龙河特大桥墩梁结合部模型试验设计北大核心

龙河特大桥为大跨超高空心薄壁柔性墩连续刚构桥,为深入探究大桥墩梁结合部力学行为特点,对墩梁结合部开展1:6缩尺模型试验。针对结构及受力特点,对模型尺寸、预应力、配重、普通钢筋、加载和测试方案等进行设计。试验按照实桥实际工况进行加载,同时对墩梁结合部进行实体有限元分析。试验结果表明,龙河大桥试验模型设计合理、试验加载方法可行,并且试验结果能较好反映实桥墩梁结合部受力特点规律。介绍的模型试验设计与试验加载方法对同类结构模型试验具有借鉴作用。     

双斜塔双索面混合梁斜拉桥主梁钢-混结合部受力分析

鄂尔多斯4号大桥主桥为双斜塔双索面混合梁斜拉桥。该桥主梁宽高比大,主梁钢-混结合部构造和受力较为复杂。文章通过有限元法对钢-混结合部进行深入分析和研究,掌握了结合部钢与混凝土的应力分布情况、传力机理及承载能力性能,对应力集中部位进行了优化设计,确保结合部受力的可靠性和合理性。     

结合梁斜拉桥钢砼结合部应力传递分析

结合部是结合梁斜拉桥结构及材料的突变部位,构造及受力状态复杂,是桥梁设计的关键。该文结合武汉二七路三塔结合梁斜拉桥,建立结合部ANSYS有限元模型,针对运营过程中六种不利工况,分析结合部主应力分布状态及传递规律。结果表明,结合部整体呈受压及低应力状态,结合部应力满足设计要求。     

混合梁结合部受力机理模型试验研究

为揭示混合梁结合部的承载性能、破坏形态和受力机理,以主跨为818m的九江长江公路大桥为研究背景,选取混合梁压剪式结合部典型格室,并设计进行比较的承剪式结合部格室,开展了两个缩尺比为1∶2的结合部局部模型承载性能试验,测试了钢与混凝土的应变及相对滑移。研究结果表明:压剪式结合部承载能力是承剪式的两倍;压剪式结合部承压板传力约占总轴力的62.5%,承压板传力减小了钢格室应力,限制了钢-混凝土间相对滑移,降低了连接件传力比例,使结合部受力更合理。     

槽型梁-拱组合桥梁拱结合部局部应力分析

拱梁结合部是拱的推力、梁的内力和支承反力汇交之处，拱脚处局部应力分布相当复杂，是拱桥结构受力关键部位之一，为确保此类桥梁的安全性，有必要对拱脚空间应力分布特征及其传力安全性作深入的分析研究。文章以武汉轨道交通跨江岸货场槽型梁拱组合桥为背景，介绍了拱脚局部构造细节，并建立了梁拱结合部局部应力分析有限元模型，对其局部应力进行了分析。     

大跨度V形刚构拱组合桥V形墩梁节点模型试验研究

对于V形刚构拱组合结构桥梁,其结构本身承力、传力相对复杂,而在小榄水道特大桥主桥V形墩梁结合部,其受力尤其复杂。有必要通过模型试验对其局部应力以及开裂后的非线性受力行为进行研究,从而考察V形刚构拱组合桥设计的合理性,并为同类桥梁提供技术参考。简单介绍了模型的相似和设计原则,对模型的加载工况、加载程序、测点布置等也进行了讨论。重点通过对试验结果的分析以及与数值计算的比较,得出多种荷载工况下V形墩梁节点局部应力分布规律;通过绘制负弯矩区钢筋荷载应变曲线以及模型梁的荷载挠度曲线,对V形墩梁节点的非线性受力行为进行了研究,得出了挠度与裂缝分布规律。研究表明,V形墩梁节点受力合理,具有较好的延性、后续变形和残余承载能力,V形刚构拱组合桥设计合理。     

预制拼装式混合梁钢混结合段设计研究

荆岳长江公路大桥主桥为主跨816m双塔不对称混合梁斜拉桥,主梁钢混结合段采用带钢格室的部分连接填充混凝土形式。该文主要是对钢混结合段连接形式进行分析比选,对结合段细部构造如承压板、剪力键、钢格室、预应力筋等合理构造进行分析研究,最后通过受力计算分析,验证预制拼装式混合梁的安全性。     

某特大跨斜拉桥施工阶段主梁受力分析

通过有限元软件对某436 m跨径的宽桥面双塔双索面钢—混结合梁斜拉桥施工阶段的结构受力进行了分析,计算结果表明,在双悬臂施工阶段、单悬臂施工阶段以及安装桥面系阶段,桥梁的混凝土面板和钢主梁应力均满足规范要求,说明该桥施工阶段主梁安全可靠。     

非满跨错位剪力墙框支转换梁的受力性能

本文就一榀转换梁１／４缩尺模型在垂直荷载和水平荷载作用下的试验和有限元分析结果，对非满跨错位剪力墙框支转换梁的受力性能进行的研究表明，非满跨错位剪力墙不但降低了转换梁的剪跨比，改变了梁端约束状态和梁的受力状态，而且因错位剪力墙的受力特性与剪力墙错位，使梁处于拉、弯、剪、扭的复杂受力状态，从而导致梁在剪跨比较小区段出现剪切破坏。     

东风水电站地下厂房岩壁吊车梁的 二维分析及其检验

简要介绍了东风水电站地下厂房岩壁吊车梁结构的设计和实践，用有限元对岩壁吊车梁结构进行了较确切的二维分析，并和现场试验结果进行了对比，二者基本一致。结果表明吊车梁的主要承载构件受力很小，结构完全可靠。最后分析了吊车梁主要承载构件（斜拉锚杆）受力不大的力学原因。     

粘钢加固混凝土梁疲劳性能试验研究

为研究粘钢加固混凝土梁的疲劳性能,进行了2根粘钢加固梁及1根对比梁的疲劳试验。试验研究表明:在钢板与混凝土粘结完好的情况下,粘贴钢板加固较大地提高了梁的抗变形能力;与未加固梁相比,因钢板端部粘结失效,加固梁主筋断裂时的疲劳循环次数反而减少,也说明在粘贴钢板加固工程中,应注意保证钢板端部的良好锚固,使钢板与混凝土良好粘结,钢板才能充分发挥作用。     

软弱地基基础刚性组合梁的作用与理论推导

本文从实际出发 ,对软弱地基基础刚性组合梁的作用和理论推导作了阐述 ,通过实践和时间的检验 ,验证了软弱地基基础设置刚性组合梁 ,能有效地将上部结构的荷载均匀地传递给地基 ,地基沉降均匀 ,地基基础安全可靠 ,理论推导与实际吻合     

钢吊车梁设计中应注意的一些问题

对吊车梁的支座连接构造设计及双层翼缘板焊接工型吊车梁的某些受力特征等进行详尽论述,可作为吊车梁设计时的参考。     

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.     

Shear strengthening of RC beams with web-bonded continuous steel plates

This paper presents the results of an experimental program and a parametric study conducted on RC beams strengthened in shear with web-bonded continuous steel plates. An experimental investigation was conducted to assess the effectiveness of web-bonded continuous steel plates for shear strengthening of RC beams having internal stirrups. A two-dimensional nonlinear finite element model was developed to simulate the overall behavior of beams with epoxy bonded steel plates. In order to develop a design methodology for beams with web-bonded steel plates, a parametric study was conducted. Main parameters considered were concrete strength, plate thickness, plate depth-to-beam depth ratio, yield strength of steel plates, beam size and the internal shear reinforcement ratio. A formula to compute the shear strength of such beams was proposed by adding up the concrete contribution, shear reinforcement contribution and the contribution of steel plates. The validity of proposed formula was checked against the results from parametric study and the experiments. It was found that the proposed formula predicts the ultimate shear strength of RC beams with web-bonded continuous steel plates very well.     

Strengthening of reinforced concrete beams in shear by the use of externally bonded steel plates: Part 1 – Experimental programme

This paper describes a programme of research to investigate the behaviour of reinforced concrete beams strengthened in shear by means of externally bonded steel plates and hence to provide engineers with appropriate design guidance. The shear strengthening and testing to failure of 15 rectangular section reinforced concrete beams was conducted. To account for the different potential types of shear failure (diagonal tension, shear compression and deep beam failure) three shear span to depth ratios were used. A further 15 experiments were then conducted using ‘T’section beams. In most cases the addition of externally bonded shear plate reinforcement provided enhancement in shear capacity comparable with that provided by conventional internal shear links designed to BS8110 [British Standards Institute (BSI). Structural use of concrete, Part 1: Code of practice for design and construction. BS 8110: Part 1: BSI. London; 1997]. Measurement of the principal strains in the plated beams showed that as well as tensile and compressive strains due to bending, strains arising from an underlying shear crack are evident. Hence the plates serve to control crack opening and catastrophic shear failure up to a certain load level, when bond failure occurs in the concrete. The use of partial depth plates with T section beams does not appear to be as successful as the use of full depth plates on rectangular section beams.     

承受短期荷载的粘钢加固梁刚度与挠度研究

为研究粘钢加固对构件刚度的影响 ,通过试验对不同形式的粘钢加固梁在短期荷载作用下的破坏形态进行观察和分析 ;结合钢筋混凝土梁的相关理论 ,提出粘钢加固构件在短期荷载作用下的刚度和挠度计算公式。计算结果表明理论计算值与试验值吻合较好 ,可供粘钢加固设计参考     

Flexural behavior of strengthened steel–concrete composite beams by various plating methods

The effect of pre-intermediate separation on the flexural behavior of strengthened steel–concrete composite beams by either adhesively bonded carbon fiber reinforced polymers (CFRP) sheet or welded/bonded steel plate was studied. In the case of strengthened by CFRP sheet, two different attachment patterns, namely, CFRP sheet wrapped around the flange of the I-beam and CFRP sheet wrapped around the flange along with a part of the web, were examined by testing four different strengthened steel–concrete composite beams under four point bending (4PB). Two of these beams were strengthened by fully bonded CFRP sheet with the two different patterns, while, the others are similar but have pre-intermediate debonding area of 50 mm length × flange width at the bottom surface of the lower flange. In the case of strengthened by steel plate, three different attachment patterns of steel plate to the soffit of the beams, namely, discontinuously welded, end welded, and bonded/welded steel plates, were also tested under 4PB.The experimental results showed that, there is no growth of the intermediate debonding before the yield of the lower flange occurred for all strengthened beams by CFRP sheet. After yielding, the beams with pre-debonding area showed lower flexural capacity than those with fully bonding due to the rapid growth of the intermediate debonding. On the other hand, there is a difference in the yield load between the three different patterns of the welded steel plates with a marginal difference in the elastic stiffness.     

碳纤维板加固RC梁试验

以11片碳纤维板加固梁模型为基础,分析了在改变碳纤维板黏贴方式、混凝土强度以及构件剪跨比等因素的条件下梁的应力-应变规律,研究了碳纤维板对梁抗弯承载力的影响.试验结果表明碳纤维板对不同加固方案梁的承载力影响程度各不相同:梁端部有良好锚固措施时,其极限承载力显著提高;端部没有锚固措施时,其极限承载力主要与碳纤维板锚固长度有关,锚固长度越长,试件极限承载力提高也越显著;剪跨比相对较大和配筋率相对较小的加固梁极限承载力提高幅度更加显著.     

钢板-混凝土组合受弯加固梁疲劳性能试验研究

通过对8根钢板-混凝土组合受弯加固简支梁（以下简称组合加固梁）的等幅疲劳加载试验,研究了组合加固梁在疲劳荷载作用下的寿命及应变变化规律。试验结果表明：组合加固梁的疲劳破坏是由钢板裂纹从栓钉焊趾处开始缓慢扩展直至贯通导致的,与普通钢筋混凝土梁相比,组合加固梁的疲劳破坏具有较好的延性;钢板应力幅对组合加固梁的疲劳性能影响较大,实际设计时应严格控制钢板的应力幅和应力上限,不宜采用高强钢材和较薄的钢板;加固层预应力可有效提高组合加固梁的疲劳性能;按TB 10002.2-2005《铁路桥梁钢结构设计规范》中规定的焊有栓钉的受拉钢板的S-N关系对钢板-混凝土组合加固梁的钢板进行疲劳设计偏于安全。另外,提出了考虑应力水平影响的组合加固梁疲劳寿命的计算方法。图19表6参12