Ezimweni ezahlukene zesakhiwo, onjiniyela kungadingeka bahlole amandla amalunga enziwe ngama-weld kanye nama-fasteners omshini. Namuhla, ama-fasteners omshini ngokuvamile angama-bolts, kodwa imiklamo emidala ingaba nama-rivets.
Lokhu kungenzeka ngesikhathi sokuthuthukiswa, ukulungiswa, noma ukuthuthukiswa kwephrojekthi. Umklamo omusha ungadinga ukuboshwa kanye nokushiselwa ukuze kusebenze ndawonye ejoyintini lapho izinto ezizohlanganiswa ziqala zihlanganiswe ndawonye bese zishintshwa ukuze kunikezwe amandla aphelele ejoyintini.
Kodwa-ke, ukunquma umthamo womthwalo ophelele wejoyinti akulula njengokuhlanganisa isamba sezingxenye ngazinye (ama-weld, ama-bolt, nama-rivets). Ukucabanga okunjalo kungaholela emiphumeleni eyinhlekelele.
Ukuxhumeka okunamabholidi kuchazwe ku-American Institute of Steel Structures (AISC) Structural Joint Specification, esebenzisa amabholidi e-ASTM A325 noma e-A490 njengokufaka okuqinile, ukulayisha kusengaphambili, noma ukhiye oshelelayo.
Qinisa ukuxhumana okuqiniswe ngokuqinile ngesiphandla sokuthinta noma umkhandi wezikhiye usebenzisa isiphandla esivamile esinamacala amabili ukuqinisekisa ukuthi izendlalelo zixhumene ngokuqinile. Ekuxhumeni okucindezelwe kusengaphambili, amabhawodi afakwa ukuze abhekane nemithwalo emikhulu yokudonswa, futhi amapuleti abhekane nemithwalo yokucindezelwa.
1. Phendula inathi. Indlela yokuphendula inathi ihilela ukuqinisa ibhawodi bese uphendula inathi inani elengeziwe, okuncike kububanzi nobude bebhawodi.
2. Linganisa ukhiye. Indlela yesikrufu esilinganisiwe ilinganisa i-torque ehlotshaniswa nokucindezeleka kwebholithi.
3. Ibholithi yokulungisa ukucindezeleka kohlobo lwe-Torsion. Amabholithi okucindezeleka ajikajikayo anezikhonkwane ezincane ekugcineni kwebholithi maqondana nekhanda. Uma i-torque edingekayo ifinyelelwa, i-stud iyasuswa.
4. Inkomba yokudonsa eqondile. Izinkomba zokucindezela okuqondile ziyizihlanzi ezikhethekile ezinamathebhu. Inani lokucindezela ku-lug libonisa izinga lokucindezela okufakwe ebholthini.
Ngokwesimo sabantu abavamile, amabhawodi asebenza njengezikhonkwane ezingosini eziqinile nezicindezelwe ngaphambili, njengephini yethusi ebambe inqwaba yephepha elinezimbobo ndawonye. Izingosini ezishelelayo ezibucayi zisebenza ngokungqubuzana: ukulayisha kusengaphambili kudala amandla okwehla, futhi ukungqubuzana phakathi kwezindawo zokuxhumana kusebenza ndawonye ukumelana nokushelela kwejoyinti. Kufana ne-binder ebamba inqwaba yamaphepha ndawonye, ​​hhayi ngoba izimbobo zibhobozwe ephepheni, kodwa ngoba i-binder icindezela amaphepha ndawonye futhi ukungqubuzana kubamba inqwaba ndawonye.
Amabhawodi e-ASTM A325 anamandla okudonsa okungenani angu-150 kuya ku-120 kg nge-inch yesikwele (KSI), kuye ngobubanzi bebhawodi, kuyilapho amabhawodi e-A490 kumele abe namandla okudonsa angu-150 kuya ku-170-KSI. Amajoyinti e-rivet aziphatha njengejoyinti eliqinile, kodwa kulokhu, amaphini ayizimbotshana ezivame ukuba cishe ziqine njengebhowodi le-A325.
Enye yezinto ezimbili ingenzeka lapho ijoyinti eliboshwe ngomshini libhekene namandla okucheba (lapho into eyodwa ivame ukushelela phezu kwenye ngenxa yamandla asetshenzisiwe). Amabholidi noma ama-rivets angaba sezinhlangothini zemigodi, okubangela ukuthi amabholidi noma ama-rivets acheke ngesikhathi esifanayo. Ithuba lesibili ukuthi ukungqubuzana okubangelwa amandla okubamba ama-fasteners aqinisiwe kungamelana nemithwalo yokucheba. Akukho ukushelela okulindelekile kulokhu kuxhumana, kodwa kungenzeka.
Ukuxhumeka okuqinile kuyamukeleka ezinhlelweni eziningi, njengoba ukushelela okuncane kungeke kuthinte kabi izici zokuxhumeka. Isibonelo, cabanga ngesilayidi esenzelwe ukugcina izinto ezihlanganisiwe. Kungase kube nokushelela okuncane lapho kulayishwa okokuqala. Uma ukushelela kwenzeka, ngeke kuphinde kwenzeke, ngoba yonke imithwalo elandelayo ifana.
Ukuguqulwa komthwalo kusetshenziswa kwezinye izinhlelo zokusebenza, njengalapho izinto ezijikelezayo zifakwa imithwalo eshintshanayo yokucindezelwa kanye neyokucindezela. Esinye isibonelo isici sokugoba esifakwa imithwalo ebuyela emuva ngokuphelele. Uma kukhona ushintsho olukhulu endleleni yomthwalo, uxhumano olulayishiwe ngaphambilini lungadingeka ukuze kuqedwe ukushelela okujikelezayo. Lokhu kushelela ekugcineni kuholela ekusheleleni okwengeziwe emigodini emide.
Amanye amalunga abhekana nemijikelezo eminingi yomthwalo engaholela ekukhathaleni. Lokhu kufaka phakathi ukucindezela, izisekelo ze-crane kanye nokuxhumeka emabhulohweni. Ukuxhumeka okubalulekile okushelelayo kuyadingeka lapho uxhumano lubhekene nemithwalo yokukhathala ngendlela ephambene. Kulezi zinhlobo zezimo, kubaluleke kakhulu ukuthi ilunga lingasheleli, ngakho-ke amalunga abalulekile ayadingeka.
Ukuxhumeka okukhona okunamabholidi kungaklanywa futhi kukhiqizwe nganoma iyiphi yalezi zindinganiso. Ukuxhumeka kwe-rivet kubhekwa njengokuqinile.
Amajoyinti ahlanganisiwe aqinile. Amajoyinti ahlanganisiwe ayaxaka. Ngokungafani namajoyinti aboshwe ngokuqinile, angashelela ngaphansi komthwalo, ama-weld akudingeki anwebe futhi asabalalise umthwalo osetshenzisiwe ngezinga elikhulu. Ezimweni eziningi, izinamathiselo zemishini ezihlanganisiwe nezinohlobo lokuthwala aziguquguquki ngendlela efanayo.
Uma kusetshenziswa ama-welds ngezibambo zemishini, umthwalo udluliselwa engxenyeni eqinile, ukuze i-weld ikwazi ukuthwala cishe wonke umthwalo, kuncane kakhulu okwabelwana ngakho ne-bolt. Yingakho kufanele kuqashelwe lapho kushiselwa, kushiselwa futhi kushiselwa. Imininingwane. I-AWS D1 ixazulula inkinga yokuxuba izibambo zemishini nama-welds. Imininingwane 1:2000 yokushiselwa kwesakhiwo - insimbi. Isigaba 2.6.3 sithi kuma-rivets noma ama-bolts asetshenziswa ezinhlanganisweni zohlobo lokuthwala (okungukuthi lapho i-bolt noma i-rivet isebenza njengephini), izibambo zemishini akufanele zicatshangelwe ukuthi zabelane ngomthwalo ne-weld. Uma kusetshenziswa i-welding, kumele zinikezwe ukuze zithwale umthwalo ogcwele ejoyintini. Kodwa-ke, ukuxhumeka okushisiwe entweni eyodwa kanye nokushiselwa noma ukushiselwa kwenye into kuvunyelwe.
Uma usebenzisa izinamathiselo zomshini zohlobo lokuthwala kanye nokwengeza ama-weld, amandla okuthwala umthwalo webhawodi awanakwa kakhulu. Ngokwalesi sigaba, i-weld kumele yakhelwe ukudlulisa yonke imithwalo.
Lokhu kufana kakhulu ne-AISC LRFD-1999, isigaba J1.9. Kodwa-ke, i-CAN/CSA-S16.1-M94 ejwayelekile yaseCanada ivumela nokusetshenziswa kwayo yodwa lapho amandla esiqiniselo noma ibholithi lomshini ephakeme kunalawo okushisela.
Kule ndaba, izindlela ezintathu ziyavumelana: amathuba okubopha ngomshini kohlobo lokuthwala kanye namathuba okushisela awahlangani.
Isigaba 2.6.3 se-AWS D1.1 sixoxa futhi ngezimo lapho amabholidi nama-weld kungahlanganiswa khona endaweni enezingxenye ezimbili, njengoba kuboniswe kuMfanekiso 1. Ama-Welds ngakwesobunxele, aboshwe ngakwesokudla. Amandla aphelele ama-welds nama-bolts angacatshangelwa lapha. Ingxenye ngayinye yoxhumano lonke isebenza ngokuzimela. Ngakho-ke, le khodi ihlukile kusimiso esiqukethwe engxenyeni yokuqala ka-2.6.3.
Imithetho esanda kuxoxwa ngayo isebenza ezakhiweni ezintsha. Ezindaweni ezikhona, isigaba 8.3.7 D1.1 sithi lapho izibalo zesakhiwo zibonisa ukuthi i-rivet noma i-bolt izogcwala kakhulu umthwalo omusha ophelele, umthwalo omile okhona kuphela okufanele unikezwe wona.
Imithetho efanayo idinga ukuthi uma i-rivet noma i-bolt igcwele kakhulu imithwalo engaguquki noma ingaphansi kwemithwalo ejikelezayo (yokukhathala), insimbi eyisisekelo eyanele kanye nama-welds kumele afakwe ukusekela umthwalo ophelele.
Ukusatshalaliswa komthwalo phakathi kwezinamathiseli zemishini kanye nama-weld kuyamukeleka uma isakhiwo silayishwe kusengaphambili, ngamanye amazwi, uma kube nokushelela phakathi kwezinto ezixhunyiwe. Kodwa imithwalo engaguquki kuphela engabekwa kuma-fasteners emishini. Imithwalo ephilayo engaholela ekusheleleni okukhulu kumele ivikelwe ngokusebenzisa ama-weld akwazi ukumelana nomthwalo wonke.
Ama-weld kumele asetshenziswe ukumelana nakho konke ukulayisha okusebenzayo noma okuguquguqukayo. Uma izinamathiselo zemishini sezivele zigcwele ngokweqile, ukwabelana ngomthwalo akuvunyelwe. Ngaphansi kokulayisha okujikelezayo, ukwabelana ngomthwalo akuvunyelwe, ngoba umthwalo ungaholela ekusheleleni unomphela kanye nokulayisha ngokweqile kwe-weld.
umfanekiso. Cabanga ngejoyinti le-lap elaliboshwe ngokuqinile ekuqaleni (bheka uMfanekiso 2). Isakhiwo sengeza amandla engeziwe, futhi ukuxhumana nezixhumi kumele kwengezwe ukuze kunikeze amandla aphindwe kabili. Ku-Fig. 3 kukhombisa uhlelo oluyisisekelo lokuqinisa izakhi. Ukuxhumana kufanele kwenziwe kanjani?
Njengoba insimbi entsha kwakudingeka ihlanganiswe nensimbi endala ngama-fillet welds, unjiniyela wanquma ukwengeza amanye ama-fillet welds endaweni yokuhlangana. Njengoba ama-bolts ayesekhona, umqondo wokuqala kwakuwukufaka ama-welds kuphela adingekayo ukuze kudluliselwe amandla engeziwe ensimbini entsha, belindele ukuthi u-50% womthwalo udlule kuma-bolts kanye no-50% womthwalo udlule kuma-welds amasha. Ingabe kuyamukeleka?
Ake siqale sicabange ukuthi akukho mithwalo engaguquki esetshenziswayo okwamanje ekuxhumaneni. Kulesi simo, isigaba 2.6.3 se-AWS D1.1 siyasebenza.
Kulolu hlobo lokuhlanganisa amabhereyitha, i-weld kanye ne-bolt akukwazi ukubhekwa njengokwabelana ngomthwalo, ngakho-ke usayizi we-weld ocacisiwe kumele ube mkhulu ngokwanele ukusekela wonke umthwalo ozinzile noguquguqukayo. Amandla okuthwala amabhereyitha kulesi sibonelo awanakucatshangelwa, ngoba ngaphandle komthwalo ozinzile, uxhumano luzoba sesimweni sokuxega. I-weld (eklanyelwe ukuthwala ingxenye yomthwalo) iqala ukuqhekeka lapho umthwalo ogcwele usetshenziswa. Ngemuva kwalokho i-bolt, nayo eyenzelwe ukudlulisa ingxenye yomthwalo, izama ukudlulisa umthwalo bese iyaphuka.
Ake sithi futhi umthwalo ongaguquki uyasebenza. Ngaphezu kwalokho, kucatshangwa ukuthi uxhumano olukhona lwanele ukuthwala umthwalo ohlala njalo okhona. Kulesi simo, isigaba 8.3.7 D1.1 siyasebenza. Ama-weld amasha adinga kuphela ukumelana nemithwalo eqhubekayo engaguquki kanye nejwayelekile ephilayo. Imithwalo efile ekhona inganikezwa izinamathiseli zemishini ezikhona.
Ngaphansi komthwalo oqhubekayo, uxhumano alugobeki. Kunalokho, amabhawodi asevele ethwele umthwalo wawo. Kube nokushelela okuthile ekuxhumaneni. Ngakho-ke, ama-weld angasetshenziswa futhi angadlulisela imithwalo enamandla.
Impendulo yombuzo othi “Ingabe lokhu kuyamukeleka?” incike ezimweni zomthwalo. Esimweni sokuqala, uma kungekho umthwalo omile, impendulo izoba negative. Ngaphansi kwezimo ezithile zesimo sesibili, impendulo inguyebo.
Ngenxa yokuthi kusetshenziswa umthwalo omile, akunakwenzeka ngaso sonke isikhathi ukuthola isiphetho. Izinga lemithwalo emile, ukufaneleka kokuxhumana okukhona kwemishini, kanye nohlobo lwemithwalo yokugcina—kungakhathaliseki ukuthi imile noma ijikeleza—kungashintsha impendulo.
UDuane K. Miller, MD, PE, 22801 Saint Clair Ave., Cleveland, OH 44117-1199, Umphathi Wesikhungo Sobuchwepheshe Bokushisela, iLincoln Electric Company, www.lincolnelectric.com. ILincoln Electric ikhiqiza imishini yokushisela kanye nezinto ezisetshenziswayo zokushisela emhlabeni jikelele. Onjiniyela kanye nochwepheshe besikhungo sobuchwepheshe bokushisela basiza amakhasimende ukuxazulula izinkinga zokushisela.
I-American Welding Society, 550 NW LeJeune Road, eMiami, FL 33126-5671, ucingo 305-443-9353, ifeksi 305-443-7559, iwebhusayithi www.aws.org.
I-ASTM Intl., 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, ucingo 610-832-9585, ifeksi 610-832-9555, iwebhusayithi www.astm.org.
I-American Steel Structures Association, One E. Wacker Drive, Suite 3100, Chicago, IL 60601-2001, ucingo 312-670-2400, ifeksi 312-670-5403, iwebhusayithi www.aisc.org.
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