共查询到20条相似文献，搜索用时 15 毫秒
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Dennis Lam 《Journal of Constructional Steel Research》2007,63(9):1160-1174
In steel-concrete composite beams, the longitudinal shear force is transferred across the steel flange/concrete slab interface by the mechanical action of the shear connectors. The ability of the shear connectors to transfer these longitudinal shear forces depends on their strength, and also on the resistance of the concrete slab against longitudinal cracking induced by the high concentration of shear force. Most of the research in composite construction has concentrated on the more traditional reinforced concrete and metal deck construction, and little information is given on shear capacity of the headed studs in precast hollowcore slabs. In this paper, a standard push test procedure for use with composite beams with precast hollowcore slabs is proposed. Seven exploratory push tests were carried out on headed studs in solid RC slabs to validate the testing procedures, and the results showed that the new test is compatible with the results specified in the codes of practice for solid RC slabs. Once a standard procedure is established, 72 full-scale push tests on headed studs in hollowcore slabs were performed to determine the capacities of the headed stud connectors in precast hollowcore slabs and the results of the experimental study are analysed and findings on the effect of all the parameters on connectors’ strength and ductility are presented. Newly proposed design equations for calculating the shear connectors’ capacity for this form of composite construction are also be given. 相似文献
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Dennis Lam 《钢结构》2008,(3)
在钢-混凝土组合梁中,剪切连接件的机械作用使得纵向剪力转移到钢翼缘/混凝土板的接合处。这种转移能力取决于剪切连接件的强度和混凝土板抵抗由剪力高度集中所导致的纵向开裂的能力。大多数对组合结构的分析都集中在传统的钢筋混凝土和金属面板结构,而对预制空心板中栓钉的剪切能力研究很少。本文对带栓钉的预制空心板组合梁结构提出标准的推力试验方法。一共进行7组测试性试验,试验结果显示新方法符合钢筋混凝土楼板规范要求。在确定这个新的标准方法后,对栓钉进行了72个足尺推力试验,确定了该类型连接件的性能,通过分析试验结果,还指出了各类参数对连接件强度和延性的作用。本文还提出了这种剪力连接件的设计公式。 相似文献
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预应力混凝土空心板桥加固设计 总被引：1，自引：0，他引：1
针对某空心板桥部分截面极限承载力不满足规范要求,需予以补强、加固的情况,提出了因地制宜的改造加固方案,并详细介绍了粘贴钢板加固的计算方法,以期指导该桥加固工作。 相似文献
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《Structural Concrete》2017,18(4):607-617
As a result of poor‐quality sealing, moisture and deicing agents had penetrated into the prestressed hollow‐core slabs of the top floor of an uncovered parking deck. The slabs showed especially severe chloride‐induced damage in the support regions near the joints. Owing to the damage, the theoretical shear capacity according to the technical approval of these slabs was highly questionable. The influence of the damage on the shear capacity of the slabs with different levels of damage was determined with the help of an experimental in situ loading test. Based on the results, the number of slabs that had to be replaced or repaired could be reduced. For the experimental investigation of the shear capacity of the hollow‐core slabs, a combination of photogrammetry, acoustic emission analysis, and curvature measurement for each section was used to determine the initial shear damage on a very low level during the test. The comparison of the results of the different measuring techniques allowed the damage processes to be clearly identified and significantly increased the quality of information about the structural condition of the slabs during the experimental investigation. 相似文献
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介绍了用条带法分析钢筋混凝土双向板和预应力混凝土双向板的简化计算方法，通过对短边长度为4．8m，跨厚比为40的矩形板进行对比，指出在适当跨厚比条件下，预应力混凝土双向板可以更好地控制裂缝和挠度。 相似文献
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火灾下钢结构楼板的薄膜作用 总被引：6，自引：0，他引：6
通过对真实火灾中的足尺火灾试验和观察显示，合组合楼板和承载钢梁的建筑物的结构承载力比现行杭大设计方法的建议值高出许多。因此规范中规定所有承载钢梁都要添加被动防火保护是不必要的。现行设计方法和实际结构性能之间产生这种差异是由于设计方法中忽略了楼板的薄膜作用。本根据国外有关资料给出了几种简单计算方法，允许在钢结构杭大设计中考虑楼板的薄膜作用。从而可以更精确地评估火灾下建筑物的真实承载能力，在给定的耐火时间内能减少相当数量钢梁的防火保护。 相似文献
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介绍一种适用于地下基坑围护的新型预制混凝土围护桩:预应力工字型桩.通过研究工字型桩受弯作用下桩身裂缝出现、发展情况及变形特征,分析其承载力及破坏特征.试验表明:预应力工字型桩满足规范要求的检验标准,有一定安全储备,但当桩身出现裂缝后截面刚度损失较大,对其抗弯性能有较大影响. 相似文献
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预应力钢筋混凝土密肋夹芯保温屋面板将结构承重和屋面保温隔热合为一体,保温隔热材料夹于密肋楼盖之中,密肋采用轻集料保温混凝土.通过分析得到了这种结构的设计计算和施工验算方法,并对这种新型结构的热工指标和经济指标进行了研究.研究结果表明,这种屋面结构既充分发挥了预应力空心板的低价优势和密肋楼盖的结构优势,又利用夹芯保温隔热... 相似文献
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针对预应力混凝土管桩的性能特点,结合工程实例,对其竖向及水平向承载力的影响因素进行了分析,并根据其影响因素,对预应力混凝土管桩的设计、施工提出了合理化建议。 相似文献
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《Beton- und Stahlbetonbau》2018,113(3):174-183
Influence of lateral constraint on the loadbearing and deformation characteristics of hollow core slabs in fire Prestressed hollow core slabs (HC slabs) are used particularly as ceiling systems in building construction for economic reasons. In 2007, a fire incident in a car park in Rotterdam caused partial detachment of the bottom concrete layer [1]. This resulted in a Europe‐wide discussion on the fire safety assessment of this type of construction. By now, many expert opinions, literature analyses and recent research on the fire resistance of constructions of prestressed hollow core slabs exist [2]. In the investigations, the bearing behaviour of HC slabs with rigid support, in particular with regard to the lateral force bearing capacity, was investigated among other things. Until now in the testing and evaluation of prestressed hollow core slabs in fire the obstruction of thermal induced lateral expansion is hardly considered. In practice, in case of fire an obstruction of the lateral expansion of the HC slabs may occur, if there is a very stiff boundary around the fire‐exposed ceiling area, e.g. by staircase cores or surrounding ceiling areas without any fire exposure. To investigate this question, appropriate experimental and numerical investigations were carried out at BAM on ceilings made of prestressed concrete hollow core slabs with different lateral restraint [3]. This article describes in detail the fire tests carried out in real scale and the results obtained from these tests. The investigations carried out at BAM have shown that with an increase in the lateral constraint, the horizontal cracking in the webs of the HC slab increases and the longitudinal cracking decreases. Despite the distinctive horizontal crack formation, the fire tests did not show a detachment of the bottom concrete layer. Likewise, there was no negative influence of the horizontal cracks on the load‐bearing and deformation behaviour of the fire‐stressed ceiling construction. The results from the fire tests will be available for the validation of numerical models in the future. 相似文献
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Miłosz Jeziorski;Wit Derkowski;Elena Michelini; 《Structural Concrete》2024,25(5):3412-3429
Precast prestressed hollow core (HC) floors are widely used in various applications within the construction sector. Such floors are usually designed as single, simply supported elements, although it is known that individual elements forming the floor interact with each other. This article presents the state of the art regarding load redistribution in HC floors in the light of experimental data, current analytical models and code provisions. While this phenomenon is widely known and recognized, only sparse, and often poorly documented experimental data are available, which represent the basis for the assessment and calibration of analytical models. Moreover, even though the available models and code provisions share similar assumptions, their outcomes are in some cases conflicting. Having recognized the existing knowledge gap, the authors outline future perspectives for the development of consistent analytical and numerical approaches supplemented by new experimental data. 相似文献
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This paper proposes a multi-level assessment strategy for reinforced concrete bridge deck slabs. The strategy is based on the principle of successively improved evaluation in structural assessment. It provides a structured approach to the use of simplified as well as advanced non-linear analysis methods. Such advanced methods have proven to possess great possibilities of achieving better understanding of the structural response and of revealing higher load-carrying capacity of existing structures. The proposed methods were used for the analysis of previously tested two-way slabs subjected to bending failure and a cantilever slab subjected to a shear type of failure, in both cases loaded with concentrated loads. As expected, the results show that more advanced methods yield an improved understanding of the structural response and are capable of demonstrating higher, yet conservative, predictions of the load-carrying capacity. Nevertheless, the proposed strategy clearly provides the engineering community a framework for using successively improved structural analysis methods for enhanced assessment in a straightforward manner. 相似文献
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我国客运专线列车设计时速将达到350km,路基轨道两侧声屏障受到的脉动力也随之增大,传统插板式声屏障采用螺栓连接的钢立柱易出现螺栓松动和钢材锈蚀等现象,为此,采用预应力混凝土立柱(PC)替代钢柱则不仅能有效解决这些问题,而且,PC柱比普通混凝土柱的抗裂、抗疲劳性更优越。此外,考虑声屏障施工工效,提出了预制PC立柱的两种快速装配连接形式,即插入式后浇连接和螺栓连接。通过4个立柱试件的模拟正负列车风压及台风风压的双向推覆荷载试验,表明了插入式连接PC立柱的插入深度达到1.5倍截面高度时,在台风的设计荷载作用下,立柱不会开裂,立柱顶部侧向位移小于L/250,结构近似保持弹性工作状态;螺栓连接PC立柱满足非台风地区时速350km客运专线路基声屏障的设计要求。 相似文献
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对集中荷载下,6个无抗剪钢筋的钢筋混凝土桥悬臂板进行试验研究。构件与实际箱梁桥甲板板层的比例是3/4,总长10m,净悬臂长2.78m,变厚度(悬臂的固定端为380mm,末端为190mm)。构件的配筋率为0.60%和0.78%。所有的试验均为集中荷载周围剪切破坏而导致的脆性破坏形式。基于线弹性剪力场,对各种试验的结果进行研究,利用试验和数值结果,提出了对钢筋混凝土桥悬臂板剪切强度进行评估的实用建议。 相似文献
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某科技馆通过大跨度过廊把两个主体混凝土框架结构连成统一建筑整体。大跨度过廊由于其一部分功能兼作常设展厅,为保证人走在上面的舒适度采用混凝土楼盖,这区别传统的钢板楼盖的天桥过廊。因此,通过对这种科技馆大跨度的过廊采用全钢结构整体方案和连体预应力网格结构方案进行比较,采用MIDAS设计软件对两种方案进行多遇地震反应谱分析及罕遇地震作用下的静力弹塑性(Pushover)分析,针对层间位移角、塑性角分布等对结构性能评估,并综合考虑施工可行性及投资。 相似文献