【作者】 董振平；

【导师】 牛荻涛；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2011， 博士

【摘要】 在大型工业厂房设计中,钢管混凝土双肢柱因其突出的承载力、变形和延性性能得到广泛应用,其构件型式、构造措施在实际中也不断得到改进。近年调查研究中发现,钢管混凝土双肢柱的肩梁与吊车梁连接部位出现了严重缺陷,对厂房正常使用和生产造成不利影响。为克服肩梁与吊车梁连接方式上的缺陷以及满足大跨度、重载厂房的需求,两种带有新型肩梁的钢管混凝土双肢柱得到了应用,其肩梁分别为单腹板改进型和双腹板两种形式。由于应用时间不长,目前这两种肩梁的受力性能和破坏机理尚不明确,其承载力也无成熟的计算方法。因此,研究这两种新型钢管混凝土双肢柱肩梁的受力性能和设计方法,对于完善钢管混凝土柱的设计理论,推广钢管混凝土柱厂房的应用具有重要的理论意义和实用价值。论文以宝钢大型工业厂房中新型钢管混凝土双肢柱为研究对象,通过工程调查、试验研究和理论分析,系统研究了钢管混凝土双肢柱中单腹板改进型肩梁和双腹板肩梁的受力性能和破坏模式,分析了肩梁刚度对厂房受力的影响规律,提出了钢管混凝土双肢柱肩梁的实用设计方法。主要研究内容如下:1.现场调查了近300根新型钢管混凝土柱的肩梁形式和使用状况;选择边柱与中柱、单腹板与双腹板四种形式的肩梁作为原型构件,对其设计资料和实际状况进行详细调查和检测,为后期的试验研究和理论分析提供了第一手的原始数据。2.根据肩梁原型构件设计制作了八根肩梁试件,并进行了静力加载试验,研究了肩梁在整个受力过程中的变形规律、应力分布特点及破坏模式。试验结果表明,肩梁承载力与腹板剪应变密切相关;肩梁的破坏模式以肩梁受压侧腹板在剪应力作用下的整体屈曲为主,同时伴随上柱根部与肩梁上翼缘受压区域的局部屈服。其中,双腹板肩梁的腹板因存在内力分配不均衡现象而呈现单侧腹板首先屈曲的破坏模式。3.建立有限元模型,对肩梁试件的受力性能进行了计算分析。其分析结果与试验结果基本吻合,从而验证了肩梁有限元模型的合理性。利用该分析模型,对四种典型的肩梁原型构件进行了系统的有限元分析,揭示了肩梁形式、肩梁高跨比、肩梁腹板厚度等因素对承载力的影响。同时分析发现,双腹板肩梁原型构件具有较高的安全储备。利用肩梁原型构件的参数分析结果,按照肩梁破坏模式提出了钢管混凝土双肢柱的实用肩梁设计公式以及构造要求。相对于目前型钢柱肩梁的设计方法,该设计公式能更合理地反映钢管混凝土双肢柱新型肩梁的承载力,更好地控制新型肩梁设计的可靠性。4.通过对钢管混凝土柱典型排架的计算分析,系统研究了上柱与下柱高度比、肩梁高跨比、肩梁与上柱线刚度比等因素对柱侧移刚度、厂房位移、肩梁荷载的影响规律,提出肩梁刚度限值的建议值,即肩梁高跨比大于0.4,肩梁与上柱线刚度比大于1.0。满足此条件下肩梁刚度变化对厂房侧移、内力变化的影响甚小。论文对钢管混凝土柱肩梁的研究工作目前在国内外比较少见,所提出的实用设计公式和构造要求能够较好地满足新型钢管混凝土双肢柱的工程需要。同时研究成果也丰富和完善了钢管混凝土柱的分析和设计理论。更多还原

【Abstract】 Concrete-filled steel tube (CFST) Columns has been extensively applied in the design of large industrial plants for its outstanding bearing capacity, deformation and ductility performance, meanwhile its component types and structural measures are also constantly improved in practice. In recent surveys, there are some serious defects in the connection of CFST columns’shoulder beam and its crane beam, which brings adverse effect on the security of the plant. Now in order to overcome the defects mentioned above and to meet the demands of big span and overloaded plant, the two new CFST columns with the improved types of shoulder beams that are unilateral webbed shoulder beams and double webbed shoulder beams put into use. However, the improved types of shoulder beams have not been used for a long time, so their mechanical properties and failure mechanism are not clear, and the calculation method of bearing capacity is not mature. Therefore, the study on mechanical properties and failure mode of CFST columns has very important theoretical and practical significance for improving the design method of plant columns and popularizing the safety of plant.This paper regards the new types of both limbs CFST columns in BAOSTEEL large industrial plants as research object. Through the engineering survey, experimental study and theoretical analysis, the paper systematically studied the mechanical properties and failure mode of the two improved shoulder-beams, analyzed the regular pattern about the influence of shoulder-beams’stiffness on the bearing capacity, and put forward the practical design method of the shoulder-beams of both limbs CFST columns. The main results are as follows:First, we investigated nearly 300 new CFST columns to ascertain the forms of shoulder-beams and the use conditions, selected side pillar, center pillar, unilateral webbed beam and double webbed beam as the prototype components, then investigated and detected design information and the actual status in detail. All of above provided the first-hand raw data for the later experiment and theoretical analysis.Second, according to the prototype component of shoulder-beams, eight specimens were made for the static loading test. The deformation, the characteristics of stress distribution and the failure modes of shoulder-beams were studied in the test. The results showed that: the bearing capacity of shoulder-beams is closely related with the shear strain webs; the main damage phenomenon is overall buckling of shoulder-beam’s compressive webs, at the same time the local yield of the root of top beam and the compressive areas of shoulder-beam’s upper flange also appears. Because of the imbalance stress distribution, double webbed shoulder-beam appears the failure modes with the buckling of unilateral webbed beam.Third, the mechanical properties of the specimens were calculated through the finite element mode analysis. Result of the analysis agrees well with that of testing, which verifies the rationality of the finite element mode of shoulder-beams. Using this finite element mode, the four types of prototype components were analyzed systematically. It shows that some elements like the form, depth-span ratio and the thickness of webs have an effect on the bearing capacity of shoulder-beams. Meanwhile, the prototype components of the double webbed shoulder-beams have the high security reserves. Using the parameters’analysis results of the prototype components, the practical design formulas and structural requirements were put forward according to the failure modes of shoulder-beams. Compared with the current design method of steel columns’shoulder-beams, this design formula can more reasonably reflect the bearing capacity and control the reliability of the design of the improved shoulder-beams.Finally, through the calculation and analysis of the typical bent of the CFST columns, it also analysis the regular pattern of the influence of the height ratio of the upper and lower column, depth-span ratio of shoulder-beams, linear stiffness ratio of shoulder-beams on upper column on the column lateral stiffness, displacement of industrial buildings, shoulder-beams loads. The rigidity limit of shoulder-beams has been presented, that is to say, when the high-span ratio is greater than 0.4 and the linear stiffness ratio of shoulder-beams to upper column is greater than 1.0. The stiffness of shoulder-beams has a minimal impact on the column under such condition.At present, the study on the shoulder-beams of CFST columns is seldom discussed both at home and abroad. The practical design formulas and structural requirements put forward in the paper can well satisfy the engineering needs of new types of CFST columns with two limbs. Meanwhile, the research results also enrich and perfect the analysis and theory design of the CFST columns.更多还原