Plasticity‐fibre model for steel triangular plate energy dissipating devices

Properly fabricated triangular‐plate added damping and stiffness (TADAS) devices can sustain a large number of yield reversals without strength degradation, thereby dissipating a significant amount of earthquake‐induced energy. A pronounced isotropic‐hardening effect is recognized in the force‐deformation relationships of the TADAS devices made from two grades of low yield strength steel. The proposed plasticity‐fibre model employing two surfaces (a yield surface and a bounding surface) in plasticity theory accurately predicts the experimental responses of the TADAS devices. This model is also implemented into a computer program DRAIN2D+ to investigate a frame response with the TADAS devices. Substructure pseudo‐dynamic tests and analytical studies of a two‐storey steel frame constructed with the low yield strength steel, LYP‐100 or LYP‐235 grade, TADAS devices confirm that the dynamic structural response can only be predicted if the proposed plasticity‐fibre model is used for LYP‐100 steel TADAS device. Copyright © 2002 John Wiley & Sons, Ltd.     

关于发展我国地下流体前兆流动观测问题的建议

介绍了地下流体前兆流动观测及其目的与意义、国内外地下流体前兆流动观测的历史与现状、我国目前存在的主要问题；针对现状与问题，提出了建议我国地下流体前兆流动观测系统的建议，其中包括指导思想、发展目标、观测网的类型与布设、观测点的建议、观测项目与观测仪器的选择、观测工作的组织与实施、观测数据的产出与共享等科学与技术问题。     

关于地震地下水观测井建设的若干问题

根据有关的国家与地震行业技术标准,结合建井的实践经验,本文论述了地震地下水观测井的定位、观测井结构设计与钻井施工的技术要求。     

Steel buckling‐restrained braced frames with single and dual corner gusset connections: seismic tests and analyses

The design of a three‐story buckling‐restrained braced frame (BRBF) with a single‐diagonal sandwiched BRB and corner gusset was evaluated in cyclic tests of a one‐story, one‐bay BRBF subassembly and dynamic analyses of the frame subjected to earthquakes. The test focused on evaluating (1) the seismic performance of a sandwiched BRB installed in a frame, (2) the effects of free‐edge stiffeners and dual gusset configurations on the corner gusset behavior, (3) the frame and brace action forces in the corner gusset, and (4) the failure mode of the BRBF under the maximum considerable earthquake level. The subassembly frame performed well up to a drift of 2.5% with a maximum axial strain of 1.7% in the BRB. Without free‐edge stiffeners, the single corner gusset plate buckled at a significantly lower strength than that predicted by the specificationof American Institute of Steel Construction (2005). The buckling could be eliminated by using dual corner gusset plates similar in size to the single gusset plate. At low drifts, the frame action force on the corner gusset was of the same magnitude as the brace force. At high drifts, however, the frame action force significantly increased and caused weld fractures at column‐to‐gusset edges. Nonlinear time history analyses were performed on the three‐story BRBF to obtain seismic demands under both design and maximum considerable levels of earthquake loading. The analytical results confirmed that the BRB and corner gusset plate achieved peak drift under cyclic loading test. Copyright © 2011 John Wiley & Sons, Ltd.     

Relationship between oceanic heat content and sea surface height on interannual time scale

The relationship between heat content and sea surface height (SSH) in the global ocean on the interannual time scale is examined with satellite altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in the upper 700 m calculated from Ishii data is geographically nonuniform. In the tropical ocean, heat content and SSH are strongly correlated and exhibit nearly the same interannual variations. In the polar ocean, their correlation is relatively weak. Further analysis with Simple Ocean Data Assimilation outputs shows that such nonuniform distribution is not from dynamical origin but from the limited integral depth selected to calculate heat content. The integral depth of 700m is inadequate to capture variation of the deep main thermocline in the polar region. The halosteric effect also contributes to the nonuniform pattern of correlation, because saline contraction becomes significant in the polar ocean owing to low temperature.     

Seismic performance evaluation of a 34‐story steel building retrofitted with response modification elements

The original structural design of this case study consisted of five basement floors and a 34‐story hotel tower in Kaohsiung, Taiwan. The construction started in 1993, and the erection of the entire steel frame and the pouring of concrete slabs up to the 26th floor were completed before 1996. However, construction of the original hotel was subsequently suspended for 10 years. Recently, this building has been retrofitted for residential purposes. Buckling restrained braces (BRBs) and eccentrically braced frames were incorporated into the seismic design of the new residential tower. This paper presents the seismic resisting structural system, seismic design criteria, full‐scale test results of one BRB member and the as‐built welded moment connections. Test results confirm that the two side web‐plate stiffening details can effectively improve the rotational capacity of welded moment connection. The paper also discusses the analytical models for simulating the experimental responses of the BRB members and the welded moment connections. Nonlinear response history analyses (NLRHA) indicate that the inelastic deformational demands of the original and the redesigned structures induced by the maximum considered earthquakes are less than those found in the seismic building codes or laboratory tests. This paper also proposes a ground motion scaling method considering multi‐mode effects for NLRHA of the example building. It is shown that the proposed scaling method worked well in reducing the scatter in estimated peak seismic demands. Copyright © 2008 John Wiley & Sons, Ltd.     

Torsional phenomena in 2008 great Wenchuan earthquake

It is well known that there are some torsional damages in earthquakes. In Taibai park, Jiangyou city, Sichuan province, most of the stone statues, which were placed upon the banisters of one zigzag bridge, exhibited different torsional phenomena in 2008 Wenchuan earthquake. This paper introduces the torsional phenomena of all the statues on the zigzag bridge firstly. Then one eccentricity model is established and the equivalent rotational accelerations are calculated in order to analyze the causes of the to...     

Recovery Factors of Oil Resources in China

This paper provides a new method to estimate recovery factors of oil resources. The China National Petroleum Assessment (2003–2007) (CNPA 2007) evaluates in-place oil resources and applies the recovery factor (RF) to estimate recoverable oil resources. The RF of oil resources plays an important role in the CNPA 2007. Based on the geological features, 24 types of oil assessment units are defined, such as the Mesozoic rift unit, the Mesozoic and Cenozoic foreland unit, etc. Through the recovery factor statistics of oil reserves (discovered) in different accumulations, as well as the potential analyses of enhanced petroleum recovery, appropriate RF valuing standards of oil resources (discovered and undiscovered) in different assessment units are developed. Calculation methods of oil resource RFs are established, including the appraisal standards, scoring, and calculation steps of oil resource RFs. Through the case studies, the valuing and appraisal standards of oil resource RFs are verified. Robust appraisal standards allow the RF method to be a valuable tool to effective assessment of China’s recoverable oil resources.