九江长江大桥横隔板制造安装施工技术

本桥横隔板为实腹式构造。由上、下两块组成,上接板与下接板直接对接。板单元制造时上接板与顶板一起组焊,梁段组装时,上接板与下接板间采用熔透对接的方式连接。钢箱梁横隔板制作发展从搭接型式开始,相继出现了全断面仰焊型式及横向熔透对接型式。根据横向熔透对接型式横隔板的结构特点,通过对横隔板下接板采用二次切割、上接板模块定位、上下接板连接采用工艺导向板定位、焊接工艺优化及配套工装完成横隔板的制作和安装,在桥梁界率先提出了一套完整的创新工艺技术。     

Bending analysis of folded plates by the FSDT meshless method

In this paper, a meshfree Galerkin method that is based on the first-order shear deformation theory (FSDT) will be introduced to analyse the elastic bending problem of stiffened and un-stiffened folded plates under different loadings and boundary conditions. Folded plates are regarded as assemblies of plates that lie in different planes. The stiffness matrices of the plates are given by the meshfree method. Employing the element concept, which is borrowed from the finite element method, and treating every plate as a big element, the global stiffness matrix of the whole folded plate is obtained by superposing the stiffness matrices of the plates. This is about the same for the analysis of stiffened folded plates. They are considered as assemblies of stiffened plates. The stiffness matrices of the stiffened plates are also given by the meshfree method. Superior to the finite element methods, no mesh is required in determining the stiffness matrices for the plates and the stiffened plates in this paper, which means time-consuming and accuracy-suffering remeshing is entirely avoided for problems such as large deformation or crack propagation in folded plates or stiffener position changes of stiffened folded plates. To demonstrate the accuracy and convergence of the method, several numerical examples are calculated by it and the finite element commercial software ANSYS. Good agreement is observed between the two sets of results.     

纤维水泥板和硅钙板生产线主机设备安装方案优化探讨

介绍了纤维水泥板和硅酸钙板生产线主机设备安装的重点,按照纤维水泥板和硅酸钙板产品特点,力求在安装阶段就按照正确的方式进行,减少因安装误差过大造成的返工及废料损失,规范纤维水泥板和硅酸钙板行业主机设备安装程序.     

IC debonding resistance of groups of FRP NSM strips in reinforced concrete beams

The use of fibre reinforced polymer (FRP) externally bonded (EB) plates in the form of pultruded and wet lay-up plates is now generally accepted as an efficient and unobtrusive technique for retrofitting reinforced concrete structures and is applied worldwide. However, EB plates, and in particular EB pultruded plates, tend to debond at strains much lower than their fracture strains. An alternative technique of adhesively bonding pultruded plates or strips in narrow grooves sawn into the concrete cover, that is near surface mounted (NSM) plates or strips, is now gradually gaining acceptance as tests have shown that the debonding strains can be much higher than that for EB plates. However, tests have also shown that NSM plates can interact with adjacent parallel NSM plates to cause intermediate crack (IC) debonding of groups of NSM strips at reduced strengths. This paper develops a mathematical model for the IC debonding resistance of groups of NSM plates for use in the flexural and shear strengthening of reinforced concrete beams.     

开椭圆孔板的应力分析

运用复变函数保角变换求解无限大板开有椭圆孔时的孔边界处的应力分布规律,通过对开椭圆孔有限板的有限元分析,找出开椭圆孔有限板的应力分布与开椭圆孔无限板的应力分布的关系,达到用开孔无限板求解开孔有限板的目的。     

Inelastic buckling behavior of stocky plates under interactive shear and in-plane bending

Inelastic buckling and postbuckling behavior of stocky plates under combined shear and in-plane bending stresses are investigated and compared to slender plates. Aluminum and steel plates having various slenderness ratios are modeled and analyzed by means of (i) numerical nonlinear finite element method and (ii) theoretical p-Ritz energy method; and both results are compared to the classic interaction equation. It is observed that whereas in slender plates, elastic buckling occurs prior to the material's proportional limit load, stocky plates buckle in an inelastic way within the post-yield stage. In contrast to slender plates with considerable postbuckling reserves, the buckling of stocky plates is immediately followed by softening. In addition, it is shown that the classic interaction equation overestimates buckling loads; and therefore, a modified equation that can safely be applied to both stocky and slender plates is proposed.     

Thermal stress measurement in steel plate strengthened by CFRP and aluminum alloy plates

In steel members strengthened by carbon-fiber reinforced polymer (CFRP) plates, the thermal stresses are introduced in the steel members, the CFRP plates and the adhesive layers when temperature changes because the linear thermal expansion coefficients of steel and CFRP are mismatched. As so far, the authors proposed a technique to reduce the thermal stress in steel members strengthened by CFRP plates, which involves bonding aluminum alloy plates with CFRP plates. In the proposed method, the thermal stress in steel member can be reduced so that there are negligible levels of stress in steel member when the cross sectional areas of CFRP and aluminum plates are designed to correspond to the coefficient of thermal expansion of steel, even though the thermal stresses are introduced in the CFRP and aluminum plates. In this study, to confirm the maintaining the thermal stress reduction in steel member by proposed method, thermal stress measurement in steel plate strengthened by CFRP and aluminum plates was carried out about 21 months. In this research, the thermal stress introduced in the steel plate strengthened by CFRP plates was also measured. Furthermore, to assume the thermal shear and normal (peel) stresses in adhesive layers, FE analysis with plane stress element was employed. As the result, it was shown the thermal stresses in steel plate with CFRP plate were able to calculate by using composite theory and measured temperature. Furthermore, in steel plate strengthened by CFRP and aluminum plates, the thermal stress introduced in steel plate was negligible-small through the all-season. It was found the thermal stresses in steel plate with CFRP plates as well as CFRP and aluminum plates were also estimated by using composite theory and measured temperature. In the steel plate strengthened by CFRP and aluminum plates, the thermal shear and normal stresses in adhesive layer glued to steel plate become smaller than that in the conventional CFRP bonded specimen. However, the shear stress in adhesive layers between CFRP and aluminum plates in proposed method was higher than the thermal stress in adhesive layers between CFRP plates in conventional method.     

外贴CFRP板加固锈蚀钢板疲劳性能试验研究

为研究外贴CFRP板对锈蚀钢板疲劳性能的影响,开展16个CFRP板加固锈蚀钢板试件的疲劳拉伸试验,研究锈蚀程度、CFRP刚度、CFRP预应力度、端部锚固及疲劳应力幅对CFRP板加固锈蚀钢板疲劳破坏模式、疲劳寿命及裂纹扩展规律的影响.研究结果表明,外贴CFRP板可以显著提升锈蚀钢板疲劳寿命,对质量损失率为9.38％、13...     

厚钢板加固混凝土梁抗弯性能试验研究

本文通过5根加固梁试验,对采用10mm厚钢板、多层粘贴薄钢板及单层粘贴薄钢板粘钢加固混凝土梁的抗弯性能从多方面进行了对比试验研究,试验结果表明,在增强锚固保证钢板与混凝土梁协同工作条件下,可采用厚钢板粘贴实现大加固量加固。     

Elastic buckling of perforated plates under shear

Finite element studies aimed at computing the buckling coefficient for plates containing cut-outs and subjected to shear are reported. The cases considered are:

1. 1. Square and rectangular plates with central circular cut-outs.

2. 2. Square plates with centrally placed rectangular cut-outs.

3. 3. Square plates with eccentrically placed circular cut-outs.

4. 4. Square plates with reinforced circular cut-outs.

5. 5. Square plates with reinforced rectangular cut-outs.

Simply supported plates as well as clamped plates have been studied and approximate formulae for the use of designers have been suggested for the practical cases where the hole dimension is generally not greater than half the width of the plate.     

A Four-Variable First-Order Shear Deformation Theory Considering the Variation of In-plane Rotation of Functionally Graded Plates

This paper presents a four-variable first-order shear deformation theory considering in-plane rotation of functionally graded plates. In recent studies, a simple first-order shear deformation theory was developed and extended to functionally graded plates. It has only four variables, separating the deflection into bending and shear parts, while the conventional first-order shear deformation theory has five variables. However, this simple first-order shear deformation theory only provides good predictions for simply supported plates since it does not consider in-plane rotation varying through the thickness of the plates. The present theory also has four variables, but considers the variation of in-plane rotation such that it is able to correctly predict the responses of the plates with any boundary conditions. Analytical solutions are obtained for rectangular plates with various boundary conditions. Comparative studies demonstrate the effects of in-plane rotation and the accuracy of the present theory in predicting the responses of functionally graded plates.     

预应力FRP板加固混凝土结构研究进展

介绍预应力FRP板加固混凝土结构的国内外研究现状 ,FRP板的力学特性及预应力的施加方法 ,预应力FRP板加固混凝土、板梁的试验研究成果 ,FRP板加固混凝土梁的承载力计算方法等。     

A closed form formula to predict the ultimate capacity of pitted mild steel plate under biaxial compression

The aim of the present paper is to investigate the effects of pitting corrosion on the ultimate capacity of mild steel rectangular plates under biaxial compression, extending earlier results of uniaxially loaded plates. A series of non-linear FEM analysis of plates with partial depth corrosion pits are carried out, changing geometrical attributes of both pits and plates, i.e., the radius, depth and location of pits and the slenderness of plates. Simulation results show that volume loss dominates the degradation of the compressive capacity of pitted mild steel plates as well as loading ratio. Plate slenderness has considerable effect on biaxial interaction curve shape. A regression analysis of FEM results is conducted leading to a closed form formula able to predict the remaining strength of pitting corroded plates, where both volume loss and plate slenderness are taken into account. The proposed formula will facilitate a quick estimation of the remaining strength of pitting corroded plates during lifetime ship design phase which is relevant to maintenance decision-making of aging ship structures and components.     

基于ANSYS的SP板极限承载力的非线性有限元分析

本文运用ANSYS对SP板进行模拟,研究了极限荷载作用下SP板的裂缝、应力和应变,数值计算结果表明运用ANSYS对SP板进行数值模拟是可行的。为以后进行类似相关方面的研究积累了经验,对实际工程中的SP板受力分析有一定的指导意义。     

竖向浅埋锚锭板的侧向极限拉拔荷载

锚锭板是一种承受土体被动抗力的结构单元,常用于支挡结构、板桩锚固和管线转弯处的设计和施工。本文采用一种描述锚锭板极限拉拔荷载的统一表达式,根据砂土中锚锭板试验结果的统计分析、粘土中锚锭板有限单元上下限解结果和试验资料的整理,给出了锚锭板极限拉拔荷载统一表达式中相应参数的取值范围。该统一表达式可直接应用于锚锭板极限拉拔荷载的估算,也可进一步应用于其它地埋结构(如侧向受荷桩)的弹塑性分析。     

Debonding of steel plates adhesively bonded to the compression faces of RC beams

Reinforced concrete beams in buildings and bridges are increasingly being retrofitted by adhesively bonding steel or FRP plates to their tension faces. However, tests have shown that tension face plates are prone to premature debonding. One way of preventing or inhibiting debonding of tension face plates in continuous beams is to extend the plate-ends past the points of contraflexure into the compression faces. In this paper: it is shown that compression face plates are less likely to debond than tension face plates; results of thirteen tests on debonding due to vertical shear forces (critical diagonal crack debonding) and curvature (flexural end plate debonding) are described; and critical diagonal crack and flexural end plate debonding models are developed for compression face plates that can be used to ensure that beams with tension face plates that are extended into the compression faces do not debond prematurely.     

钢板带加强型型钢混凝土低矮剪力墙抗震性能试验研究

为进一步改善一字型内置竖向型钢混凝土低矮剪力墙的抗震性能,设计和完成了2个剪跨比为1.0的钢板带加强型内置竖向型钢混凝土低矮剪力墙低周往复水平加载试验,并与1个未设置钢板带的内置竖向型钢混凝土低矮剪力墙进行对比分析。试验结果表明:钢板带的设置使剪力墙的水平承载力有显著提升,极限位移角提高20%左右,满足了相关规范极限位移角大于1/100的要求;钢板带的设置使试件破坏模式发生变化,总耗能有大幅度提升;钢板带的设置要适度,不能过强,以免形成新的薄弱区。     

The influence of complex initial deflection modes on the behaviour and ultimate strength of rectangular plates in compression

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.     

拱型波纹钢屋盖小波纹板等效弯曲刚度试验研究

以梯形和矩形截面的银河拱型波纹钢屋盖为研究对象 ,把小波纹板简化成正交各向异性平曲板 ,通过弯曲试验 ,得到了反映小波纹板两个方向抗弯刚度的荷载 -挠度曲线和等效弯曲弹性模量 ,并与平板进行了比较     

Numerical study on the permissible gap of intermittent fillet welds of longitudinally stiffened plates under in plane axial compression

Intermittent fillet welding of stiffeners to plates and its influence on the collapse behaviour of stiffened plates is investigated applying the finite element method. Special attention is paid to the modelling of the fillet welds at the plate-to-stiffener junction. Some available experimental results are simulated in order to obtain reliable numerical results. A series of numerical analyses of stiffened steel plates subjected to an in plane axial compressive load has been performed. Stiffened plates are selected from the deck structure of real sea-going ships and inland waterway vessels. Complete equilibrium paths are traced up to collapse for the non-linear elastoplastic response of stiffened plates. Finally a proposal is presented for the permissible gap of welds in intermittent fillet welding of stiffened plates.