Experimental study on centrifugal concrete-filled steel tubes under bending and torsion

INTRODUCTIONConcrete filledsteeltubesarenowwidelyusedinfactories ,powerstations,bridges ,etc .Centrifugalconcrete filledsteeltubesarehollowstructuralmemberscentrifugatedbyhigh speedcentrifuge ,andarethereforeofconsiderablylessweightthantraditionaltubes .A…     

Unified expression for failure of reinforced concrete members in bridge

INTRODUCTION Reinforced concrete elements with box section are commonly used in horizontal subsystems and in vertical support of bridge structures. The horizontal structural members normally have box section and top flange. The vertical supports of the bridge usually have a box section also. To simplify the deduction of such structural member under combined forces, the box sections without top flange are discussed here. Fig.1 shows the typical section types of reinforced concrete members.…     

弯曲内力计算的多种方法

弯曲内力计算的一般方法是截面法,本文给出了另外几种计算方法。这几种方法的特点是不需要先计算支座约束反力,而是由荷载直接计算出梁的内力。     

用积分法绘制梁的剪力图和弯矩图

研究了用积分法绘制架的剪力图、弯矩图的方法,这种方法对绘制复杂载荷梁的剪力图、弯矩图是比较简便的。     

探讨建立短跑途中跑后蹬、摆腿、着地缓冲的合理技术模式

人们的运动不是一个静态的过程,而是一个连续的不可分割的动态过程,所以我们在进行技术动作研究就应从整体上去进行。本文基于这一角度考虑,通过文献资料法,对比分析法和运动生物力学分析法探讨建立后蹬、摆腿与前扒着地缓冲的合理技术模式,为广大体育教师和教学和教练员、运动员的训练提供可行性参考。     

钢筋混凝土双向受弯构件斜截面受剪性能理论研究

钢筋混凝土及预应力混凝土受弯构件的正截面强度及斜截面抗剪问题是混凝土结构理论的一个重要研究领域。文章总结了近年来国内外有关钢筋混凝土双向受弯构件斜截面受剪性能研究,并展望了今后该领域的研究方向。     

关于梁端弯矩调幅问题的探讨

对框架结构梁端弯矩应如何调幅问题做一探讨，对以往设计提出修正性的建议。     

Mechanical behaviour of cross-country ski racing poles during double poling

The purpose of this study was to evaluate the behaviour of cross-country ski poles during double poling on a treadmill using three-dimensional kinematics. The results were compared with standard laboratory tests of the pole manufacturers. A total of 18 skiers were analysed at two speeds (85% and 95% of the maximal speed) at grades of 1.5% and 7%. Variables describing cycle characteristics, bending stiffness, bending behaviour, and trajectories of the pole markers were analysed. Triangular-shaped poles demonstrated the greatest stiffness and lowest variability in maximal bending. Softer poles demonstrated greater variability in bending behaviour and lost ground contact at high skiing speeds, which for some skiers resulted in failure to complete high-speed tests. Considerable variations in pole behaviour for similar poles between skiers were observed, which might be attributed to differences in technique, indicating that mechanical properties of the poles did not exclusively determine pole behaviour in the dynamic situation. The greatest magnitude of pole bending was in the middle part of the pole, which differed from the standard static pole analysis of the manufacturer. Increases in grade demonstrated the greatest effect on pole bending. Distinct differences from the pole manufacturers' laboratory measures were apparent, suggesting that basic pole testing might be adapted.     

Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer(CFRP) layer under long-term load action that lasted for 330 d.We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest.The conducted experiments showed that the additional anchorage influences the slip of the external layer with respect to the strengthened element.Thus,concrete and carbon fibre composite interface stiffness decreases with a long-term load action.Therefore,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.