scholarly journals A Passive Rotary System for Seismic Risk Mitigation of Steel Structures

2014 ◽  
Vol 2 (2) ◽  
pp. 72 ◽  
Author(s):  
Ricky Chan ◽  
Peter Wong
Keyword(s):  
Earthquake Engineering ◽  
Risk Mitigation ◽  
Steel Structures ◽  
Earthquake Risk ◽  
Earthquake Excitation ◽  
Ground Shaking ◽  
Floor Slabs ◽  
Seismic Risk Mitigation ◽  
Displacement Based ◽  
Bracing System

This paper presents a novel bracing system designed for earthquake risk mitigation for steel structures. It involves a rotary system which a Chebyshev linkage connected to the ground and the building frame. Upon earthquake excitation, movement of structure floor slabs causes a rotational motion in the disc. Displacement-based dampers are installed between the rotary system and the ground which damp the structural vibrations. The system amplifies the travel of the dampers and efficiency is enhanced. In addition, the cross-brace members are always in tension, permitting the use of very slender sections. The paper first reviews the governing equations of the system, followed by a physical model demonstration. A 3-degree-of-system model with the proposed rotary system was subjected to simulated ground shaking. Acceleration on top floor was measured. Results demonstrated that proposed system effectively supresses the vibrational characteristics of the structure, and represents a viable and inexpensive solution to mitigate seismic risks.Keywords: Earthquake engineering, passive energy dissipation

scholarly journals 2-DIMENSIONAL GROUND RESPONSE ANALYSIS: A REVIEW

2020 ◽  
Vol 5 (1) ◽  
pp. 35-40
Author(s):  
Norazah Arjuna ◽  
Azlan Adnan ◽  
Nabilah Abu Bakar ◽  
Nabila Huda Aizon ◽  
Noor Sheena Herayani Harith
Keyword(s):  
Risk Mitigation ◽  
Soil Surface ◽  
Future Research ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Heterogeneous Distribution ◽  
Near Surface ◽  
Ground Shaking ◽  
Seismic Risk Mitigation

Earthquake is one of the natural disasters that is caused by ground shaking in soil. Ground response analysis is conducted to obtain the ground motion acceleration on soil surface. Conventional 1-D ground response analysis often suggests that soils are horizontally layered, with little consideration for heterogeneous distribution of soil properties. In this study, literature on 2-D ground response analysis studies has been study as it covers vertically and horizontally waves. Therefore, researcher works were presented in numerical modelling as substantial parameters for studies in near-surface structure. Besides, aspects for future research in the area 2-Dimensional Ground Response Analysis are included. The paper contributes to the under- standing of 2-Dimensional Ground Response Analysis for the application of seismic risk mitigation.

scholarly journals Damage and intensities in the magnitude 7.8 1929 Murchison, New Zealand, earthquake

1994 ◽  
Vol 27 (3) ◽  
pp. 190-204 ◽  
Author(s):  
David J. Dowrick
Keyword(s):  
New Zealand ◽  
Earthquake Engineering ◽  
Earthquake Risk ◽  
Fault Rupture ◽  
The South ◽  
Ground Shaking ◽  
The Future ◽  
Seismically Induced Landslides ◽  
Intensity Map ◽  
Made In

This paper is the result of a study of the Ms= 7.8 Murchison earthquake which occurred in the South Island of New Zealand, on 16(UT) June 1929, a few years prior to the introduction of the first earthquake loadings code in New Zealand. It gives the first description of the damage to buildings in this event in modern earthquake engineering terms, and presents the first Modified Mercalli (MM) intensity map for the event determined from the original felt information. Some definitions of "well-built" pre-code buildings are proposed: these should help in dealing with safety and conservation issues raised when considering the future of such "earthquake risk" buildings. No evidence was found for MM10 intensities, although ground shaking of this strength probably occurred in the unpopulated mountainous countryside close to the fault rupture. Recommendations for improving the criteria for determining MM intensity are made in respect of (1) pre-code buildings and (2) seismically-induced landslides.

APPLICATION OF PROBABILISTIC DECISION MODELS FOR SEISMIC REHABILITATION OF STRUCTURES

2011 ◽  
Vol 10 (02) ◽  
pp. 309-331 ◽  
Author(s):  
JOONAM PARK ◽  
ANN BOSTROM ◽  
BARRY J. GOODNO ◽  
JAMES I. CRAIG
Keyword(s):  
Earthquake Engineering ◽  
Risk Mitigation ◽  
Cost Model ◽  
Joint Probability ◽  
Decision Models ◽  
Earthquake Risk ◽  
Building Structures ◽  
Seismic Risk Analysis ◽  
Multicriteria Decision ◽  
Seismic Rehabilitation

This paper outlines a decision framework that incorporates state-of-the-art earthquake engineering information and decision maker preferences into multicriteria decision models to support earthquake risk mitigation decisions. Seismic risk analysis of a structure is utilized for probabilistic estimation of the anticipated seismic losses, which in turn is used as inputs to the decision analysis for seismic rehabilitation of the structure. Three decision models are used to provide insight into the value of system interventions to reduce earthquake risks: (1) an equivalent cost model, (2) multi-attribute utility theory, and (3) joint probability decision making. Guidelines for selecting and applying multicriteria decision models for seismic rehabilitation of building structures are derived based on preferences for including risk attitudes and for measuring values. The detailed procedures for the selection and application of the decision models for seismic rehabilitation of building structures are demonstrated through a case study, where a collection of hospitals in a metropolitan area is examined.

Proactive Actions Based on a Resilient Approach to Urban Seismic Risk Mitigation

2020 ◽  
Vol 14 (1) ◽  
pp. 321-335
Author(s):  
Marco Vona
Keyword(s):  
Urban Planning ◽  
Emergency Management ◽  
Seismic Risk ◽  
Risk Mitigation ◽  
Housing Stock ◽  
Mitigation Strategies ◽  
Housing System ◽  
Management Tools ◽  
Natural Risk ◽  
Seismic Risk Mitigation

Background: Seismic risk mitigation is an important issue in earthquake-prone countries, and needs to be solved in those complex communities governed by complex processes, where urban planning, socioeconomic dynamics, and, often, the need to preserve cultural assets are present simultaneously. In recent years, due to limited financial resources, mitigation activities have often been limited to post-earthquake events, and only a few in periods of inactivity, particularly in urban planning. At this point, a significant change in point of view is necessary. Methods: The seismic risk mitigation (and more generally, natural risk mitigation) must be considered as the main topic in urban planning and in the governance of communities. In fact, in several recent earthquakes, significant socioeconomic losses have been caused by the low or lack of resilience of the communities. This is mainly due to the high vulnerability of private buildings, in particular, housing units. Results: Therefore, in recent years, several studies have been conducted on the seismic resilience of communities. However, significant improvements are still needed for the resilience assessment of the housing stock, both qualitatively and quantitatively. In this study, which is applied to the housing system, a proposal regarding a change in urban planning and emergency management tools based on the concept of resilience is reported. As a first application, a case study in Italy is considered. Conclusion: The proposal is focused on defining and quantifying the improvement of the resilience of the communities and this must be obtained by modifying the current Civil Protection plan. New tools are based on a new resilience community plan by encompassing urban planning tools, resilient mitigation strategies, and consequently, emergency management planning.

scholarly journals Exceedance of design actions in epicentral areas: insights from the ShakeMap envelopes for the 2016–2017 central Italy sequence

2021 ◽  
Author(s):  
Iunio Iervolino ◽  
Pasquale Cito ◽  
Chiara Felicetta ◽  
Giovanni Lanzano ◽  
Antonio Vitale
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Structural Engineering ◽  
Central Italy ◽  
Civil Defense ◽  
Point Of View ◽  
Seismic Sequence ◽  
Ground Shaking ◽  
Motion Effect ◽  
Observed Damage

AbstractShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.

Seismic Risk Mitigation of Historical Masonry Towers by Means of Prestressing Devices

2010 ◽  
Vol 133-134 ◽  
pp. 843-848 ◽  
Author(s):  
Adolfo Preciado Quiroz ◽  
Silvio T. Sperbeck ◽  
Harald Budelmann ◽  
Gianni Bartoli ◽  
Elham Bazrafshan
Keyword(s):  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Risk Mitigation ◽  
Numerical Models ◽  
Failure Mechanisms ◽  
Masonry Towers ◽  
Seismic Risk Mitigation ◽  
Historical Masonry ◽  
Observed Damage ◽  
And Behavior

This work presents the investigation of the efficiency of different prestressing devices as a rehabilitation measure for the seismic risk mitigation of historical masonry towers. As a first phase, the seismic vulnerability of theoretical masonry towers was assessed by means of numerical models validated with information from the literature, observed damage and behavior of these structures due to passed earthquakes (crack pattern and failure mechanisms), and mainly taking into account the engineering experience. Afterwards, the validated models were rehabilitated with different prestressing devices; analyzing the results and concluding which device or the combination of them improved in a better way the seismic performance of the masonry towers. Finally, the methodology will be applied in two historical masonry towers located in seismic areas; the medieval tower “Torre Grossa” of San Gimignano, Italy, and one of the bell towers of the Cathedral of Colima, Mexico.

Evaluating the cost and benefits of earthquake protection of buildings

2018 ◽  
Vol 11 (2) ◽  
pp. 263-278 ◽  
Author(s):  
Benedetto Manganelli ◽  
Marco Vona ◽  
Pierfrancesco De Paola
Keyword(s):  
Real Estate ◽  
Seismic Risk ◽  
Risk Mitigation ◽  
Tax Incentives ◽  
Seismic Retrofitting ◽  
Content Type ◽  
Seismic Risk Mitigation ◽  
The Cost ◽  
Earthquake Protection ◽  
Real Estate Assets

Purpose The purpose of this study is the evaluation of the cost and benefits of earthquake protection of buildings to verify whether the legislative push, through tax incentives, will produce results and lead to a redevelopment of private real estate assets. Design/methodology/approach Through contingent valuation, this research aims to measure the propensity of homeowners to invest in the seismic security of their properties. The sample of homeowners was selected in a southern Italy city, which was characterized by a medium-high seismic hazard. The willingness to pay, once made independent from the family income, was compared with the actual cost of a seismic retrofitting technique to assess its cost-effectiveness. Findings The analysis developed on an example case shows that the economic sustainability of the intervention is only verified when considering the current tax incentives for this type of intervention. Practical implications Choosing to introduce a system to compulsory insurance against seismic risk could certainly be a strong incentive for the implementation of retrofitting interventions on private real estate assets. In this direction, investigations like this can be fundamental to establish the fair risk premium. Originality/value The need for effective seismic risk mitigation policies is also based on the growing awareness of the, often fatal, effects of seismic events, emphasized by the recent medium and high intensity events that hit Italy. The issue of the security of residential buildings is therefore a very topical issue in view of their high seismic vulnerability and the vast number of buildings requiring major seismic retrofitting. Therefore, the propensity of owners to intervene in improving the seismic performance of their properties can be crucial in seismic risk mitigation.

Earthquake Performance Analysis of Steel Structures with A3 Plan Irregularities

2021 ◽  
Vol 10 (12) ◽  
pp. 174-179
Author(s):  
Özlem Çavdar
Keyword(s):  
Earthquake Engineering ◽  
Design Method ◽  
Steel Structures ◽  
Nonlinear Static Analysis ◽  
Seismic Performance Evaluation ◽  
Moment Resisting Frame ◽  
Earthquake Effect ◽  
Steel Building ◽  
Moment Resisting ◽  
Earthquake Performance

In earthquake engineering, a performance-based design method is used to determine the level of the expected performance of the structures under the earthquake effect. The level of performance is related to the damage situation that could be occurred in the structure after the earthquake. In the performance-based structural design, it is predicted that more than one damage levels emerge under one certain earthquake effect. In this study, the seismic behavior of steel structures with plan irregularities in the Turkey Building Earthquake Code in the 2018 (TBEC-2018) is investigated by the nonlinear static analysis methods. The selected steel structures are located in İzmir, Turkey. The Turkey Earthquake Code in 2018 is considered for assessing seismic performance evaluation of the selected moment-resisting frame steel building. Four different A3 type irregularity was investigated. The steel building with no irregularity in its plan. was selected as the structure of the reference. The performance goals of the five different steel structures are evaluated by applying the pushover and procedures of the TBEC-2018. The steel structures were compared by obtaining pushover curves for both the X and Y directions. The results show that the effects of A3 type irregularity should be not considered in design and buildings without irregularities are safer.

scholarly journals Actuator saturation control of a benchmark structure using hedge-algebras-based fuzzy controller

2015 ◽  
Vol 37 (2) ◽  
pp. 91-104
Author(s):  
Bui Hai Le
Keyword(s):  
Fuzzy Controller ◽  
Actuator Saturation ◽  
Fuzzy Model ◽  
Linguistic Variable ◽  
Linguistic Terms ◽  
Earthquake Excitation ◽  
Saturation Control ◽  
Linguistic Hedges ◽  
Bracing System

In this paper, the problem of actuator saturation control of a benchmark structure using hedge-algebras-based fuzzy controller (HAC) is presented. In HAC, linguistic values of linguistic terms are obtained through semantically quantifying mappings (SQMs) based on few fuzziness parameters of each linguistic variable without using any fuzzy set and inherent order relationships between linguistic values of each linguistic variable are always ensured. Hence, the design of a HAC leads to determining parameters of SQMs, which are fuzziness measures of primary terms and linguistic hedges occurring in a fuzzy model. As a case study, a HAC is designed to actuator saturation control of a benchmark structure with active bracing system (ABS) subjected to earthquake excitation. Control performance of the controller is also discussed in order to show advantages of the proposed method.

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