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河南新乡铁西国家粮食储备库新建2栋粮仓 ,每栋粮仓平面结构尺寸为21m×60m ,建筑面积1296m2。采用先张法预应力拱板屋架 ,屋架实际长22.94m(两端各出轴线0.97m) ,宽1.98m。屋架下弦板为40mm厚平板(主筋48b5) ,上弦板为50mm厚抛物线型折线板(主筋21b5) ,上下弦板之间间隔2.1m ,用40mm厚混凝土隔板连接(图1)。上下弦板为C40 ,隔板为C20混凝土。根据工期要求及现场实际情况(建设单位无预制场地) ,经分析决定在高空一次定位现浇成型拱板屋架。为此将屋架在圈梁以外的8… 相似文献
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河南新县、新蔡等地国家粮食储备库工程 ,其屋盖结构设计均为预制18m跨拱板屋架。拱板下弦安装标高7.800m ,拱板平面尺寸为19.94m×1.98m ,矢高1.80m(图1)。其下弦板为平板 ,板厚40mm ;上弦板为抛物线弧板 ,板厚50mm。上弦板和下弦板的两侧均为70mm×150mm的肋梁 ,上下弦板间每隔1.8m用40mm厚预制隔板连接。拱板分布筋均为4LL550@150冷轧带肋钢筋 ,混凝土强度等级上下弦板为C40 ,隔板C20。由于拱板屋架跨度大 ,构件壁薄 ,结构刚度差 ,给制作、运输和吊装带来困难 ,经… 相似文献
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某国家粮食储备库工程为18m跨钢筋混凝土拱板屋盖结构,设计上拱板为二次抛物线薄板非预应力预制结构,全高1800mm,每榀宽1980mm。上下弦板采用C40混凝土,厚度为50mm和40mm,每1800mm用预制隔板连接。隔板采用C20混凝土,厚度为40mm,肋梁高150mm,宽60~70mm。上下弦板主筋为冷轧带肋钢筋CRB550(d=5mm)。两幢仓库共80榀拱板。如果采用预制方案,需占用大量场地硬化作底胎,费工费料,而且需等混凝土强度达到设计强度标准值的100%方可吊装,影响工期。采用高空原位现浇工艺,可以加快进度,又能确保拱板施工质量。拱板简图见图1。一、施工工艺1.隔板预… 相似文献
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本文以广西柳州粮食储备库工程作为工程实例,主要介绍了粮库屋架拱板的隔板预制、高处现浇平台搭设、上弦板模板支设的施工方法、施工工艺流程;拱板高处原位现浇施工、模板安装、钢筋绑扎和混凝土浇筑等施工技术。 相似文献
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锦州铁合金厂原料库工程24米跨的后张预应力屋架,采用了平卧式重叠法预制浇筑,用塑料布隔离。因屋架挑梁外侧的塑料布没铺好,有50毫米没隔离布,造成上、下两层屋架混凝土粘结。在张拉上层屋架时,由于张拉力作用,屋架下弦产生压缩,使屋架挑梁内侧混凝土受拉,产生裂缝。缝宽1毫米,长85 相似文献
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中美合资的百事亚洲饮料有限公司项目位于广州经济技术开发区东区 ,现已投产。其主厂房建筑面积为14 4 0 0 0m2 ,为单层排架结构 ,层高 7 5m ,6× 1 5m大型屋面预应力板 ,30m跨预应力钢筋混凝土折线型屋架。屋架是根据国家标准图集《预应力钢筋混凝土折线型屋架图集》G4 15(五 )制作。屋架共 5 6榀 ,均安排在现场平卧重叠预制 ,叠层一般为 3~ 4层 ,采用预应力后张法。1 裂缝产生原因分析屋架制作开始于 3月下旬 ,结束于 4月中旬。最早于 3月 31日发现 5号屋架上弦上表面 (平卧时 )出现横向裂缝 ,随后其他榀屋架也在上下弦陆续出现一… 相似文献
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针对顶部曲线较平缓的大跨度拱形钢结构,通过设置可抵抗拱方向荷载的张弦索和可抵抗反拱方向风吸力的斜索,形成了预应力张弦索-斜索钢桁架结构体系,同时改善了拱形结构体系在不同方向荷载作用下的受力性能。采用有限元分析与实际工程设计相结合方式,以西来峰煤化工分公司焦化厂二期储煤场封闭项目为例,对非预应力钢桁架结构体系、预应力张弦钢桁架结构体系、预应力张弦索-斜索钢桁架结构体系方案进行了体系选型研究。对上述3种结构体系的支座反力、主拱桁架弦杆轴力、结构竖向变形等方面进行对比分析,证明了张弦索-斜索钢桁架结构体系的优越性,同时针对预应力张弦索-斜索钢桁架结构体系进行了布索方案分析,分析改变张弦索和斜索锚固端位置对结构弦杆受力及变形的影响,得出了张弦索布索范围覆盖拱架上弦受压区、锚固端位置接近拱架曲率最大处时,斜索上锚固端在拱架跨度的35%~40%位置时,对结构最有利;另外对张弦索、斜索的初拉力取值进行了方案比选,得到了拉索初拉力取值对结构杆件内力的影响规律,确定了张弦索、斜索初拉力取值均为1000kN较为合理。 相似文献
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三主桁连续板桁组合桥空间计算方法研究 总被引:1,自引:0,他引:1
针对三主桁连续板桁组合桥的构造特点,通过构造结合梁单元的位移模式,利用势能原理推导结合梁单元的刚度矩阵,提出2种结合梁法,结合梁法一的特点是把桥面板作为主桁架弦杆的上翼缘并与主桁架弦杆形成钢-混结合梁,结合梁法二的特点是把桥面板作为纵、横梁的上翼缘并与纵、横梁形成钢-混结合梁;而常规的板梁组合法的特点是桥面板为连续各向... 相似文献
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Christoph Ackermann 《Stahlbau》2005,74(10):729-734
Building bridges with new materials: Pedestrian bridge over the Bayerstraße in Munich. For the pedestrian bridge across the Bayerstraße in Munich, grade S 690 high‐strength steel was used for the first time (fig. 1). The bridge provides a barrier‐free connection for pedestrians and cyclists between a local railway station, Hackerbrücke and the Theresienwiese, where the ‘Oktoberfest’ is held annually. It was planned as a hybrid arch construction and spans 38 meters, crossing a major traffic artery consisting of two tram lanes, four car lanes, two bicycle lanes and two footpaths. The use of circular hollow steel sections in this new grade S 690 resulted in a slim, elegant, lightly curved design with minimal dead weight. A spatial truss, rigid in torsion and made up of a concrete slab as upper chord, a circular steel section as bottom chord (grade S 690) and steel tubes as diagonal bracing between the two, serves to stabilize the arch. The bridge superstructure, including the concrete slab, was completely prefabricated and transported to the site in one piece on a low‐boarding truck. It took a mobile crane only a few hours to heave the bridge onto its supports. 相似文献
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《Construction and Building Materials》2000,14(1):7-16
A reinforced concrete pier manifested cracking and spalling at its top slab/wall joint, apparently due to twisting of the top 1.5-m-thick slab. The pier supports a kiln at one of its tires, through two steel rollers. Field and laboratory tests and structural analyses were performed to determine the cause and extent of the problem and to recommend a remedial measure. It was found that torsional moments result when the tire contacts with only one of the rollers on top of the pier. It was also found that the walls and top slab of the structure were not provided with adequate steel reinforcement to take care of the torsional moments. This, in addition to the low strength of concrete, has caused cracks to develop. The problem was solved by repairing the defective joint and other areas, and then casting a heavily-reinforced 240-mm-thick shotcrete jacket around the exterior of the structure. 相似文献
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山西省晋城市文体馆屋盖结构形式为双钢拱支承的球面钢结构,包括两个互相平行的桁架式钢拱、拱间的联系桁架和球面上由主次钢梁组成的屋面体系。屋面钢梁在外圈支承在预应力钢筋混凝土环梁上,在中间通过V形吊架与钢拱下弦连接。为了平衡钢拱的水平推力,在拱脚之间设计了预应力钢筋混凝土拉杆。 相似文献
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东莞生产力大楼依地势而建,分南、中、北三区,中区为总长105m、跨度30m的连跨拱桥建筑。针对该拱桥以及与之相联的斜桥的设计施工,做出论述。拱桥的主要特点:①拱桥的下弦为楼面,使用功能为宴会厅,拱桥的上弦为屋面,使用功能为屋顶花园。②斜桥分别从南区、北区办公楼的顶层斜向与拱桥的中部相联。③拱桥的宽度为22m,设置3榀桁架拱,桁架拱之间采用钢框架连接形式。④钢构件采用箱型截面。⑤桁架拱为连跨整体,设置若干现场拼接节点。 相似文献
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拱式转换层结构竖向受力分析 总被引:2,自引:0,他引:2
针对常用转换层结构的优缺点,提出拱式转换层结构,分析竖向荷载作用下该转换层的受力性能,由此提出应适当控制上、下弦杆线刚度比及拱高跨比,以供工程设计参考。 相似文献
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Shear Strength of Reinforced Concrete Members without Transverse Reinforcement A new theoretical model concerning the shear strength of reinforced concrete members without transverse reinforcement is presented, considering free‐bodies unilaterally bounded by a fictitious crack, inclined at π/4 to the tension chord and extending from the tension chord to the compression chord. It is assumed that the shear stress that can be transferred across a crack decreases linearly with the crack width and that the crack width at the level of the tension chord is proportional to the product of the tension chord strain at the crack and the chord distance. This results in a linear‐hyperbolic relationship between the shear strength and the (elastic) tension chord force at the crack, allowing to determine the governing crack location and other relevant quantities via equilibrium considerations. Due to potential strut or arch action for the transfer of loads applied in the vicinity of supports the crack location is somewhat restricted; it is assumed that the corresponding length is equal to twice the chord distance. 相似文献
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封丘国家粮食储备库扩建工程1号、2号仓屋盖系统采用先张法预应力带肋钢筋混凝土拱板,由于现场无室外预制场地,故利用仓内地面作为拱板制作场地,起重机进入仓内吊装就位,节省了场地,缩短了工期及构件养护、吊装时间,拱板质量良好。 相似文献