Minimum Design Loads for Buildings and Other Structures provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, as well as their combinations, which are suitable for inclusion in building codes and other documents. This Standard, a revision of ASCE/SEI 7-05, offers a complete update and reorganization of the wind load provisions, expanding them from one chapter into six. The Standard contains new ultimate event wind maps with corresponding reductions in load factors, so that the loads are not affected, and updates the seismic loads with new risk-targeted seismic maps. The snow, live, and atmospheric icing provisions are updated as well. In addition, the Standard includes a detailed Commentary with explanatory and supplementary information designed to assist building code committees and regulatory authorities. Standard ASCE/SEI 7 is an integral part of building codes in the United States. Many of the load provisions are substantially adopted by reference in the International Building Code and the NFPA 5000 Building Construction and Safety Code. Structural engineers, architects, and those engaged in preparing and administering local building codes will find this Standard an essential reference in their practice. Note: New orders are fulfilled from the second printing, which incorporates the errata to the first printing.

Minimum Design Loads for Buildings and Other Structures

Wind speeds over the world’s oceans have increased over the past two decades, as have wave heights. Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. We find a general global trend of increasing values of wind speed and, to a lesser degree, wave height, over this period. The rate of increase is greater for extreme events as compared to the mean condition.

https://researchbank.swinburne.edu.au/file/bca43746-6f16-4ad2-a4b7-27f8d8d60fed/1/PDF (Published version).pdf

Global trends in wind speed and wave height over the past 25 years

Metallic biomaterials are used in medical devices in humans more than any other family of materials. The corrosion resistance of an implant material affects its functionality and durability and is a prime factor governing biocompatibility. The fundamental paradigm of metallic biomaterials, except biodegradable metals, has been “the more corrosion resistant, the more biocompatible.” The body environment is harsh and raises several challenges with respect to corrosion control. In this invited review paper, the body environment is analysed in detail and the possible effects of the corrosion of different biomaterials on biocompatibility are discussed. Then, the kinetics of corrosion, passivity, its breakdown and regeneration in vivo are conferred. Next, the mostly used metallic biomaterials and their corrosion performance are reviewed. These biomaterials include stainless steels, cobalt-chromium alloys, titanium and its alloys, Nitinol shape memory alloy, dental amalgams, gold, metallic glasses and biodegradable metals. Then, the principles of implant failure, retrieval and failure analysis are highlighted, followed by description of the most common corrosion processes in vivo. Finally, approaches to control the corrosion of metallic biomaterials are highlighted.

Corrosion of Metallic Biomaterials: A Review

Piezoelectric coefficients are constrained by the intrinsic crystal structure of the constituent material. Here we describe design and manufacturing routes to previously inaccessible classes of piezoelectric materials that have arbitrary piezoelectric coefficient tensors. Our scheme is based on the manipulation of electric displacement maps from families of structural cell patterns. We implement our designs by additively manufacturing free-form, perovskite-based piezoelectric nanocomposites with complex three-dimensional architectures. The resulting voltage response of the activated piezoelectric metamaterials at a given mode can be selectively suppressed, reversed or enhanced with applied stress. Additionally, these electromechanical metamaterials achieve high specific piezoelectric constants and tailorable flexibility using only a fraction of their parent materials. This strategy may be applied to create the next generation of intelligent infrastructure, able to perform a variety of structural and functional tasks, including simultaneous impact absorption and monitoring, three-dimensional pressure mapping and directionality detection. Piezoelectrics convert force into electrical charge, and vice versa, but the coefficients that determine piezoelectric behaviour are constrained by crystal structure. Here, metamaterials are 3D printed that show arbitrary piezoelectric coefficients.

Three-dimensional printing of piezoelectric materials with designed anisotropy and directional response.

Cyclic performance of extended end-plate connections equipped with shape memory alloy bolts

International Roughness Index prediction for flexible pavements using novel machine learning techniques

This study mainly treats a new type of the bracing friction damper system, which is able to minimize structural damage under ea rthquake loads. The slotted bolt holes are placed on the shear faying surfaces with an intention to dissipate considerable amount of fri ction energy. The superelastic shape memory alloy (SMA) wire strands are installed crossly between two plates for the purpose of enhancing re centering force that are able to reduce permanent deformation occurring at the friction damper system. The smart recentering friction dam per system proposed in this study can be expected to reduce repair cost as compared to the conventional damper system because the proposed system mitigates the inter-story drift of the entire frame structure. The response mechanism of the proposed damper system is firstly investigated in this study, and then numerical analyses are performed on the component spring models calibrated to the experimental results. Based on the numerical analysis results, the seismic performance of the recentering friction damper system with respect to recentering c apability and energy dissipation are investigated before suggesting optimal design methodology. Finally, nonlinear dynamic analyses are condu cted by using the frame models designed with the proposed damper systems so as to verify superior performance to the existing damper sy stems.Key words : Superelastic shape memory alloy (SMA), Friction damper, Energy dissipation, Bracing system초 록본 연구는 지진에 대한 구조물의 손상을 최소화 하기 위하여 슬립 저항력을 활용한 새로운 형태의 마찰 댐퍼형 가새 시스템의 설계와 개발을 주로 다루고자 한다. 가새 부재 내에서 전단력에 의한 마찰 거동으로 상당량의 에너지를 수동적으로 소산하기 위하여 플레이트 전단 이음부 위에 슬롯 형태의 볼트 구멍을 설치한다. 여기에 전단 마찰 거동으로 인해 발생되는 잔류변형을 줄이고자 상온에서 원형복원이 가능한 초탄성 형상합금 와이어를 꼬아서 만든 연선을 설치하여 댐퍼 시스템 내에 복원성을 증진 시켰다 . 기존에 주로 사용된 수동적인 변위 제어 장치와 비교하여 본 연구에서 다루고자 하는 자동복원이 가능한 마찰 댐퍼형 가새 시스템은 중심 가새 프레임 구조물에 손쉽게 설치하여 지진발생 후에 구조물에 발생하는 층간 잔류변위를 최소화하여 유지 보수에 소모되는 비용의 대폭적인 절감을 기대할 수 있다 . 본 연구에서는 자동복원이 가능한 마찰 댐퍼형 가새 시스템의 역학적인 거동 메커니즘을 살펴보고 실험값으로 보정되어 신뢰성을 확보한 스프링 모델을 사용하여 해석을 실시하였다 . 시스템에 다양한 설계 변수를 적용하여 복원성과 에너지 소산 능력 측면에서 제안된 댐퍼의 성능 동향을 분석을 하고 최적의 설계 방식을 제안하고자 한다 . 마지막으로 자동복원이 가능한 마찰 댐퍼를 중심 가새 프레임 구조물에 설치하여 비선형 동적 해석을 실시하고 기존의 시스템과 비교하여 성능적인 우수성을 입증하고자 한다 .검색어 : 초탄성 형상기억합금, 마찰 댐퍼, 자동복원, 에너지 소산, 가새 시스템 Structural Engineering

/pdf/optimum-design-and-structural-application-of-the-bracing-55kwo920xr.pdf

Optimum Design and Structural Application of the Bracing Damper System by Utilizing Friction Energy Dissipation and Self-Centering Capability

Impact Assessment of the Land Use Dynamics and Water Pollution on Ecosystem Service Value of the Nile Delta Coastal Lakes, Egypt

This paper is principally performed to survey end-plate connection are described in the next part based on ideal limit states. The determination of end-plate based on the full plastic strength of the steel beam in accordance with 2001 AISC-LRFD manual and AISC/ANSI 358-05 Specifications. The bolted connections considered herein were performed to include the end-plate component of moment connections. This study is intended to investigate economic design for end-plate connections. In addition, the proposed end-plate model is evaluated by comparing the required factored bolt strength. The end-plates using 8 high strength bolts with wider gages demonstrated this design. The equations belonging to the step-by-step design procedure are described based on complete proving of design. Finally, new design methodology is applied to end-plate connections suggested in this study.

New Bolted End-Plate Connection Design

Geological CO2 sequestration is a promising method to reduce atmospheric CO2. Deep saline aquifers are one of the most important sites due to their capacity for CO2 storage. Thus, a better understanding of immiscible brine-CO2 mobility and their saturations including invading patterns in deep saline aquifers as CO2 storage sites is required. Microfluidic model provides the opportunity to discover unrecognized processes and to explore existing theories in fluid flow through porous media. In this study, the microfluidic model is used to explore the effects of both the supercritical carbon dioxide (scCO2) injecting velocity and ionic strength in saline aquifers on scCO2 invading patterns in geological CO2 sequestration. The results show that scCO2-brine displacement ratio increases with (1) increased scCO2 injecting velocity up to 40 μL/min, and (2) decreased ionic strength in the range of 1M~5M NaCl.

Jong Wan Hu

Papers

International Roughness Index prediction for flexible pavements using novel machine learning techniques

Optimum Design and Structural Application of the Bracing Damper System by Utilizing Friction Energy Dissipation and Self-Centering Capability

Impact Assessment of the Land Use Dynamics and Water Pollution on Ecosystem Service Value of the Nile Delta Coastal Lakes, Egypt

New Bolted End-Plate Connection Design

CO2-Brine Displacement in Geological CO2 Sequestration: Microfluidic Flow Model Study