Ukucindezela ngemuva (post tensioning) kuyindlela eyinkimbinkimbi yokuqinisa ukhonkolo eye yaguqula ukwakhiwa kwesimanje ngokuvumela izikhala ezinde, amapulangwe amancane, kanye nokuguquguquka okukhulu ekwakhiweni. Ngokungafani nokuqiniswa okuvamile, okuncike ezintweni zensimbi ezingasebenzi ezisebenza kuphela lapho kunomthwalo, ukucindezela ngemuva kuhilela ukucindezela izintambo zensimbi ezinamandla amakhulu ngemuva kokuba ukhonkolo usuthelwe futhi womile. Le ndlela icindezela ukhonkolo ngenkuthalo, ithuthukisa kakhulu ukusebenza kwawo kwesakhiwo nokumelana nokuqhekeka. Onjiniyela nosonkontileka emhlabeni wonke baya ngokuya bekhetha ukucindezela ngemuva emaphrojekthini asukela ezakhiweni eziphakeme kuya emabhulohweni amakhulu, ngoba kunikeza izilinganiso eziphakeme zamandla nesisindo futhi kwandisa impilo yokusebenza. Ukuqonda izisekelo zokucindezela ngemuva kubalulekile kunoma yimuphi uchwepheshe wezokwakha ofuna ukusebenzisa kahle izinto zokwakha nokunciphisa izindleko zokulungisa isikhathi eside. Ochwepheshe abaningi bomkhakha babheka ukucindezela ngemuva njengenye yezinto ezintsha ezibalulekile kwezobunjiniyela bezakhiwo eminyakeni engamashumi amahlanu edlule, futhi ukwamukelwa kwayo kuya ngokuya kushesha njengoba abanikazi bamaphrojekthi befuna izixazululo eziphumelelayo neziqinile.

Kuvame ukudideka phakathi kwe-post tension ne-pre tension, izindlela ezimbili ezihlukene zokucindezela ezinikeza izidingo ezahlukene zomsebenzi. I-post tension ne-pre tension zombili zihilela ukufaka ingcindezi yokucindezela kukhonkolo, kodwa zihluka lapho noma nini ukucindezela kwenzeka. Ku-pre tensioning, izintambo zensimbi ziyacindezelwa ngaphambi kokuba ukhonkolo uthelwe, futhi ukubopha phakathi kukakhonkolo nensimbi kudlulisa ingcindezi ngemva kokuphola. Ku-post tensioning, izintambo zifakwa emapayipini noma emikhakheni, zicindezelwe ngemva kokuba ukhonkolo uqinile, bese ziboshelwa kukakhonkolo uqobo. Lo mehluko obalulekile wenza i-post tensioning ivumelane kakhulu nokwakha endaweni yomsebenzi ngoba ayidingi umbhede wokucindezela oqondile futhi ingamukela amaphrofayili ezintambo agobile. Ikhono lokucindezela izintambo ngezigaba lenza i-post tensioning ilungele ukwakhiwa kwamabhuloho ezigaba kanye nezicelo ezinkulu ze-post tension slab lapho ukucindezela ngokulandelana kudingekile. Emaqenjini okwakha ahlola isu elihle kakhulu lokuqinisa, ukuqonda imithelela yokusebenza nezindleko zendlela ngayinye kubalulekile ekwenzeni izinqumo ezinolwazi.

I-Post tensioning inikeza inhlanganisela ephawulekayo yezinzuzo zezakhiwo, ezomnotho, kanye nokusimama, okuyenza ibe ukukhetha okuthandwayo ekwakhiweni kukakhonkolo wesimanje. Enye yezinzuzo eziphuthumayo amandla okuklama amabanga amade ngaphandle kwezinsika eziphakathi, okudala izinhlelo zaphansi ezivulekile neziguquguqukayo ezaziswa kakhulu ngabaklami bezakhiwo nabanikazi bezakhiwo. I-post tension slab eklanywe kahle ingahlanganisa amabanga angaphezu kwama-30 kuya kwangama-50 ephesenti kunamaslab aqinisiwe ngendlela evamile anobukhulu obufanayo, inciphisa inani lezinsika nezisekelo ezidingekayo. Lokhu ngokuqondile kuhumushela ezindlekweni eziphansi zezinto zokwakha, izinhlelo zokwakha ezisheshayo, kanye nezindleko eziphansi zabasebenzi ngenxa yokuthi kunokhonkolo nokuqiniswa okuncane okufakwayo. Ukwengeza, ukuncipha kobukhulu beslab kwehlisa ukuphakama kwesakhiwo sonkana, okungaveza ukonga okukhulu ezintweni zokumboza, izinhlelo zemishini, kanye nezokuthutha eziqondile. Ngokombono wokusebenza kwesakhiwo, i-post tensioning inciphisa ukuchezuka nokuqhekeka ngaphansi kwemithwalo yokusebenza, ikhiqize isakhiwo esiqinile, esihlala isikhathi eside futhi esidinga ukulungiswa okuncane empilweni yaso yonke. Kubanikazi bamaphrojekthi abagxile ezindlekweni zomjikelezo wokuphila, inhlanganisela yokusetshenziswa kwezinto ezincishisiwe nokuqina okuthuthukisiwe kwenza i-post tensioning ibe utshalomali olukhanga kakhulu.

Enye inzuzo ebalulekile ye-post tensioning umthelela wayo ekusebenzeni okusimeme kokwakha. Ngenxa yokuthi i-post tensioning ivumela imiklamo ukuthi isebenzise ukhonkolo ongaphansi ngamaphesenti angama-30 kanye nensimbi yokuqinisa engaphansi ngamaphesenti angama-60 uma kuqhathaniswa nokhonkolo oqinisiwe ovamile, umkhondo wekhabhoni ohlanganisiwe wephrojekthi wehliswa kakhulu. Lokhu kuhambisana ngqo nemizamo yomhlaba wonke yokwehlisa ukukhishwa kwama-greenhouse gas emkhakheni wezokwakha, okubangela cishe amaphesenti angama-40 e-CO₂ ehlobene namandla emhlabeni wonke. Ngaphezu kwalokho, ukulawulwa kwemifantu okuthuthukisiwe okuhlinzekwa yi-post tensioning kwandisa impilo yezakhiwo, kunciphisa imvamisa yokulungiswa kanye nesidingo sokudilizwa nokwakhiwa kabusha ngaphambi kwesikhathi. Uma kusetshenziswa ezinhlelweni zangaphandle ze-post tension ezisetshenziswa emabhulohweni nasezakhiweni zokupaka, ukumelana nokugqwala kwemicu ehlanganisiwe noma egcotshwe ngamafutha futhi embozwe embozweni kuthuthukisa ukuphila isikhathi eside ezindaweni ezinobungozi. Kothuthukisi noma osonkontileka abafuna izitifiketi zokwakha eziluhlaza ezifana ne-LEED noma i-BREEAM, ukusebenza kahle kwezinto zokwakha kanye nokuqina kwe-post tensioning kunikeza amakhredithi abalulekile. Ngokucacisa izingxenye zekhwalithi ephezulu ze-post tensioning ezivela kumkhiqizi othembekile, amaqembu okwakha angakwazi ukuletha amaphrojekthi ngokuqiniseka okungcono kwezomnotho futhi ahloniphe imvelo.

Ukusebenza nokwethembeka kwanoma yiluphi uhlelo lwe-post tensioning kuncike ngqo ekhwalithini yezingxenye zalo ngazinye, okuhlanganisa ama-anchor, izintambo, ama-wedge, nazo zonke izinsiza ezihambisana nazo. Ama-anchor ayizinto ezibalulekile zokudlulisa umthwalo ezivala intambo ecijile endaweni ngemva kokucinwa; kufanele akhiqizwe ngokunembile ukuze abambe i-wedge ngokuphephile ngaphandle kokushibilika noma ukukhasa phakathi nempilo yesakhiwo. Ama-anchor asezingeni eliphezulu ngokuvamile akhandwa noma acutshungulwe ngensimbi esezingeni eliphezulu futhi ahlolwa ngokuqinile ukuze aqinisekise amandla awo angashintshi nawokukhathala. Okubaluleke ngokulinganayo izintambo ze-post tensioning ngokwazo, ezihlanganisa izintambo eziningi ezinamandla aphezulu ezigcotshwe ngamafutha ngazinye futhi zimbozwe ngesembozo se-polyethylene ukuze kuvinjwe ukugqwala futhi kuvumele ukunyakaza mahhala ngesikhathi sokucinwa. Izintambo kufanele zihlangabezane namazinga aqinile omhlaba wonke wamandla okudonsa kanye nezici zokuphumula, ukuze kuqinisekiswe ukusebenza okungaguquki kuwo wonke ama-tendon. Ama-wedge, nakuba mancane, adlala indima enkulu ekuvikelekeni kohlelo ngoba abamba intambo ngesenzo sokugwinya okufanele sibe ngokushesha futhi sihlale unomphela ngaphansi komthwalo ogcwele. Abakhiqizi abahlonishwayo banikeza izinhlelo eziphelele lapho zonke izingxenye ziklanywa, zihlolwe, futhi ziqinisekiswa ukuthi zisebenza ndawonye njengomkhakha ohlanganisiwe, kuqedwe izingozi zokuhambisana ezingavela lapho kuhlanganiswa izingxenye ezivela kubakhiqizi abahlukene.

Ngaphezu kwama-anchor, izintambo, nama-wedge, uhla oluphelele lwemikhiqizo ye-post tensioning luhlanganisa izinsiza ezehlukene ezenza ukufakwa kube lula futhi kuthuthukise ukuqina. Lokhu kuhlanganisa ama-trumpet cones ama-pocket formers, i-spiral reinforcement ukuvimbela ukuqhuma kukakhonkolo ezindaweni zama-anchor, kanye namashubhu okushintsha avikela intambo njengoba iphuma ku-anchor. Ezinhlelweni zangaphandle ze-post tension, kudingeka izingxenye ezengeziwe ezinjengamapayipi e-deviator, ama-saddle assemblies, nezembozo zokuvikela ukugqwala ukuze kuhlangatshezwane nokuma okukhethekile nokuchayeka emvelweni kwama-tendon angaphandle. Ama-duct couplers, ama-grout vents, nezembozo zokujova zisekela izinhlelo ze-bonded post tensioning lapho amashubhu egcotshwa ngemva kokuqinisa ukuze kudaleke ukuhlanganisa okungapheli phakathi kwentambo nesakhiwo. Amathimba okwakha kufanele athole wonke umkhiqizo we-post tensioning kumthengisi oyedwa onokwethenjelwa ukuze kuqinisekiswe ukungaguquguquki kobukhulu kanye nokusebenza okuqinisekisiwe kuzo zonke izingxenye. Izinkampani ezinjenge德州中科新材料有限公司 banikeza ikhathalogi ephelele yemikhiqizo yokucindezela ngemuva (post tensioning) eklanyelwe ukuhlangabezana namazinga ekhwalithi omhlaba, enikeza osonkontileka ukuthenga okulula nokusekelwa kwezobuchwepheshe. Ukukhetha izingxenye ezifanele akukhona nje ukuhlangabezana nezimfuneko, kodwa ukuvikela ukuphepha kwesikhathi eside nokusebenza kahle kwesakhiwo sonke.

Ukuqinisekiswa kwekhwalithi kuwumgogodla wanoma yimuphi umsebenzi ophumelelayo wokucindezela ngemuva (post tensioning) ngoba imiphumela yokwehluleka kwezingxenye ingaba yinhlekelele kwezimali nakwezabantu. Abakhiqizi abanegama elihle basebenzisa izinhlelo eziphelele zokuphatha ikhwalithi ezihlanganisa zonke izigaba kusukela ekuhlolweni kwezinto ezingavuthiwe kuze kufike ekuhlolweni komkhiqizo wokugcina. Insimbi esetshenziselwa imicu (strands) kumele ithengwe ezimbonini ezigunyaziwe futhi ihlolwe ukwakheka kwamakhemikhali, amandla okudonsa (tensile strength), ukunwebeka (ductility), kanye nezici zokuphumula (relaxation characteristics). Imizimba yama-anchor, ama-wedge, namapuleti okuthwala (bearing plates) kuhlolwa ubukhulu, ubulukhuni, namandla okuthwala umthwalo ukuze kuqinisekiswe ukuthi angamelana namandla omklamo ngokuphepha. Abakhiqizi abahamba phambili abaningi banezitifiketi ezifana ne-ISO 9001, okubonisa ukuzibophezela ezinqubweni zekhwalithi ezingaguquki, kanye nezimvume eziqondene nomkhiqizo ezivela ezinhlanganweni ezifana ne-International Code Council (ICC), i-European Technical Assessment (ETA), noma isiphathimandla sezakhiwo sendawo. Lezi zitifiketi zangaphandle zinikeza onjiniyela nosonkontileka ukuzethemba kokuthi izingxenye zokucindezela ngemuva abazifakayo zihlolwe ngokuzimela ukuze zihlangabezane noma zeqe amazinga emboni. Lapho uhlola abahlinzeki abangaba khona, kubalulekile ukucela amakhophi ezitifiketi zamanje kanye nemibiko yokuhlola ukuze kuqinisekiswe izimangalo zabo, kunokuba uthembele kuphela ezintweni zokukhangisa.

Ngaphandle kokuqinisekiswa komkhiqizo okuyisisekelo, ukulawulwa kwekhwalithi okuqhubekayo ngesikhathi sokukhiqiza kanye nokulandeleka emkhakheni wokuhlinzeka kubalulekile ngokulinganayo. Yonke insimbi eshisayo, yonke ibhajethi yokukhiqiza yama-wedge, kanye nokubunjwa kwe-anchor ngakunye kufanele kunikezwe ikhodi yokuhlonza eyingqayizivele evumela ukulandeleka okugcwele emuva ezintweni ezingavuthiwe kanye namarekhodi okukhiqiza.I-Dezhou Zhongke New Materials Co., Ltd.Isebenza ngaphambili kwezobuchwepheshe bokhonkolo kusukela ngo-2003, yakha idumela lokuqinisekisa ikhwalithi eqinile kuzo zombili izithako zayo zamakhemikhali kanye nemikhiqizo yayo yokucindezela ngemuva. Izindawo zayo zokukhiqiza zihlonyiswe ngemishini yokuhlola ethuthukile, okuhlanganisa imishini yokuhlola yonke, izihloli zobulukhuni, kanye nabahlaziyi be-metallographic, ukuqinisekisa ukuthi ingxenye ngayinye ephuma efektri ihlangabezana nemibandela yokusebenza ecacisiwe. Kosonkontileka nonjiniyela, ukukhetha umthengisi onezinhlelo zekhwalithi eziqinisekisiwe kanye nezitifiketi eziqinisekisiwe kunciphisa ubungozi bephrojekthi futhi kwenze inqubo yokugunyazwa ibe lula nabonjiniyela abaxhumanayo kanye neziphathimandla zokwakha. Embonini lapho ukwehluleka kwesakhiwo kungaholela ekumangaleleni nasekulimaleni kwedumela, ukutshala imali emikhiqizweni eqinisekisiwe, enekhwalithi ephezulu yokucindezela ngemuva ukuphela kokukhetha okunesibopho.

Itechnologyi ye-Post tensioning isetshenziswa emikhakheni eminingi yezokwakha, ngayinye inezidingo ezihlukile ezisebenzisa izinzuzo zale ndlela. Ekwakheni amabhuloho, i-post tensioning ivumela ukwakhiwa kwezakhiwo ezinamabanga amade njenge-segmental box girders, amabhuloho e-cantilever, kanye namabhuloho e-cable-stayed okungenzeka ukuthi angakwazi ukwakhiwa ngokuqiniswa okuvamile kuphela. Ikhono lokuhlanekezela ama-tendon ngezigaba livumela abakhi bamabhuloho ukuthi bangeze amabhuloho kancane kancane futhi bafinyelele i-camber edingekayo kanye nokusabalalisa kwengcindezi ngokunemba. Izinhlelo ze-external post tension zithandwa kakhulu ekulungiseni nasekuqiniseni amabhuloho ngoba zingafakwa ngaphandle kokuphazamisa ukuhamba kwezimoto futhi zivumela ukuhlolwa nokuhlanekezelwa kabusha esikhathini esizayo. Amabhuloho emigwaqo emikhulu, amabhuloho kaloliwe, kanye namabhuloho abahamba ngezinyawo wonke ahlomula emiklameni emincane kanye nesisindo esinciphile esinikezwa yi-post tensioning, okunciphisa umthwalo wezisekelo kanye nezidingo zokuzamazama komhlaba. Kubanikazi bengqalasizinda abagxile ekuphileni isikhathi eside nasekugcinweni okuphansi, ukuvikelwa kokugqwala okunikezwa izinhlelo ze-post tensioning ezivalwe ngokugcwele kuyisici esinqumayo ekwandiseni impilo yesevisi ngaphezu kweminyaka eyi-100.

Ezintweni zokwakha kanye namapulangwe, ukwakhiwa kwepulangwe eliqinisiwe ngemuva kokucindezela (post tension slab) kusetshenziswa kakhulu emibhedeni emide yezindlu zokuhlala, ezakhiweni zamahhovisi ezohwebo, izakhiwo zokupaka izimoto, kanye nezindawo zezimboni. Ikhono lokuklama amapulangwe ayisicaba ngaphandle kwamaphaneli okwehla noma imishayo lidala izindawo ezingaphansi ezihlanzekile, linciphisa ukuphakama phakathi kwemikhandlu, futhi lenze kube lula ukufakwa kwezinto zikagesi nemishini. Abathuthukisi bavame ukukhetha ukuqinisa ngemuva kokucindezela (post tensioning) kumaphrojekthi amakhulu epulangwe eliqinisiwe ngemuva kokucindezela, njengezitolo ezinkulu, izikhumulo zezindiza, kanye nezikhungo zokusabalalisa, ngoba kunciphisa igebe lokuhlangana kwezinto futhi kunciphisa ingozi yokuqhekeka okubangelwa ukukhanya. Ezakhiweni zokupaka izimoto, ukuqinisa ngemuva kokucindezela kunikeza izinzuzo ezimbili zokunciphisa ubukhulu besakhiwo ukuze kukhuliswe umkhawulo wokupaka kanye nokuthuthukisa ukulawulwa kokuqhekeka ukuze kuvikelwe ukuqiniswa emanzini ane-chloride kanye nosawoti wokuncibilikisa iqhwa. Izindlela zokuqinisa ngemuva kokucindezela (post tension) nangaphambi kokucindezela (pre tension) ngezinye izikhathi ziyahlanganiswa ezakhiweni eziyingxubevange njengemishayo eqinisiwe ngaphambi kokucindezela (precast prestressed beams) enezitezi eziqinisiwe ngemuva kokucindezela (cast-in-place post tensioned decks), okwenza kube ngcono amandla endlela ngayinye. Ukusebenza ngezindlela eziningi kokuqinisa ngemuva kokucindezela kunabela ezakhiweni ezikhethekile njengezinkundla zezemidlalo, amathangi amanzi, kanye nemikhumbi yokugcina izinto zenuzi, lapho ukwethembeka kwendlela kanye nokusebenza kwayo ngaphansi kwemithwalo enzima kubalulekile. Kukho konke lokhu kusetshenziswa, ukhiye wempumelelo usekuklanyweni okufanele, ezintweni ezisezingeni eliphezulu, kanye nokufakwa okunamakhono okusekelwa umhlahlandlela ophelele wezobuchwepheshe ovela kumkhiqizi womkhiqizo.

Uma kukhethwa umhlinzeki wezinhlelo zokucindezela ngemuva (post tensioning), ochwepheshe bezokwakha abadingi nje imikhiqizo kuphela, badinga umlingani onobuchwepheshe bokukhiqiza, ukwesekwa kobunjiniyela, kanye nomlando oqinisekisiwe. 德州中科新材料有限公司(Inkampani i-Dezhou Zhongke New Materials Co., Ltd.) ineminyaka engaphezu kwamashumi amabili yobuchwepheshe ezintweni zokwakha ezithuthukisiwe, njengoba isebenza embonini kusukela ngo-2003 njengenkampani yobuchwepheshe obuphezulu egxile ezintweni zokuhlanganisa ukhonkolo kanye nezinhlelo zokucindezela. Amandla abo okukhiqiza ahlanganisa imigqa yokukhiqiza yesimanje enokulawulwa okuqinile kwenqubo, okubenza bakwazi ukukhiqiza ama-anchor, izintambo, ama-wedge, kanye nezinsiza ezengeziwe ezihlangabezana noma ezedlula amazinga okusebenza aphesheya. Ngokungafani nabathengisi abajwayelekile abavele bathengise kabusha imikhiqizo, i-Zhongke isebenzisa isikhungo sayo sokucwaninga nokuthuthukisa kanye nelabhorethri yokuhlola, okuvumela ukuthuthukiswa okuqhubekayo kwemikhiqizo kanye nezixazululo ezenziwe ngokwezidingo eziqondile zephrojekthi. Lokhu kuhlanganiswa okuqondile kunikeza amakhasimende ukufinyelela okuqondile kobuchwepheshe ngesikhathi sokuklama, ukwesekwa ekuxazululeni izinkinga endaweni, kanye nensizakalo yokuthengisa engemuva enempendulo eqondile, okususa ukukhungatheka kokusebenzisana nabameli. Emakhasimendeni aphesheya, ulwazi lwenkampani lokuthumela emakethe ezifundeni zase-Asia, Middle East, kanye ne-Afrika lukhombisa ikhono labo lokuhambisa izinto zokuthutha, imibhalo, kanye nezidingo zokuthobela imithetho.

Ukukhetha i-Zhongke njengomhlinzeki wakho we-post tensioning kungenye isizathu esiqinile sokwenza kanjalo. Ngokulawula izinqubo zokukhiqiza kusukela ekutholeni izinto zokusetshenziswa kuze kube umkhiqizo ophelile, inkampani ithola amanani ancintisanayo ngaphandle kokuyekethisa ngekhwalithi noma ukuphepha. Banikeza izixazululo ezenziwe ngokwezifiso ezifana nejometri yama-anchor engejwayelekile, izembozo ezikhethekile zemicu, kanye nokupakishwa okulungiselelwe amaphrojekthi akude, baqinisekisa ukuthi yonke i-oda lihambisana ngqo nezindlela zokufaka zesontraktha kanye neshejuli. Ukuzibophezela kwenkampani ekubeni sobala kuhlanganisa ukuhlinzeka ngamashidi obuchwepheshe anemininingwane, izincwajana zokufaka, kanye nemibiko yokuhlolwa yomuntu wesithathu eyenza inqubo yokugunyazwa ibe lula nonjiniyela abelulekayo kanye neziphathimandla zezakhiwo. Kosonkontileka abazisa ukuthembeka nobudlelwano besikhathi eside, inhlanganisela ye-Zhongke yokujula kokukhiqiza, ukwesekwa kobunjiniyela, kanye nokuncintisana kwezindleko kubenza babe ukukhetha okuvelele emakethe yomhlaba wonke ye-post tensioning. Ukuze uhlole uhla lwabo oluphelele lwemikhiqizo futhi uxoxe ngezidingo zakho eziqondile zephrojekthi, vakashela iwebhusayithi yabo.ikhasi lomkhiqizo noma uxhumane nethimba labo lobuchwepheshe ngqo.

Ukuqala umyalo womkhiqizo we-post tensioning nomthengisi othembekile kuyinqubo eqondile uma bobabili amaqembu evumelene ngemininingwane, ubuningi, nezikhathi zokulethwa. Isinyathelo sokuqala ukuhambisa isicelo esinemininingwane esihlanganisa izidingo zakho zephrojekthi ezifana nobubanzi nesignesha yentambo, uhlobo nobuningi be-anchor, uhlobo lwesistimu (eboshwe noma engaboshiwe), kanye nanoma yiziphi izidingo ezikhethekile zokuvikela ukugqwala. Ukuhlinzeka ngemidwebo yobunjiniyela noma imidwebo ye-tendon layout kulesi sigaba kusiza umthengisi aqinisekise ukuthi izingxenye ezihlongozwayo ziyahambisana nomklamo wakho nokulandelana kokufaka. Iningi labakhiqizi abahlonishwayo liphendula ngezilinganiso eziphelele ezihlukanisa izindleko zomkhiqizo, ukupakishwa, izinsuku ezilinganiselwe zokuthunyelwa, kanye nemigomo yokukhokha. Kuyalulekwa ukuthi ucele amasampula ama-wedge nama-anchor ukuze ahlolwe ngaphambi kokugunyazwa ngaphambi kokuzibophezela ekukhiqizeni okugcwele, ikakhulukazi emaphrojekthini anezimo ezingavamile zokulayisha noma izikhathi ezinzima zokugunyazwa. Uma isilinganiso samukelwa, umthengisi uzokhiqiza umdwebo wefekthri noma iphakethe lokuhambisa ukuze libuyekezwe futhi ligunyazwe, liqinisekisa ukuthi ingxenye ngayinye iyahambisana nemininingwane yephrojekthi ngaphambi kokuba kukhiqizwe.

Ukuthunyelwa kanye nokuhambisa kwemikhiqizo ye-post tensioning kudinga ukuhlela ngokucophelela ngoba ama-anchor nama-wedge ayizinto ezinzima zensimbi kuyilapho imicu ithunyelwa ngamakhoyili noma emaroli. Abahlinzeki abathembekile njenge-Dezhou Zhongke New Materials Co., Ltd. banolwazi lokuhlanganisa izimpahla ukuze kube nokuthunyelwa ngomkhumbi, ngendiza, noma ngezindlela ezihlukene emazweni omhlaba. Bahlinzeka ngamalisti okupakisha, izimpawu zokuthunyelwa, kanye nemibhalo yesitifiketi semvelaphi ukuze kube lula ukugunyazwa empahleni. Ngemva kokuba i-oda lifakiwe, amakhasimende angalindela izibuyekezo ezijwayelekile zokukhiqiza kanye nemibiko yokuhlola, kanye nethuba lokuhlola umuntu wesithathu uma kudingeka. Kwabathengi bokuqala, ithimba lokusekela lobuchwepheshe lomhlinzeki lingasiza ngoqeqesho lokufaka, lincoma imishini yokucindezela ehambisanayo, futhi linikeze ukugadwa endaweni uma kudingeka. Ukuze ucele isilinganiso sezindleko noma uxoxe ngephrojekthi yakho ezayo, vakashela inkampani.ikhasi lokusekela lapho ungagcwalisa ifomu lokuxhumana noma ushayele ithimba labo lokuthengisa ngqo. Ukuqala kusenesikhathi esigabeni sokuhlela iphrojekthi kuqinisekisa ukuthi izinto zokucindezela ngemuva (post tensioning) zifika endaweni ngesikhathi esifanele, okugcina ishejuli yakho yokwakha ihamba kahle futhi kugwenywa ukubambezeleka okubizayo.

I-Post tensioning iyindlela yokuqinisa ukhonkolo ngokucindezela izintambo zensimbi ezinamandla aphezulu ngemva kokuba ukhonkolo usulukhuni, icindezela ngenkani ukhonkolo ukuze ithuthukise amandla nokumelana nokuqhekeka. Ukuqiniswa kwendabuko kuncike ezintanjeni zensimbi ezingenzi lutho ezingamelana nokudonswa kuphela ngemva kokuba ukhonkolo usuqhekezile. Umehluko omkhulu ukuthi i-post tensioning isebenzisa amandla acindezelayo angaphambi kokuba ukucindezeleka kwenzeke, okuholela ezakhiweni eziqinile, eziqinile ezinamabanga amade kanye namapulangwe amancane.

I-post tension ne-pre tension zombili izinhlobo zokucindezela ngaphambi kwesikhathi kodwa zihluka ngesikhathi nangendlela. Ekucindezeleni ngaphambi kwesikhathi (pretensioning), imicu iyacishwa ngaphambi kokuba ukhonkolo uthelwe futhi incike ekudlulisweni kwebhondi ngemva kokuphola; lokhu kuvame ukwenziwa embonini yokukhiqiza izinto ezingakapheli. Ekucindezeleni ngemva kwesikhathi (post tensioning), imicu ifakwa emapayipini, icishwe ngemva kokuqina kukakhonkolo, futhi iboshelwe kukakhonkolo uqobo, okwenza kube yinto ekahle ekwakhiweni endaweni kanye namaphrofayili emicu egobile.

I-slab ye-post tension iyisilabhu sikakhonkolo esiqiniswe ngezintambo zokucindezela (post tensioning tendons) eziqiniswa ngemva kokuba ukhonkolo usulungile. Isetshenziselwa ukuthola ubude obude ngaphandle kwezinsika, ukunciphisa ubukhulu besilabhu, ukunciphisa ukuqhekeka, kanye nokwehlisa isisindo sonke sesakhiwo. Ama-slabs e-post tension avamile ezakhiweni eziphakeme, izakhiwo zokupaka, kanye nezitezi zezentengiselwano lapho ukuhleleka okuvulekile nokusebenza kahle kwezindleko kubalulekile.

Izingxenye eziyinhloko zihlanganisa izintambo zensimbi ezinamandla aphezulu (amakhebula), imihlangano ye-anchor (ipuleti elithwala, umgqomo, nama-wedge), ukugqokwa noma amapayipi okuvikela ukugqwala, kanye nezinsiza ezinjengezimpondo zomculo, ukuqinisa okusongelwe, namapayipi okushintsha. Ingxenye ngayinye kufanele ikhiqizwe ngokunembile futhi ihlolwe ukuze kuqinisekiswe ubuqotho besistimu. Ama-anchor nama-wedge asezingeni eliphezulu abaluleke kakhulu ekudluliseleni umthwalo okuthembekile nokuphepha kwesakhiwo isikhathi eside.

I-post tension yangaphandle ibhekisela emisipheni egijima ngaphandle kwesigaba esinqamulelayo sikakhonkolo, ngokuvamile ngaphakathi kwebhokisi legiya lebhuloho noma eceleni kwesakhiwo. Imisipho ibekwa emhubheni futhi ingahlolwa, igadwe, futhi iqiniswe kabusha phakathi nempilo yesakhiwo. Isetshenziswa kabanzi ekuqiniseni ibhuloho, ekwakhiweni kwebhuloho elihlukanisiwe, nasekulungiseni izakhiwo zokupaka lapho kudingeka khona ukufinyelela ukuze kulungiswe esikhathini esizayo.

Kufanele ubheke isitifiketi sokuphathwa kwekhwalithi i-ISO 9001, izimvume eziqondene nomkhiqizo ezivela ezinhlanganweni eziqashelwayo ezifana ne-ICC-ES, i-ETA, noma iziphathimandla zokwakha zendawo, kanye nemibiko yokuhlolwa yomuntu wesithathu eqinisekisa amandla okudonsa, ukumelana nokukhathala, kanye nokwakheka kwempahla. Abahlinzeki abathembekile banikeza ukulandeleka okugcwele futhi bazimisele ukwabelana ngezitifiketi zamanje kanye namarekhodi okukhiqiza ukuqinisekisa izimangalo zabo.

Yebo, ukucindezela kwangemuva (post tensioning) kusetshenziswa kakhulu ekwakhiweni kwezindlu, ikakhulukazi ezisekelweni zamatshe ezindaweni ezinomhlabathi ovuvukalayo, ezindongeni ezingaphansi komhlaba, kanye nezitezi zamafulethi ezakhiwo ezinemitehe eminingi. Kusiza ukunciphisa ubukhulu besitezi, ukulawula ukuqhekeka okubangelwa ukunyakaza komhlabathi, kanye nokwehlisa izindleko zokwakha. Abakhi abaningi bezindlu bacacisa ukusetshenziswa kwezinhlelo zamatshe acindezelwe ngemuva ukuze kukhuliswe indawo esetshenziswayo futhi kuncishiswe ubukhulu besakhiwo.

Izintambo zokucindezela kwangemuva ezikhiqizwe kahle futhi zafakwa kahle zingahlala iminyaka engu-50 kuye kwengu-100 noma ngaphezulu, ikakhulukazi uma kusetshenziswa izinhlelo ezivalwe ngokuphelele ezinikeza ukuvikeleka ekugqwaleni ngamafutha, izembozo, kanye nezikhonkwane ezivaliwe. Ubude besikhathi sokuphila buncike ezimweni zemvelo, ikhwalithi yezinto zokwakha, kanye nokulandela izindlela ezingcono zokufaka. Izinhlelo zokuhlola njalo zingandisa isikhathi sokusebenza ngokuthola izinkinga kusenesikhathi.

Izikhathi zokulinda ziyahlukahluka kuye ngobunzima be-oda, inani, kanye nezinhlelo zokukhiqiza zamanje. Izingxenye ezijwayelekile njengosayizi bama-anchor avamile namakhoyili e-strand ngokuvamile zingathunyelwa phakathi namasonto angu-2 kuya kwangu-4, kuyilapho imihlangano eyenziwe ngokwezifiso noma ama-oda amaningi angadinga amasonto angu-6 kuya kwangu-8. Kunconywa ukuthi u-oda kusenesikhathi esigabeni sokuklama iphrojekthi ukuze uvumele ukuvunywa, ukukhiqiza, kanye nokuthunyelwa.

Ukuze ucele isilinganiso sezindleko, xhumana nomthengisi ngemininingwane yephrojekthi yakho ehlanganisa ububanzi be-strand, uhlobo lwe-anchor kanye nenani, uhlobo lwesistimu (eboshelwe noma engaboshelwe), kanye nendawo yokulethwa. Ukuhlinzeka ngemidwebo noma imidwebo yokuhlelwa kwe-tendon kusiza umthengisi ukuthi alungiselele isilinganiso sezindleko esinembile. I-Dezhou Zhongke New Materials Co., Ltd. yamukela imibuzo nge-ikhasi lokusekela futhi iphendula ngemininingwane enembile yamanani nobuchwepheshe.