钢筋砼圆板在线性分布荷载下的极限分析

本文用极限平衡法(屈服线理论)推导了钢筋砼圆板在线性分布荷载(静水压力)作用下的极限强度上限解,并提出了实用的简化公式。该公式与均布荷载下的公式相同,仅荷载集度须以线性分布荷载的平均集度代替。比较表明,采用简化公式计算引起的误差最大不超过3％,在工程计算所允许的范围内。     

钢筋混凝土矩形板误差分析

就钢筋混凝土矩形单向板和钢筋混凝土矩形双向板在均布荷载作用下内力计算的相对误差进行对比分析，为钢筋混凝土矩形单向板和钢筋混凝土矩形双向板的划分提供理论计算依据，并说明了这种划分的合理性．     

钢筋混凝土梯形板的一种修正算法

提出了一种求解钢筋混凝土周边固支等腰梯形板内及板边最大弯矩的一种修正算法。目前 ,在均布荷载作用下 ,计算钢筋混凝土周边固支等腰梯形板通常是用经验算法即是把钢筋混凝土等腰梯形板简化成当量矩形板进行计算。经分析表明 ,此经验算法相对误差较大 ,难以达到工程设计的要求。通过钢筋混凝土周边固支等腰梯形板及其当量矩形板的当量关系 ,并利用周边固支矩形板的近似算法对等腰梯形板进行计算 ,且对相对误差进行修正 ,获得了较为满意的效果。这种修正算法具有精度高、实用性强、计算方便等特点。     

按部分剪力连接计算压型钢板-混凝土组合板承载力的简化方法

提出多种荷载作用下,简支压型钢板-混凝土组合板承载力的部分剪力连接简化计算方法。分析组合板纵向剪切破坏的部分剪力连接理论模型,阐明组合板纵向剪切破坏的机理,以及控制截面位置和极限荷载的求解思路。通过公式推导,分别得到了组合板在两点对称荷载和均布荷载作用下的承载力计算公式。在此基础上,提出点荷载和均布荷载共同作用下的组合板承载力计算方法,通过参数分析,对该方法进行简化,得到多个荷载作用下组合板承载力的简化计算公式。结合12个简支组合板的静力试验结果,进行公式验证,计算结果与试验值吻合良好。通过小比例滑块试验得到压型钢板与混凝土的界面强度参数,即可用该方法计算组合板的承载力。     

钢筋混凝土正方形双曲扁壳极限平衡理论的研究

本文根据极限平衡理论的基本原理[1][2]和试验研究结果,提出了钢筋混凝土正方形双曲扁壳在均布垂直荷载作用下的强度计算、变形计算及抗裂强度计算,并初步提出壳体达到极限状态时内力分布规律及变形分布规律的计算。不当之处,请批评指正。     

环板在边缘弯矩和局部均布荷载共同作用下的塑性极限分析

本文应用奇异函数法简化计算环板在边缘弯矩和局部均布荷载共同作用下的极限荷载状态。文中分别针对内、外边界支承的简支、固支环板及具有内、外悬臂的环板,给出了在最大弯矩极限条件下边缘弯矩和均布荷载所满足的关系式。     

火灾下混凝土简支板等效火灾荷载的简化计算

根据热传学原理,得出高温下钢筋混凝土板截面温度场的分布,计算出火灾下钢筋混凝土简支板极限抗弯承载力,得出钢筋混凝土简支板的等效火灾荷载,为火灾下钢筋混凝土极限抗弯承载力的计算提供了方便。     

半无限弹性体内垂直应力的感应值

本文以韦斯脱卡特(H.M.Westergaard)公式为依据,获得了计算地基中垂直应力的一些公式。这些公式是分别适用于下列各种荷载情况: (1)三角形荷载作用在矩形面积上; (2)均布荷载作用在一无限长的直线上; (3)均布荷载作用在无限长的条形面积上; (4)三角形荷载作用在无限长的条形面积上。 为了使实际计算得到简化,对于上述各种荷载情况,以及对于均布荷载作用在一矩形面积上和一圆形面积上时,本文均已将其感应值制成表格。     

钢筋混凝土双坡梁矩形截面纵筋截面的计算

<正> 钢筋混凝土矩形截面单跨等截面梁,纵向钢筋按最大弯矩计算就可以了。但对坡梁来说,最大弯矩截面不一定是危险截面,如在均布荷载作用下单跨双坡梁,危险截面不在弯矩最大的跨中。因此,对于坡梁的计算,应首先求出危险截面位置,纵向钢筋应按此截面计算。一、矩形载面单跨双坡梁在均布荷载作用下截面的精确计算法双坡梁在均布荷载作用下如图l所示,距支座A为x截面的弯矩可表示为:     

钢筋混凝土L形板的极限设计

根据作者所进行的试验研究,对承受均布荷载的钢筋混凝土L形板的极限设计做了介绍,论述了板面荷载分区及其传递、斜向板条的计算跨度以及极限设计方法,并有实例计算以说明具体应用.     

Analysis of containment structures for randomly arriving transient loads

Hydrodynamic loads such as those due to safety relief valve discharges and a postulated accidental loss of coolant are some of the major loads on boiling water reactor (RWR) containments. Structural analysis of containments for these highly transient loads can be more efficiently carried out if the response transfer function approach is used. The formulation of such an approach is developed for axisymmetric containment structures. The load parameters, e.g. the maximum intensity, arrival time and predominant frequency may be randomly defined. To obtain the design response, repeated analyses for various sets of parameter values may be required. In such cases the transfer function approach as presented here is computationally very efficient. The formulation to obtain the mean and standard deviation of response for uniformly distributed load arrival time is also provided and the numerical results for a typical BWR containment are given.     

竖向荷载和水平荷载共同作用下钢管拱平面内稳定承载力设计研究

采用二阶弹塑性有限单元法对竖向荷载和水平荷载共同作用下的圆形截面两铰抛物线钢管拱的平面内稳定承载力进行研究。考虑材料非线性、残余应力、初始几何缺陷、矢跨比和长细比等因素对钢管拱平面内力稳定承载力的影响。结果表明：残余应力对其竖向承载力影响很小;初始几何缺陷会显著降低中等长细比钢管拱的承载力;矢跨比和长细比是影响钢管拱承载力的重要因素,但拱的竖向承载力并不随矢跨比和长细比的均匀变化而变化。研究竖向荷载和水平荷载共同作用下两铰抛物线钢管拱达到平面内极限状态时的N-M相关关系,并拟合两铰压弯抛物线钢拱承载力N-M相关关系统一表达式。提出了竖向荷载为全跨均布和半跨均布荷载,同时考虑水平方向荷载作用的两铰抛物线钢拱平面内整体稳定承载力设计建议,可供相关设计问题参考应用。     

Probability-based patterned live loads for design

Probability-based patterned live loads for design are discussed with regard to probabilistic models of load-effects due to sustained live loads on floors. Statistics are presented for equivalent uniformly distributed loads (EUDLs) and equivalent patterned loads (EPLs) for a continuous beam and for continuous floor slab systems. It is shown that EPLs (rather than EUDLs) are required to realistically model structural load-effects that are sensitive to random load patterns. Furthermore, it is shown that an appropriate set of EPLs (for load-effects that are compounded by loading in the vicinity of the load-effect) can be approximated using a standardised EUDL (dependent on the area over which it acts) on the critical structural bay(s) in the vicinity of the load-effect, together with a constant (mean) uniformly distributed load acting on the other structural bays. Accordingly, ‘chequerboard’ design loads are not required. Indeed, it is shown that chequerboard EPLs are not appropriate for design, because their statistics are sensitive to the structural type and they are significantly different from the statistics of the standard EUDLs that are the basis of the standard design loads specified in design codes.     

Flexural-torsional buckling of shallow arches with open thin-walled section under uniform radial loads

An arch with an open thin-walled section that is subjected to a radial load uniformly distributed around the arch axis may suddenly buckle out of its plane of loading and fail in a flexural-torsional buckling mode. The classical flexural-torsional buckling load for an arch with an open thin-walled section under a uniform radial load has been obtained by a number of researchers, based on the consideration that the uniform radial load produces a uniform axial compressive force without in-plane bending prior to the occurrence of flexural-torsional buckling. This assumption is correct for deep arches. However, the uniform radial load may produce substantial bending actions in shallow arches prior to flexural-torsional buckling, and so the classical buckling analysis based on the assumption of uniform axial compression may produce incorrect flexural-torsional buckling loads for shallow arches. This paper investigates the flexural-torsional buckling of shallow arches with an open thin-walled section that are subjected to a radial load uniformly distributed around the arch axis. It is found that shallow arches under a uniform radial load are subjected to combined in-plane compressive and bending actions prior to flexural-torsional buckling, and that using the classical buckling solution for circular arches under uniform compression produces incorrect buckling loads for shallow arches. A rational finite element model is developed for the flexural-torsional buckling and postbuckling analysis of shallow arches with an open thin-walled section, which allows the buckling loads to be obtained correctly.     

Live load factors for parking garage members

This paper proposes a simplified, but effective, algorithm to obtain critical design moments for clamped and/or elastically supported parking garage girders, beams and slabs. Maintaining the uniformly distributed load concept, the equivalent vehicle load factors which can simulate vehicle load effects without conducting additional sophisticated numerical analyses for the concentrated loads are introduced. After determining a standard design vehicle of 2.4 tons through an investigation of small to medium-sized vehicles made in Korea, finite element analyses for concentrated wheel loads were carried out by referring to the influence lines for the girders and beams and influence surfaces for the slabs. Based on the obtained member forces, we determined the equivalent vehicle load factors for the girders, beams and slabs which represent the ratios of member forces under vehicle loads to those under uniformly distributed loads. In addition, the relationships between the equivalent vehicle load factors and sectional dimensions were established by regression and used to obtain the design moments by vehicle loads. The member forces calculated by the proposed method are compared with the results of different approaches mentioned in current design codes with the objective of establishing the relative efficiencies of the proposed method.     

悬挑环板的内力计算

本文根据弹性平板理论推导出在均布荷载、内外边缘集中荷载作用下悬挑环板板内任一点的内力计算公式 ,可供工程设计应用。     

Distortional buckling in braced-cantilever I-beams

This paper deals with distortional buckling of braced-cantilever monosymmetric I-beams under three types of load: a tip point load, a uniformly distributed load and a moment at the end. Top-flange and bottom-flange load positions are considered for the first two load cases. ABAQUS is used for the investigation. The effect of different types of bracing on buckling load is investigated. Results are compared with results from previous experimental investigations. It is also found that top lateral bracings are very effective for beam sections having larger bottom-flanges when a point load or a uniformly distributed load acts at the top-flange, and for the uniform moment case, except for the T-section or the inverted T-section cantilever beams. On the other hand, bottom lateral bracings are very effective for beam sections having larger top-flanges. When loads are placed at the bottom-flange, position of any kind of lateral bracing has practically no effect on the buckling capacity of a monosymmetric cantilever beam, except for the inverted T-section cantilever beams.     

Lateral–torsional buckling of steel web tapered tee-section cantilevers

In this paper an analytical model is presented to describe the lateral–torsional buckling behaviour of steel web tapered tee-section cantilevers when subjected to a uniformly distributed load and/or a concentrated load at the free end. To validate the present analytical solutions finite element analyses using ANSYS software are also presented. Good agreement between the analytical and numerical solutions is demonstrated. Using the present analytical solutions, the interactive buckling of the tip point and uniformly distributed loads is investigated and a parametric study is carried out to examine the influence of section dimensions on the critical buckling loads. It is found that web tapering can increase or decrease the critical lateral–torsional buckling loads, depending on the flange width of the beam. For a beam with a wide flange (width/depth = 0.96) the critical buckling load is increased by 2% by web tapering, whereas for a beam with a narrow flange (width/depth = 0.19) web tapering reduces the buckling load up to10% and 6% for the tip point loading and the uniformly distributed load respectively.