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

As the development of structural system and material enable to construct many high-rise buildings. However, high rise buildings are vulnerable to the strong wind rather than seismic excitation, because they have relatively long period. Recently, intensity and frequency of extreme wind such as hurricane and typhoon have been increased with the weather change all over the world. Therefore, in this study, 50-story building with three types of braces which are diagonal brace, X-brace, Chevron brace are modelled and compared with non-braced 50-story building by changing wind speed. Finally, all the results from four cases are compared for wind performances. As a result, buildings reinforced with X-brace and Chevron braces have a good performance subjected to the strong wind.

An Analytical Study on the Performance of Wind Resistant System Considering Climate Change

This paper explores rotational capacities and demands in thick top-and-seat (cleated) angle partially restrained connections subjected to monotonic and cyclic loads. The results of test on full-scale angle connections are described first, and are then compared to published curve-fitting models for these types of connections. The data indicates that the curve-fitting constants of some existing mathematical models cannot be extrapolated to thick angles. The results indicate that these connections are capable of providing very ductile behavior and constitute an ideal back-up structural system in steel frames.

Analytical Models for Determining Rotational Capacity of Clip-Angle Connections under Seismic Loading

Development and Verification of Fatigue Testing Device for Rail Fastening Clamps

Based on some of experimental results for components and full-scale connections, this paper investigates the strength, stiffness and ductility behavior of heavy clip angle connection components subjected to static loading. The results of tests on heavy clip angle connection (t=25mm) are described first, and then a methodology to generate the response of the clip angle connection using nonlinear finite element models (FE) is presented. Extensive experience with 3D numerous models is discussed, including the effect of boundary conditions, introduction of the pretension force into the bolts, and effects of small changes in geometry on the deformation capacity of the angles. Possible strategies for the extension of this modeling approach to cyclic loads are also described.

Analytical Characterization of the Performance of Steel Heavy Clip Angle Connections

Several conventional structural systems require sufficient retrofitting design procedures, improvements, and reconstructions to withstand lateral loads and to decrease the occurrence of damage. High strength capacity and ductility for seismic lateral resisting systems improve the structural vulnerabilities and limit damage concentrations in areas subject to seismic conditions. Several types and shapes of structural systems with appropriate ductility and energy dissipation features are currently established as structural fuses to enhance the general performance of the structures and decrease seismic ramifications. To enhance the energy dissipation performance and concentration of the inelasticity, improving the ductile behavior and limiting the unpredictable accumulation of plastic strains is essential. The conventional eccentrically braced systems are examined and reestablished, and the effects of shear fuses used in high-rise buildings are investigated for prototype buildings by implementing the verified simulations. Next, seismic protective fuse systems with innovative dampers consisting of several butterfly-shaped shear links are established. Ultimately, the design guidelines are established based on the conventional eccentrically braced frames (EBFs), which are redesigned with the use of noble seismic protective fuses, and the hysteretic behavior is obtained and compared accordingly.

/pdf/development-of-innovative-lateral-resistance-systems-1c2302xu.pdf

Jong Wan Hu

Papers

An Analytical Study on the Performance of Wind Resistant System Considering Climate Change

Analytical Models for Determining Rotational Capacity of Clip-Angle Connections under Seismic Loading

Development and Verification of Fatigue Testing Device for Rail Fastening Clamps

Analytical Characterization of the Performance of Steel Heavy Clip Angle Connections

Development of Innovative Lateral Resistance Systems Featuring Earthquake-Protective Dampers