[中英文PPT]砌体结构设计原则

1、 Chapter 2 Design theory of masonry structures2.1 Review of the design method of masonry structures (砌体结构设计方法的历史回顾)2.2 Determination of the coefficient (分项系数的确定)12.1 Review of the design method of masonry structuresAncient experientialmethod古代经验法Allowable stress design method容许应力设计法Failure stage des

2、ign method破坏阶段设计法Limit state design method极限状态设计法Development process22.1 Review of the design method of masonry structures2.1.1 Allowable stress design method 容许应力设计法2.1.2 Failure stage design method 破坏阶段设计法Limit state design method 极限状态设计法 2.1.3 Limit state design method expressed with three coeffi

3、cients 三系数表达的极限状态设计法（ 1956年后） 2.1.4 Limit state design method expressed with many coefficients 多系数分析总系数表达的极限状态设计法（GBJ3-73） 2.1.5 Limit state design method expressed with partial coefficients 以分项系数表达的极限状态设计法（GBJ3-88） 2.1.6 Design method of the code for design of masonry structures 现有砌体结构设计规范的设计方法（GB5

4、0003-2001）32.1.1 Allowable stress design method General expressions： - stress of the element due to the load on the basis of the materials mechanics (按材料力学的方法计算构件在外荷载作用下的应力)， -Allowable stress of the masonry materials Safety coefficient k should be taken into accounted to ensure the structural safet

5、y.为保结构安全，根据经验引入一大于1的安全系数 K 则容许应力： Characteristics: simplicity, plasticity of the materials was not considered. (简单明了，但未考虑材料的塑性性能)。42.1.2 Failure stage design methodThe Failure stage design method was formally adopted by Soviet Union in 1943, in which the amend coefficient was introduced to consideri

6、ng the difference between the elastic calculated results and the experimental results.（引入修正系数调整弹性理论计算和破坏试验结果的差异，原苏联规范（Y-57-43）1943年正式采用按破坏阶段的设计方法.） General expressions：where，K is the safety coefficient according to the experience。At the beginning of the liberation, the failure stage design method wa

7、s adopted in some areas in China.（解放初期，我国部分地区采用前苏联规范按破坏阶段进行设计。） Characteristics: take into account the stress redistribution of the section, Load-bearing capacity of the whole section is the judge criterion. (考虑截面应力重分布后，以全截面承载力作为标准)。52.1.3 Limit state design method expressed with three coefficientsG

8、eneral expression:（considering the uncertainties of the load and variability of the material strength 考虑荷载的不确定性和材料强度的变异性）： three coefficients (三系数) （1）load coefficient n consider the load is beyond the statistics characteristic value (考虑统计荷载标准值的超载 )(图例) （2）material coefficient k variability of the m

9、aterial performance (考虑材料性能变异)（图例） （3）working coefficient m considering under different working condition the effect of the materials is changeable (考虑材料在不同工作条件下作用发挥程度)62.1.3 Limit state design method expressed with three coefficients Characteristics: considering the characteristics of statistical m

10、athematics, but the guarantee rate is uncertain.(引入了统计数学的概念，但无法定量确定所设计结构具有的保证率)。 After 1956, Limit state design method expressed with three coefficients was adopted in China.(1956年后我国砌体结构设计采用前苏联规范的三系数极限状态设计方法)Three kind of limit states: （1）Load-bearing capacity limit state (承载能力极限状态)； （2）Deformation

11、 limit state(变形极限状态)； （3）crack appearance and deformation development limit state (裂缝出现和变形开展极限状态)。72.1.4 Limit state design method expressed with many coefficients In 1973, Limit state design method of partial statistics and partial experience was adopted in China. 1973年砖石结构设计规范（GBJ373）半统计、半经验的极限状态设

12、计计算方法.the design expression of the load-bearing capacity: (承载能力设计计算表达式为)：where： K1 variability influence coefficient of the masonry strength 砌体强度变异影响系数（同类试件统计分析）K2 variability influence coefficient of the masonry strength lack of system experimental statistics 缺乏系统试验对砌体强度变异影响系数K3 influence coefficie

13、nt of laying quality (砌筑质量影响系数)82.1.4 Limit state design method expressed with many coefficientsK4 influence coefficient of deviation of dimension and calculated assumption (尺寸偏差，计算假定误差等影响系数)K5 variability coefficient of load(荷载变异影响系数)C combination coefficient (组合系数)Merit: analyze based on many coef

14、ficient and express based on single coefficient, calculate simplyShortcomings: the guarantee rate of the design element is uncertain.优点：以多系数分析、单系数表达确定安全系数，计算方便直观缺点：无法定量计算所设计的结构具有多少保证率。9 In 1988, Limit state design method based on the statistics theory was adopted in the “Code for design of masonry s

15、tructures ”（GBJ3-88）. Two ultimate limit states were considered in design according to the “Unified standard for reliability design of building structures ”（GBJ6884）（1）Load-bearing capacity limit state (assured by design and checking )（2）Serviceability limit state (assured by taking corresponding st

16、ructure measures in design)1988年我国砌体结构设计规范（GBJ388）采用了以概率理论为基础的极限状态设计法。以1984年颁布的建筑结构设计统一标准（GBJ6884）为依据，设计考虑了两种极限状态： （1）承载能力极限状态 设计验算保证 （2）正常使用极限状态 构造措施保证2.1.5 Limit state design method expressed by partial coefficient 102.1.5 Limit state design method expressed by partial coefficient Characteristics:

17、 the probability theory is considered when the structure is designed. The probability level is certain.(将概率理论引入结构的设计，可定量估计结构的可靠水平)， Calculated expressions of masonry structures based on the load-bearing capacity limit state 砌体结构按承载能力极限状态设计时的计算公式为：11Safety ClassesFailure resultsType of buildingClass

18、1Very seriousImportant buildingClass 2SeriousGeneral buildingClass 3Less SeriousSubsidiary buildingSafety classes of building structure2.1.5 Limit state design method expressed by partial coefficient 安全等级破坏后果建筑物类型 一级很严重重要的房屋二级严重一般的房屋三级不严重次要的房屋建筑结构的安全等级122.1.6 Design method in the “Code for design of

19、 masonry structures” （GB50003-2001）In 2002, Code for design of masonry structures was published.（GB50003-2001） The two main revised contents are listed as following: 1.Important coefficient and design working life are corresponding. 2.Composite expression composed mainly of gravity load effect is re

20、plenished and the reliable degree of the masonry structure is appropriately adjusted on the basis of the “Unified standard for reliability design of building structures ” GB500682002年我国颁布了新的砌体结构设计规范（GB50003-2001）采用分项系数表达的极限状态设计法局部修改（1）将结构重要性系数和设计使用年限对应；（2）针对砌体结构自重较大的特点，增加了以自重为主的荷载效 应组合计算公式；132.1.6 D

21、esign method in the “Code for design of masonry structures”Where masonry structure are designed as per limit state of load-bearing capacity , calculation shall be conducted on the basis of worst combination in the formulas below:Composite expression composed mainly of gravity load effectWhere masonr

22、y structures are considered to be a rigid body and required to check its stability of integrity, such as over turning, gliding, drifting, etc, the checking shall be conducted as per the following formula:(当砌体结构作为一刚体，需验算整体稳定时，例如倾覆、滑移、漂浮等，应按下列设计表达式进行验算)142.2 Definition of partial coefficient 分项系数的确定1、

23、the basis of definition of partial coefficient 确定分项系数的基础Design reference period：设计基准期（50年） Design working life 设计使用年限（100、50年）Function demand of structure, reliability and reliable degree 结构的功能要求、可靠性与可靠度 Function demand： safety serviceability durabilityReliability of the structure（结构可靠性）： The capaci

24、ty of the structure is scheduled to undertake within the prescribed time and on the prescribed conditions(结构在规定的时间内、规定的条件下完成预定功能的能力。)Reliable degree of the structure（结构可靠度）： The probability of the structure is scheduled to undertake within the prescribed time and on the prescribed conditions(结构在规定的时

25、间内、规定的条件下，完成预定功能的概率.)15Formulas of ultimate limit state （极限状态方程） Z R-Sg(R,S) Z0，that is RS，the structure is located in reliable state (表示结构处于可靠状态)； Z0， that is RS，the structure is located in failure state (表示结构处于失效状态)； Z0， that is RS，the structure is located in limit state (表示结构处于极限状态)。 2.2 Definiti

26、on of partial coefficient 16Probability of failure and reliability index （失效概率和可靠指标） 2.2 Definition of partial coefficient 17Probability of failure and reliability index （失效概率和可靠指标） 2.2 Definition of partial coefficient 18Safety ClassesDuctility FailureBrittle FailurepfpfClass 13.71.1x10-44.21.3x10-5Class 23.26.9x10-43.71.1x10-4Class 32.73.5x10-33.26.9x10-4 Masonry structure is brittle structure, the objective reliability index of load-bearing limit state is 3.7.(砌体结构属脆性结构