筒仓新型桁架支撑平台研究

发布时间：2018-03-15 12:24

本文选题：筒仓仓顶　切入点：旋转盘口　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着经济的发展,筒仓结构因其贮存方便、贮存容量大得到越来越广泛的应用。在筒仓的设计和施工过程中,仓顶施工是其中的重点和难点。目前国内外学者对筒仓仓顶支撑平台的研究多集中在满堂架形式,或空间桁架加中心井架形式,仍需依赖竖向支撑,施工安装不便,因此有必要对仓顶支撑平台展开详细的研究。本文提出了一种新型旋转盘口式桁架支撑平台,该体系形式简单、传力路径明确、组装拆卸方便、可重复利用,采用空间水平支撑,摆脱了竖向支撑,能弥补其他支撑平台的不足,大大缩短了工期,提高了安全保障。对新型旋转盘口式桁架构件进行试验,包括杆件试验、球节点试验,分析构件的承载力和失稳情况。结果显示受拉试件组承载力最大,断面发生颈缩现象,承载力满足要求;三组压缩杆件均发生不同程度的压弯失稳,压弯失稳发生钢管中间部位。三组受压球节点试件,屈曲位置发生在球节点与钢管链接的焊缝附近;所有试件的承载力均满足设计和使用要求,可用于桁架结构。对21m直径新型旋转盘口式桁架进行足尺试验,并根据试验进行有限元分析,验证桁架承载力,探寻桁架变形规律,为新型旋转盘口式桁架的推广使用和施工提供依据。结果表明21m直径新型旋转盘口式桁架在周边设置一圈拉索情况下所能承受最大荷载为2260kN;杆件连接间隙对桁架挠度和杆件应力影响较大,分析中采用刚度折减来考虑连接间隙等因素的影响;有限元分析结果表明旋转盘口式扣件桁架计算值与试验值吻合较好,说明建模和计算方法行之有效。根据21m直径新型旋转盘口式桁架进行足尺试验和有限元分析模型,对30m直径新型旋转盘口式桁架进行有限元分析,研究其能否满足施工要求,并对其行进施工安全分析。结果表明30m直径的筒仓可以采用旋转盘口桁架支撑平台进行仓顶施工,平台承载力满足施工要求;对结构进行施工安全分析,在第二阶段施工中当应力最大的拉索连续失效时,结构仍能满足承载力要求;在第三阶段施工中当应力最大的拉索连续失效时,结构仍具有较高承载力,所以对第三圈拉索进行优化设计,经对比分析发现,第三圈拉索为12根时为最优方案,既能保证结构有一定的安全性,又节省材料方便施工。
[Abstract]:With the development of economy, silos have been widely used in the design and construction of silos because of their convenient storage and large storage capacity. The construction of silo roof is one of the key and difficult points. At present, most of the researches on silo roof supporting platform are concentrated in the form of full roof frame or space truss plus central Derrick, which still depend on vertical support, so it is inconvenient to install in construction. Therefore, it is necessary to carry out detailed research on the roof support platform. In this paper, a new type of rotary disc mouth truss support platform is proposed, which has the advantages of simple form, clear force transfer path, convenient assembly and disassembly, and can be reused. The horizontal space support is used to get rid of the vertical support, which can make up for the deficiency of other supporting platforms, shorten the time limit greatly, and improve the safety and security. The test of the new type of rotating disc mouth type truss member, including the test of the bar and the test of the ball joint, is carried out. The results show that the bearing capacity of the tensile specimen group is the largest, the necking of the section occurs, the bearing capacity meets the requirements, and the three groups of compression members have different degrees of compression and bending instability. The buckling position of three groups of compressed spherical joints occurs near the weld of the connection between the ball joint and the steel pipe, and the bearing capacity of all the specimens meets the requirements of design and application. It can be used in truss structure. The full-scale test of 21m diameter rotating diskhead truss is carried out, and the finite element analysis is carried out according to the test to verify the bearing capacity of truss, and to find out the deformation law of truss. The results show that the maximum load of 21m diameter new rotary diskhead truss is 2260kNwhen a circle of cable is installed around the truss, and the connection clearance of the member to the truss is provided. The deflection and the stress of the bar are greatly affected. In the analysis, stiffness reduction is used to consider the influence of the connection clearance, and the finite element analysis results show that the calculated value of the rotary disc opening fastener truss is in good agreement with the experimental value. According to the full-scale test and finite element analysis model of the 21m diameter new rotary diskhead truss, the paper makes a finite element analysis of the 30m diameter new rotary diskhead truss, and studies whether it can meet the construction requirements. The results show that the silo with 30m diameter can be constructed by rotating disc mouth truss support platform, the bearing capacity of the platform can meet the construction requirements, and the construction safety of the structure can be analyzed. In the second stage of construction, the structure can still meet the bearing capacity requirements when the cable with the greatest stress fails continuously, and in the third stage, when the cable with the greatest stress fails continuously, the structure still has a higher bearing capacity. Therefore, the optimum design of the third circle cable is found by comparison and analysis. It is found that the optimal scheme is 12 cables in the third circle, which can not only guarantee the safety of the structure, but also save materials for construction.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU731

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