Ukukhusela i-armature ekorozini
Ngokwe-Eurocodes zangoku kucacisiwe ubuncinane ubukhulu bomaleko okhuselayo wekhonkrithi (cnom). Ubukhulu baloo maleko wekhonkrithi bubuncinane bomgama ukusuka kumphezulu ongaphandle wendawo enekhonkrithi eqinisiweyo ukuya kwinginginya yokuqala yentsimbi yokuqinisa. Kwizinto zomgca yileyo stirrup, yaye kwizinto zomphezulu yile yokuqinisa ubude esezantsi. Umaleko okhuselayo ogama lingu nominal uchazwa ngolu hlobo: cnom = cmin + Δcdev
cmin ngumaleko omncinane wokhuselo obekiweyo, ixabiso lawo lixhomekeke kwiimeko zokubambelela kwekhonkrithi nentsimbi yokuqinisa, iimeko zokusingqongileyo, iingubo ezikwithayile yokuqinisa, njl. Δcdev lixabiso elimele ukutenxa ekwenzeni. Ngokuxhomekeke kwiklasi yokuvezwa kwelungu lekhonkrithi eyaqiniswa kukho amaxabiso ahlukeneyo omaleko wokhuselo oqhelekileyo; ngokuqhelekileyo usukela ku-2,5 cm ukuya ku-3,5 cm. Kwiindlela zokusekwa kusetyenzwa ukuba yi-5cm.
Ukuziphatha kodaka lwesamente nekhonkrithi xa kufudunyezwa kwaye kupholiswa rhoqo
Amandla ekhonkrithi entsha anokunyuswa ngokukhawuleza ngokuyifudumeza kancinci-kancinci ngomphunga okanye ngokuyibamba emanzini afudunyezwa ngokuthe ngcembe, aze emva koko apholiswe kancinci. Ngale ndlela, emva kwenkqubo yosuku olunye kuvela amandla afumaneka kuphela emva kweeveki ezininzi kwindlela eqhelekileyo. Iqondo lesehlo lixhomekeke kwisamente nakuhlobo lwe-aggregate, kodwa nangona kunjalo ngekhonkrithi eyonqenayo kufunyanwa iziphumo ezingcono kakhulu kunale inamafutha.
Kwimeko apho ukufudumeza nokupholisa kwenziwa kwimida ebanzi, kuya kuvela uxinzelelo olukhulu kwilungu lekhonkrithi ukuba ukufudumeza nokupholisa kwenziwa ngokukhawuleza. Kule meko, yaye ngakumbi xa kuphindaphindwa rhoqo, kufuneka kulindelwe ukuvela kweecrack ezingena zisuka ngaphandle ziye ngaphakathi, zinefuthe kwiimpawu zoomatshini bekhonkrithi. Kule nto, iisamente ezahlukeneyo ziziphatha ngokwahlukileyo, yiyo loo nto kusetyenziso olusebenzayo kucetyiswa ukukhetha isamente ngononophelo.
Ukudlulisa ubushushu kwekhonkrithi
I-coefficient yokuhanjiswa kobushushu yekhonkrithi ixhomekeke kwiimpawu ze-aggregate kunye nesamente, kwisixa sesamente, kwisixa samanzi okuxuba, kumxholo wokufuma kwekhonkrithi, nakwizinga lobushushu. Ngovavanyo ngeepaneli ezino 10 cm ubukhulu nasekhonkrithi eyomiswe kakhulu, kufunyaniswe ukuba i-coefficient yokuhanjiswa kobushushu λ ingu 1,163 W/mK kwi 10 oC, kwaye ngeepaneli zekhonkrithi ebelele emanzini ifikelela ku 2,326 W/mK. Iipaneli ezityebileyo zinike iicoefficients eziphezulu zokuhanjiswa kobushushu; elona xabiso liphezulu lalingu 2,38 W/mK.
Ukwandiswa kwekhonkrithi ngenxa yobushushu
Ukwanda kuxhomekeke kakhulu kwi-aggregate, emva koko kubumanzi bekhonkrithi, kwanakwisamente uqobo. Amaxabiso omda awaziwayo ukuya ku 0 ukuya ku 40 oC amalunga ne 6 ukuya ku 13*10-6 m/m nganye kwinqanaba ngalinye.
Ukuxhathisa kumthwalo ophindaphindwayo
1. Amandla ocinezelo xa kukudinwa. Ingcamango yamandla xa kukudinwa isetyenziswe apha ngentsingiselo ebanzi; ekusetyenzisweni kobugcisa kufuneka isoloko kuchazwa amandla okudinwa (ucinezelo, ukutsalwa, ucinezelo nokutsalwa okutshintshanayo, ukugoba, ukusika ngeshearing, shearing ecocekileyo, ukugoba) kwakunye nendlela yokulayisha (ngokuzolileyo kuphela, ngokuphindaphindiweyo kuphela, inxenye ngokuzolileyo nenxenye ngokuma).
Amandla oxinzelelo ekudinweni ngenxa yomthwalo ozolileyo: kufuneka kulindeleke ukuba ukuxhathisa kumthwalo wexesha elide kube ubuncinane ¾ wamandla avelayo kuvavanyo oluqhelekileyo loxinzelelo.
Amandla okucinezela xa kukho ukudinwa ngenxa yemithwalo ephindaphindwayo (amandla asisiseko adinamiki): kuye kwabonakala ukuba amandla asisiseko adinamiki okucinezela eentsika zekhonkrithi ezineentlobo ezahlukeneyo, ingakumbi ezinemixholo eyahlukeneyo yesamente kunye negranulation eyahlukeneyo, ubuncinane ayalingana 0,5 wamandla eprism phantsi komthwalo oqhelekileyo ade aphuke. Kule meko kwenziwe 260 imijikelo yomthwalo ngomzuzu; inani lilonke lemijikelo apho la mandla asisiseko adinamiki bekumiselwa khona lalingamakhulu amabini amawaka. Ngokwandisa inani lemijikelo ngomzuzu (kwaye kwavavanywa 10 ukuya ku 450 imijikelo ngomzuzu), likhule kwakhona inani lokuphindaphinda elikhokelela ekophukeni.
Amandla acinezelayo xa ediniwe ngenxa yefuthe elidibeneyo lemithwalo ezolileyo neziphindaphindwayo: Xa imithwalo ezolileyo yongezwa kwimithwalo ephindaphindwayo, ke ngokwanda kwemithwalo ezolileyo amaxabiso ee-amplitudes zemithwalo ephindaphindwayo, ezaziphindaphindwa izigidi ezibini zeemeko, ayehla. Ngokomzekelo, umz. 1 ubonisa ukuba ii-amplitude zemithwalo ephindaphindwayo S zazilingana no:
- xa kukho umthwalo ozolileyo ku σu = 6 kg/cm2 S = 109 kg/cm2
- phantsi komthwalo ozolileyo kwi σu = 118 kg/cm2 S = 39 kg/cm2
- ngaphantsi komthwalo ozolileyo ku-σu = 157 kg/cm2 S = 8 kg/cm2
Umz. 1
Fig. 2
2. Amandla okugoba ekonkrithi xa kudinwa. Iimvavanyo eziboniswe kumz. 2 zeemiqulu ezigcinwe ngokusisigxina zimanzi, zibonise, phantsi komthwalo osisiseko we-dynamic ukuba amandla okugoba xa kudinwa angama 28 kg/cm2, ngelixa amandla aqhelekileyo okugoba ayengama 53 kg/cm2, nto leyo ehambelana nomlinganiselo 0,53.
Ikhonkrithi ekhaphukhaphu
Ikhonkrithi ekhanyayo (ikhonkrithi enobunzima obungaphantsi kwe-18 kN/m3) ifumaneka ngokusebenzisa ii-aggregate ezikhanyayo, ezinemingxuma ezifana nezi: ipumice, islag evela kwiziko elikhulu, islag yeekheyila, kwaye kwakhona ngokusebenzisa udaka olusuka kwisanti yendalo okanye eyenziweyo kunye nomgubo onezongezo ezithi ngexesha lokulungiselela udaka zivelise igesi (ikhonkrithi yegesi) okanye zibangele ugwebu kudaka (ikhonkrithi enogwebu).
Ikhonkrithi ekhaphukhaphu, phakathi kwezinye izinto, isetyenziswa kakhulu ekwenzeni iibhloko zokwakha neepleyiti zepumice zeendonga nophahla; kwimeko eyomileyo ayisiyondluliseli yobushushu ilungileyo; amandla ayo aphakathi, kodwa kulula ukuyilungisa, ukuze kuveliswe ngokuzithemba iibhloko ezikhaphukhaphu zeendonga ezithwele imithwalo zezakhiwo zokuhlala.
Njengesixhobo sokwenza igesi kwikhonkrithi eneegesi kusetyenziswa umgubo wealuminiyam. Ngokuxhomekeke kwisixa sezongezo kwakunye nezinye iimeko, kufumaneka izinto ezinemingxuma emininzi okanye embalwa, ezinobunzima kwimeko eyomileyo obumalunga ne-3 kN/m3 nangaphezulu.
1. Ubunzima bomthamo bekhonkrithi ekhaphukhaphu. Ngepumisi yendalo kunokuqinisekiswa ubunzima bomthamo – kuthatyathwa njengobekwimo eyomiswe ku105 oC – ukuqala ku7 kN/m3 nangaphezulu, ngamandla oxinzelelo angu2 MPa. Ubunzima bomthamo ekulindeleke ukuba bufumaneke bumalunga nesimbuku se-aggregate nesamente kwisimo esifunjwe. Ikhonkrithi enegesi enobunzima bomthamo obungaphezulu kwe8 kN/m3 idla ngokungafaneleki ngokobugcisa.
2. Amandla acinezelayo ekhonkrithi ekhanyayo. Kwikhonkrithi yokuzalisa kunokufezekiswa, ngaphandle kwamanyathelo athile akhethekileyo, amandla e 8 MPa, kwaye ngamatye amancinci de kufikeleleke nokuba 12 MPa. Kufuneka kuhlolwe rhoqo ukufaneleka kwayo. Ikhonkrithi enezimbobo (ikhonkrithi yegesi kunye nekhonkrithi enogwebu) ifanelekile kwiindonga ezithwala umthwalo kuphela emva kokuba iqinisiwe phantsi koxinzelelo lomphunga. Ngezinto ezisetyenziswa ngokufanelekileyo kunokuqinisekiswa ubunzima bevolyum obuyi 6 kN/m3 kunye namandla acinezelayo ayi 5 MPa.
3. Amandla okugoba ekhonkrithi ekhaphukhaphu. Ubudlelwane phakathi kwamandla okugoba kunye namandla okunyanzelisa buye babonakala, ngaphakathi kwemida yeemfuno zokuqhelisela, bukhulu ngokuthelekisa, yaye njengoko amandla esanda olo lwalamano luyancipha.
4. Iqondo lokushwabana kwekhonkrithi elula. Iqondo lokushwabana lixhomekeke ikakhulu ekunwebekeni kwe-aggregate, kwakunye nesixa sesakhiwo sesamente esomeleleyo; ukushwabana kwekhonkrithi elula kukhulu kunokushwabana kwekhonkrithi yamatye amancinane. Ikhonkrithi eyenziwe ngamaqhekeza ezitena ibonise ngexesha lonyaka olunye iqondo lilonke lokushwabana elimalunga 0,65 mm/m. Izinto ezisandul’ ukuhanjiswa ezenziwe ngepumice yendalo, kwi14 m iinyanga, zancipha malunga 0,8 mm/m. Iisampuli zekhonkrithi yegesi kunye nekhonkrithi enegwebu ezibulelwe emoyeni zibonise ukushwabana okukhulu ngakumbi, kwade kwaba ngaphezulu 2 mm/m. Akufuneki kulityalwe ukuba yonke ikhonkrithi xa ifumiswa yimvula okanye likhephu elinyibilikileyo iyadumba, yaye xa yomile kamva iyashwabana kwakhona.
Umz. 3
5. I-coefficient yokudlulisa ubushushu. I-coefficient yokudlulisa ubushushu iyancipha ngokobunzima bomthamo, kwaye phantsi kwezinye iimeko ezifanayo iba ncinane ngakumbi kokukhona iipore zomoya zincinci kwaye zisasazeke ngokulinganayo. Kwikhonkrithi egcwalisiweyo eyomileyo emoyeni yayingu (λ = 0,4625 for 9 kN/m3; λ = 0,58 – 0,7 for 12 kN/m3; λ = 0,81 – 1,05 for 16 kN/m3). Kwikhonkrithi yegesi eyomileyo emoyeni iinkcukacha zinikwe kumz. 3.
IQAPHELO:
- 0,1 kcal/mhoC = 0,1163 W/mK
- 0,1 kg/dm3 = 100 kg/m3 = 1 kN/m3