Quasi-non-linear fracture mechanics analysis of splitting failure in simply supported beams loaded perpendicular to grain by dowel joints

A quasi-non-linear fracture mechanics model based on beam on elastic foundation theory is applied for analysis of the splitting failure of dowel joints loaded perpendicular to grain. Simply supported beams symmetrically loaded by two dowels are considered, and the effects of edge distance, dowel spacing, and distance between dowels and supports are accounted for. The foundation modulus used in the beam on elastic foundation model is chosen so that the perpendicular-to-grain tensile strength and fracture energy properties of the wood are correctly represented. This ensures that a conventional stress analysis and failure criterion lead to the same solution as the compliance method of fracture mechanics. A semiempirical efficiency factor is proposed to account for the influence of the total beam depth, which does not enter the beam on elastic foundation model, but the effect of which is evident from tests. It is shown that the so-called Van der Put/Leijten model, which recently has been adopted in Eurocode 5, appears as a special case of the model presented. Tests on simply supported beams with a single dowel joint at midspan are compared with the theoretical predictions. Various edge distances, beam depths, and spans were tested.     

在桩基础设计中两种规范的差异比较--《建筑地基基础设计规范》与《建筑桩基技术规范》

通过对二部规范的对比，阐明“地基基础”与“桩基”相比在桩基础设计中作了较大的调整，这样既节省了工程造价又提高了桩基础设计质量。     

深基坑锻锤基础冬期施工

在冬期施工，对于土方开挖、钢筋绑扎、人员的通行、砼的浇铸、砼的温度控制，基坑的保温等都带来一定困难，为此提出了深基坑锻锤基础才是最佳实践应用。     

42所农业高等院校学报之比较

通过对42所农业高等院校学报的载文量、影响因子、篇均被引频次和基金论文比四项指标的统计对比,进而反映出各校学报在42所院校学报中所处的位子。     

高层建筑桩基础沉降预测

高层建筑施工过程可近似地看为一个线性加载的过程。在沉降-时间曲线特征的基础上,建立了高层建筑桩基础的龚帕兹沉降-时间预测模型,其中3个参数a、b和c可以简单求解得到。两个个工程实例的应用证明了该模型在桩基沉降预测中的合理性和实用性。     

钢支撑代替混凝土支撑可行性分析

在地铁深基坑施工中，围护结构对基坑的安全起着至关重要的作用。本文依据合肥地铁一号线明光路站，施工过程中，由于车站3号出入口为出土口，原计划的第一道钢筋混凝土支撑无法实现，更改为钢支撑，通过有限元分析软件MIDAS-GTS\NX，建立二维模型进行数值模拟，对围护结构的变形和地表沉降进行分析，结果表明：第一道支撑采用钢支撑代替钢筋混凝土支撑对围护结构的侧移值影响不大，钢筋混凝土支撑控制地表沉降的效果要比钢支撑好，对今后类似工程变更提供依据。     

特色农产品集群品牌与企业品牌互动机制理论基础述评

该文通过对现有文献的梳理,阐释了特色农产品集群品牌与企业品牌之间互动关系的4大基础理论,即原产地效应、信号理论、品牌理论和生态系统理论,并指出原产地效应和品牌相关理论对特色农产品领域的相关研究具有重要意义。     

机电设备安装工程中常见问题及对策分析

机电设备安装工程施工是一项技术领域的工作,涉及到了多个工种和多道工序,因此存在特殊的要求。文章对机电设备安装施工中存在的一些常见问题进行了分析,并为提高机电设备的安装质量提出了一些建议。     

Reinforcement Treatment on the Uneven Subsidence of Foundation

There are several methods to cope with the common problem of the uneven subsidence of foundation. The reason for uneven settlement of foundation of the frame structure was analyzed in this paper. Considering the limitation of the construction site and the principle of consolidation, a feasible reinforcement measure was taken. Meanwhile, a practical construction pattern was chosen upon the comparison of the reinforcement technology analysis and the construction method. The observation of the settlement result after consolidation of the structure shows that the result of this reinforcement treatment pattern is effective.     

Research on Dynamics of Installation Way for Active Isolation Actuator on Flexible Foundations

The dynamic characteristic of active isolation atuator on flexible foundations was studied under the installation of parallel structure and foundation cancellation.The influencing relationships between active isolation force of the different installation ways and passive isolation system and flexible foundation were analyzed and compared.Scientific basis for selecting installation ways of active isolator is provided in this paper.