Umthamo wokuthwala womqadi ulinganiselwe phantse kuzo zonke iimeko kukugoba kwebhanti elixinzelelweyo. Oku kuvela kuphela xa sele kufikelelwe kumda wesivuno emva kokulingana kweengcinezelo kuyo yonke indawo kwilungu elixinzelelweyo. Kuphela xa kukho ukuxhaswa okuqinileyo emacaleni kunokunyuswa uxinzelelo lwasekupheleni olunokuthwala ukuya kummandla wokuqiniswa kwentsimbi yolwakhiwo. Xa kuvavanywa umthamo wokuthwala kufuneka kuthathelwe ingqalelo ulwabiwo lokwenene lweengcinezelo. Ukuba bekucingelwa ulwabiwo lweengcinezelo oluthe tye, umthamo wokuthwala ubuya kujongelwa phantsi. Iimeko zokungazinzi kufuneka zivavanywe ngokukhethekileyo.
Ukuncitshiswa kwemingxuma kwiinkxaso ezithwele ukugoba
Kwindawo etsaliweyo yesibonda kubakho buthathaka bamacandelo njengakwimivalo etsaliweyo (ukuqhekeka kwebhanti etsaliweyo kwicandelo elibuthathaka). Malunga nokuchasa imingxuma ngale ngqiqo kusebenza imigaqo efanayo naleyo yemivalo etsaliweyo.
Kuba imingxuma ezaliswe ziirivethi kwicala elicinezelweyo lesithwali inefuthe elincinane kakhulu ekusasazekeni koxinzelelo nasekuguqukeni, yaye amandla okuthwala ikakhulu ancitshiswa kukugoba ecaleni kwebhanti elicinezelweyo, ubungakanani bokuncipha kwicandelo kwizithwali ezinecandelo elilinganayo aluchaphazeli kakhulu umthwalo wokuthwala. Ngoko ke sele u F. Hartmann wabuza ukuba ingaba kuyimfuneko na kwizithwali ezilinganayo ukuba kuthathelwe ingqalelo konke konke ukuncipha okubangelwa yimingxuma. Kumacandelo angalinganiyo (icala elicinezelweyo linamandla ngakumbi) ukutsalwa kwemingxuma kwicala elitsalwayo lesithwali kungaba yinto egqibayo kumthamo wokuthwala. Phantsi komthwalo ophindaphindwayo rhoqo imingxuma iba nefuthe elibonakalayo, nokuba ikude kakhulu kwiintsinga ezisemaphethelweni.
Namhlanje ekubalweni komthamo wokuthwala wecandelo ekugobeni kusetyenziswa icandelo elipheleleyo neline-net (ukongeza kwezinye iindlela ezisebenzayo zokuqhawuka). Ukuqhawuka ngecandelo elipheleleyo kwenzeka kwinxalenye yecandelo engabuthathanga amandla ngenxa yemingxuma. Ukuqhawuka ngecandelo le-net kwenzeka kwicandelo elibuthathaka ngenxa yemingxuma, yaye indawo ethathelwa ingqalelo yindawo epheleleyo etsolo indawo yemingxuma yonke isuswe kuyo.
Iirivethi entanyeni nasentloko
Xa kugobile, ngaphandle koxinzelelo oluqhelekileyo, kuvela kwakhona iingeni zokucheba, ezithi kwizixhaso ezineebhanti ezihambelanayo zilingane nomkhosi onqamlezayo Q. Kwimimnqamlezo eyinkimbinkimbi, iirivethi ezidibanisa iiprofayili ezithile eziqengqelekileyo zifumana uxinzelelo lokucheba kwiindawo zonxibelelwano phakathi kwazo. Ukwabiwa kwemikhosi yokucheba T kwimbambo kumesembhile, kwiibhanti phantse kumgca othe tye. Kwizixhaso ezineebhanti ezinzima, T kwimbambo yahluke kancinci kwixabiso eliphakathi Tm, elihlala lanele kuqikelelo lokuqala.
Umz. 1
Izikhonkwane entloko (fig. 1b) kufuneka kunye zithwale amandla e-tenon TK < TH. Amandla e-tenon phakathi kweelamella ezahlukeneyo zebhanti asezantsi nangakumbi, yaye ngenxa yoko asatyalaliswa kwimeko ekwifig. 1c nakwinani elikhulu lezikhonkwane.
Ukwandiswa komthwali
Ukongezwa ngobude kwepleyiti ethe nkqo kuyafuneka xa ubude bepleyiti bungaphezulu kobubanzi beesinyithi ezikhoyo. Kunokuba yimfuneko kwakhona ngenxa yokwenziwa nokuthutha. Izibophelelo kunye neerevethi ekongezweni ngobude kwesixhasi kufuneka zithwale loo mandla inye TL, awayeya kuba nawo ipleyiti engangezelwanga kwindibaniselwano yobude. Kuba ukuncipha okubangelwa ngemingxuma kwizibophelelo kulingana ncam noko kwipleyiti ethe nkqo, ubukhulu besibophelelo kufuneka bube bukhulu okanye bulingane nobukhulu bembambo.
Sl. 2 - Ulwandiso olude lwephepha lesinyithi elime nkqo
Iyongezo esinqamlezayo phantsi komthwalo wokugoba sinokugutyungelwa ngeendlela ezahlukeneyo ziibhanti zokubophelela. Umz. 3 ubonisa amathuba aliqela eendawo zokuhlanganisa zefektri, apho iqhubeka kuphela ishiti elithe nkqo. Ukuba iibhanti zokubophelela zikho kuphela phakathi kweekona zeebhanti (umz. 3a), kusala imicu engagutyungelwanga yeshiti elithe nkqo phantsi kweekona zeebhanti. Emva koko iikona nezikhonkwane kummandla wokuqhubeka kweshiti elithe nkqo ziba nomthwalo omkhulu kakhulu, ngoko olu hlobo lwezihlanganisi kufuneka luthintelwe kwiintambo ezingabalulekanga ezinamandla amancinane. Kufuneka kusoloko kukhethwa isihlanganisi esigutyungelwe ngokupheleleyo. Iibhanti zokubophelela ezikhethekileyo kwiingalo ezithe nkqo zeekona zamkela iinzame ezide zale micu, kodwa zithatha inxaxheba kancinane kuphela ekwamkeleni amandla anqamlezayo. Uphuculo oluthile koku luziswa ngumz. 3c. Xa amandla emakhulu kufuneka kujongwe kwiibhanti zokubophelela kubude bonke beshiti elithe nkqo (umz. 3d), nto leyo ethetha ukuba iikona zeebhanti kufuneka ziqhawulwe. Iibhanti zokubophelela zifumana ubukhulu bengalo yekona, yaye xa iikona zinobukhulu obukhulu kusetyenziswa izibiyeli zokulinganisa ukuze konge kwizidima ezingeyomfuneko zebhanti lokubophelela.
Sl. 3 - Umdibaniso onqamlezileyo (owenziwa efektri) wepleyiti ethe nkqo
Umdibaniso wepleyiti ethe nkqo phantsi komthwalo wamandla enqamlezileyo: Umthwali kwindawo yomdibaniso unomthwalo kuphela Q (M = 0). Kumdibaniso onemigama efanayo yee-rivet (sl. 4) kufuneka kucingelwe ukuba amandla kwiirivet NiQ ahambelana ngokusondeleyo nento yendawo e*t yomdibaniso womdibaniso, oko kukuthi ukuba amandla kwiirivet asasazwa njengoxinzelelo lokucheba ukuphakama komthwali, NiQ = e*t*τi = e*Ti. Nangona kunjalo, ekulinganiseni kubalwa ukwabiwa okufanayo kuzo zonke iirivet n, NiQ = Q/n.
Sl. 4 - Ukuqhubekeka kwephepha elithe nkqo ngokusasazwa kwamandla okusika aphambili
Sl. 5 ibonisa isandiso seworkshop yentsimbi ethe nkqo (ii-engile zokuqinisa kunye neelamela ziqhubekisiwe kwenye indawo).
Umz. 5
Ukugoba ngokuqina okuqhelekileyo: Izixhasi ezithwala ngaxeshanye amaxesha okugoba kunye namandla aqhelekileyo ziyalinganiswa ngokwemigaqo efanayo nangaphantsi kwengcinga yosabelo loxinzelelo oluthe tye. Xa kususwa ngokupheleleyo iirivethi kuzo zombini ii-flange, icandelo elisebenzayo kunye nendawo yomgca onguziro azixhomekeki kuhlobo lomthwalo, ukuze uxinzelelo oluvela ku_M_ no_N_ lunokudityaniswa ngokulula. Umthwalo kwiirivethi ekuqhubekeni ufunyanwa ngokudityaniswa kwamandla avela kwiimeko zomthwalo ezinxenye M, okanye N.
Ukuxhaswa kunye nokudityaniswa kwenkxaso
Apha kuya kuqwalaselwa kuphela esona sisombululo siqhelekileyo phakathi kwezininzi. Xa kuvavanywa, kufuneka kusoloko kucingelwa ngemikhosi eyongezelelweyo efunyanwa ngenxa yokuphambuka kweendlela zokubala ukumelana, ezinamazinga amaninzi okanye amancinci okuba zigqibelele.
Ukuxhasa okulula kwesibambi esinye kwibhanti ephezulu yenye into yokwakha kuyasebenza xa kukho ukuphakama okukhulu kwesakhiwo okufumanekayo. Imeko eqhelekileyo yinqhagamshelo eliqinileyo ngeerivethi okanye izikrufu. Kumz. 6 kuboniswe ukuxhasa okuqhelekileyo kwee-I-roof trusses eziqhubekayo ekwakheni, okukwathintela ukubhola kwiimilenze ezimxinwa ze-I. Iisibambi kufuneka, kwimeko enikiweyo, zikhuselwe ekubhekelweni ngaphezulu nakwimimandla ethe nkqo (umz. 7 no 8). Ekwakhiweni kweebhulorho iisibambi zisoloko zidityaniswa ngababini (umz. 9); ukuxhaswa okungashukumiyo kwesibambi sobude kwisisibambi esinqamlezayo (umz. 10). Iisibambi kufuneka, xa kukho amandla amakhulu okuxhasa, zomelezwe ngee-angle irons ezifakelweyo okanye iiprofayili ezidibeneyo (umz. 8 ukuya ku 10). Kwiisibambi ezinzima, umthwalo kufuneka uqondiswe kwimbambo.
Umz. 6 - Ukuqinisa ii-rožnjača
Fig. 7 kunye 8
Sl. 9 no 10
Uqhagamshelo lweribhoni: Kwifig. 11 no 12 kuboniswe amakhonkco e-I-beam, asetyenziswa ekwakhiweni njengeziqhagamshelo eziqhelekileyo. Ukusikwa kufumana ujikelezo olukhulu, ukuze kuthintelwe ukuqhekeka kweribhoni yomqadi. Ukuqiniswa okuthambileyo kokuqhagamshelwa kweribhoni kuzisa ukonyuka okuthile kumthamo wokuthwala umthwalo. Iinguqu ezichaziweyo nangona kunjalo azinabungozi phantsi komthwalo ogudileyo ikakhulu, njengasemabhulorhweni amadala.
Sl. 11. - Uqhagamshelo oluqhelekileyo lwe-I-beam enecandelo lokugqibela elithe nkqo
Umz. 12 - Iidibaniso eziqhelekileyo ezinemiphetho ye-I-beam esikiweyo
Iinqhagamshelo eziqinileyo ekugobeni zenziwa xa kufunekayo uqhagamshelo ngaphandle kotshintsho lwe-engile (abaxhasi abaqhubekayo, iikona eziqinileyo zesakhelo) okanye xa kukho ingozi yokophuka ngenxa yokudinwa phantsi komthwalo oguquguqukayo, ingakumbi kwiibhulorho kaloliwe. Kungasetyenziswa iilamela zokuqhubekeka, iinqhagamshelo eziqinileyo ekugobeni. iikona eziqinileyo ekugobeni, iikona zesakhelo.
- Iilamela zokuqhubekeka – Ukuba kufuneka kudityaniswe abathwali abahleli kwinqwelomgca enye, ke omabini amabhanti aphezulu adityaniswa nge_ilamela_ okanye ibhandi yokuqhubekeka. Ngale ndlela, izikhonkwane zonxibelelwano ziyakhululeka kumandla okutsala yaye kuthintelwa ukuguquka okukhulu.
Sl. 13 - Uqhagamshelo olunelamela lokuqhubekeka
Sl. 14 - Unxibelelwano lwabathwali abade a) lwebhulorho kuhola wendlela; b) lwebhulorho kaloliwe
- Unxibelelwano oluqinileyo ekugobeni – Olu hlobo lonxibelelwano sifumana kwiikhonsoli eziqinileyo zeendlela zabahambi ngeenyawo kwiibhulorho zendlela. Kwiimomenti ezincinci ipleyiti yawo ethe nkqo iqhagamshelwe kuphela kabini phakathi kwee-angle zokuqinisa isibambi esiphambili. Imomenti efakwe apho isasazwa ngobuqiniso obongeziweyo kubo bonke ubude besibambi esiphambili, oko kukuthi ifakwa kwiibhanti zayo njengomdibaniso wamandla.
Umz. 15 kunye no 16
- Iikona eziqinileyo ekugobeni – Iikona eziqinileyo ekugobeni phakathi kweekholamu neepali ezixhasayo kwizakhiwo kufuneka zenziwe ngendlela yokuba ikona ingatshintshi yaye kungabikho kukhula kwengcinezelo kwindawo ethile. Uqhagamshelwano oluthembekileyo kwiikona lwenziwa, umzekelo, ngokwe sl. 16 xa kusetyenziswa iipleyiti ezinamaphiko okanye ngokwe sl. 100 xa i-moment yokubanjwa kwiibhanti zekholamu ithathwa njengeqela leemikhosi.
- Iikona zesakhelo – Kwiisakhelo ezineepoligoni, isandiso sinokwenziwa kwindawo yokugoba ukuba umahluko we-engile umncinci; iintonga ezidibeneyo zigqunywa ngamaqhina njengoko kusenziwa kwiintonga ezitsaliweyo nezinzima. Amandla okujika agxininiswe kwindawo yokugoba yaye kufuneka athatyathwe zii-stiffeners. Kwifig. 101 qaphela umahluko kwindlela kugqunywa ngayo isandiso nakwi-stiffening, kuxhomekeke kwicala lomzuzu wokugoba namandla okujika. Kwimeko yamandla amakhulu kunye nomahluko omkhulu kwi-engile, kuyathintelwa ukuba isandiso singene kwinxalenye egobile kakhulu yesakhelo. Izandiso ecaleni kweekona zesakhelo zivumela ubume obungcono bokwakha yaye zenza kube lula ukwenziwa. Imizekelo enezandiso ezijijelweyo zomhlaba wonke kumacala omabini endawo yokugoba iboniswa ngeefig. 102a kunye nefig. 102b, apho ikona iqulunqwe yinxalenye edityanisiweyo. Kwifig. 103 kuboniswa unxibelelwano oluqinileyo ekugobeni lwesithuba sesakhelo kunye ne-crossbar eqhubekayo.
Umz. 17a
Umz. 17b
Uqhagamshelo oluthambekileyo: Kwiinqhagamshelo ebezithethwe ukuza kuthi ga ngoku, ii-rib bezime nkqo enye kwenye. Ukuba i-engile, nangona kunjalo, ayikho tye, ke ii-angles (sl. 18) ziyajikwa, kwi-engile ezibukhali kakhulu kusetyenziswa iziqhoboshi ezimile njengomkrozo. Sebenzisa amabhanti okuqhubekeka kunye neziqwenga zokuxhasa kwimeko enikiweyo njengakwiinqhagamshelo ezithe tye. Amapleyiti aqhagamshelayo agobileyo (sl. 19) adityaniswe nge-eccentricity enkulu kunye nemikhosi eyongezelelweyo ebalulekileyo. Ukwenziwa kweenqakupheko ezithambekileyo kuyancedakala xa kusetyenziswa iiplate ezincinane ezidityaniswe ngentsimbi yokuwelda (sl. 20).
Fig. 18
Umz. 19
Umz. 20