共查询到20条相似文献,搜索用时 15 毫秒
1.
灌芯混凝土砌体抗剪强度的理论分析和试验研究 总被引:2,自引:0,他引:2
对灌芯混凝土砌体抗剪强度进行了试验研究 ,应用刚塑性极限分析理论进行了灌芯混凝土砌体抗剪强度的理论分析 ,提出了灌芯混凝土砌体抗剪强度的理论计算式 ,根据试验研究得出了它的实用计算式 相似文献
2.
体外预应力加固低强度钢筋混凝土简支梁的试验分析 总被引:4,自引:0,他引:4
通过试验研究证明,预应力加固技术是对低强度混凝土构件加固的较好的方法之一,这不仅提出了一些关于预应力加固技术在低强度混凝土构件加固中应用的理论研究,又对工程实践具有一定的理论指导作用。 相似文献
3.
4.
5.
Seismic behavior of bolted beam-to-column connections for concrete filled steel tube 总被引:1,自引:0,他引:1
Lai-Yun Wu Lap-Loi Chung Tung-Ju Shen 《Journal of Constructional Steel Research》2005,61(10):1387-1410
Concrete-filled steel tubes (CFT) have the advantage of high strength, high stiffness and being constructed quickly. However, because the behavior of the beam-to-column connection for CFT is complicated and its design has not been sufficiently verified, their use has been limited.In this paper, a new design of bolted beam-to-column connections for CFT is proposed. A mechanical model is established in order to derive theoretical equations for calculating the stiffness, the yielding shear strength and the ultimate shear strength of the panel zone. Also, a series of cyclic loading experiments have been conducted. The experimental results and theoretical results are very close, which demonstrates that the bolted connections have superior seismic resistance in stiffness, strength, ductility and energy dissipation mechanisms. From the laboratory studies, even though the story angular drift reaches 7% and the plastic angular displacement reaches 5%, the structure still stands. Those results indicate that the seismic resistance exceeds those specified in Taiwan and the US. 相似文献
6.
A review of floc strength and breakage 总被引:19,自引:0,他引:19
The main focus of the paper is to review current understanding of floc structure and strength. This has been done by reviewing current theoretical understanding of floc growth and breakage and an analysis of different techniques used for measuring floc strength. An overview has also been made of the general trends seen in floc strength analysis. The rate of floc formation is a balance between breakage and aggregation with flocs eventually reaching a steady-state size for a given shear rate. The steady-state floc size for a particular shear rate can, therefore, be a good indicator of floc strength. This has resulted in the development of a range of techniques to measure floc size at different applied shear levels using a combination of one or more of the following tools: light scattering and transmission; microscopy; photography; video and image analysis software. Floc strength may be simply quantified using the initial floc size for a given shear rate and the floc strength factor. More complex techniques have used theoretical modelling to determine whether flocs break by large-scale fragmentation or smaller-scale surface erosion effects, although this interpretation is open to debate. Impeller-based mixing, ultrasound and vibrating columns have all been used to provide a uniform, accurate and controllable dissipation of energy onto a floc suspension to determine floc strength. Other more recent techniques have used sensitive micromanipulators to measure the force required to break or compress individual flocs, although these techniques have been limited to the measurement of only a few hundred flocs. General trends emerge showing that smaller flocs tend to have greater strength than larger flocs, whilst the use of polymer seems to give increased strength to only some types of floc. Finally, a comparison of the strength of different types of floc (activated sludge flocs, organic matter flocs, sweep flocs and charge neutralised flocs) has been made highlighting differences in relative floc strength. 相似文献
7.
8.
9.
10.
有效应力决定饱和岩土材料抗剪强度的摩擦学解释 总被引:4,自引:0,他引:4
有效应力决定了岩土材料的变形和强度,有效应力概念虽然已在岩土工程中广泛应用,但是,对于决定饱和岩土材料抗剪强度的有效应力,其理论解释至今却并不充分且受到质疑。为此,通过文献分析,确定了宏观抗剪强度与粒间摩擦强度之间的正相关关系,并运用摩擦学中的黏着摩擦理论,推导了排水和不排水条件下,粒间接触面黏着结点的生长公式和抗剪强度公式。通过对比分析这两种条件下的应力状态对抗剪强度的作用影响,得到了与 Terzaghi 一致的有效应力表达式,并在此基础上,探讨了有效应力和有效应力原理的基本概念和定义。 相似文献
11.
12.
Detailed theoretical analyses have been performed on the elasto-plastic large-deflection behaviour of rectangular plates with complex modes of initial imperfection loaded in compression. The influence of the initial deflection on the performance of the plate, especially on the ultimate strength has been clarified. In the case of thin plates, one component of the initial deflection which becomes stable above the buckling load plays an important role in the collapse, and in the case of thick plates, the maximum curvature of the initial deflection influences the plastification process below the buckling load.Based on these observations, two methods, a deflection method for thin plates and a curvature method for thick plates, have been formulated and they have been shown to predict the ultimate strength of plates with very good accuracy. 相似文献
13.
配筋砌块砌体剪力墙抗剪承载力研究 总被引:4,自引:0,他引:4
对配筋砌块砌体剪力墙抗剪承载力进行了理论分析和试验研究。在综合分析影响配筋砌块砌体剪力墙抗剪承载力的各种因素的基础上 ,按结构可靠度设计原则 ,提出了配筋砌块砌体剪力墙抗剪承载力的设计计算公式。其计算结果与试验结果吻合较好。 相似文献
14.
15.
Simplified theoretical solution of circular toroidal shell with ribs under uniform external pressure
《Thin》2015
The toroidal shell with stiffened ribs is a new-style structure in ocean engineering especially in underwater engineering. This paper attempts to provide a simple theoretical method to obtain the stress solution of toroidal shell with ribs for its strength assessment. Firstly according to the structural property of toroidal shell with ribs and theory of curve-beam, a simple model for toroidal shell with ribs has been developed; then coupled with theory of thin-shell and elastic beam, its stress and deformation have been solved and can be expressed into analytic formulas; lastly by finite element method (FEM) and model experiment method, this simple theoretical solution has been verified to be reasonable and quite accurate. Thus this simple theoretical solution could be applied for analysis and design of pressure equipment in such toroidal structure type. 相似文献
16.
UH模型系列研究 总被引:2,自引:0,他引:2
岩土材料的本构模型是岩土工程学科的重要理论基础。合理的本构模型既能定性地揭示岩土的变形强度机制,也能定量地进行岩土体强度和变形计算。笔者20余年来潜心于土的本构模型研究,取得了以下3个方面的理论成果:1在修正剑桥模型的基础上,通过引入统一硬化(unified hardening,UH)参数,建立UH模型,该本构模型能够反映饱和超固结土的剪缩、剪胀、硬化、软化和应力路径相关性等特性,模型所用土性参数与修正剑桥模型完全相同;2扩展UH模型,使其考虑多种外部因素(温度、时间和基质吸力)、复杂特性(各向异性、结构性和小应变特性)和复杂加载条件(循环荷载、部分排水即渐近状态)等的影响;3提出广义非线性强度准则和满足热力学定律的变换应力三维化方法,从而实现了本构模型的合理三维化。UH模型已被嵌入到数值计算软件中,并被用于分析岩土工程问题。以上研究包括本构建模、强度准则、三维化方法和数值分析等方面,形成了独具特色的岩土本构理论和应用体系。 相似文献
17.
18.
轻质泡沫混凝土吸能特性及其压溃流动应力方程 总被引:3,自引:0,他引:3
轻质泡沫混凝土是一种拦阻冲出跑道飞机的重要阻滞材料,为了揭示其压缩力学性能及变形破坏机制,利用CSS4410电子万能试验机、Instron Dynatup9250落锤试验机以及VHS 8800高应变率系统,对密度为0.21、0.31 g/cm 3的轻质泡沫混凝土,在压缩速度2×10 -5~12 m/s范围内的力学特征、破坏及变形机理等进行了系统研究,用理论模型对不同压头面积下的挤压强度进行预测,并建立挤压压溃流动应力方程。结果表明:此材料变形、压溃碎化到压实过程中,以压溃前驱界面运动为特征,变形具有显著的局部失稳特性;压缩强度依赖密度和冲击速度;所采用的理论模型可以较准确的预测不同压头面积下的挤压强度;所建立的压溃流动应力方程可以很好的描述材料的压缩挤压力学特性。 相似文献
19.
Effects of three types of curing on coconut shell aggregate concrete have been studied for long term performance. The pore structure of coconut shell has been studied through scanning electron microscope (SEM). The pore structures in coconut shell behave like a reservoir. Intermittent curing produced the highest coconut shell aggregate concrete strength, followed by full water, and then by air-dry curing. Biological decay was not evident as the concrete cubes gained strength even after 365 days. Up to an age of 90 days, the samples under all types of curing conditions showed improved response on the pulse velocity and subsequently an insignificant drop. The ultimate bond strength of coconut shell aggregate concrete under all types of curing conditions was much higher compared to the theoretical bond strength as per BS 8110 and IS 456. Bonding between the cement paste and the coconut shell aggregate has been studied by measuring fissure between the coconut shell and the cement paste through SEM analysis. It shows a tendency of narrowing the fissure due to its age, which shows that the bond appears to be better between the coconut shell and the cement paste. 相似文献
20.
Experimental study on steel tubular columns in-filled with plain and steel fiber reinforced concrete
An experimental investigation on the structural behaviour of steel tubular columns in-filled with plain and steel fiber reinforced concrete is presented in this study. A total of 16 concrete-filled steel tubular columns were constructed and tested subjected to biaxial bending and short-term axial load. The main variables considered in the test study were the cross section, slenderness, concrete compressive strength and the load eccentricity. In the presented study, a theoretical method for the prediction of ultimate strength capacity and load-deflection curves of concrete filled steel tube columns is proposed. In the analysis procedure, the nonlinear behaviour of the materials is considered and the slenderness effect has been taken into account. The experimental ultimate strength capacities and load-deflection curves of both plain and steel fiber concrete-filled tube columns have been compared with the analysis results and discussed in the paper. The results indicate that the addition of steel fibers in core concrete has considerable effect on the behaviour of concrete-filled steel tube columns. 相似文献