Performance Based Design

Bridges with deck supported on either sliding or elastomeric bearings are very common in mid-seismicity regions. Their main seismic vulnerabilities are related to the pounding of the deck against abutments or between the different deck elements. A simplified model of the longitudinal behavior of those bridges will allow to characterize the reaction forces developed during pounding using the Pacific Earthquake Engineering Research Center framework formula. In order to ensure the general applicability of the results obtained, a large number of system parameter combinations will be considered. The heart of the formula is the identification of suitable intermediate variables. First, the pseudo acceleration spectral value for the fundamental period of the system (Sa(7i)) will be used as an intensity measure (IM). This IM will result in a very large non-explained variability of the engineering demand parameter. A portion of this variability will be proved to be related to the relative content of high-frequency energy in the input motion. Two vector-valued IMs including a second parameter taking this energy content into account will then be considered. For both of them, a suitable form for the conditional intensity dependence of the response will be obtained. The question of which one to choose will also be analyzed. Finally, additional issues related to the IM will be studied: its applicability to pulse-type records, the validity of scaling records and the sufficiency of the IM. KEY WORDS: seismic performance; pounding; PEER formula Earthquakes can induce pounding between neighboring structures or different parts of the same structure. This phenomenon can be explained by differences in vibration characteristics leading to out-of-phase motion or insufficient spacing. Extensive pounding related damage have been reported after many events (i.e.

Seismic fragility curves measure induced levels of structural damage against strong ground motions of earthquakes, probabilistically. These curves play an important role in seismic performance assessment, seismic risk analysis and making rational decisions regarding seismic risk management of structures. It has been demonstrated that the calculated fragility curves of structures are changed while the structures are excited by near-field strong ground motions in comparison with far-field ones. The objective of this paper is to evaluate the extents of modification for various performance levels and variety of structural heights. To achieve this goal, Incremental Dynamic Analysis (IDA) method is applied to calculate seismic fragility curves. To investigate the effects of earthquake characteristics, two categories of strong ground motions are assumed through IDA method, i.e. near and far-field sets. To study the extent of modification for various heights of structures, 4-6 and 10 stories moment-resisting concrete frames are considered as case studies. Furthermore, to study the importance of involving near-field strong ground motions in seismic performance assessment of structures, the damage levels are considered as the renowned structural performance levels (i.e. Immediate Occupancy, Life Safety, Collapse Prevention and Sidesway Collapse). Achieved results show that the fragility curve of low-rise frame (i.e. 4-story case study) for IO limit state presents more probability of damage applying near-fault sets in comparison with far-fault set. Investigating fragility curves of the other performance levels (i.e. LS, CP and Collapse) and the higher frames, a straightforward conclusion, regarding probability of damage. To achieve the rational results for the higher frames, mean annual frequency of exceedance (MAFE) and probability of exceeding limit states in 50 years are calculated. MAFE is defined as the integration of structural fragility curve over seismic hazard curve. According to the achieved results for 6story frame, if the structure is excited by near-field strong ground motions the probability of exceedance for LS, CP and collapse limit states in 50 years will be increased up to 11%, 2.4%, 0.7% and 0.4% respectively, comparing with the calculated probabilities while far-field strong ground motions are applied. On the other hand, while the 10-story case study is excited by near-field strong ground motions, the exceedance probability values for mentioned limit states decreases up to 20%, 5%, 4% and 4%, respectively. Consequently, it can be concluded that the lower is the height of the structure, the more will be the increment of probability of damage in the near-field conditions. Furthermore, this increment is much more for IO limit state in comparison with other limit states. These facts can be applied as a precaution for seismic design of low-rise structures, while they are located at the vicinity of active faults.

This paper presents a macro-element for simulating the seismic behavior of the soil-shallow foundation interaction. The overall behavior in the soil and at the interface is replaced by a macro-element located at the base of the superstructure. The element reproduces the irreversible elastoplastic soil behavior (material non-linearity) and the foundation uplift (geometric non-linearity) at the soil-foundation interface. This new macro-element model with three degrees-of-freedom describes the force-displacement behavior of the footing center. The single element is restrained by the system of equivalent springs and dashpots. The footing is considered as a rigid body. It is solved by a suitable Newmark time integration scheme and implemented in Matlab to simulate the nonlinear behavior of soil-shallow foundation interaction under seismic loading. A reduce scaled soil-foundation system has been tested on a shaking table at the University of Transport and Communications, Hanoi, Vietnam. Five series of earthquake motions were used with maximum acceleration increased from 0.5 𝑚/𝑠 2 to 2.5 𝑚/𝑠 2. The comparison of numerical results obtained from the simulation and experimentations shows the satisfactory agreement of the model. The proposed macro-element can be used to predict the seismic behavior of a wider variety of configurations.

Fire safety in high-rise residential buildings is a complex issue, especially when it comes to electrical shaft fires. These enclosed vertical shafts help the rapid spread of smoke, toxic gases and heat across different floors and pose a high risk to the occupants and affect the evacuation process. However, the actual life fire outbreaks show that the existing measures are still wanting as far as evacuation safety is concerned. These issues are addressed in this research through the use of performance-based fire design (PBFD) to assess fire behaviour and evacuation patterns in high-rise buildings. The study then simulates using PyroSim and Pathfinder simulation software, the visibility of smoke, reduction of visibility, CO and CO2 levels, temperature changes, and congestion of the evacuation corridors. Unlike other studies, this paper combines both fire development and occupants’ response to give a holistic approach to the issue of evacuation challenges. One of the findings of this research is the analysis of the ASET and RSET whereby it was found that the current provisions in fire safety do not ensure a safe exit. It was established that RSET is much higher than ASET, which points to a severe lack in current fire safety solutions. Simulations incorporating NBC-2016 (National Building Code-2016) provisions—such as fire-rated doors, sprinklers, and mechanical ventilation—demonstrate improved outcomes, reducing RSET from 1,272 seconds to 746 seconds. However, persistent challenges such as congestion, bottlenecks, and hazardous gas levels highlight the need for enhanced fire safety strategies. This research offers practical recommendations to improve evacuation effectiveness through better ventilation, compartmentalization, and advanced suppression systems. The findings contribute to risk mitigation strategies, expand the knowledge base for fire safety, and provide a foundation for improving fire safety regulations in high-rise buildings.

Recent developments in performance-based seismic design and assessment approaches have emphasised the importance of properly assessing and limiting the residual (permanent) deformations typically sustained by a structure after a seismic event, even when designed according to current code provisions. In this contribution, the performance-based design framework for residual deformations, previously developed by the authors for 2-D regular structures, is further extended to the behaviour of 3-D irregular (asymmetric in-plan) buildings. The seismic response of a set single storey systems, comprising of seismic resisting frames, and made of alternative materials (concrete or steel), is investigated under uni-directional earthquake loading excitations. Different layouts in plan, leading to either torsionally unrestrained or restrained systems, are considered. Sensitivity analyses are carried out in order to identify the influence of varying levels of torsional restraint on the residual deformations/displacements in the response of a 3-D irregular building, the irregularity being given by an imposed mass eccentricity.

Recent developments in performance-based seismic design and assessment approaches have emphasised the importance of properly assessing and limiting the residual (permanent) deformations typically sustained by a structure after a seismic event, even when designed according to current code provisions. In this contribution, the performance-based design framework for residual deformations, previously developed by the authors for 2-D regular structures, is further extended to the behaviour of 3-D irregular (asymmetric in-plan) buildings. The seismic response of a set single storey systems, comprising of seismic resisting frames, and made of alternative materials (concrete or steel), is investigated under uni-directional earthquake loading excitations. Different layouts in plan, leading to either torsionally unrestrained or restrained systems, are considered. Sensitivity analyses are carried out in order to identify the influence of varying levels of torsional restraint on the residual deformations/displacements in the response of a 3-D irregular building, the irregularity being given by an imposed mass eccentricity.

Recent experimental and analytical research on seismic behavior of shallow foundations is illustrated. The most significant results on the seismic bearing capacity of footings with pseudo-static approaches are reviewed first, including an analytical formula recently proposed for the new version of the "seismic" Eurocode 8. Afterwards, we present the salient experimental results of large-scale cyclic tests of a shallow foundation model (lm x lm in plan) resting on a large volume of sand, with relative densities 45% and 85%, discussing them in detail. Under earthquake-like cyclic loading, with peak values close to the pseudo-static failure limit, significant permanent settlement and rocking were observed, approaching serviceability limit states in lowdensity soil conditions. A series of displacement cycles of increasing amplitude was subsequently applied, up to the ultimate capacity of the soil-foundation system. Although the experimental cyclic bearing capacity is much higher than that predicted by pseudo-static approaches, this advantage is offset by the occurrence of large permanent deformations that may lead the structure to collapse. Finally, a recent theoretical method for performing simple nonlinear dynamic soil-structure interaction analyses is reviewed, and applied to estimating the reduction of response spectrum ordinates in strong earthquakes. Reductions up to 30%-50% were found for spectral accelerations exceeding 0.4g.

Despite the increasing adoption of Performance-Based Earthquake Engineering (PBEE) in seismic risk assessment and design of buildings, earthquakes resulted in around 1.8 million injuries (three times the number of fatalities) over the past two decades. Several existing PBEE-based methodologies use rudimentary models that may not accurately estimate earthquake-induced casualties. Even when models are suitable for predicting the total number of fatalities and critical injuries, they may fail to adequately differentiate between different levels of injury severity. This paper draws attention to the importance of extending the seismic casualty assessment method by broadening the perspective on injury severity. To this cause, a probabilistic model is developed to predict fatalities and injuries due to earthquakes. The proposed model adopts the FEMA P-58 framework for risk assessment and considers six injury severity levels (minor, moderate, serious, severe, critical and fatal), in accordance with the Abbreviated Injury Scale (AIS). The aforementioned framework evaluates the casualty risk with five modules: seismic hazard analysis, structural analysis and response evaluation (using incremental dynamic analysis), building collapse simulation, detailed casualty assessment caused by structural, nonstructural, and content components of the building, and injury severity assessment. The injury severity assessment module assumes two modes of injury: occupants falling on the floor resulting in injury and injuries caused by unstable building contents hitting occupants as a result of sliding or overturning. The framework uses an occupant-time location model to predict the number of injuries and a set of building content fragility curves for sliding and overturning failure modes, developed by the incremental dynamic analyses. The proposed model was applied to a case study of a reinforced concrete, moment-frame office building furnished with 21 different content objects. The results show that the frequency of injuries resulting in hospitalization can be up to 30 times more than that of the fatal injuries at low shaking intensity levels and may amplify by 20 times at high intensity shaking.

This study investigates mixed convection heat transfer in laminar non-Newtonian flows within helical coil heat exchangers using nanofluids. The research examines nanoparticle volumetric concentrations ranging from 0% to 2% and power-law indices of 0.81, 0.85, and 0.91. The momentum and energy equations were solved using the finite volume method with the SIMPLE algorithm. We analyzed the effects of power-law index, Richardson number, helical coil pitch, and nanoparticle concentration on the Nusselt number. Results indicate that the heat transfer coefficient increases with nanoparticle concentration from 0% to 2%. The Nusselt number shows an inverse relationship with both the power-law index and friction coefficient. Additionally, increasing the coil pitch and nanoparticle concentration enhances the heat transfer coefficient, with a 7% increase in Nusselt number observed when the coil pitch varies from 0.05 to 0.1. Buoyancy forces significantly influence temperature distribution patterns and flow velocity in helical coils, leading to more uniform temperature distributions at higher buoyancy forces.

The practical implementation of performance-based fire safety design of reinforced concrete (RC) structures hinges on the availability of accurate numerical simulation tools for the behavior of RC members exposed to fire. This paper presents a three-dimensional (3D) finite element (FE) model for the accurate prediction of both the thermal and the mechanical behavior of RC beams exposed to fire. In this FE model, particular attention is paid to the modeling of interfacial bond-slip behavior between the reinforcing steel and the concrete, an aspect which has rarely been considered by previous numerical studies. Results obtained from this FE model are compared with existing test data to examine the accuracy of the model. This comparison shows that the inclusion of the steel-to-concrete interfacial behavior leads to more accurate predictions of the deflection of RC beams exposed to fire. Predictions from this FE model also allow the complex distribution and evolution of stresses in the reinforcing steel and the concrete to be examined in detail, leading to a better understanding of the local responses of RC beams exposed to fire. The FE model presented in the paper can be used directly in performance-based fire safety design of RC beams; it can also be employed in parametric studies aimed at developing simple design rules.

Application of machine learning methods as an alternative for building simulation software has been progressive in recent years. This research is mainly focused on the assessment of machine learning algorithms in prediction of daylight and visual comfort metrics in the early design stages and providing a framework for the required analyses. A dataset was primarily derived from 2880 simulations developed from Honeybee for Grasshopper. The simulations were conducted for a side-lit shoebox model. The alternatives emerged from different physical features, including room dimensions, interior surfaces’ reflectance factor, window dimensions, room orientations, number of windows, and shading states. Five metrics were applied for daylight evaluations, including useful daylight illuminance, spatial daylight autonomy, mean daylight autonomy, annual sunlit exposure, and spatial visual discomfort. Moreover, view quality was analyzed via a grasshopper-based algorithm, developed from the LEED v4 e...

In this article the most fundamental decomposition-based optimization method -block coordinate search, based on the sequential decomposition of problems in subproblems -and building performance simulation programs are used to reason about a building design process at micro-urban scale and strategies are defined to make the search more efficient. Cyclic overlapping block coordinate search is here considered in its double nature of optimization method and surrogate model (and metaphore) of a sequential design process. Heuristic indicators apt to support the design of search structures suited to that me thod are developed from building-simulation-assisted computational experiments, aimed to choose the form and position of a small building in a plot. Those indicators link the sharing of structure between subspaces ("commonality") to recursive recombination, measured as freshness of the search wake and novelty of the search moves. The aim of these indicators is to measure the relative effectiveness of decomposition-based design moves and create efficient block searches. Implications of a possible use of these indicators in genetic algorithms are also highlighted.

The construction industry faces significant challenges in reducing the environmental impact of buildings, particularly high-rise structures. One of the key strategies to address these challenges is the integration of sustainable materials and advanced design methodologies. This paper focuses on the integrated life-cycle assessment (LCA) and performance-based design (PBD) of hybrid cold-formed and hot-rolled steel structural systems for high-rise buildings. The study evaluates the environmental performance, economic viability, and structural efficiency of these hybrid systems in urban environments, where space limitations and sustainability concerns are crucial. A combination of LCA tools and performance-based design principles is applied to assess the long-term sustainability and resilience of the proposed systems. The findings indicate that hybrid steel systems provide a promising solution to enhance the sustainability of high-rise construction, offering reduced environmental impacts without compromising structural integrity.

Audible and intelligible fire alarms play a critical role in ensuring occupant safety in emergencies. Although various experimental and theoretical methods exist to measure and predict alarm sound levels, the variability and limitations of these methods, especially in complex layouts, remain underexplored. Building on both established fire engineering research and advanced alarm management concepts from process safety, this study evaluates the effectiveness of fire alarm placement within residential units by comparing in situ measurements, calculation-based estimates, and machine learning predictions. The findings show that open doors result in higher sound levels than closed doors, and corridor-based alarms typically fail to meet the recommended 75 dBA threshold needed to awaken sleeping occupants. Moreover, established calculation methods show an average error rate of about 9 %, especially in geometrically complex or acoustically variable settings. By contrast, the machine learning model achieves a notably lower error rate at around 2 % underscoring its potential to integrate uncertainty factors such as distance, partitions, and acoustic attenuation more effectively than traditional formulas. From a risk management perspective, these results highlight the value of data-driven, risk-based alarm design, aligning with hybrid alarm modeling approaches seen in process industries. The study concludes that installing fire alarms within each dwelling unit, coupled with interconnected sounders in sleeping areas, significantly enhances occupant alertness and system reliability in residential buildings.

Introdução: O geoprocessamento tem se consolidado como uma ferramenta essencial no planejamento e design arquitetônico, permitindo análises detalhadas do espaço urbano e contribuindo para projetos mais eficientes e sustentáveis. Objetivo: Este estudo busca explorar as potencialidades e limitações do geoprocessamento no planejamento arquitetônico, analisando sua aplicação prática e os desafios enfrentados pelos profissionais da área. Método: A pesquisa é qualitativa e exploratória, baseada em revisão bibliográfica e análise de estudos de caso, incluindo projetos como o Porto Maravilha, Museu do Amanhã, Sede da Apple e Urbanização de Barcelona. Resultados principais: O geoprocessamento demonstrou benefícios significativos em eficiência energética, sustentabilidade e redução de custos, com economia média de 25% nos projetos analisados. No entanto, desafios como a falta de capacitação técnica e resistência à mudança foram identificados. Conclusão: A tecnologia é fundamental para a criação de cidades mais sustentáveis e resilientes, mas sua adoção em larga escala requer superação de obstáculos relacionados à formação profissional e integração tecnológica.

ÖZET
Çalışma, farklı disiplinler için önemini sürdüren temel tasarım olgusunu, onun kuramsal kökenlerini
eleştirel bir perspektifle inceleyerek gelecekteki potansiyel dönüşüm yollarını araştırmayı
amaçlamaktadır. Temel tasarım, yalnızca bir başlangıç eğitimi olmanın ötesinde, bilgi, anlam ve değer
üreten bir yapı olarak ele alınmakta ve tarihsel süreçte bu yapının nasıl şekillendiği araştırılmaktadır.
Bu bağlamda, temel tasarımın bilgi yapısının oluşumunda etkili olan üç önemli düşünsel odak
belirlenmiştir: 1. Bauhaus, 2. Geştalt Kuramı, 3. Sanat Eğitimi Geleneği. Çalışma, bu üç odak noktasının
temel tasarımın kuramsal kökenlerini nasıl şekillendirdiğini, ilgili aktörlerin birincil kaynakları ve
söylemsel analizleri üzerinden incelemektedir. Araştırma, temel tasarımın tarihsel, kültürel ve düşünsel
bağlamlarını açığa çıkarmayı hedeflemekte ve bu olgunun hem değişen hem de değişime direnen
yönlerine odaklanmaktadır. Tasarım öğeleri ve ilkeleri üzerine kurulu paradigmanın içindeki temelcilik
(foundationalism), eleştirel bir perspektifle incelenerek, bu yapıların sorgulanmasının önemine dikkat
çekilmektedir. Ayrıca, temel tasarımın dayandığı epistemolojik çerçeve; kozmolojik/ontolojik, psikolojik,
bilimsel ve estetik unsurlar üzerinden değerlendirilmektedir. Araştırma, temel tasarımın sabit ve mutlak
olarak kabul edilen yönlerini eleştirel bir bakışla değerlendirerek, bunların yerine araştırmaya dayalı,
dinamik ve bağlamsal bir tasarım anlayışının nasıl geliştirilebileceğini tartışmaktadır. Temel tasarımın
geleceğini düşünmek, yalnızca bir teknolojik adaptasyon sorunu değil; bilgi yapısının derinlemesine
sorgulanmasını gerektiren bir süreç olmalıdır. Bu tür bir sorgulamanın, alternatif ve yaratıcı
yaklaşımların gelişmesine kuramsal bir katkı sağlayabileceği düşünülmektedir.
Anahtar Sözcükler: Temel Tasarım, Bauhaus, Gestalt Kuramı, Sanat Eğitimi Geleneği, Tasarım
Kuramı, Tasarım ve Gelecek

ABSTRACT
This study critically examines the theoretical foundations of basic design, a phenomenon that remains
significant across various disciplines, and explores potential pathways for its transformation. Rather
than a mere introductory education, basic design is conceptualized as a system that generates
knowledge, meaning, and value. This research investigates its historical development, identifying three
key epistemological pillars: 1. Bauhaus, 2. Gestalt Theory, and 3. The Tradition of Art Education.
Through primary sources and discourse analysis, the study explores how these frameworks have
shaped the theoretical foundations of basic design. By situating basic design within its historical,
cultural, and intellectual contexts, the research highlights both its adaptability and resistance to change.
Foundationalism, which underpins the paradigm of design elements and principles, is critically
examined to underscore the necessity of questioning its structures. Additionally, the epistemological
framework of basic design is analyzed across cosmological/ontological, psychological, scientific, and
aesthetic dimensions. Rather than treating basic design as a fixed and absolute construct, this study
argues for a research-based, dynamic, and context-driven approach to design education. Addressing
the future of basic design extends beyond mere technological adaptation; it requires a fundamental
inquiry into its underlying knowledge structures. A critical reevaluation of these structures is essential
for fostering alternative and creative design methodologies.
Keywords: Basic Design, Bauhaus, Gestalt Theory, Art Education Tradition, Design Theory, Design
and Future

With the Worcester Polytechnic Institute student body increasing, campus space must be expanded. Salisbury Estates presents an opportunity for redevelopment. Through interviews and research, multiple building layouts were considered, and preliminary designs for a residential and an academic building were finalized. Floor plans, life safety, and cost analysis were conducted. A complete framing plan with structural analysis of beams, columns, and footings was created for the academic building. Deliverables include a report, structural calculations, AutoCAD drawings, and a cost estimate.

The determination of structural and nonstructural damage under earthquake excitations is usually considered as a key factor in performance-based seismic design (PBSD) methods is In this regard, various damage indices have been developed in recent years to quantitatively estimate structural damage. The aim of this study is to develop a simple method to evaluate performance levels of zipper-braced frame (ZBF) structures by using damage indices based on the results of nonlinear static and dynamic analyses. To this end, 5, 7, 10, 12 and 15 story zipper-braced frames (ZBF) are modeled and undergone to twenty different synthetic ground motion records and their damage values have been computed. In dynamic damage analysis procedure, the performance levels of the ZBF models have been computed based on the FEMA-356 standard. Considering the results of the nonlinear dynamic analyses, the correlation between FEMA-356 performance levels and damage indices has been investigated and some simplified formula is presented. On the other side, in static damage analysis approach, by using pushover analysis the performance points of ZBF models have been estimated based on capacity spectrum method (CSM) provided by ATC-40 standard. Then, the correlation between ATC-40 performance levels and some static damage indices has been investigated and some simple equations have been proposed. These relations can be utilized to estimate the performance levels of structures from damage indices. Finally, tables are represented for determination of the structural damage index values for assumed performance levels of the ZBF structures based on static and dynamic damage analysis.

Performance-based seismic design, which is a relatively new concept, came into existence as a means to ascertain the likely performance of an existing building structure during an earthquake. However, this approach is equally applicable to new buildings being designed. Herein is explained why there is a growing consensus among designers to follow this approach as a replacement of the existing force-based design procedures. It is explained as to what constitutes a performance objective which relates the desired performance level to a perceived hazard level. The analytical approach calls for a nonlinear seismic analysis for which the simpler nonlinear static method is often adopted. This is termed as the pushover analysis which is described in detail. Both subsets of this method, viz., the capacity spectrum method and the seismic coefficient method, are explained in detail. The merits and limitations of this method of analysis are also pointed out. The recent drive for use of performance-based approach for design as well as assessment of building structures has led to rapid developments to enhance the reliability of this analytical approach.

The earthquake-resistant design methodology in most existing codes of practice is based on ensuring "no collapse" during the most severe event expected at the given site while most of the input energy is dissipated through inelastic deformations. Evolution of the performance-based design over the last decade has seen a few performance levels added up to this so that the structure remains functional even after a moderately strong event. This methodology however overlooks the possibility that in case of multiple earthquake events expected during the design life of the structure, the structure may get gradually damaged and that it may not be feasible to carry out repairs in the structure after every damaging event. As a result, the structure may collapse earlier than expected and perhaps during an event of moderate intensity. To address such a concern, a new spectrum, called as design force ratio (DFR) spectrum, is proposed in this paper. DFR spectrum gives the ratio by which the design yield force level of a conventionally-designed singledegree-of-freedom structure should be raised such that the damage caused by all earthquake events expected to occur during its lifetime is limited to a specified level. A numerical study is carried out for a hypothetical seismic region by following a simple procedure based on several assumptions, and DFR spectra are obtained for elastic-perfectly plastic oscillators when the return periods of earthquakes follow exponential distribution over the entire range of magnitudes.

The technical committees responsible for ACI committee reports and standards strive to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents are requested to contact ACI via the errata website at DocumentErrata.aspx. Proper use of this document includes periodically checking for errata for the most up-to-date revisions. ACI committee documents are intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publication is provided "as is" without warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose or non-infringement. ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Participation by governmental representatives in the work of the American Concrete Institute and in the development of Institute standards does not constitute governmental endorsement of ACI or the standards that it develops. Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).

The earthquake behaviour of three large dams is investigated with an emphasis on damping representation in seismic analyses. Three-dimensional numerical models were prepared for the dam-reservoir-foundation systems and these models were calibrated on the basis of previous, extensive in-situ forcedand ambientvibration dynamic tests. Earthquakes that occurred in the vicinity of the dams were recorded by accelerographs installed at various locations inside the structures and the foundation rock. The recorded free-field ground-motions were then used as inputs to the models and the acceleration responses computed with two different dam-foundation interaction models, i.e. a massless foundation model and an energydissipating foundation model (water compressibility is taken into account in both models). The calculated dam motions are compared to the recorded ones and the damping values are varied until a satisfactory match between both is obtained.

Highlights • Use of multi-stage triaxial tests to investigate the post-cyclic behaviour of liquefied sand • Derivation of instability curves for assessment of post-cyclic deformation of liquefied sloping grounds • Demonstration of use of instability curves through real case study of post-liquefaction failure of Lower San Fernando Dam

No que diz respeito ao diálogo com a área de tecnologia, este trabalho propõe a tectônica como estratégia pedagógica em ateliês de projeto nos cursos de arquitetura e urbanismo. A partir de dois recortes, um teórico e outro prático, procura-se enfatizar a importância dessa abordagem por meio de um estudo de caso. O artigo traz um resumo atualizado do campo teórico da tectônica, para enfatizar a necessidade de subsidiar as estratégias de ensino em ateliê em um contexto fundamentado não apenas pela prática de projeto, mas também pela teoria que a embasa. Apresenta-se como caso o trabalho desenvolvido em 2023 no ateliê de projeto do 3º período do Curso de Arquitetura e Urbanismo da PUC-Rio. Caso que representa o resultado de 12 anos de experiência na área de tecnologia desse ateliê, durante os quais foi se consolidando, aos poucos, a pesquisa sobre tectônica e a integração de saberes estabelecida no Projeto Pedagógico do Curso. Neste sentido, comprova-se o encontro entre intenção e resultado. PALAVRAS-CHAVE: tectônica. estratégia pedagógica. ateliê de projeto. arquitetura. teoria.

The amount of total and relative sway of a framed or a composite (frame-shear wall) building is of utmost importance in assessing the seismic resistance of the building. Therefore, the design engineer must calculate the sway profile of the building several times during the design process. However, it is not a simple task to calculate the sway of a three-dimensional structure. Of course, computer programs can do the job, but developing the three-dimensional model becomes necessary, which is obviously tedious and time consuming. An easy to apply analytical method is developed, which enables the determination of sway profiles of framed and composite buildings subject to seismic loading. Various framed and composite three-dimensional buildings subject to lateral seismic loads are solved by SAP2000 and the proposed analytical method. The sway profiles are compared and found to be in very good agreement. In most cases, the amount of error involved is less than 5 %. The analytical method i...

Certain commercial entities, equipment, products, or materials are identified in this document in order to describe a procedure or concept adequately or to trace the history of the procedures and practices used. Such identification is not intended to imply recommendation, endorsement, or implication that the entities, products, materials, or equipment are necessarily the best available for the purpose. The policy of NIST is to use the International System of Units (metric units) in all publications. In this document, however, units are presented in metric units or the inch-pound system, whichever is prevalent to the discipline. Conversion tables are provided in this report.

The introduction of AASHTO's LRFD (load-and-resistance factor design) method for the design of MSE (mechanically stabilized earth) walls in 2004 has gradually replaced conventional state-of-the-practice seismic ASD (allowable stress design) method in some states, and by FHWA mandate should completely replace the ASD method by 2010. Limit equilibrium analyses based on Mononabe-Okabe (M-O) pseudo-static method had been the standard method of estimating the seismic external thrust and inertia force for MSE walls. Considering the flexible nature of MSE walls that allow deformation without compromising structural integrity, in the LRFD method, the displacement based pseudo-static method that was developed from Newmark sliding block analyses is used. In this paper, parametric studies are used to highlight the variations of soil reinforcement length/wall height ratios and internal lateral stresses between the LRFD and the current state-of-the-practice ASD methods. The results are compared with referenced past experimental studies and recorded seismic field performance of MSE walls. In addition, results from preliminary dynamic constitutive models are provided for comparison with displacements based on M-O pseudo static method. This paper shows that, by selecting an appropriate amount of tolerable wall deformation (i.e. between 25 and 200 mm as specified in AASHTO and FHWA), the seismic LRFD method for MSE walls is conservative and in general is in agreement with the conventional ASD method that has been widely used in the design of the MSE walls that have performed well during past major seismic events.

The introduction of AASHTO's LRFD (load-and-resistance factor design) method for the design of MSE (mechanically stabilized earth) walls in 2004 has gradually replaced conventional state-of-the-practice seismic ASD (allowable stress design) method in some states, and by FHWA mandate should completely replace the ASD method by 2010. Limit equilibrium analyses based on Mononabe-Okabe (M-O) pseudo-static method had been the standard method of estimating the seismic external thrust and inertia force for MSE walls. Considering the flexible nature of MSE walls that allow deformation without compromising structural integrity, in the LRFD method, the displacement based pseudo-static method that was developed from Newmark sliding block analyses is used. In this paper, parametric studies are used to highlight the variations of soil reinforcement length/wall height ratios and internal lateral stresses between the LRFD and the current state-of-the-practice ASD methods. The results are compared with referenced past experimental studies and recorded seismic field performance of MSE walls. In addition, results from preliminary dynamic constitutive models are provided for comparison with displacements based on M-O pseudo static method. This paper shows that, by selecting an appropriate amount of tolerable wall deformation (i.e. between 25 and 200 mm as specified in AASHTO and FHWA), the seismic LRFD method for MSE walls is conservative and in general is in agreement with the conventional ASD method that has been widely used in the design of the MSE walls that have performed well during past major seismic events.

Terrorist attacks have nowadays become an important issue for the structural design of constructions such as bridges. Indeed, during the last decades, the increase in the number of terrorist attacks has resulted in the loss of many human lives and socio-economic impact on our society. The aims of this research consist in a series of preliminary analyses in view of a study of the effects of an explosion on a long-span suspension bridge. As a suspension bridge was considered the project of the bridge over the Strait of Messina, having as main span of 3300 meters. The structure was modeled using ABAQUS/Explicit software using beams-type 3D finite element modeling. The objectives of the research are double. The first one is the study of the pressures generated by an explosive charge to model the phenomenon during numerical simulations while, the second objective, is to test different discretizations to have a reliable numerical response.

با توجه به گستردگی میادین نفتی تحت مدیریت شرکت ملی مناطق نفتخیز جنوب و پراکندگی محل چاههای چاههای نفت و همچنین
لزوم اجرای ابنیه های بتن مسلح مانند فونداسیون دکل حفاری، گودال دیسپوزال، کورال، گودال سوخت و .... جهتت استت رار دکتل هتای
حفاری نفت، استفاده از مصالح نوین مانند خانواده بتن الیافی ن ش بسزایی در تسهیل عملیات اجرایی، ارت ا کیفیت بتن و همچنین کاهش
هزینه ها گردد. در مناطق نفتخیز جنوب با توجه به حجم بالای اجرای بتن و همچنین مشکلات اجرایی بتن های معمول (ترک ختوردگی
بتن و خوردگی فولاد و)... ، اداره طرح های راه و ساختمان مناطق طرح پژوهشی را در دو فاز مطالعاتی و آزمایشگاهی در م یاس واقعی در
دستور کار خود قرار داده است که نتیجه فاز اول (مطالعاتی) در این م اله ارائه می گردد. در بخش مطالعتاتی ابتتدا روا طراحتی پتدهای
بتنی الیافی با الیاف ماکروسینتتیک  POLYTAR-GT600و م ایسه آن با بتن مسلح با میلگرد فولادی متورد توجته قترار گرفتته استت.
حذف میلگرد فولادی و استفاده از الیاف بصورت پراکنده در جسم بتن (پدهای بتنی) هدف این مطالعه می باشد. نتیجه این مطالعه منجتر
به صرفه جویی سالانه بیش از  1000تن میلگرد فولادی و جلوگیری از انتشار  1500تن گاز گلخانه ای در پروژه های احداث موقعیت چاه
های نفت در پهنه عملیاتی مناطق نفتخیز جنوب می گردد

Perhaps a few words regarding the history of this study would be of interest to the sponsors and the reader. The study was initiated in 1974. Dr. P. Charkabarti participated in formulating the essential ampects of the analysis procedure and developed the computer programs during 1974 and 1975, at which time he left Berkeley to accept a position in India. Thereafter, Dr. G. Dasgupta was involved in the study for a short tms, ncorxporatinq some improvements in the analysis procedure ard compute -a. Eis efforts were then diverted to developing dynamic stiffness iat the foundation required in obtaining the numerical results for this a .. At this juncture, in 1976, Sunil Gupta, a graduate research assistani. bu.am associated with the project. He produced the large volume of computer results presented in this report, and assisted in interpretating these results and preparing the report. Because there was some discontinuity between the tLsms Chakraarti, Dasgupta, and Gupta worked on this project# because considerable time was required to develop the results on dynamic stiffness matrices for the foundation; and for other reasons beyond our control, our efforts on this study have been sporadic. This resulted in considerable, unanticipated delay in completion of the study. * * * ** 4 p *a ASP .,SN.

The paper presents a simple and an innovative idea regarding vibration isolation technique of a multistory building using magnetic field and is proposed to application in the field of civil engineering structures. This idea is fully based on hypothetical concept, but the objective is to explore this idea or concept in to the entire community which may be a potential sector for the effective vibration isolation system. The technique is described based on the magnetic properties of materials and a magnetic field characteristic which depends on the amount of current flow, number of turns in coil, distance between electromagnet and the magnetic materials. Therefore using magnetic field, the attraction induced between magnet and magnetic materials, a force could finally be developed on the floor of building. This force would become effective until and unless the power is cutoff. Therefore this induced force is actually acts as a live load on the structure which indirectly increases the weight and this has been described in this paper.

Models of real systems are of fundamental importance in virtually all disciplines. Models make possible to predict or simulate a system's behavior. Since the quality of the model typically determines an upper bound on the quality of the final problem solution, modeling is often the bottleneck in the development of the whole system. As a consequence, a strong demand for advanced modeling and identification schemes arises. In this paper it is shown, via the development of a system for the analysis of the seismic response of rockfill dams, that neurogenetic techniques are a better option than analytically-based procedures in this kind of studies. To buttress this assertion, El Infiernillo dam, which has an ample history of being shaken by a great variety of seismic events, is used to this end.

In this paper, dynamic response of the two most common retaining walls in geotechnical engineering practices (conventional gravity retaining walls and geosynthetic reinforced soil (GRS) walls) to blast loading are investigated and compared using FLAC 2D. After large number of numerical simulations, it was concluded that performance of the GRS walls is better than conventional gravity retaining walls. Also it is observed that deformation modes of these two types of walls are different. In all analysis, dominant mode of lateral deformation for the gravity types of walls (for both 5 and 10 m) was overturning mode combination with sliding at base of wall, whereas for GRS walls in addition to sliding at base, deformation modes are start from bulging at low blast intensity loading and tends to overturning mode with increasing blast loading intensity. Therefore location of the maximum lateral displacement of gravity walls is occurred at wall crown in all the analysis, whereas in GRS walls, location of the maximum lateral displacement start from middle of the wall height in bulging mode and shift to the surface of the wall with increasing blast loading because of overturning mode domination. Also, it is concluded that soil damping and distance from blast loading adversely affected blast induced deformation of the walls.

There is no guidance existing to help the engineers determine the mechanical properties or to indicate in which field of the structures this product can be used. With the aims at providing quantitative data for these purposes and at introducing a simplified model of EMP working in shear, description and comparison of the results of 22 monotonic and cyclic experiments of 4 profiles of EMP in small and large scale is presented. Numerical approach with FINELG, a nonli University of Liege, is used to calibrate and simulate the tests. A good correlation between tests and numerical simulations is observed.

Bu çalışmada mimari araştırma yöntemlerinin uygulama ile kurdukları ilişki
dereceleri uygulama odaklı ve uygulamaya dayalı kavramları üzerinden
tartışılmış ve tasarım temelli düşüncenin tabanını oluşturan yaratıcı sürece
ne derece yakın oldukları incelenmiştir. Bu sayede çalışma, mimari
araştırmalarda, tasarım uygulamasına yönelik bilgi üretiminin temel bir
faaliyeti olan yaratıcılığın yerini sorgulamaktadır. Groat ve Wang’in (2013)
Architectural Research Methods isimli kitabında tanımladığı yedi yöntemin
ilişkilerine göre sistematize edilen şekil üzerinden, geçirgen ilişkilerle analiz
edilen mimari araştırma yöntemleri, ulusal ve uluslararası ölçekte
tamamlanmış doktora tezleri üzerinden analitik olarak incelenmiştir.
Çalışmanın sonucunda, incelenen tezlerden yapılan çıkarımlarla araştırma
yöntemlerinin uygulama ile olan ilişkileri önerilen yeni bir ölçekle
değerlendirilmiş ve tüm bu analizlerden elde edilen verilerle yaratıcılık
bağlamında yeni bir kategorizasyon sunulmuştur. Önerilen bu çerçeve,
tasarım temelli araştırma yöntemlerini kullanan araştırmacılara
araştırmaları/projeleri ile nasıl ilişki kurabileceklerine dair yeni bir
farkındalık ve çalışmaları için uygun kombinasyonlara dair öneri
sağlayabilmektedir. Araştırma yöntemleri, uygulama ve yaratıcılık
arasındaki etkileşime odaklanan bu çalışma mimari araştırma alanındaki
bilgiye katkıda bulunmayı amaçlamaktadır.

Concentrically braced frames represent a convenient structural typology for multi-storey buildings located in high-seismicity areas, offering a good strength and stiffness. The present paper presents the technical solution of 29 storey building located in Bucharest, Romania, with a mixed lateral force resisting system: reinforced concrete shear walls and steel braces. It is concerned with the experimental and numerical validation of seismic performance of brace connections on one hand, and of the overall brace assembly on the other hand. A connection with gusset plates and pin was adopted. One of the brace connections uses an eccentric pin, allowing for variation of the pin-to-pin length, which facilitates erection on one hand, and allows compensation for axial forces in braces due to gravity loads on the other hand. High strength steel was used for gusset plates and the pin in order to keep dimensions to a minimum. Preliminary finite element simulations have shown that the buckling plane of the brace is undetermined (the buckling strength in the plane of the connection and out-of plane are similar), due to the fact that the brace is made of a circular hollow section. Due to peculiarity of the connection, finite element analyses and experimental tests were performed in order to validate the cyclic performance of the connection and the brace. Four tests were performed on a scaled model of the brace, for two different pin-to-pin lengths.

Displacement Based Design method represents a new approach to performance-based design. This research tries to assess the Direct Displacement Based Design (DDBD) method for regular steel moment resisting frames and develop a reliable design method for them so that they withstand various seismic levels within certain performance levels. For this purpose, regular steel frames with 4, 8, 12, 16 stories are designed based on DDBD approach utilizing displacement spectrum of the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800). In order to evaluate seismic response of the designed structures, a series of non-linear time-history analyses have been performed under different records compatible with Standard No. 2800. All the non-linear analyses were carried out using the fiber-element models developed in Seismostruct computer program. According to the results, inter-story drift profile of the structure which is corresponding to its damage was less than the allowable value in most cases. Also, Maximum displacement profile of the structure along its height is completely matched with the primary assumed design profile. The structures have mostly experienced similar residual drift values under different records. In summary, the method performed quite satisfactorily in terms of story maximum displacements, maximum interstory drifts and story ductility demands, even for tall models.

Performance assessment implies that the structural, non-structural, and content systems are given and that decision variables, DVs, (e.g. expected annual loss, mean annual frequency of collapse) are computed and compared to speciÿed performance targets. Performance-based design (PBD) is di erent by virtue of the fact that the building and its components and systems ÿrst have to be created. Good designs are based on concepts that incorporate performance targets up front in the conceptual design process, so that subsequent performance assessment becomes more of a veriÿcation process of an e cient design rather than a design improvement process that may require radical changes of the initial design concept. In short, the design approach could consist of (a) specifying performance targets (e.g. tolerable probability of collapse, acceptable dollar losses) and associated seismic hazards, and (b) deriving engineering parameters for system selection, or perhaps better, using the relatively simple design decision support tools discussed in this paper. Copyright ? 2005 John Wiley & Sons, Ltd.

Hysteretic dampers in bridges with seismically isolated decks are coupled with shock transmitters in order to prevent their engagement during thermal displacements of the deck. An alternative design approach is presented in this paper where the dampers are attached to the deck using elongated holes (gaps) which are sized to accommodate the thermal displacements and hence to keep the dampers from being activated during thermal displacements. The gaps are sized based on the expected maximum thermal displacement in each pier. The gap length will thus be different for different piers. With this arrangement, number of the dampers engaged during an earthquake will depend on the magnitude of displacements. The distinct feature in this design is: (i) preventing the engagement of dampers under thermal displacements during service life without using shock transmitters and (ii) sequential engagement of dampers as a function of magnitude of seismically-induced displacements. This paper presents a sample application of this methodology in design of a major viaduct. The performance goals of the bridge require no damage at 475-year return period earthquake and repairable damage at 2475-year return period earthquake. The bridge is designed with a seismic isolation system composed of spherical bearings and hysteretic dampers (Multidirectional torsional hysteretic damper (MTHD)). Design features of this seismically isolated bridge and results of nonlinear time-history analyses are presented in this paper.

Hysteretic dampers in bridges with seismically isolated decks are coupled with shock transmitters in order to prevent their engagement during thermal displacements of the deck. An alternative design approach is presented in this paper where the dampers are attached to the deck using elongated holes (gaps) which are sized to accommodate the thermal displacements and hence to keep the dampers from being activated during thermal displacements. The gaps are sized based on the expected maximum thermal displacement in each pier. The gap length will thus be different for different piers. With this arrangement, number of the dampers engaged during an earthquake will depend on the magnitude of displacements. The distinct feature in this design is: (i) preventing the engagement of dampers under thermal displacements during service life without using shock transmitters and (ii) sequential engagement of dampers as a function of magnitude of seismically-induced displacements. This paper presents...

This paper is focused on a proposed seismic retrofitting system (PRS) configured to upgrade the performance of seismically vulnerable reinforced concrete (RC) buildings. The PRS is composed of a rectangular steel housing frame with chevron braces and a yielding shear link connected between the braces and the frame. The retrofitting system is installed within the bays of an RC building frame to enhance the stiffness, strength and ductility of the structure. The PRS and a conventional retrofitting system using squat infill shear panels (SISPs) are used in an existing school and an office building. Nonlinear time history analyses of the buildings in the original and retrofitted conditions are conducted for three different seismic performance levels (PLs) to assess the efficiency of the PRS. The analyses results revealed that the building retrofitted with the PRS has a more stable lateral force-deformation behavior with enhanced energy dissipation capability than that of the one retrofitted with SISPs. For immediate occupancy PL, the maximum inter-storey drift of the building retrofitted with the PRS is comparable to that of the one retrofitted with SISPs. But for life safety and collapse prevention PLs, the maximum interstorey drift of the building retrofitted with the PRS is considerably smaller than that of the one retrofitted with SISPs. Furthermore, compared with the building retrofitted with SISPs, the building retrofitted with the PRS experiences significantly less damage due to the more ductile behavior of the system at the life safety and collapse prevention PLs.

This paper presents a statistical approach to develop the soil column profiles and surface seismic response spectra for soil-structure interaction (SSI) analyses of structures founded on layered soil sites. The soil profile is developed using the statistical mean value of measured in-situ soil properties as determined from site boreholes and soil testing. The individual randomized soil profiles are input into a separate iterative soil column seismic analysis program to develop the seismic strain compatible soil profiles and surface acceleration response spectra consistent with the site design basis earthquake hazard. The median and median plus one standard deviation of the statistically developed surface response spectra developed using the results of thirty randomized soil columns are presented to demonstrate the influence of variation in soil properties and layer geometry. The development of median design response spectra based on the mean seismic hazard established for the site i...