基于ANSYS的木框架有限元静力弹塑性分析   总被引：1，自引：0，他引：1  

阿肯江·托呼提  亓国庆 《地震工程与工程振动》2007,27(4):167-171

采用大型有限元软件ANSYS10.0对单调水平荷载作用下一榀门式木框架及其各种加固方案进行了静力弹塑性计算分析。通过各种加固方式屈服荷载、极限荷载大小的比较以及相对于未加固木框架提高程度的比较,从中得出了对门式木框架加固的最佳方案,为木柱、梁-土坯组合墙体的抗震加固提供方案。  相似文献   

Gas and Particle Partitioning Behavior of Aldehyde in the Presence of Diesel Soot and Wood Smoke Aerosols     

Sangdon?Lee  Richard?M.?Kamens  Myoseon?JangEmail author 《Journal of Atmospheric Chemistry》2005,51(2):223-234

Outdoor smog chamber experiments were performed to investigate gas/particle (G/P) partitioning behavior of aldehyde compounds in atmospheric acidic aerosols. Diesel soot and wood smoke aerosols were selected as acidic aerosols and octanal, decanal, undecanal, and cis-pinonaldehyde for aldehydes compounds. Aerosol acidity was measured with the equivalent sulfuric acid amounts in aerosol mass: 0.2–0.6 wt% in diesel soot and 0.04–0.1 wt% in wood smoke aerosols. Experimentally determined partitioning coefficients of aldehyde along with other classes of semivolatile organic compounds (SOCs) were compared with the estimation. All experimental G/P partitioning coefficients of aldehyde compounds were 10–200 times higher than estimated partitioning coefficients. Aldehyde partitioning coefficients in wood soot were similar or less than diesel soot aerosols.  相似文献   

新昌硅化木揭示的早白垩世东南沿海地区古气候特征分析     

薛根元娄伟平  张维祥吴春华 何凤翩 《南京气象学院学报》2005,28(5):666-671

根据浙江省新昌硅化木的分布与特点，应用硅化木记录的可知性和植物学的类比原理，通过该地区硅化木、其他植物化石和岩性组合等综合分析，初步探讨了早白垩世新昌盆地南洋杉型木的生态环境，以此研究该时期东南沿海地区的古气候主要特征。研究表明：该地区早白垩世古气候的主要特点是温暖、湿润及有时存在相对干旱的季节，同时呈现由温湿逐渐转变为干旱炎热的气候变化趋势；新昌硅化木中有明显的树木年轮，表明这种古气候可能存在一定的季节变化。  相似文献   

饵料浓度对中华哲水蚤摄食的影响   总被引：15，自引：2，他引：13  

张武昌  王荣 《海洋学报》2000,22(6):88-94

用饵料浓度差减法和排粪率法研究中华哲水蚤(Calanus sinicus)在饵料(青岛大扁藻、新月菱形藻)浓度从1500到350000个/cm3时摄食率的变化。实验证明中华哲水蚤具有很强的摄食潜力,摄食率在实验饵料浓度范围内一直在增加,在较低的饵料浓度(如青岛大扁藻4000个/cm3)下停止摄食。  相似文献   

北京延庆硅化木的矿物学特征分析     

程素珍 《地质与资源》2022,31(1):21-27

通过X射线荧光、红外光谱和X射线衍射等检测方法分析了延庆硅化木的矿物学特征.结果表明:2个不同植物种属但在同一埋藏地形成硅化木标本成因相似,其颜色与所含元素种类及含量密切相关.X射线衍射分析表明,不同颜色和植物种属的硅化木主要组成物相一致,为SiO2,其他矿物极其微量.2个硅化木标本的红外吸收谱带基本一致,均显示典型的...  相似文献   

现代测量技术在古树名木保护中的应用     

吴洁 《东北测绘》2014,(2):206-208

以上海市为例,简要介绍在古树名木保护工作中,应用航测立体采集的方法有效提高内业数据处理工作效率和成果精度。实践证明,采用航测立体采集技术可以较低的成本获取高精度和信息丰富的古树名木现状数据,为绿化市容部门开展古树名木的保护提供准确的基础数据。  相似文献   

Shaking‐table tests of a full‐scale single‐story masonry veneer wood‐frame structure     

Hussein O. Okail  P. Benson Shing  William M. McGinley  Richard E. Klingner  Seongwoo Jo  David I. McLean 《地震工程与结构动力学》2011,40(5):509-530

This paper presents the findings of shaking‐table experiments conducted to examine the seismic performance of a full‐scale, one‐story, wood‐framed structure with masonry veneer. The structure was designed and constructed in accordance with current U.S. code provisions. The veneer was attached to the wood backing with two kinds of metal anchors, corrugated ties fastened with 8d nails and rigid ties fastened with #8 screws. The tests have shown that the use of nails to fasten veneer anchors to the wood studs is highly unreliable due to the high variation of the nail extraction capacity, which can be influenced by the moisture content of the wood. Other than this, both the wood frame and the masonry veneer performed well under severe ground motions far exceeding a design level earthquake for Seismic Design Category D. Good performance was observed for the rigid veneer ties, which were attached to the wood studs with screws. The results have shown that the veneer walls parallel to the direction of shaking helped to restrain the motion of the wood structure and therefore should not be simply treated as added mass. The detailing of wood roof diaphragms requires special attention in consideration of the out‐of‐plane inertia force of the veneer that can be transmitted through the top plate of the wood‐stud wall to the rim joist. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Seismic performance of wood‐frame houses in south‐western British Columbia     

Katsuichiro Goda  Gail M. Atkinson 《地震工程与结构动力学》2011,40(8):903-924

The seismic performance of conventional wood‐frame structures in south‐western British Columbia is analytically investigated through incremental dynamic analysis by utilizing available UBC‐SAWS models, which were calibrated based on experimental test results. To define an adequate target response spectrum that is consistent with information from national seismic hazard maps, record selection/scaling based on the conditional mean spectrum (CMS) is implemented. Furthermore, to reflect complex seismic hazard contributions from different earthquake sources (i.e. crustal events, interface events, and inslab events), we construct CMS for three earthquake types, and use them to select and scale an adequate set of ground motion records for the seismic performance evaluation. We focus on the impacts of adopting different record selection criteria and of using different shear‐wall types (Houses 1–4; in terms of seismic resistance, House 1>House 2>House 3>House 4) on the nonlinear structural response. The results indicate that the record selection procedures have significant influence on the probabilistic relationship between spectral acceleration at the fundamental vibration period and maximum inter‐story drift ratio, highlighting the importance of taking into account response spectral shapes in selecting and scaling ground motion records. Subjected to ground motions corresponding to the return period of 2500 years, House 1 is expected to experience very limited extent of damage; Houses 2 and 3 may be disturbed by minor damage; whereas House 4 may suffer from major damage occasionally. Finally, we develop statistical models of the maximum inter‐story drift ratio conditioned on a seismic intensity level for wood‐frame houses, which is useful for seismic vulnerability assessment. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Radiocarbon constraints on the Holocene flood deposits of the Ning‐Zhen Mountains,lower Yangtze River area of China     

Shi‐Yong Yu  Cheng Zhu  Fubao Wang 《第四纪科学杂志》2003,18(6):521-525

Lying athwart both the temperate and subtropical zones, the Ning‐Zhen Mountains are particularly prone to extreme floods in the summer months when cold fronts collide with the subtropics‐derived warm airmasses. The Holocene flood deposits in the region may provide a long‐term perspective on hydrographical change and its palaeoclimatic implications. Radiocarbon dates on carbonised wood preserved in flooding sediments reveal that the region has experienced a number of catastrophic floods throughout the middle Holocene. These extreme flooding events cluster into three periods: (i) 9200–8200 cal. yr BP, (ii) 7600–5800 cal. yr BP and (iii) 5200–4000 cal. yr BP, corresponding to the times when the East Asian monsoon has been intensified under warm conditions. The significant falls in flooding frequency around 8200 cal. yr BP, 5800 cal. yr BP and 4000 cal. yr BP may have resulted from substantial reduction in regional precipitation, probably associated with meridional displacement of the planetary frontal system. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Video monitoring of in-channel wood: From flux characterization and prediction to recommendations to equip stations     

Zhi Zhang  Hossein Ghaffarian  Bruce MacVicar  Lise Vaudor  Aurélie Antonio  Kristell Michel  Hervé Piégay 《地球表面变化过程与地形》2021,46(4):822-836

Wood flux (piece number per time interval) is a key parameter for understanding wood budgeting, determining the controlling factors, and managing flood risk in a river basin. Quantitative wood flux data is critically needed to improve the understanding of wood dynamics and estimate wood discharge in rivers. In this study, the streamside videography technique was applied to detect wood passage and measure instantaneous rates of wood transport. The goal was to better understand how wood flux responds to flood and wind events and then predict wood flux. In total, one exceptional wind and seven flood events were monitored on the Ain River, France, and around 24,000 wood pieces were detected visually. It is confirmed that, in general, there is a threshold of wood motion in the river equal to 60% of bankfull discharge. However, in a flood following a windy day, no obvious threshold for wood motion was observed, which confirms that wind is important for the preparation of wood for transport between floods. In two multi-peak floods, around two-thirds of the total amount of wood was delivered on the first peak, which confirms the importance of the time between floods for predicting wood fluxes. Moreover, we found an empirical relation between wood frequency and wood discharge, which is used to estimate the total wood amount produced by each of the floods. The data set is then used to develop a random forest regression model to predict wood frequency as a function of three input variables that are derived from the flow hydrograph. The model calculates the total wood volume either during day or night based on the video monitoring technique for the first time, which expands its utility for wood budgeting in a watershed. A one-to-one link is then established between the fraction of detected pieces of wood and the dimensionless parameter “passing time × frame rate ”, which provides a general guideline for the design of monitoring stations.  相似文献