scholarly journals Hybrid posttensioned rocking (HPR) frame buildings: Low-damage vs low-loss paradox

2021 ◽  
Vol 54 (4) ◽  
pp. i-viii
Author(s):  
Rajesh Dhakal
Keyword(s):  
New Zealand ◽  
Seismic Performance ◽  
Experimental Tests ◽  
Financial Impact ◽  
System Level ◽  
Regulatory Regime ◽  
Structural Systems ◽  
Structural System ◽  
Financial Loss ◽  
Building Components

The 2010-11 Canterbury Earthquake Sequence inflicted seismic losses worth more than $40B, which is about 25% of the GDP of New Zealand (as per 2011 data). More than 80% of these losses were insured, which comprised of more than $10B covered by the Earthquake Commission (a New Zealand crown entity providing insurance to residential property owners) and more than $22B (comprising of roughly equal split between domestic and commercial claims) by private insurers [1]. The scale of financial impact has been perceived to be disproportionately large given the building regulatory regime in New Zealand is relatively stringent and the earthquakes and aftershocks were of moderate magnitude. As it is well known that some of the major faults spread in the Wellington region and the subduction boundary passing through the centre of New Zealand can generate much bigger earthquakes (upwards of magnitude 8), people are left pondering whether New Zealand is able to cope with the financial impact of larger earthquakes. This fearful realisation gradually led to people being dissatisfied with merely life-safe buildings and demanding more resilient buildings that meet the objectives of performance based design; i.e. suffer less damage, incur less loss, and can remain functional after earthquakes. In light of the extensive building damage resulting in high financial loss in recent earthquakes, practicing engineers and researchers in New Zealand have been advocating for revising the current design approach to improve performance of new structures and infrastructure in future earthquakes [2-5]. As a result, large proportion of buildings constructed in the last decade (including those built to replace earthquake-damaged buildings) have shied away from the traditional damage-friendly ductile structural systems and instead adopted one of the new and emerging structural systems claimed to be “low-damage”. In many cases, the adopted structural systems are not covered by existing design standards and are approved as alternate solutions through expert peer review. The “low-damage” attribute of most structural systems has been validated by component (or sub-assembly) level experimental tests, but their interactions with other building components and implications of their use in buildings have not been rigorously scrutinised. Hence, the rushed adoption of some of these systems in buildings can surprise the engineering community in future earthquakes with mismatch between the expected and real performances of the buildings; akin to what New Zealand engineering fraternity is currently going through due to realisation of poor seismic performance of precast hollow-core flooring system that has been widely used in New Zealand buildings without rigorous scrutiny. One such “low-damage” structural system is precast post-tensioned rocking frames with supplemental energy dissipaters. This paper summarises the development of this structural system, critically reviews the literature reporting the seismic performance of this system, and qualitatively evaluates system-level implications of its use in buildings. This paper is intended to better inform engineers of the likely seismic performance of buildings with this structural system so that they can optimise its benefits by giving due consideration to its effect on other building components.

scholarly journals Investigation of the effect of moisture on the critical parameters of stability of frame-rod structural systems made of wood

2021 ◽  
Vol 274 ◽  
pp. 03030
Author(s):  
Ksenia Dubrakova ◽  
Victoriia Solodilova
Keyword(s):  
Static Loading ◽  
Compressive Force ◽  
Experimental Tests ◽  
Critical Force ◽  
Critical Parameters ◽  
Structural Systems ◽  
Individual Element ◽  
Structural System ◽  
Laboratory Studies ◽  
Shear Forces

The work of end moments and shear forces is taken as a criterion influencing the value of the limiting compressive force. It was found that the form of bifurcation of an individual element (active or passive) has a significant effect on the value of the critical parameters of stability of the entire system as a whole. A frame-rod structural system made of wood is considered. The influence of humidity on the type of bifurcation of its compressed elements (constrained or forced) and the critical parameters of stability of the system as a whole under various modes of force loading are determined. It is shown that with a change in humidity, individual elements can go from passive loss of stability to active, which will change the value of the critical force by an average of 20 %. To check the obtained analytical dependencies, experimental tests of frame-bar structures made of wood were carried out under their power static loading and variable humidity. At the same time, it was noted that the results of numerical and laboratory studies showed satisfactory agreement, on average by 95 %, which indicates the reliability of the developed methodology.

scholarly journals A Review on the Seismic Performance Assessment of Steel Diagrid Structures

2021 ◽  
Author(s):  
Nourin N ◽  
Hazeena R ◽  
Asif Basheer
Keyword(s):  
Performance Assessment ◽  
Seismic Performance ◽  
Cost Effective ◽  
Structural Systems ◽  
Lateral Loads ◽  
Structural System ◽  
Seismic Performance Assessment ◽  
Structural Efficiency ◽  
High Rise ◽  
Major Factors

In recent years, there is rapid increase in the construction of high rise structures due to the increase in population, high cost of land and restriction in horizontal growth due to less space. The advancements in the development of technological solutions and construction methods of high rise structures led to the innovative structural systems. One of the important criteria that need to be considered in the design of high rise structures is minimization of lateral loads. Hence, the importance of lateral load resisting system increased than structural systems that resist gravitational loads. Lateral loading due to wind and earthquake are the major factors that have to be considered in the design of high-rise structures. Diagrid structural system is recognized as a unique system in construction of high rise structures which is a variation of tubular structures. It consists of inclined members instead of vertical columns in conventional structures to carry both gravity and lateral loads. It gains popularity due to its structural efficiency and aesthetic potential gained by its unique geometric configuration. The present work reviews studies regarding seismic performance assessment of steel diagrid structures, studies on seismic performance factors of steel diagrid structures, impact of shear-lag effect and comparative studies on diagrids. Diagrids are found to be an efficient structural system for high rise structures in terms of structural efficiency as well as aesthetics. Also, it provides more economy, in terms of consumption of steel, thus making it cost-effective and eco-friendly.

scholarly journals Serviceability fragility functions for New Zealand residential windows

2020 ◽  
Vol 53 (3) ◽  
pp. 137-143
Author(s):  
David Carradine ◽  
Aman Kumar ◽  
Roger Fairclough ◽  
Graeme Beattie
Keyword(s):  
New Zealand ◽  
Seismic Performance ◽  
Fragility Functions ◽  
Financial Loss ◽  
The Past ◽  
Physical Injuries ◽  
Window Systems ◽  
Significant Damage ◽  
Residential Structures

Glazing and window systems in New Zealand have been shown to be susceptible to significant damage as evidenced by the past decade of earthquakes. The seismic performance of glazing and window systems has resulted in considerable financial loss, disruption in business and physical injuries following earthquakes.  In order to investigate the vulnerability of residential windows in typical light timber framed buildings racking testing was conducted on six wall configurations.  Numerous observations of window performance were made during the testing and from these results fragility functions were developed for timber and aluminium framed windows.  These fragility functions suggest that even at low displacement levels damage can occur to windows that can potentially affect weather-tightness and require repairs following an earthquake.  These functions can inform decisions around designing for resiliency in residential structures in New Zealand.

scholarly journals Improving seismic performance

2008 ◽  
Vol 41 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Trevor E. Kelly
Keyword(s):  
Seismic Performance ◽  
Lower Cost ◽  
Performance Based Design ◽  
Building Performance ◽  
Existing Buildings ◽  
Structural System ◽  
Nonlinear Analyses ◽  
Frame Buildings ◽  
Building Components ◽  
Structural Engineers

Structural engineers typically improve the seismic performance of deficient structures by adding strengthening elements to the structural system, which also add stiffness to the structure. However, as performance based design becomes more common practice, the focus is on the total performance of not only the structural system but the building components and contents. A stiffer and stronger building will generally be subjected to lower drifts but higher floor accelerations than a weaker and/or more flexible building. Reduced drift related damage may be accompanied by increased damage to components and contents which are sensitive to accelerations. This paper examines two common forms of hardware used to strengthen existing buildings, buckling restrained braces (BRB) and viscous damping devices (VDD). Both types of device augment the existing structural system, rather than replace it. A series of nonlinear analyses is used to quantify the performance of two prototype frame buildings strengthened with each type of device. It is shown that equivalent structural performance, in terms of overall deformations, can be achieved with both types of device, and generally for lower cost by BRBs if only moderate levels of drift reduction are required. However, when the total building performance is examined the VDDs provide additional benefits in the form of reduced floor accelerations. The benefits of this may besufficient to warrant the higher cost solution.

COMPREHENSIVE REFORMING OF TECHNOLOGICAL, FUNCTIONAL AND STRUCTURAL SYSTEMS OF SKIN UNITS OF HOSPITALS

2020 ◽  
pp. 211-218
Author(s):  
Владимир Григорьевич Донцов ◽  
Елена Владимировна Донцова ◽  
Любовь Анатольевна Новикова ◽  
Лариса Николаевна Борзунова
Keyword(s):  
Service System ◽  
Medical Examination ◽  
Structural Systems ◽  
Structural System ◽  
Structural Units

В статье доказана порочность переустройства только одной структурной системы (реструктуризации), так как это чревато поломками элементов, звеньев и блоков, сомой системы кожной службы. Допустимо лишь незначительная адаптация к конкретным условиям больниц, где это будет внедряться. Сформулированы понятия конечного результата работы врачей и структурных подразделений медицинских стационаров в современных условиях общественно-политической формации. Описаны преимущества реконструкции комплекса систем судебно-медицинской экспертизы как экспериментальной службы для кожного отделения городской многопрофильной больницы и работы самого кожного отделения. Описана форма структурного построения судебно-медицинской и кожной служб. По аналоги с экспертным учреждением ожидаются аналогичные изменение конечного результата в кожном подразделении многопрофильного стационара The article proves the viciousness of the reorganization of only one structural system (restructuring), since this is fraught with breakdowns of elements, links and blocks, the soma of the skin service system. Only slight adaptation to the specific conditions of the hospitals where it will be implemented is acceptable. The concepts of the final result of the work of doctors and structural units of medical hospitals in the modern conditions of the socio-political formation are formulated. The advantages of reconstruction of a complex of forensic medical examination systems as an experimental service for the skin department of a city multidisciplinary hospital and the work of the skin department itself are described. The form of structural structure of forensic and skin services is described. By analogy with an expert institution, a similar change in the final result is expected in the skin department of a multidisciplinary hospital

scholarly journals Parametric Analysis of the Shear Lag Effect in Tube Structural Systems of Tall Buildings

2020 ◽  
Vol 11 (1) ◽  
pp. 278
Author(s):  
Ivan Hafner ◽  
Anđelko Vlašić ◽  
Tomislav Kišiček ◽  
Tvrtko Renić
Keyword(s):  
Parametric Analysis ◽  
Numerical Models ◽  
Tall Buildings ◽  
Structural Systems ◽  
Structural Elements ◽  
Structural System ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Lag Effect ◽  
Secondary Structural Elements

Horizontal loads such as earthquake and wind are considered dominant loads for the design of tall buildings. One of the most efficient structural systems in this regard is the tube structural system. Even though such systems have a high resistance when it comes to horizontal loads, the shear lag effect that is characterized by an incomplete and uneven activation of vertical elements may cause a series of problems such as the deformation of internal panels and secondary structural elements, which cumulatively grow with the height of the building. In this paper, the shear lag effect in a typical tube structure will be observed and analyzed on a series of different numerical models. A parametric analysis will be conducted with a great number of variations in the structural elements and building layout, for the purpose of giving recommendations for an optimal design of a tube structural system.

Practitioner-friendly design method to improve the seismic performance of RC frame buildings

2021 ◽  
pp. 875529302098801
Author(s):  
Orlando Arroyo ◽  
Abbie Liel ◽  
Sergio Gutiérrez
Keyword(s):  
Seismic Performance ◽  
Design Method ◽  
Three Dimensional ◽  
Rc Frame ◽  
Structural System ◽  
Standard Code ◽  
Frame Buildings ◽  
Rc Frame Buildings ◽  
Mathematical Justification ◽  
Story Building

Reinforced concrete (RC) frame buildings are a widely used structural system around the world. These buildings are customarily designed through standard code-based procedures, which are well-suited to the workflow of design offices. However, these procedures typically do not aim for or achieve seismic performance higher than code minimum objectives. This article proposes a practical design method that improves the seismic performance of bare RC frame buildings, using only information available from elastic structural analysis conducted in standard code-based design. Four buildings were designed using the proposed method and the prescriptive approach of design codes, and their seismic performance is evaluated using three-dimensional nonlinear (fiber) models. The findings show that the seismic performance is improved with the proposed method, with reductions in the collapse fragility, higher deformation capacity, and greater overstrength. Furthermore, an economic analysis for a six-story building shows that these improvements come with only a 2% increase in the material bill, suggesting that the proposed method is compatible with current project budgets as well as design workflow. The authors also provide mathematical justification of the method.

The Psychological and Financial Impact of Cybercrime Victimization: A Novel Application of the Shattered Assumptions Theory

2021 ◽  
pp. 089443932098382
Author(s):  
Jildau Borwell ◽  
Jurjen Jansen ◽  
Wouter Stol
Keyword(s):  
Negative Impact ◽  
Secondary Analysis ◽  
Well Being ◽  
Policy Implications ◽  
Financial Impact ◽  
Financial Loss ◽  
Data Set ◽  
Loss Compensation ◽  
Shattered Assumptions ◽  
The Impact

While criminality is digitizing, a theory-based understanding of the impact of cybercrime on victims is lacking. Therefore, this study addresses the psychological and financial impact of cybercrime on victims, applying the shattered assumptions theory (SAT) to predict that impact. A secondary analysis was performed on a representative data set of Dutch citizens ( N = 33,702), exploring the psychological and financial impact for different groups of cybercrime victims. The results showed a higher negative impact on emotional well-being for victims of person-centered cybercrime, victims for whom the offender was an acquaintance, and victims whose financial loss was not compensated and a lower negative impact on emotional well-being for victims with a higher income. The study led to novel scientific insights and showed the applicability of the SAT for developing hypotheses about cybercrime victimization impact. In this study, most hypotheses had to be rejected, leading to the conclusion that more work has to be done to test the applicability of the SAT in the field of cybercrime. Furthermore, policy implications were identified considering the prioritization of and approach to specific cybercrimes, treatment of victims, and financial loss compensation.

New Zealand translocations: theory and practice

1995 ◽  
Vol 2 (1) ◽  
pp. 39 ◽  
Author(s):  
Doug P. Armstong ◽  
Ian G. McLean
Keyword(s):  
Population Dynamics ◽  
New Zealand ◽  
Experimental Tests ◽  
Theory And Practice ◽  
Habitat Requirements ◽  
Metapopulation Dynamics ◽  
Behavioural Adaptation ◽  
New Locations ◽  
History Of ◽  
Tests Of Hypotheses

One of the most common tools in New Zealand conservation is to translocate species to new locations. There have now been over 400 translocations done for conservation reasons, mainly involving terrestrial birds. Most translocations have been done strictly as management exercises, with little or no reference to theory. Nevertheless, translocations always involve some underlying theory, given that people must inevitably choose among a range of potential translocation strategies. We review theory relevant to translocations in the following areas: habitat requirements, susceptibility to predation, behavioural adaptation, population dynamics, genetics, metapopulation dynamics, and community ecology. For each area we review and evaluate the models that seem to underpin translocation strategies used in New Zealand. We report experiments testing some of these models, but note that theory underlying translocation strategies is largely untested despite a long history of translocations. We conclude by suggesting key areas for research, both theoretical and empirical. We particularly recommend that translocations be designed as experimental tests of hypotheses whenever possible.

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