead of
facilitating it.
Keywords Suspended buildings· Shake table tests· Passive seismic control· Prefabricated
modules· Airpot dampers· Numerical modeling
Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s1051
8-020-00902 -3) contains supplementary material, which is available to authorized users.
* Gang Wu
g.wu@seu.edu.cn
Extended author information available on the last page of the article
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Seismic investigation on multi-storey modular suspended structures attached to the mainframe and core showed enhanced seismic performance in both fundamental and higher vibration modes [111][112][113][114]. To achieve architectural freedom to place stability units, such as in the centre or perimeter, Gunawardena et al. used rigid modular units with concrete walls, replacing the rigid concrete core with a steel core [100]. ...
... Two new systems with flexible vertical intermodular joints and damping systems have recently been developed. They allow modular unit floor cassettes to transfer lateral loads to cores or primary frames via diaphragm action [111][112][113][114]. The fusetype dampers connected floor cassettes to the core or frame system in one system, while dampers were installed between stacked modules in the other. ...
... Therefore, simplified numerical modelling techniques are adapted where intermodular joints are replaced with nonlinear springs, hinges or connectors, intramodular joints with ties, couplings or rigid nodes, and structural sections with 1D beam elements. Various commercial software, such as ABAQUS [260], ANSYS [144], ETABS [61], SAP2000 [202], MIDAS [117], RUAUMOKO 3D [101], OpenSees [113] and SeismoStruct [73] are so far adapted for the analysis of multi-storey PFVMS buildings with simplified numerical models. ...
Exploration of the multidirectional stability and response of prefabricated volumetric modular steel structures
Article
  • Jul 2021
  • J CONSTR STEEL RES
Prefabricated volumetric modular steel construction (PFVMSC) has a sustainable behaviour that reduces construction time, waste resources, and onsite workload, resulting in improved quality, faster, safer, and more environmentally sustainable construction. This gradually encourages its adaptation to modern urbanisation as an acceptable alternative to traditional construction in multi-storey structures. The structural instability is not noticeable in low-rise buildings and low seismic zones, so PFVMSC is frequently used. However, lateral loads from winds and earthquakes in high seismic zones significantly impact high rise modular steel building (MSB) since the building's height rises. Thus, PFVMSC's applicability to high-rise engineering projects is hampered by a lack of information about high-rise structures' stability due to extreme multidirectional forces. Therefore, this research summarises key technical issues related to the structural stability and robust performance of multi-storey PFVMS structures. Because of the study's versatility, the module classification is briefly introduced to PFVMSC, followed by a structural system discussion. The structural response of the stability systems and recent connection advancements, on which the multidirectional structural stability of multi-storey PFVMS buildings is highly dependent, is discussed in detail. It was accompanied by a summary of the associated challenges, structural requirements, a research evaluation of recent advancements and associated performance studies that can significantly improve multi-level vertical stacking and multidirectional force transmission. Despite increased research into PFVMSC's structural performance, a thorough understanding of the subject has yet to be gained, posing a threat to its continued prevalence in multi-storey buildings and areas where hazardous events may occur. As a result of this development, numerous significant research sectors have proposed expanding the use of PFVMSC on a multi-storey level.
View
... With a non-rigid horizontal diaphragm, the interaction between multiple or hybrid SU through LP is more complicated than that in conventional buildings. In the modularized suspended building structure [35,36], the modularization provides an innovative inter-story drift pattern within the suspended segment and enhances the tuning between the modules and the core-tube. Those system-level interactions between SU and LP have not been systematically discussed yet. ...
... From this perspective, it can be regarded as the SU which shares the lateral load from the module group. Another example of the passive-control system is the modularized suspended building system proposed by Ye et al. [12,35,36]. In this system, the modularization introduces an innovative drift pattern within the suspended segment. ...
... SU2 SU3 SU4 SU5 Moment-resisting frame [8,32] Braced frame [8] Core tube [29] Other passive-control systems [12,35,36]. stiffness, reliability, and the redundancy of load delivery paths. ...
State-of-the-Art Review and Investigation of Structural Stability in Multi-Story Modular Buildings
Article
  • Sep 2020
Prefabricated 3D modules are widely adopted in building construction for better quality, lower demand on labor and construction space, faster construction, and less emission. Various types of modular structures and connections have been tested and are commercially available. A large number of actual applications demonstrate that the structural system of a modular building can be flexibly organized to suit for the topmost utility architecturally. However, in terms of the stability of the structural system, the role of prefabricated modules widely varies. A systematic summary and categorization of different structural stability systems and layout patterns, especially in multi-story modular buildings where load sharing and transfer between the units are necessary, has yet to be made. This paper provides a state-of-the-art review which focuses on four major structural aspects, e.g., module connection, individual module structure, layout pattern, and additional stability unit. Recommended combinations of structural parts of the system are provided. Nonlinear static or pushover analysis is carried out with the numerical model based on available experimental data to demonstrate the roles of individual modules and additional stability units on system stability. A rating procedure for the modular structural system is proposed to briefly evaluate several aspects of the multi-story modular building structures. Trends in design and usage of modular structure systems are presented using examples of 20 unique applications.
View
... It harnesses prefabricated 3D modules (Giriunas et al. 2012;Lawson et al. 2014;Ye et al. 2021) to overcome the drift-induced damage of the suspended segment and to achieve multi-mode tuning. In MSBS, the vertical distribution of the secondary structure parameters can be optimized to achieve satisfactory spacing of modal frequencies, leading to the desirable multi-mode control effect (Ye et al. 2019(Ye et al. , 2020b. Moreover, a previous study (Ye et al. 2020a) reveals that multiple EDPs in MSBS contribute differently to the system-level seismic fragility. ...
... (2) The setting of regional Rayleigh damping is based on the strategy developed in the previous shake-table testing study (Ye et al. 2020b), which has shown satisfactory performance in capturing the experimentally revealed features; (3) The modeling of the shallow foundation adopts the Beam-on-Nonlinear-Winkler-Foundation (BNWF) model, wherein parameters are set at common values as adopted in literature (Tang and Zhang 2011) except for the different geometry parameters, as listed in 6 in the appendix; (4) Min-max element is harnessed to capture the mechanism in which the dampers fail once over-stroke. Besides the aforementioned features, major modeling parameters are listed in Tables 6 and 7 in the Appendix. ...
Optimum weighted arithmetic means of peak- and spectral-based intensity measures for probabilistic seismic demand modeling of modularized suspended buildings
Article
Full-text available
  • Aug 2022
  • B EARTHQ ENG
Optimum intensity measures of ground motions have been extensively investigated in order to improve the quality of probabilistic seismic demand models. Common scalar-type intensity measures prevail in availability and computability but are less satisfactory when predicting seismic responses of systems with multiple contributing vibration modes and different forms of nonlinearity. For complex primary-secondary tuning structures, such as the modularized suspended building systems, optimal forms of scalar-type intensity measures have yet to be investigated. This study addresses this gap and particularly explores weighted arithmetic means of spectral accelerations or peak ground responses. Multi-objective optimizations of the weighting factors and the IM parameters are conducted for 5 performance indices and 10 targeted responses of a 10-story modularized suspended building on a shallow foundation when subjected to 660 ground motions. Frequency domain analysis and Pareto pattern analysis are used to interpret optimization results. It is shown that multiple elastic and elongated modes are attended to by the combination of spectral accelerations with various levels of modal periods and damping ratios, leading to a 0.22 proficiency index and a 0.96 correlation index which are 38% and 5% improvements from those of PGA. Optimal combinations of fractional order peak ground responses show distributions of derivative order between 0 and 3, achieving a 0.25 proficiency index and a 0.95 correlation index, but with notably fewer optimizing parameters.
View
... A modularized suspended building structure (MSBS) is an ideal target structure to investigate the NSOSI. MSBS [34][35][36] belongs to mega-sub-control structure systems [37][38][39] with tuning features, thus having a sensitivity to dynamic disruption. Two other factors are also considered. ...
Investigation on multi-directional free-standing-object-structure interactions in mega-sub-control suspended buildings with tuning features
Article
  • Jan 2024
  • SOIL DYN EARTHQ ENG
The seismic roles of non-structural parts have been extensively investigated, and conclusions have been drawn that non-structural components and objects contribute to both dynamic features and seismic loss of structural systems. In light-weighted seismic-response-control structures wherein non-structural parts could compose a non-negligible portion of the total weight, the aforementioned roles could be amplified, possibly disrupting beneficial structural characteristics. Current studies have yet to systematically investigate the dynamic interaction effects between a tuning structure and non-structural objects. This study addresses this gap and particularly explores three major pairs of free-standing object behavior in different directions, namely, sliding-impact, rocking-overturning, and throwing-landing, as well as the influences on the seismic response control of mega-sub-control suspended buildings. Comprehensive frequency- and time-domain analyses are conducted, while tuning indices, object-structure response correlation, and object statistics are also calculated to interpret the phenomena. Results show that, with a linear structure, pure sliding reduces low-frequency responses of both primary and secondary structures, while throwing reduces high-frequency ones; other types of interactions are overall detrimental. As excitation intensifies, the interactions become more beneficial to high-frequency responses and detrimental to low-frequency responses. With a nonlinear structure subjected to seismic excitation, structural period-elongation mixes with interaction-induced detuning; the detrimental effects on the primary structure are undermined and thus overwhelmed by beneficial ones. At the PGV level of 0.7 m/s, the maximum of averaged envelopes of seismic-induced primary structure displacement show a 9% reduction, while those of secondary structure horizontal acceleration show a 185% increment caused by object-structure interactions. Sliding accompanied by impact is statistically identified as the major detrimental factor for secondary structure acceleration, and the effect is sensitive to the located floor level of the object.
View
... The results were predominantly caused by the existing suspended part consuming the seismic energy through vertical vibration and the larger suspended span consuming more energy; this resulted in smaller horizontal displacement and acceleration. These results also confirm the previous reports [32][33][34][35] in that the suspended structure presented better horizontal anti-seismic behavior. The vertical response results of the asymmetrical suspended structure are presented in Figure 11c,d. ...
Analytical Study on the Random Seismic Responses of an Asymmetrical Suspension Structure
Article
Full-text available
  • May 2023
An asymmetrical suspension structure, without vertical column support and without supplying the flexibility of spatial arrangement, is more sensitive to ground movement. The structural responses of an asymmetrical suspension structure subjected to Clough–Penzien spectrum excitation were analytically investigated in this study. First, the governing equation was decoupled into an independent state equation in generalized coordinates through the real mode decomposition method and by creatively combining it with finite element methods to acquire modal coefficients. Through the pseudo excitation method (PEM), the frequent domain solution of the dynamic response was acquired, and its power spectrum density function was then quadratically decomposed to obtain its corresponding 0–2-order spectral moments. A practical case study was performed to verify the high accuracy and computational efficiency of the proposed closed-form solution comparative to the traditional PEM. Finally, an extended analysis of the effect of the suspended span and comparisons to a normal framed structure and symmetrical suspension structures were carried out. The analysis results indicate that the larger suspended span could consume more seismic energy and result in smaller horizontal displacement and acceleration. Moreover, the comparison results also point out that the existence of the suspension part showed better seismic energy dissipation capacity compared to the normal framed structure, and two symmetrical suspension parts also performed better than a single asymmetrical part in seismic energy dissipation.
View
Modularized Suspended Building Structure
Chapter
  • Jan 2023
This chapter introduces modularized suspended building structures, which can be categorized as mega-sub control configurations with precast/prefabricated components. Intrinsic seismic attenuation mechanisms of passive-control suspended buildings are illustrated mainly from the perspective of a large-mass-ratio TMD-structure system. The structural features of prefabricated modular structures are summarized before modularization of the secondary structure within the suspended building is proposed to induce a harmless pattern of secondary-structure-inter-story drift. Shake-table experiments are also conducted. The results of those investigations show that the modularized suspended building has a satisfactory multi-mode tuning effect induced by the aforementioned inter-story drift pattern, and thus an enhanced seismic control performance.KeywordsSuspended buildingPrefabricated modulePassive controlLarge-mass-ratio TMDNumerical optimizationShake-table experiment
View
Effectiveness of the Use of Suspended Structures in Seismic Areas
Chapter
  • Jan 2022
In high-rise construction, suspended structures of buildings and structures for various purposes are widely used, which can be implemented in one way or another. Meanwhile, in the practice of earthquake-resistant construction, there are still no recommendations for the use of these structures in earthquake prone areas due to their lack of knowledge. The article analyzes the existing design proposals for the implementation of suspended structures, including for seismic areas, and presents some results of computational studies of these structures under seismic impact. The analysis of the effectiveness of the using suspended structures in earthquakes was carried out by comparing the natural period of oscillations of buildings and the stresses in the load-bearing elements of the systems. The parameters of the computed models were determined in the SCAD computing complex by the finite elements method. The initial results show that the use of suspended structures can increase the natural period of oscillations of buildings and reduce the seismic load in the elements of the system. It is shown that under certain seismic impacts, additional elements of high-rise buildings’ seismic protection systems should be provided for the considered design solutions, ensuring their stability in case of earthquakes.KeywordsHigh-rise buildingsSuspended structuresSeismic impact
View
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The key task of the building design is the comprehensive elimination of hazards arising from various impacts on buildings, including seismic ones. Recently, new structural systems have been developed to ensure the earthquake resistance of buildings, as well as the already known ones are being improved. One of the types of structural systems that can be used in seismically active areas are buildings with suspended structures. There are many design solutions for buildings with suspended structures that differ in the type of supporting structure, suspension system and geometric shape. The possibility of using suspended structures under dynamic influences is explained by a load decrease in the load-bearing elements of the building due to the flexibility of these structures, as well as a large natural period of oscillations of buildings with suspended structures. Some aspects of the use of buildings with suspended structures are not fully understood, which prompted a study of the behavior of these buildings using various structural solutions in earthquake conditions. For the effective use of these structures in the practice of earthquake-resistant construction, an important issue is to understand the behavior of suspended structures under seismic influences of a wide frequency spectrum. The results of the study are presented in the paper.
View
Probabilistic seismic demand and fragility analysis of a novel mid-rise large-span cassette structure
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View
Vibration characteristics and higher mode coupling in intermediate isolation systems (IIS): a parametric analysis
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Intermediate isolation system (IIS) is currently spreading and gaining significant popularity, mainly in Japan. However, its potentials are not so well-known in European countries, and in USA only one application to building retrofit is registered. The dynamic behaviour of intermediate isolation systems, more complex than the two-degree-of-freedom behaviour of base isolation systems, gives rise to a twofold control mode, which combines isolation and mass damping strategies. However, the research contributions provided in the scientific literature usually concentrate on one single control mode, either isolation or mass damping, and the relevant design methods and criteria. This paper addresses the IIS design problem from a wider perspective and presents an explorative study on the vibration characteristics and dynamic behaviour of IIS, in order to identify the range of different behavioural modes and to propose relevant design guidelines. For these aims, a parametric analysis is carried out, varying the main design parameters, namely: isolation period and ratio, location of isolation layer and mass ratio, distributions of stiffness and mass in the upper and lower structures. A classical modal approach is initially assumed for assessing the contributions of each vibration mode on the global dynamic behaviour of IIS, with a particular focus on the effect of coupling of higher modes. However, since IIS is a non-proportionally damped system, a state space formulation is subsequently adopted for establishing the cases for which the simplified classical approach, only considering two damping values for the isolation and structural parts, can be adopted in a preliminary design stage. Finally, frequency response analysis is carried out for identifying the ranges of predominant isolation and mass damping behaviour and the effect of mode coupling both in terms of local and global response of the isolated models. Design implications are finally derived from the analysis results.
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A combinatorial optimization approach for multi-hazard design of building systems with suspended floor slabs under wind and seismic hazards
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The possibility of structures experiencing multiple hazards of different types during their service life has always been present. However, design of structures has primarily been geared towards addressing the most dominant hazard at the location of interest. In recent years, the design philosophy of structures has shifted towards a more holistic approach of addressing multiple hazards to ensure adequate performance under different loading scenarios. This requires the utilization of new structural systems and the development of effective optimization methods that can address multiple hazards. In this study, a suspended floor slab-isolated structure is utilized as an optimization test system subjected to wind and seismic demands. To perform the optimization a new combinatorial optimization approach is proposed, which is a combination of two methods – Nelder-Mead and Coevolutionary Matrix Adaptation Evolution Strategy (CMA-ES). The two algorithms are integrated simultaneously to optimize three key design variables of the suspended slab system and to obtain a family of optimal solutions that can accommodate varying level of participation of each hazard. In doing so, a set of alternatives is provided to the designer to accommodate wide variations and combinations in hazards intensities. The results of the study highlight the effectiveness of tuning the suspended slab system to meet the wind and seismic performance objectives. The system is seen to be more effective in case of taller structures than shorter structures. For taller structures, the system can be optimized to improve performance under both wind and seismic hazards without significant trade-off on individual hazard performance. Furthermore, the system is seen to be more sensitive to wind loading than earthquake loading.
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Seismic control of modularized suspended structures with optimal vertical distributions of the secondary structure parameters
Article
  • Mar 2019
  • ENG STRUCT
Suspended building systems with vibration control features dissipate seismic energy by the interaction between their main parts and the suspended parts; they are also architecturally appealing. A modularized suspended structure has been previously proposed to overcome the fragility of its secondary structure and to enhance overall attenuation. However, the full potential of modularization is yet to be achieved via the previous configuration, especially in terms of multi-mode control. In this study, the protection effect of prefabricated modules is further harnessed in such a way that drastic vertical-irregularities of inter-story stiffness and dampers within the suspended segment are allowed. Vertical distribution vectors of structural parameters were set as the variables in genetic-algorithm optimizations, with the maximum mean square moment of the primary structure being the main objective. The results show considerably improved attenuation of responses in multiple modes instead of only the fundamental mode. In the optimized distributions, peaks of damping coefficient occur at the troughs of inter-story stiffness, but without a highly concentrated pattern. Models with different irregularity levels have well-separated Pareto fronts; this indicates that comprehensive improvement can be obtained at compromised choices. The main mechanism is that, with the well-designed irregularities, the secondary structure provides satisfactory dissipation and tuning to the primary structure in the major modes. The analysis with non-stationary excitations reveals that optimized vertical distributions further quicken the vibration decay. The time-history performance verifications and the structural uncertainty analysis are also carried out.
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Optimal lateral aseismic performance analysis of mega-substructure system with modularized secondary structures
Article
  • Jul 2017
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A major type of mega-substructure system is yet to fulfill its full potential of vibration control because of the fragility originating from excessive inter-story drift of its secondary structures during earthquake. We propose an innovative subtype of mega-substructure system to overcome this fragility and further improve its lateral aseismic performance. This subtype takes advantage of modular construction techniques. The secondary structures, which consist of suspended discrete modules, provide protection to nonstructural members against excessive inter-story drift. Additionally, springs that provide inter-story stiffness remain elastic. These effects extend the inter-story drift limit of secondary structure and make sufficient relative motion possible. We carried out single-objective and dual-objective optimizations to derive optimum parameters and capture the potentials of representative models. Mean square responses under power spectral density functions of ground acceleration were set as optimization objectives. It is shown that the proposed systems further suppress the response of primary structure at the expense of additional response of secondary structure, which can be accommodated by the aforementioned protection effect. Mechanisms are revealed in the perspective of transfer function curves. Robustness and time history performances are also verified.
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Seismic evaluation of modular steel buildings
Article
  • Sep 2016
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Modular steel construction is a relatively new construction technique that considerably reduces the time spent on the construction site. However, due to the detailing and assembly requirements of multi-story modular steel buildings (MSBs), these systems are prone to undesirable failure mechanisms during large earthquakes. In this paper a 4-story MSB is designed considering realistic constraints posed during the modular construction. Using a detailed model in OpenSees an assessment of the seismic demand and capacity of this MSB is provided by performing nonlinear static pushover and incremental dynamic analyses (IDA) in two and three dimensions. Diaphragm interactions, relative displacements and rotations between modules, the force transfer through horizontal connections, column discontinuity coupled with possible high inelasticity concentration in vertical connections are some other important aspects that are specifically considered. The results that are summarized with relevant conclusions provide a better insight to the dynamic behavior of multi-story MSBs.
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The 'Bell Building': a new type of earthquake resistant structure.
Article
  • Jan 1987
An alternative structural concept is presented for multi storey buildings, especially when an open first floor is required. The improved seismic performance makes possible the construction of such a building even in environment where strong earthquakes have to be taken into consideration. Due to the boundary conditions of different structural components, the bell will practically remain in vertical position, even during an earthquake. Because the 'Bell Building' structure remains in elastic range under all loading combinations, including strong earthquakes, the self centring should never be a problem.
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Shaking table experiment of vibration-controlling suspended-floor structure equipped with viscous dampers
Article
  • Oct 2012
A shaking table experiment of suspended-floor structures equipped with fluid viscous dampers has been conducted in this paper. The effects of link types and the mass ratios between the primary structure and suspended floors and distribution patterns of dampers on responses of suspended-floor structure models were verified. These responses included the frequency, the mode-damping and maximum displacements of suspended-floor structures. Test results show that the frequencies and the mode damping of suspended-floor structures installed with dampers are adjusted and the first three modes are mainly influenced by the shear drift of suspended floors compared with traditional suspended-floor structures with rigid-bar links. Maximum displacements of the primary structure's top floor of the suspended-floor structure with dampers are smaller than the traditional suspended-floor structure and slightly smaller than the free suspended-floor structure without links. Moreover, the relative larger mass of the suspended segment is helpful to control the primary structure's dynamic responses. Besides, suspended-floor structures with dampers can effectively control the displacement of suspended floors relative to the primary structure and story drifts of suspended floors compared with free suspended-floor structures. When the lateral stiffness of suspended floors is relatively little, the uniform distribution of dampers is more effective to control the relative displacements of suspended floors than the congregating distribution of dampers.
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