500kA铝电解槽支承主梁的设计研究

针对某工程500kA铝电解槽支承主梁结构形式的方案优选,采用综合评价法定量分析后,得出对于大跨度支承主梁采用箱型梁结构形式更加合理。分析计算了主梁所承受的载荷,并对主梁危险截面进行了校核计算,最后,利用ANSYS-Workbench有限元仿真平台进行模拟校核计算。结果表明,主梁的强度、刚度和稳定性均满足设计要求。     

钢筋混凝土矩形梁板配筋的实用设计计算方法

本文介绍了一种有关钢筋混凝土矩形梁板的截面设计及配筋计算方法，它在土建工程设计中既简便又实用，对于提高设计质量，设计效率有着十分现实的意义。     

基于疲劳强度设计的铸造起重机箱梁结构研究

偏轨箱形梁是大型铸造起重机主梁广泛采用的结构型式,工作级别为A5级以上的铸造起重机,应进行疲劳强度验算。本文依据起重机设计规范中关于主梁疲劳强度设计的具体细则,详细介绍偏轨箱形主梁疲劳强度计算的方法,同时介绍了提高主梁疲劳强度的若干措施。     

铝合金超静定矩形薄壁梁的刚度理论研究与数值计算

对两端固支闭口薄壁梁的刚度进行理论研究,得出任意闭口截面梁在加载处的抗弯刚度及抗扭刚度计算公式,进而推导出矩形薄壁梁抗弯刚度及抗扭刚度的理论计算公式。通过算例对不同壁厚铝合金矩形薄壁梁的抗弯及抗扭刚度进行理论及数值计算,得出理论与数值的计算结果相同,从而验证了理论的正确性,为客车的矩形梁设计提供了一定的基础。     

工业与民用建筑中钢筋温凝土单筋梁的优化设计

提出了钢筋混凝土单筋梁优化设计方法。该法以梁单位长度的造价为目标函数；以规范对单筋梁的正、斜截面强度及构造要求为约束条件；以梁截面尺寸，主筋直径、根数，箍筋直径、间距等为设计变量。最后对各分项的经济性做了分析比较。     

铸造起重机端梁铰接轴联接固定结构的改进设计

八钢二炼钢区域的大吨位冶金铸造起重机为四梁四轨双小车结构,在使用过程中出现连接固定失效、铰接轴非正常磨损的情况。起重机端梁铰接点连接失效会造成起重机主梁与副梁分离的严重设备事故。介绍了对原设计的结构方式进行的改进设计,改进后消除了铰接连接失效的事故隐患。     

变截面钢吊车梁挠度计算的近似公式

对于变截面钢吊车梁,一些设计手册中仅给出了一种变截面形式的梁在特定条件下的挠度计算公式、。本文利用共轭梁法提出现有各种开荒为截面钢吊车梁挠度计算的一般公式,同时论证了吊车梁挠度计算的一般公式只能是近似式。     

箱型桥式起重机主梁焊接CAPP系统的开发

分析了箱型桥式起重机主梁制造工艺设计现状,讨论了工艺设计内容、要求和流程,以及主梁焊接CAPP系统的基本要求,提出一种基于数据库的主梁焊接CAPP系统结构。采用Delphi编程,开发了基于开放式数据库的桥式起重机主梁焊接CAPP系统,可以完成主梁制造工艺设计。该CAPP系统可以加快工艺设计速度和效率、提高设计质量和继承性,为工艺设计标准化和最优化创造了条件。     

60m跨箱形吊车梁结构设计

在吊车梁的设计中由于跨度太大,且梁高受到限制,决定采用箱形钢吊车梁,阐述了梁的构造要求及应重点考虑的问题。     

大型铸造起重机选型及安全维护策略探讨

大型铸造起重机按照起重机主梁结构划分,主要有四梁四轨型式和四梁六轨型式两种型式;按照主起升机构的结构划分,可以分为整体减速器和行星差动三减速器结构型式.介绍了两种主梁结构铸造起重机的型式及主起升机构减速器的特点,明确主起升机构关键部件的维护方式以保证大型铸造起重机的安全运行,同时对大型铸造起重机的结构、主起升机构以及安全装置的选型提出建议.     

Literature Review in Analysis of Box-Girder Bridges

The curvilinear nature of box girder bridges along with their complex deformation patterns and stress fields have led designers to adopt approximate and conservative methods for their analyses and design. Recent literature on straight and curved box girder bridges has dealt with analytical formulations to better understand the behavior of these complex structural systems. Few authors have undertaken experimental studies to investigate the accuracy of existing methods. This paper presents highlights of references pertaining to straight and curved box girder bridges in the form of single-cell, multiple-spine, and multicell cross sections. The literature survey presented herein deals with: (1) elastic analysis, and (2) experimental studies on the elastic response of box girder bridges.     

Design for Shear in Curved Composite Multiple Steel Box Girder Bridges

Modern highway bridges are often subject to tight geometric restrictions and, in many cases, must be built in curved alignment. These bridges may have a cross section in the form of a multiple steel box girder composite with a concrete deck slab. This type of cross section is one of the most suitable for resisting the torsional, distortional, and warping effects induced by the bridge’s curvature. Current design practice in North America does not specifically deal with shear distribution in horizontally curved composite multiple steel box girder bridges. In this paper an extensive parametric study, using an experimentally calibrated finite-element model, is presented, in which simply supported straight and curved prototype bridges are analyzed to determine their shear distribution characteristics under dead load and under AASHTO live loadings. The parameters considered in this study are span length, number of steel boxes, number of traffic lanes, bridge aspect ratio, degree of curvature, and number and stiffness of cross bracings and of top-chord systems. Results from tests on five box girder bridge models verify the finite-element model. Based on the results from the parametric study simple empirical formulas for maximum shears (reactions) are developed that are suitable for the design office. A comparison is made with AASHTO and CHBDC formulas for straight bridges. An illustrative example of the design is presented.     

武钢烧结整粒系统三次筛箱梁故障分析及处理

针对四烧整粒筛分系统三次A、B直线振动筛箱梁反复出现开裂的现象,通过现场振幅测量分析,认为两筛所受激振力偏大、中间轴变形及箱梁本身结构等问题是引起箱梁开裂的主要原因.通过对激振器偏心块、中间轴及箱梁进行相应处理和改进,有效地解决了箱梁开裂问题,提高了设备作业率,确保了烧结机正常生产.     

Shear Strength of a Lightweight Self-Consolidating Concrete Bridge Girder

Lightweight self-consolidating concrete (LWSCC) is advantageous in the bridge industry because members made with this material have a significantly lower self-weight, and in its fresh state, LWSCC has a low viscosity which eliminates the need for vibration during fabrication. A composite section was fabricated with a single precast bulb-tee LWSCC beam and a lightweight concrete cast-in-place deck. A simply supported test configuration was constructed with two point loads to quantify the web-shear strength of the girder. The experimental shear strength is compared to four analytical models from different AASHTO specifications. Based on the results of this limited study, the theoretical predictions for the web-shear strength of this girder were all conservative when compared to the experimentally measured failure strength. With these results in mind, further research is recommended on the use of LWSCC girders in the bridge industry to better understand the material properties, structural properties, and cost advantages.     

Distribution of Wheel Loads on Continuous Steel Spread-Box Girder Bridges

Composite concrete-steel spread (multispine) box girder bridges remain one of the most common types constructed. Current design practices in North America recommend few analytical methods for the design of such bridges in simply supported construction. However, the effects of continuous construction have not been dealt with fully. In designing a continuous bridge, it is important to determine the maximum negative and positive stresses, maximum reactions, and shears in the bridge subjected to various loadings. This paper presents an extensive parametric study using a finite-element model in which 60 continuous bridge prototypes of various geometries, each subjected to various loading conditions, are analyzed for the distribution of flexural stresses, deflection, shears, and reactions. The parameters considered in the study are span length, number of spread boxes, and number of lanes. Distribution factors for maximum flexural stresses, deflection, shears, and reactions, suitable for design, are deduced for AASHTO truck loading. Results from tests on five box girder bridge models verify the finite-element model. A design example is presented to illustrate the use of the deduced formulas for the distribution factors.     

Examination of Level of Analysis Accuracy for Curved I-Girder Bridges through Comparisons to Field Data

To evaluate the accuracy of different levels of analysis used to predict horizontally curved steel I-girder bridge response, a field test was performed on a three-span structure. Collected strain data were reduced to determine girder vertical and bottom flange lateral bending moments. Experimental moments were compared to numerical moments obtained from three commonly employed levels of analysis. Level 1 analysis includes two manual calculation methods: a line girder analysis method described in the AASHTO Guide Specification for Horizontally Curved Highway Bridges, and the V-load method. Grillage models represent Level 2 and were created using three commercially available computer programs: SAP2000, MDX, and DESCUS. Level 3 consists of three-dimensional (3D) finite element models created using SAP2000 and the BSDI 3D system. Responses obtained from each level are compared and discussed for a single radial cross section of the structure, and the compared results involve truck loads and placement schemes that do not represent those used for bridge design. The field test and numerical data presented are used solely to determine the accuracy of each level of analysis for predicting structure response to a specific live load at a specific cross section. Results showed that Level 2 and Level 3 analyses predict girder vertical bending moment distributions more accurately than Level 1 analyses throughout the tested cross section. The comparisons indicate that Level 3 girder vertical bending moment distributions offered no appreciable increase in accuracy over Level 2 analyses. The study also indicates that both Level 1 and Level 3 analyses provide bottom flange lateral bending moment distributions that do not correlate well with field test results for the studied bridge cross section.     

Research on Finite Element Determinant of Orthotropic Plate in Steamlined Steel Box Girder

A new type of streamlined girder bridge with orthotropic plates steel box girder is evaluated via testing and analysis. Although the use of finite element modeling has become indispensable for the detailed calculation of certain details and connections, an analytical approach remains a very effective method to determine the internal forces and moments in the box girder. Two new theoretical analysis models are undertaken to study the behavior of aimed bridge. The FE determinants of the two models are built. The validity of the proposed methods is checked by full finite element calculation using shell elements. In addition, a total experimental model is set up to verify the reliability of computational models. The computation results compare well with the experimental results. It is illustrated that it is an effective method to predict properties of this kind of bridges.