| When it comes to the second order effect, people often mention that thesecond-order effects of structure under the bearing capacity limit state. From thedomestic and foreign research so far is concentrated in the20th century, is mainlystudying the second-order effect of the structure under the bearing capacity limit state.But with the development of modern industry, concrete structure in large span and largespace direction development, coupled with the increasing popularity of high-strengthsteel used, the normal usage limit state has gradually become the control index ofstructure design. Therefore, second order effects in the normal usage limit state on theinfluence of the structure, it is very necessary. In this paper, based on the project "forthe "specification design of concrete structures"GB50010-2010design method ofsecond-order effect follow-up study of the problem" of standard specification that oneof the legacy of further research work, which makes serious gap about considering themethods of the second-order effects between calculating the maximum crack width ofthe eccentric compression member under the normal usage limit state and the bearingcapacity limit state. To address this serious gap considering of the second-order effectsmethods in both states in the same specification, this thesis mainly made the followingwork and discussion:(1) By way of summarizing related provisions on the second-order effect underthe bearing capacity limit state and considering the second-order effect when calculatingthe maximum crack width of eccentric compression member under the normal usagelimit state in Chinese national codes and regulations of vision1989,2002and2010,illustrates this a few of the version of the specification about the characteristics of thesecond order effect rules, understanding and analysis the background of second ordereffect in codes and regulations. Follow-up question on the2010specification of thedesign methods about the second-order effects were summarized, pointed out theprovisions of the second-order effects that easily make engineering misunderstood hasnot corrected under the normal usage limit state, instructions the method consideringsecond-order effects is unreasonable in specification when checking maximum crackwidth of biasing member.(2) Summarized the background knowledge in the research of reinforced concretemember crack, through analysis and illustrates the required prerequisite about calculating the maximum crack width of the eccentric compression member usingDesign of Concrete Structures eccentric compression member calculated maximumcrack width.(3) A series of eccentric compression columns cracks trials is summarized whichdeformation cracks in the project team is responsible for the unit was tested. Based onthe test data, checking eccentric compression column`s maximum crack width using themaximum crack width formula in Design of Concrete Structures and make acomparative analysis with experimental data.(4) Establish structural model which needs considering second-order effects whencalculating pillars crack width under the normal usage limit state, make an analysis ofthe pillars about its crack under the normal usage limit state. Calculated the crack widthof pillars using the formula belongs to the2010version of the specification, analysissummary the calculation results.(5) Analysis the influence of second-order effects to the structure using finiteelement analysis software ETABS9.7.4under the normal usage limit state, and testingthe applicability of the second-order effect using the method of l0under the normalusage limit state in the specification of2010edition.(6) After induction, summarized and theoretical analysis, put forward three kindsof design of the proposed provisions which can be chosen by the specifications setconsidering the second-order effect when calculating the maximum crack width of theeccentric compression member under the normal usage limit state. |
PDF Full Text Request