1、結構設計四分之一高度構造設定修正的原理astructuralengineeringprojectcanbedividedintothreephases :規(guī)劃、設計和構建。structuraldesigninvolvesdeterminingthemostsuitableproportionsofastructureanddimensioningthestructuralelementsanddetailsofwhich 確定結構最佳的比例尺寸，確定主要構件和細節(jié)的尺寸) thisisthemosthighlytechnicalandmathematicalphaseofastructural

2、engineeringproject。 butitcannotandcertainlyshouldnot-beconductedwithoutbeingfullycoordinatedwitheplanningandconstructionphasesoftheproject。 是項目工程中技術最高、數(shù)學嚴密性最強的階段，但與修訂和施工階段完全協(xié)調，不能合作就不應該付諸實行)。 thesuccessfuldesignerisatalltimesfullyconsciousofthevariousconsiderationsthatwereinvolvedinthepreliminaryplan

3、ningforthestructu ofthevariousproblemsthatmaylaterbeencounteredinitsconstruction特別是， thestructuraldesignofanystructurefirstinvolvestheestablishmentoftheloadingandotherdesignconditionsthatmustberesistedbythestruc ndthereforemustbeconsideredinitsdesign.(結構設置修訂需要首先確定結構所需的載荷和其他設置修訂條件。 他們是結構設定修訂的必要條件) th

4、encomestheanalysis (or computation ) oftheinternalgrossforces (thrust、shears、bending moments )。 失真實踐、失真、選擇、和重定向按加載、臨時、鏈接、創(chuàng)建， or other design conditions.(然后分析在負荷、溫度、收縮、徐變及其他設定修正條件下由結構產(chǎn)生的總內(nèi)力(軸力、剪切力、玩具、扭矩)、應力強度、應變、變形及反作用力) finallycomesproportioningandselectionofmaterialsofthembersandconnectionssoastore

5、sistadequatelytheeffectsproducedbythedesignc 的尺寸，由于抵抗選擇那個材料的設定修正條件的作用) thecriteriausedtojudgewhetherparticularproportionswillresultinthedesiredbehaviorreflectaccumulatedknowledge現(xiàn)場和模型測試， 與實踐行為)，實踐， and judgement直觀判別的方法) formostcommoncivilengineeringstructuressuchasbridgesandbuildings， theusualpracti

6、ceinthepasthasbeentodesignonthebasisofacomparisonofallowablestressintensitieswithoseproducedbytheserviceload inn ditions.(在橋梁和房屋等最一般的土木工程構造中，將許用應力與使用負荷和其他的設定修正條件下產(chǎn)生的應力進行比較是過去最一般的，并且根據(jù)它進行設定修正)。 thistraditionalbasisfordesigniscalledelasticdesignbecausetheallowablestressintensitiesarechoseninaccordance

7、withtheconceptthatttthatt pondingtotheyieldpointofthematerialshouldnotbeededatthemosthighlystressedpointsofthestructure.(原因選擇是， 此類傳統(tǒng)設置修訂基礎被稱為柔性設置修訂) of course theselectionoftheallowablestressesmayalsobemod orbrittlefractureorbyconsiderationofthepermissibledeflectionsofthestructuredependingonthetypeo

8、fstructureandtheconditionsinvolved是指： thestressintensitiescomputedbintheanalyticalmodeloftheactualstructurefortheassumeddesignconditionsmayormaynotbeincloseagreemen esproducedinactualstructurebytheactualconditionstowhichitisexposed .按設想的設定修正條件修正的應力強度和實際的結構在實際的條件下產(chǎn)生的應力強度可能一致或不一致thedegreeofcorresponde

9、nceisnotimportant，providedthatthecomputedstressintensitiescanbeinterpretedintermsofpreviousexperience. theselectionoftheserviceconditionsandallowablestressintensitiesprovidesamarginofsafetyagainstfailure.theselectionofthemagnitu hedegreeofuncertaintyregardingloading、analysis、design、materials、andcons

10、tructionandontheconsequencesoffailure.(儲備量值的選擇為相關負荷取決于施工和失效結果不真實自我的程度) For example，ifanallowabletensilestressof 20000 pisselectedforstructuralsteelwithayieldstressof 33000 psi。 themarginofsafety (orfactorofsafety ) providedagainsttensileyieldingis 33000/20000，或or 1.65.(例如，在結構鋼的情況下，屈服應力為330 )the allo

11、wable-stressapproachasanimportantdisadvantageinthatitdoesnotprovideauniformoverloadcapacityforallpartsandalltypesoos c As a result，thereistodayarapidlygrowingtendencytobasethedesignontheultimatestrengthandserviceability witholderallowable-stressapproachservingasanalternativebasisfordesign .由此，基于以往的容

12、許應力法的設定修正只是可選方案之一)。 thenewerapproachcurrentlygoesunderthenameofstrengthdesigninreinforced-concretedesignliteratureandplasticdesigninsteel -。 ture.(最新的設定修正方法在鋼筋混凝土設定修正規(guī)范中稱為強度設定修正，在鐵元素骨設定修正規(guī)范中稱為塑性設定修正) whenproportioningisdoneonthestrengthbasis， theanticipatedserviceloadingisfirstmultipliedbyasuitablel

13、oadfactor (greater than1)、themagnitudeofwhichdependsupontheuncertainty 可持續(xù)發(fā)展轉換基礎架構、與、加載組合、likelihood、frequency， anddurationoftheparticularcombination .結構服務期間發(fā)生變化的可能性和荷載組合中各負荷的相似性、出現(xiàn)頻率及其特殊組合的持續(xù)時間) inthisapproachforreinforced-concrete design thetheoreticalcapacityofastructuralelementisreducedbyacapacity-reductionfactortoprovideforsmalladversevariationsinmaterial hs thestructureisthenproportts dependingonthegove