Yog vim li cas rau qhov zoo tib yam pob zeb tawg:
1. Kev tawg los ntawm kev thauj khoom
Cov kab nrib pleb uas tsim los ntawm cov pob zeb hauv qab cov pa zoo li qub thiab cov dynamic loads thiab cov kev ntxhov siab thib ob yog hu ua cov kab nrib pleb, uas tuaj yeem ua tiav raws li cov kab nrib pleb ncaj qha thiab cov kab nrib pleb theem nrab. Cov kab nrib pleb ncaj qha hais txog cov kab nrib pleb uas tsim los ntawm kev ntxhov siab ncaj qha los ntawm cov khoom siv sab nraud, thiab cov kab nrib pleb theem nrab yog hais txog cov kab nrib pleb uas tsim los ntawm cov kev ntxhov siab thib ob los ntawm cov khoom sab nraud. Cov yam ntxwv ntawm cov kab nrib pleb nyob rau hauv load sib txawv nrog txawv loads thiab tam sim no yam ntxwv sib txawv. Cov kab nrib pleb zoo li no feem ntau tshwm sim hauv thaj chaw nruj, thaj chaw shear lossis qhov chaw vibration hnyav. Txawm li cas los xij, nws yuav tsum tau taw qhia tias yog tias muaj tev lossis tawg luv luv raws li cov kev taw qhia compression hauv thaj chaw compression, nws feem ntau yog ib qho cim qhia tias cov qauv tau mus txog qhov txwv ntawm nws cov kabmob muaj peev xwm thiab ua ntej rau kev ua haujlwm tsis ua haujlwm. Yog vim li cas feem ntau yog qhov loj me me dhau.
2. Kev tawg los ntawm qhov kub thiab txias:
Qhob muaj cov cuab yeej ntawm thermal expansion thiab contraction. Thaum qhov chaw sab nraud lossis qhov kub thiab txias ntawm cov qauv hloov, cov pob zeb yuav deform. Yog tias qhov deformation raug txwv, kev ntxhov siab yuav tshwm sim hauv cov qauv. Thaum qhov kev ntxhov siab tshaj qhov ua vaj tse tensile lub zog, kub tawg yuav tshwm sim. Hauv qee qhov txuas txuas ntev, qhov kub thiab txias tuaj yeem ncav cuag lossis ntau tshaj qhov kev ntxhov siab nyob. Lub ntsiab feature ntawm qhov kub thiab txias tawg uas txawv lwm cov kab nrib pleb yog tias lawv yuav nthuav los yog kaw nrog qhov kub thiab txias
3. Kev tawg los ntawm shrinkage:
Nyob rau hauv qhov tseeb engineering, cov kab nrib pleb tshwm sim los ntawm shrinkage ntawm pob zeb yog feem ntau. Ntawm cov hom pob zeb shrinkage, yas shrinkage thiab shrinkage (qhuav shrinkage) yog lub ntsiab yog vim li cas rau lub ntim deformation ntawm pob zeb, thiab kuj muaj autogenous shrinkage thiab carbonization shrinkage.
Yas shrinkage tshwm sim thaum lub sij hawm tsim kho thiab li ntawm 4 mus rau 5 teev tom qab cov pob zeb pouring. Lub sijhawm no, cov cement hydration cov tshuaj tiv thaiv yog khaus, cov saw hlau molecular tau maj mam tsim, los ntshav thiab dej evaporate sai, thiab cov pob zeb ua rau poob vim poob dej. dab dej, yog li cov pob zeb tseem tsis tau hardened, uas yog hu ua yas shrinkage. Qhov loj ntawm cov yas shrinkage yog loj heev, txog li 1 feem pua. Yog hais tias lub aggregate raug thaiv los ntawm steel bar thaum lub sij hawm sinking txheej txheem, cov kab nrib pleb raws cov kev taw qhia ntawm steel bar yuav tsim. Nyob rau hauv vertically variable seem ntawm cov tivthaiv, xws li cov hlws ris ntawm lub web ntawm lub T beam thiab lub thawv girder thiab lub sab saum toj thiab hauv qab daim hlau, cov kab nrib pleb nyob rau hauv lub web kev taw qhia ntawm lub nto yuav tshwm sim vim uneven sinking ua ntej hardening. Yuav kom txo tau cov yas shrinkage ntawm cov pob zeb, cov dej-cement piv yuav tsum tau tswj thaum lub sij hawm tsim kho kom tsis txhob muaj kev ntxhov siab ntev, cov khoom yuav tsum tsis txhob raug txiav sai heev, qhov kev vibration yuav tsum ntom, thiab qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv yuav tsum yog. ncuav nyob rau hauv txheej.
Shrink kom ntsws (ua thiab ntsws), tom qab cov pob zeb tsim nyuaj, raws li cov txheej saum toj kawg nkaus ntawm cov av noo evaporates zuj zus, cov av noo zuj zus tuaj, qhov ntim ntawm cov pob zeb txo qis, yog hu ua thiab shrunk kom ntsws (ua kom ntsws). Vim tias qhov poob sai sai ntawm cov dej noo ntawm qhov chaw ntawm cov pob zeb thiab qhov kev poob qis, qhov tsis sib xws tshwm sim nrog qhov loj ntawm qhov shrinkage thiab me me hauv shrinkage. Qhov saum npoo shrinkage deformation yog txwv los ntawm cov pob zeb sab hauv, ua rau cov pob zeb saum npoo los tuav lub zog tensile. , shrinkage tawg tshwm sim. Shrinkage tom qab hardening ntawm pob zeb yog tsuas yog shrinkage. Piv txwv li, rau cov khoom uas muaj qhov sib npaug loj (ntau dua 3 feem pua), qhov kev txwv ntawm qhov kev txhawb nqa ntawm lub qhov txhab ntawm cov pob zeb yog pom tseeb dua, thiab cov kab nrib pleb yog qhov ua rau tawg ntawm cov pob zeb.
Autogenous shrinkage, autogenous shrinkage yog cov tshuaj tiv thaiv dej ntawm cov cement thiab dej thaum lub sij hawm hardening txheej txheem ntawm pob zeb. Qhov shrinkage no tsis muaj dab tsi ua rau cov av noo sab nraud, thiab nws tuaj yeem ua tau zoo (uas yog, shrinkage, xws li portland cement pob zeb) lossis tsis zoo. (xws li nthuav dav, xws li slag cement pob zeb thiab ya tshauv cement pob zeb).
Carbonization shrinkage yog lub shrinkage deformation tshwm sim los ntawm cov tshuaj tiv thaiv ntawm carbon dioxide nyob rau hauv cov huab cua thiab cement hydrate. Carbonization shrinkage tsuas yog tshwm sim thaum cov av noo yog li 50 feem pua, thiab nws yuav nrawm dua li qhov concentration ntawm carbon dioxide nce. Carbonization shrinkage feem ntau tsis suav.
Cov pob zeb shrinkage yog cov yam ntxwv los ntawm qhov tseeb tias feem ntau ntawm lawv yog cov kab nrib pleb, qhov tawg qhov dav kuj yog nyias, thiab lawv yog criss-crossed, tawg thiab tsis zoo nyob rau hauv cov duab.
4. Kev tawg los ntawm lub hauv paus deformation:
Vim yog qhov tsis sib luag ntsug lossis kab rov tav hloov pauv ntawm lub hauv paus, kev ntxhov siab ntxiv yog tsim nyob rau hauv cov qauv, tshaj lub peev xwm tensile ntawm lub pob zeb, uas ua rau tawg ntawm cov qauv.
5. Kev tawg los ntawm steel corrosion:
Vim yog cov pob zeb tsis zoo lossis tsis txaus ntawm cov txheej txheem tiv thaiv, cov pob zeb tiv thaiv txheej yog eroded los ntawm carbon dioxide thiab carbonized rau saum npoo ntawm steel bar, uas txo cov alkalinity ntawm cov pob zeb nyob ib ncig ntawm lub steel bar, los yog vim muaj kev cuam tshuam ntawm cov hlau bar. chlorides, cov ntsiab lus ntawm chloride ions nyob ib ncig ntawm lub steel bar yog siab, uas yuav ua rau oxidation ntawm lub steel bar Lub membrane raug puas tsuaj, thiab cov hlau ions nyob rau hauv lub steel bar reacts nrog oxygen thiab noo noo intruded rau hauv lub pob zeb, thiab Lub ntim ntawm cov xeb hlau hydroxide nce li ntawm 2 mus rau 4 npaug piv nrog cov thawj, yog li tsim kev nthuav dav ntawm cov pob zeb uas nyob ib puag ncig, ua rau tawg thiab tev ntawm cov txheej tiv thaiv pob zeb, tawg tshwm sim longitudinally raws steel bar, thiab xeb seeps. nyob rau hauv lub pob zeb nto. Vim yog corrosion, qhov zoo ntawm qhov chaw seem ntawm lub steel bar yog txo, lub binding quab yuam ntawm lub steel bar thiab lub pob zeb yog tsis muaj zog, lub structural bearing muaj peev xwm raug txo, thiab lwm yam ntaub ntawv ntawm cov kab nrib pleb yuav induced, uas yuav aggravate lub corrosion ntawm steel bar thiab ua rau cov qauv kev puas tsuaj. Txhawm rau tiv thaiv corrosion ntawm steel tuav, qhov dav ntawm cov kab nrib pleb yuav tsum tau tswj raws li cov kev cai tshwj xeeb thaum lub sij hawm tsim, thiab cov thickness txaus ntawm cov txheej tiv thaiv yuav tsum tau saws (ntawm chav kawm, txheej tiv thaiv yuav tsum tsis txhob tuab heev, txwv tsis pub qhov siab zoo ntawm cov khoom yuav raug txo, thiab qhov dav ntawm qhov tawg yuav nce ntxiv thaum siv zog); Tswj cov dej-cement piv ntawm cov pob zeb, ntxiv dag zog rau kev co, ua kom lub compactness ntawm cov pob zeb, tiv thaiv cov pa oxygen nkag, thiab nruj me ntsis tswj tus nqi ntawm admixture uas muaj chlorine ntsev, tshwj xeeb tshaj yog nyob rau hauv ntug hiav txwv dej los yog lwm qhov chaw uas muaj zog corrosive huab cua thiab dej hauv av.
