Search

This study concerns the structural stability of the Asinelli Tower in Bologna. This building is the tallest and, with the Garisenda Tower, the most undisputed symbol of the City of Bologna. The stability conditions of the tower were analyzed by means of the Acoustic Emission technique. Specifically, this approach was used to analyze the influence of repetitive and impulsive events of natural or anthropic origin, such as earthquakes, wind, or vehicle traffic on the damage evolution of the tower. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Natural disasters can have a damaging effect on human society. To understand the magnitude of risk of a natural disaster at the macro scale, basic socioeconomic parameters such as population or gross domestic product (GDP) are often used as proxies to evaluate value of specific asset classes (e.g., urban assets, agricultural land, etc.). However, such information is not always available and it becomes a challenge to perform cost-benefit analysis of tailored strategies to protect an asset class from natural disaster risk. Recent studies showed the prospects of relating GDP and population to produced capital representing urban assets. However, the methods used in earlier studies are unclear and resulted in different outcomes that need further clarification and generalization. This study aims to demonstrate the potential of developing a more generalized method to characterize the relation between produced capital and basic socioeconomic parameters at the global scale. We include purchasing power parity (PPP) into the country GDP and produced capital data, respectively. We develop a more generalized method that incorporates the uncertainty range to quantify the produced capital. This is an improvement from previous studies. The new approach might be useful for macro scale risk assessment within the context of climate change. [ABSTRACT FROM AUTHOR]

This paper presents the record of damages which were observed in Pakistan due to a strong earthquake on 16 April 2013 in Iran. Mashkel was the nearest town in Pakistan close to the epicentre of earthquake. The damages were documented by a survey team during the visit of Mashkel. The intensity of earthquake in most of the visited areas was found to be VIII on the Modified Mercalli Intensity scale. The infrastructure facilities were undamaged and were operating satisfactorily. On the other hand, heavy damage to adobe buildings was caused by the earthquake. Most of the building failure was resulted by the out-of-plane wall collapse; nearly 40 % adobe buildings were collapsed due to ground shaking in some of the affected areas. Reinforced concrete and cement concrete block masonry buildings performed better than adobe buildings. Using the data of building damage and earthquake intensity fragility curves for adobe buildings in Mashkel were developed. [ABSTRACT FROM AUTHOR]

Due to the increased frequency of extreme rainfall events caused by climate change, flooding in urban areas is becoming increasingly recurrent. Nevertheless, mitigation and response actions to flood events are still defined according to the best judgments of civil protection authorities, based on their experience and on simple flood modelling tools. In this paper we present the methodological structure of an innovative prototype tool for dynamic pluvial-flood emergency planning. The tool is aimed at helping civil protection authorities (and the population) in the preparation, mitigation and response to flood events. The 2009 flood in the Agualva village (Terceira Island, Azores, Portugal), is used to exemplify the model's calibration and to illustrate the prototype capabilities. The results highlight the importance of considering a dynamic approach in the design of pluvial-flood emergency planning. [ABSTRACT FROM AUTHOR]

The impacts of floods on housing are increasing due to more frequent and severe weather events as well as the ongoing development of settlements in flood-prone areas together with the rising vulnerability of assets at risk. Therefore, the improvement of the resilience properties of buildings to better cope with flooding has become a key issue towards more flood resilient cities in European research in recent years. The implementation of flood resilience technologies (FReT) on the individual property scale provides a previously untapped potential to reduce flood damage to buildings due to insufficient transparency of their effects. To overcome this obstacle, the paper presents a four-step extension of a synthetic approach for flood vulnerability analysis to provide evidence on the potential effects of FReT uptake concerning flood damage mitigation. The proposed approach has been integrated in the GIS-based flood damage simulation model HOWAD to support the assessment of FReT alternatives. The simulation of flood damage to buildings in the case study Heywood, Greater Manchester (United Kingdom) revealed the potential of the extended approach to determine the consequences of FReT implementation on building scale. [ABSTRACT FROM AUTHOR]

These thoughts will not be new to the experienced building surveyor, but a professional reputation is often influenced by those with less experience. This paper has been written to assist those who are new to surveying. Those who may consider its comments to be too obvious may need to exercise some patience. These are the author's opinions and they are not necessarily shared by the RICS. This paper is an extended version of a short piece produced for the RICS on flooding, for circulation during the spring floods. [ABSTRACT FROM AUTHOR]

Abstract: A field reconnaissance study of the volcanic geology of Isarog volcano (Luzon, Philippines), complemented with radiocarbon dating, geochemical and petrological data, shows evidence for repeated explosive activity generating pyroclastic density currents and block-and-ash flows, including Holocene events. The chemical composition of juvenile material is dominantly andesitic. As there are several indications for magma mixing taking place, the andesitic composition possibly represents a hybrid composition between mixed magmas. In addition to explosive eruptions, unambiguous field evidence is provided for a sector collapse generating a debris avalanche deposited to the NW. The deposit shows characteristic hummocky and ridge topography, highly brecciated jigsaw-cracked blocks and relict internal stratigraphy in transported masses. In a first-order approximation the deposit volume is estimated to be ~6–8km3. The run-out distance is 21–25km — the distal parts of the deposit were transported into San Miguel Bay. [Copyright &y& Elsevier]

The analysis of the risks in which cities are exposed to -specially those towns located near the littoral- is one of the biggest challenges faced by the human race in the XXI century. The article contributes to enhance the knowledge on this subject by evaluating urban vulnerability of coastal settlements of the littoral of Santiago de Cuba Bay, when faced with anthropic and natural threats. The Rosales B.'s methodology was used for assessing urban vulnerability. This methodology was adapted to the specific conditions of the territory, providing a new stage of study. Vulnerability assessment allowed asserting that out of the seven zones under study, three are classed with high vulnerability, three with moderate vulnerability and one with levels of low vulnerability. The different options that must be considered to lessen the vulnerability of coastal settlements are stated as another result of the research. [ABSTRACT FROM AUTHOR]

This paper discusses the development of bridge monitoring in Japan. Firstly, the background of the development of bridge monitoring is described. The need for monitoring was originally influenced by geographical conditions. Due to the fact that Japan is prone to natural disasters and has a severe environment for deterioration; monitoring of the environment and loading conditions with respect to natural hazards has been conducted for several decades. In the last decade, bridge monitoring has extended its function as an instrument for an efficient stock management. Based on the accumulation of bridge stock and concentrated construction in former years, many bridges in Japan are expected to have serious deterioration problems within the next decade. The second part of the paper describes the concept of bridge monitoring as an essential part of risk reduction. To improve bridge safety, monitoring technologies for risk and vulnerability are implemented. In this concept, structural health monitoring serves as a tool for vulnerability monitoring. The third part of the paper outlines strategies implemented for bridge monitoring in Japan. They are categorised into three main groups according to the purpose of monitoring: natural hazard and environment condition, effective stock management, and failure prevention. Examples of bridge monitoring systems that implement these strategies and the lessons learned from monitoring experiences are also presented in this paper. [ABSTRACT FROM AUTHOR]

Abstract: The December 26th tsunami of 2004 caused an unprecedented disaster in the Indian Ocean. In Sumatra, a third of the Banda Aceh area was destroyed and 70,000 people died. The Tsunarisque Program – a French–Indonesian research project – brings new considerations to tsunami dynamics and damage intensity in this urban area: An original method of damage spatial analysis is based on field surveys, photo interpretations and GIS. The first result is a very accurate cartography of the tsunami breaking zone that is shown by a steep drop in the damaging gradient around 2.7 km from the coast. The second is a new “macro-tsunamic” intensity scale based on special typologies of buildings and damages. This analysis is complemented by fragility curves that give the statistical relationships between mean damage intensities and wave heights. These results will allow developing application in tsunami potential losses modelling. [ABSTRACT FROM AUTHOR]

The article discusses the methods to minimize damages to flooded buildings. It presents steps on how to rehabilitate a flooded building such as reducing the water content of the building material at an appropriate level and eliminate unwanted changes including the static failures that occurred as a result of water infiltration. It also highlights the external thermal insulation systems and other methods of building construction particularly the consideration about utility of plasters removing.

Floods in both riverine and coastal zones can cause significant damage to infrastructure, including possible structural failure of buildings. Methodologies commonly used to estimate flood damage to buildings are typically based on aftermath surveys and statistical analyses of insurance claims data. These methodologies rarely account for flooding hydrodynamics, and thus do not differentiate between the damage caused by floodwater contact and those caused by floodwater velocity. A new stochastic methodology has been developed to estimate the direct impact of flood actions on buildings and to determine the expected damage. Building vulnerability is modeled based on analytical representations of the failure mechanisms of individual building components. The flood actions generated during different flooding events are assessed and compared to the resistance of each building component. The assessed flood actions include: hydrostatic and hydrodynamic forces, waves, turbulent bores, debris impacts, and time-dependent local soil scour. Monte Carlo simulation was used to synthetically expand the available building data, to perform load-resistance analysis, and to account for the uncertainty of input parameters. The primary result from this study is the expected flood damage to individual buildings, and it is expressed as a three-dimensional functions dependent on both floodwater depth and floodwater velocity. The results show how floodwater velocity can increase the magnitude of the flood damage outcome compared to those that solely consider water depth. This demonstrates the real need for considering floodwater hydrodynamics in the vulnerability assessment of buildings located in flood prone areas. Although the present study focuses on the vulnerability of reinforced concrete frame buildings with infill concrete-block walls, the methodology can also be applied to other types of structures. This methodology could serve as a decision-making tool to assist engineers and emergency management agencies to identify zones of high risk, and to implement the necessary preventive measures and mitigation strategies to minimize the adverse impact of potential flooding events. [ABSTRACT FROM AUTHOR]

The article offers information on the history of several extreme weather events and their related hazards over the Arctic regions. The event was caused by heavy rain in association with unusually warm temperatures that caused rapid snowmelt in the higher terrain. A record-breaking wind event took place in February 2007 in which winds gusting up to 140 km caused extensive damage to building.

Abstract: The benefits of reducing the thermal effect of global warming and structural damage by severe storms have renewed interest and drives to heavyweight constructions. One type of heavyweight construction using earth-sheltered construction known as an ‘Earthship’ has been developed and pioneered by US architect Michael Reynolds and recently introduced to the UK. The ‘Earthship’ takes on the concept of an ‘independent vessel’, which operates on a self-sufficient basis and is constructed largely from recycled and reclaimed materials. Although there are up to 3000 globally, only two Earthships have been built in the UK – one in Brighton and one in Scotland. The publicity resulting from the planning approval granted in April 2007 for the construction of sixteen domestic Earthships at the seafront of Brighton have raised public awareness to this type of unconventional construction. A key feature of the Earthship design is the use of a thermal store, which acts as a seasonal heat buffer to absorb heat in the summer and to release heat in the winter, to regulate the room temperature. This paper reports on the initial findings of a long-term study on the thermal behaviour of the thermal store and its effect to the indoor environment. It introduces the design and construction principles of the Earthship and outlines the process and equipment used in the thermal monitoring of the building. Indicative results from the analyses of the data collected at the early stage are reported and discussed. Initial findings have demonstrated the effectiveness of the thermal charging and discharging of the earth-rammed thermal mass, which appeared to moderate the extreme external temperatures. [Copyright &y& Elsevier]

Abstract: In the paper the first attempt at the definition of a model to assess the impact of a range of different volcanic hazards on the building structures is presented. This theoretical approach has been achieved within the activities of the EXPLORIS Project supported by the EU. A time history for Sub-Plinian I eruptive scenario of the Vesuvius is assumed by taking advantage of interpretation of historical reports of volcanic crises of the past [Carafa, G. 1632. In opusculum de novissima Vesuvij conflagratione, epistola isagogica, 2a ed. Napoli, Naples; Mascolo, G.B., 1634. De incendio Vesuvii excitato xvij. Kal. Ianuar. anno trigesimo primo sæculi Decimiseptimi libri X. Cum Chronologia superiorum incendiorum; & Ephemeride ultimi. Napoli; Varrone, S., 1634. Vesuviani incendii historiae libri tres. Napoli], numerical simulations [Neri, A., Esposti Ongaro, T., Macedonio, G., Gidaspow, D., 2003. Multiparticle simulation of collapsing volcanic columns and pyroclastic flows. J. Geophys. Res. Lett. 108, 2202. doi:10.1029/2001 JB000508; Macedonio, G., Costa, A., Longo, A., 2005. HAZMAP: a computer model for volcanic ash fallout and assessment of subsequent hazard. Comput. Geosci. 31,837–845; Costa, A., Macedonio, G., Folch, A., 2006. A three-dimensional Eulerian model for transport and deposition of volcanic ashes. Earth Planet. Sci. Lett. 241,634–647] and experts'' elicitations [Aspinall, W.P., 2006. Structured elicitation of expert judgment for probabilistic hazard and risk assessment in volcanic eruptions. In: Mader, H.M. Coles, S.G. Connor, C.B. Connor, L.J. (Eds), Statistics in Volcanology. Geological Society of London on behalf of IAVCEI, pp.15–30; Woo, G., 1999. The Mathematics of Natural Catastrophes. Imperial College Press, London] from which the impact on the building structures is derived. This is achieved by an original definition of vulnerability functions for multi-hazard input and a dynamic cumulative damage model. Factors affecting the variability of the final scenario are highlighted. The results show the high sensitivity of hazard combinations in time and space distribution and address how to mitigate building vulnerability to subsequent eruptive phenomena [Baxter, P., Spence, R., Zuccaro, G., 2008-this issue. Risk mitigation and emergency measures at Vesuvius]. The first part of the work describes the numerical modelling and the methodology adopted to evaluate the resistance of buildings under the combined action of volcanic phenomena. Those considered here for this multi-hazard approach are limited to the following: earthquakes, pyroclastic flows and ash falls. Because of the lack of a systematic and extensive database of building damages observed after eruptions of such intensity of the past, approaches to this work must take a hybrid form of stochastic and deterministic analyses, taking into account written histories of volcanic eruptions and expertise from field geologists to build up a semi-deterministic model of the possible combinations of the above hazards that are situated both in time and space. Once a range of possible scenarios has been determined, a full stochastic method can be applied to find a sub-set of permutations and combinations of possible effects. This preliminary study of identification of the possible combination of the phenomena, subdividing them into those which are discrete and those which are continuous in time and space, enables consideration the vulnerability functions of the combinations to be feasible. In previous works [Spence, R., Brichieri-Colombi, N., Holdsworth, F., Baxter, P., Zuccaro, G., 2004a. Vesuvius: building vulnerability and human casualty estimation for a pyroclastic flow (25 pages). J. Volcanol. Geotherm. Res. 133, 321–343. ISSN 0377-0273; Spence, R., Zuccaro, G., Petrazzuoli, S., Baxter, P.J., 2004b. The resistance of buildings to pyroclastic flows: theoretical and experimental studies in relation to Vesuvius, ASCE Nat. Hazards Rev. 5, 48–50. ISSN 1527–6988; Spence, R., Kelman, I., Petrazzuoli, S., Zuccaro, G., 2005. Residential Buildings and Occupant Vulnerability to Tephra Fall. Nat. Hazards Earth Syst. Sci. vol. 5. European Geosciences Union, pp.1–18; Baxter, P.J., Cole, P.D., Spence, R., Zuccaro, G., Boyd, R., Neri, A., 2005. The impacts of pyroclastic density currents on buildings during the eruption of the Soufrière hills volcano, Montserrat. Bull. Volcanol. vol. 67,292–313] the authors investigated, by means of experimental and analytical methods, the limiting resistance of masonry and reinforced concrete buildings assuming each action separately. In this work the first attempt to estimate the response of the buildings to the volcanic seismic action or to the lateral dynamic pressure due to pyroclastic flow combined with an extra vertical load on the roof due to ash fall is performed. The results show that up to a certain limit of ash fall deposit, the increment of structure weight increases the resistance of a building to pyroclastic flow action while it reduces its seismic resistance. In particular the collapse of the top storey of R.C. buildings having large roofs could occur by accumulation of ash and a strong earthquake. Seismic and pyroclastic flow vulnerability of tall R.C. and masonry buildings with rigid floors is less sensitive to ash fall load combination. The model allows any sequence of events (earthquake, ash fall, pyroclastic flow) to be assumed and evaluates the spatial distribution of the cumulative impact at a given time. Single impact scenarios have been derived and mapped on a suitable grid into which the territory around Vesuvius has been subdivided. The buildings have been classified according to the constructional characteristics that mostly affect their response under the action of the phenomena; hence the vulnerability distribution of the buildings are assigned to each cell of the grid and by taking advantage from the combined vulnerability functions the impact is derived at time t. In the paper the following impact simulations are presented: [−] single cases of selected seismic sequence during the unrest phase (Sub-Plinian I) [−] ash fall damage distribution compatible to a Sub-Plinian I eruption [−] pyroclastic flow cumulative damage scenarios for selected cases (Sub-Plinian I). The model also allows either Monte Carlo simulation to evaluate the most probable final scenario or maximisation of some parameter sensitive to Civil Protection preparedness. The analysis of the results derived for a Sub-Plinian I-like eruption has shown the importance of the seismic intensities released during the unrest phase that could interfere with the evacuation of the area and the huge number of partial collapses (roofs) due to ash fall. [Copyright &y& Elsevier]

In the field of disaster management the detection and classification of building damage play an important role. Airborne lidar data is very suitable as a basis for damage analyses because it can be acquired for large areas directly after a disaster. In building damage classification methods, plane surfaces extracted from post-event lidar data are often used as one input. Various different algorithms exist for automatic plane detection from lidar data, of which two are presented in this paper and applied to lidar data of undamaged and damaged buildings. Finally, the suitability of these two algorithms for a more detailed building damage classification is studied and analysed. [ABSTRACT FROM AUTHOR]

The random vibration analyses of gradually yielding shear-frame buildings are considered using a recently proposed constitutive model that is used to calculate the detailed degradation of the stiffness of structures which permits the prediction of their global responses, as well as the states of stress in their members. It is shown that the detailed stress degradation model can also be used in connection with a global force-displacement model, such as the Bouc and Wen model, to predict the time evolution of the various stress-related variables and time passages to failure. The two models are applied in separate analyses and are exemplified using both a single-story building and a four-story building subjected to artificial ground motions. The corresponding probability density functions of the various stress-related responses, including the strains and plastic hinge lengths, and the first time passages to failure are presented and discussed. [ABSTRACT FROM AUTHOR]

A vertical ship lift under earthquake excitation may suffer from a violent whipping effect due to the sudden change of building lateral stiffness at the top of ship lift towers. This paper presents an experimental investigation to explore the validity of using a magnetorheological (MR) isolation system to prevent the whipping effect manipulated by neuro-fuzzy control algorithm. The two-story building was constructed as a ship lift model, in which the first story was much stiffer than the second story and the plates of the second story were divided into two mass pieces. MR isolation systems were used to link those two mass pieces. The dynamic characteristics of the model with rigid connection and with only seismic isolator connection were first identified. The models with those two connections and with MR isolation system connection were then tested under the scaled Three Gorge artificial ground motion and the scaled El Centro 1940 north-south ground motion. Finally, the seismic responses of the ship lift model were recalculated with the modified structural parameters through measured natural frequencies and were compared with the experimental seismic responses. The experimental results show that an MR isolation system manipulated by neuro-fuzzy control algorithm can achieve a significant reduction in seismic whipping effect on the building model. The comparison consequences indicate that the theoretical simulation results are accurately consistent with the experimental results. [ABSTRACT FROM AUTHOR]

This article discusses different aspects of natural disasters in Peru over the last decades, due to the fact that the territorial features of this country result in a permanent natural risk that threatens its geography, where cities suffer part of the most important catastrophes. For this reason, this article suggests the need for a disaster prevention policy to foresee and mitigate the impact of these disasters, highlighting the idea that this is a mission for all members of society, and putting forward the role of urban and territorial planning as a tool for prevention. An important part of this investigation is the result of innumerable actions taken by the State and by different private and public civil organizations of the Republic. [ABSTRACT FROM AUTHOR]

The application of the saddlepoint approximation to reliability analysis of dynamic systems is investigated. The failure event in reliability problems is formulated as the exceedance of a single performance variable over a prescribed threshold level. The saddlepoint approximation technique provides a choice to estimate the cumulative distribution function (CDF) of the performance variable. The failure probability is obtained as the value of the complement CDF at a specified threshold. The method requires computing the saddlepoint from a simple algebraic equation that depends on the cumulant generating function (CGF) of the performance variable. A method for calculating the saddlepoint using random samples of the performance variable is presented. The applicable region of the saddlepoint approximation is discussed in detail. A 10-story shear building model with white noise excitation illustrates the accuracy and efficiency of the proposed methodology. [ABSTRACT FROM AUTHOR]

Many urban areas are located in regions of moderate seismicity and are subjected to strong wind. Buildings in these regions are often designed without seismic provisions. As a result, in the event of an earthquake, the potential for damage and loss of lives may not be known. In this paper, the performance of a typical high-rise building with a thick transfer plate (TP), which is one type of building structure commonly found in Hong Kong, is assessed against both earthquake and wind hazards. Seismic- and wind-resistant performance objectives are first reviewed based on relevant codes and design guidelines for high-rise buildings. After a brief introduction of wind-resistant design of the building, various methodologies, including equivalent static load analysis (ESLA), response spectrum analysis (RSA), pushover analysis (POA), linear and nonlinear time-history analysis (LTHA and NTHA), are employed to assess the seismic performance of the building when subjected to frequent earthquakes, design based earthquakes and maximum credible earthquakes. The effects of design wind and seismic action with a common 50-year return period are also compared. The results indicate that most performance objectives can be satisfied by the building, but there are some objectives, such as inter-story drift ratio, that cannot be achieved when subjected to the frequent earthquakes. It is concluded that in addition to wind, seismic action may need to be explicitly considered in the design of buildings in regions of moderate seismicity. [ABSTRACT FROM AUTHOR]

Se presentan un ensayo fotográfico sobre los efectos de la inundación del Río Bíobio en la zona de Gran Concepción, Chile, en julio de 2006.

The collapses of building structures during recent earthquakes have raised many questions regarding the adequacy of current seismic provisions to prevent a partial or total collapse. They have also brought up questions as to how to determine the collapse safety margin of structures, what is the inherent collapse safety margin in code-designed structures, and how to strengthen structures to effectively augment such margin. The purpose of this paper is to present a comprehensive review of the analytical methods that are currently available to assess the capacity of building structures to resist an earthquake collapse, point out the limitations of these methods, describe past experimental work in which specimens are tested to collapse, and identify what is required for an accurate evaluation of the seismic collapse capacity of a structure and the safety margin against such a collapse. It is contended that further research is needed before the collapse capacities of structures and their safety margin against collapse may be evaluated with confidence. [ABSTRACT FROM AUTHOR]

Performance of structures in different areas of Sikkim, during the earthquake of 14 February 2006, is reviewed. The earthquake caused damage to heritage structures as well as modern buildings. Both masonry and reinforced concrete buildings showed poor performance. On the other hand, traditionally constructed wooden houses performed extremely well. The damage seen in and around Gangtok was clearly disproportionate to the size of the earthquake, which was a moderate 5.7 on the Richter scale. This very clearly establishes the high level of seismic vulnerability of the region. The damage is primarily attributed to poor design and construction practices, and lack of quality control. Urgent need for trained human resources and for creation of a system of checks and balances, to ensure safe constructions in Sikkim is highlighted. [ABSTRACT FROM AUTHOR]

In this paper, a preliminary design procedure of magnetorheological (MR) dampers is developed for controlling building response induced by seismic excitation. Hysteretic biviscous model which is simple and can describe the hysteretic characteristics of MR damper, is used for parametric studies. The capacity of MR damper is determined as a portion of not the building weight but the lateral restoring force. A method is proposed for the optimal placement and number of MR dampers, and its effectiveness is verified by comparing it with the simplified sequential search algorithm. Numerical results indicate that capacity, number and placement can be reasonably determined using the proposed design procedure. [ABSTRACT FROM AUTHOR]

In this paper, we suggest the new intelligent fluid applying MR fluid, and new base-isolation system using that new intelligent fluid. At first, new intelligent fluid suggested in this paper as MSF (Magnet Solidification Fluid) consist of some magnetic fluid and special particles. The most remarkable characteristic of the MSF is that this fluid gives stable and optional yield sharing stress by gathering the properties of containing materials. By the way, in the region where the earthquake often occurs, buildings and industrial equipments must be provided for earthquakes. Then, fuse property is considered as the most anticipative idea for base-isolation system at present. That is, base-isolation system holds an upper structure by stable holding force at usual condition or slight earthquake. On the other hand, when a severe earthquake occurs, it releases holding force and insulates transfer of excitation force of earthquake at the isolation layer of system by yielding relative displacement between ground and an upper structure. According to such idea, we developed new base-isolation system utilizing characteristic of MSF. [ABSTRACT FROM AUTHOR]

Presents a study which analyzed the overall collapse of the World Trade Center buildings in New York City on September 11, 2001. Elastic dynamic analysis; Analysis of inelastic energy dissipation; Conclusions.

This paper reviews the performance of welded steel moment frame buildings during the Northridge earthquake. Some of the studies being undertaken in the United States as part of the FEMA-funded SAC Steel Project are described. The intent of these studies is to devise improved methods for designing new steel frame structures; for inspecting, evaluating, and repairing seismic damage to these types of structures following a major earthquake; and for inspecting, evaluating, and retrofitting existing at-risk steel frame buildings. General observations resulting from these studies are highlighted and the overall format for the new design provisions is presented. [ABSTRACT FROM AUTHOR]

This paper presents the findings from a computational investigation performed on the Borax corporate headquarters building, a four-story steel frame structure in which 75% of the steel moment-resisting connections suffered brittle fractures during the 1994 Northridge earthquake. A companion paper provides detailed documentation of the forensic investigation and repair design performed immediately following the earthquake on this structure, which was less than one year old when the earthquake struck. This paper describes a series of preliminary analyses conducted shortly after the forensic investigation and repair were completed. The main objectives were to investigate the behavior of the structure during the earthquake, and to determine whether different levels of established, advanced analysis techniques could estimate the distribution and extent of the damage. The results showed that a three-dimensional nonlinear dynamic analysis using a site-specific accelerogram provides strong correlation with the observed damage, while elastic static and dynamic analyses, two-dimensional nonlinear static and dynamic analyses, and three-dimensional nonlinear static analyses show less correlation. In addition, the results indicate that substantial redistribution of forces may have occurred, and that force distribution most likely had a noticeable effect on the pattern of failures observed in the structure. [ABSTRACT FROM AUTHOR]

This paper summarizes the review and interpretation of data collected on welded steel moment frames (WSMFs) that were damaged in the January 17, 1994, Northridge Earthquake. The study was part of the Phase I, Task 2 SAC Steel Project funded by the Federal Emergency Management Agency. The data assessment included 89 WSMFs surveyed by structural engineers, 150 buildings covered under a survey of owners, and ground motion contour maps with the geographic distribution of all WSMF buildings surveyed. Data collected from interviews with the structural engineers familiar with the buildings and their locations were used to independently validate the database and provide guidance on its interpretation. General conclusions on the significant trends in the data are presented, along with suggested future (Phase II) data gathering and statistical analysis. [ABSTRACT FROM AUTHOR]

The Borax corporate headquarters building, a low-rise steel moment frame, was less than one year old when it sustained significant structural damage during the 1994 Northridge earthquake. Seventy-five percent of its steel moment-resisting connections suffered severe brittle fractures. This paper presents a detailed documentation of the forensic investigation performed on this structure immediately following the earthquake. A companion paper presents the findings from a subsequent computational investigation performed on the structure. The two primary failure modes at the Borax building were column flange fracture and pull-out of the girder flange from the column. The failures are primarily attributed to a fundamental flaw in the standard code-prescribed welded-flange bolted-web connection and the extreme ground motion at the site. The paper also describes the repairs made to the structure. These repairs were completed before the SAC research that now guides repair and retrofit of these structures was available. [ABSTRACT FROM AUTHOR]

A two-story, steel moment frame building that was severely damaged during the Northridge earthquake (1994) is studied in detail. Immediately following the earthquake, the building was judged unsafe for occupancy due to a residual displacement of 7.6 cm (3 in.) in the first story. Opening of the exterior facade revealed severe cracking in the moment connections. All connections contained cracks that started in the weld at the bottom flange of the beam and propagated across the column flange and into the column panel zone. Four welded, beam-to-column, moment connections were taken from the building for additional cyclic testing under controlled conditions in the laboratory to evaluate their residual strength and deformation capacity. Results indicate that the badly damaged specimens still have significant residual strength and deformation capacity. All damaged specimens were tested to 3% rotation. [ABSTRACT FROM AUTHOR]

A two-story waffle–flat-plate reinforced-concrete model structure was subjected to cyclic loading simulating a severe earthquake. The test structure was a one-third-scale model that represented a structural system that is common in Mexico City and that had a high rate of damage during the 1985 Mexico earthquake. The structure was designed with widely spaced column transverse reinforcement and with closed stirrups in the slab solid heads around the columns. At failure, the specimen showed severe flexural and shear damage in columns, and large flexural distress in waffle slabs. The structure had a low lateral stiffness, which is overestimated by current building code provisions. Results also demonstrated that the specimen had relatively low energy-dissipation and displacement-ductility capacities, which are commonly associated with poor seismic behavior during strong earthquakes. It is considered that a satisfactory seismic behavior in terms of lateral stiffness and strength can only be attained by the addition of bracing or structural walls. [ABSTRACT FROM AUTHOR]

The article focuses on a study that presents a summary of the main statistical characteristics of fatalities and casualties due to floods in Japan since 1947. In this paper, the authors propose empirical formulas for predicting the number of flood affected residential buildings and whether the event is a flash flood or rainy season one. However, the proposed fatality functions are not useful in predicting flood-induced fatalities and injuries as the study suggests. Furthermore, the formulas are based on regression models with low correlation factors, especially for the most recent records from 1980-2001.