Haɗaɗɗen gine-gine

** Muhimmiyar sanarwa da fasaha da aminci:** Wannan rubutun ilimi ne, ba ƙirar tsari ba, ƙididdigewa a tsaye, ma’auni mai dacewa, dalla-dalla na haɗin gwiwa ko umarni don aiwatarwa, walda, haɗawa, shoring, prestressing ko gyarawa. Duk ainihin ƙididdiga, alamomi, girma, kayan aiki, matakai da da’awar ana canja su ba tare da tabbatarwa ba bisa ga ƙa’idodin yau. Zanewa da aiwatar da sifofi masu haɗakar ƙarfe-kwankwalwa nasa ne na musamman na injiniyoyin farar hula masu izini, masu zanen tsari, ƴan kwangila da kulawa dangane da takamaiman abu, kaya, ƙasa, abu da ƙa’idodi masu dacewa.

Gine-ginen da aka haɗa ba sabis na musamman ba ne a cikin tayin jama’a na Savo Kusić na yanzu. Abin da ake mayar da hankali a yanzu shine gilashin katako, itace-aluminum Taga da kofofin al’ada. Don aikin taga ko kofa, zaku iya aika da buƙatun ƙira.

Gabatarwa

A wasu gine-gine, ana amfani da ƙwanƙwaran siminti masu goyan bayan ƙarfe, kamar shingen gadoji na gadoji a kan ginshiƙai na I-tsawon tsayi ko maɗaukakiyar ɗakuna a cikin gine-gine akan I-girders. A baya can, irin waɗannan tsarin sun kasance masu girma a ƙarƙashin zaton cewa waɗannan abubuwa biyu za su iya motsawa tare da juna kuma cewa lokutan da ke cikin jagorancin babban lokaci an karɓa ne kawai ta hanyar tallafin karfe. Ƙarƙashin kankare ya canza nauyin kaya zuwa ginshiƙan ƙarfe, amma bai shiga cikin karɓar daidaitattun ƙididdiga ba (fig.1).

Hoto1- Mai ɗaukar kaya guda biyu, tsarin

Don wannan hanyar gini, ana hango mahaɗan da ke jujjuyawa a cikin simintin siminti a lokaci-lokaci, don ba da damar raguwar simintin da aka ƙarfafa da kuma guje wa faɗuwar da ba a so, watau ƙarin damuwa. Duk da haka, kwarewa ta nuna cewa ainihin dakarun da ke cikin irin wannan tsarin sun bambanta da waɗanda aka ƙidaya. A hulɗar da ke tsakanin simintin simintin da aka ƙarfafa da goyon bayan karfe, babban juzu’i yana faruwa (danniya adhesion), don haka abubuwa biyu suna yin aiki koyaushe.

Rashin hasara na tasirin haɗin gwiwa wanda ba a tsammani ba shine bayyanar sakamako mai mahimmanci a kan haɗin gwiwa na shinge na kankare. Matsanancin ƙarfi tare da saman abutment yana ƙaruwa sosai kusa da haɗin gwiwa, kama da damuwa mai ƙarfi a ƙarshen kabu na gefe. Tunda matsayin layin sifili a haɗin gwiwa a zahiri baya canzawa, damuwa na yau da kullun a cikin tallafin ƙarfe na iya zama babba fiye da waɗanda aka ƙididdige su don haɗawa iri ɗaya. An fara daga wannan daraja, ƙwarewar mannewa na iya faruwa wanda ke yaɗuwa gaba. Sabili da haka, haɗin gwiwa a cikin shimfidar shimfidar wuri ba su cika aikin su ba kuma ba su da tasiri.

Masu ɗaukar kaya guda biyu

A cikin yanayin goyon bayan haɗin gwiwa, an ɗauka cewa dakarun da aka yi wa shinge a kan haɗin gwiwa tsakanin goyon bayan karfe da shinge na kankare za a iya yada su cikin aminci (ƙarfi a cikin katako). Ka’idar ita ce shingen kankare yana dogara kai tsaye a kan bel na sama na tallafin karfe kuma cewa babu motsin dangi. A wannan abin da ake kira rigid coupling yana amfani da hanyoyin haɗin gwiwa na musamman (sanduna, masu motsa jiki, anchors), waɗanda aka haɗa su cikin siminti.

Za mu yi la’akari da yanayin katako mai haɗe tare da shingen kankare ba tare da haɗin kai ba. Idan wani nau’i (misali lokacin lanƙwasawa) yana aiki na ɗan gajeren lokaci, madaidaicin damuwa da nakasar Δσ, resp. Δε bisa ga kimiyyar ƙarfin farko, kama da siminti mai ƙarfi. Matsaloli a cikin ƙarfe da kankare, a wani ƙayyadaddun haɓakawa, suna tsayawa dangane da yanayin elasticity ɗin su: σst/σb = Est/Eb = n. Idan nauyin ya kasance na dogon lokaci, lalacewar simintin yana faruwa saboda raguwa da gudana. Idan tare da ε0= σ/E0 Alama nakasar saboda nauyin ɗan gajeren lokaci a halin yanzu t =0, nakasar tana ƙaruwa ƙarƙashin nauyin dindindin saboda gogayya har zuwa lokacin t zuwa ƙimar εt = ε0(t + φt). A ƙarƙashin yanayi guda, ana ƙididdige nakasar amfanin gona kamar dai sun yi daidai da matsi. Shi ya sa aka ce dokar Hooke ta shafi nakasa saboda kwarara. Matsakaicin kwarara φt ya dogara da lokaci, aji na kankare, zafin jiki na waje, zafi na iska, lokacin loda kayan, da sauransu.

Maimakon lankwasawa bisa ga Bernoulli\ da Navier, dangantaka ta bambanta ta bayyana, watau rarraba damuwa ya kamata a ƙayyade daga ma’auni daban-daban don gudana. Sakamakon kwararar ruwa, damuwa a cikin simintin yana raguwa, yayin da damuwa a cikin karfe ya karu. Wadannan canje-canje na damuwa sun dogara, ban da ma’auni na giciye, akan ma’auni na roba da lokacin kaya. Irin wannan sakamakon kamar daga kwarara yana faruwa daga raguwar kankare. Yawan shrinkage matakan εs ya dogara da kankare, hanyar samar da shi, da kuma yanayin yanayi. Ƙunƙarar ƙanƙara ba ta dogara da nauyin da aka yi amfani da shi ga kashi ba.

Haɗin kai yana nufin

Dole ne hanyoyin haɗin haɗin gwiwa su canza duk ƙarfin da ke cikin siminti da saman ƙarfe a cikin tuntuɓar, saboda nauyin da ke faruwa, don haka hana zamewa. Bugu da ƙari, ya kamata su karbi manyan rundunonin tashin hankali, idan saboda girman su, sashin simintin kanta ba zai iya karɓar su ba. An ƙayyade girman sojojin bisa ga ka’idar lanƙwasa ta farko. Ana ɗaukar waɗannan a matsayin hanyoyin haɗin gwiwa:

- Maɗaukakin haɗaɗɗiya: Waɗannan faranti na ƙarfe ne zagaye ko lebur, waɗanda aka yi musu walda zuwa bel na sama na abin ɗamara na ƙarfe, waɗanda ke aiki daidai da lanƙwasa ƙarfafan katakon siminti. Ana yin su azaman ƙugiya ko ƙugiya, a tsaye ko a tsaye. Waɗannan angarorin suna aiki ne kawai a hanya ɗaya kuma ba su da tasiri idan ƙarfin ƙarfi ya canza alamar.

- Girders: An haɗa su zuwa saman saman goyon bayan karfe, za su iya karɓar dakarun shearing a bangarorin biyu. Ya kamata a bambanta tsakanin kwakwalwa masu laushi da tauri a cikin hanyar da ake yi da karfi. Kwayoyin kwakwalwa masu laushi suna fama da nakasu mai mahimmanci kuma suna rarraba karfin juzu’i a saman su. Ƙunƙarar takalmin gyaran kafa na samar da ingantacciyar rarraba ƙarfi a ƙananan nakasassu.

Hoto2- Gada akan Kogin Ruhr kusa da Herdecke

• Ƙarfafawar Karfe: Yana dogara ne akan tallafin ƙarfe kuma ana walda shi a wuraren tuntuɓar. Spirals ba su dace da manyan rundunonin haɗin gwiwa ba. Haka abin yake ga gwanayen karfe. A matsayin misali na hanyoyin haɗin gwiwa akan gadoji, a cikin fig.2ana nuna kwakwalwar gadar kan kogin Ruhr kusa da Herdecke (kwakwalwa60x40tare da motsa jiki na tsaye ϕ12, waɗanda ake welded zuwa kwakwalwa da kansu, don guje wa ƙarin yanke daga walda; a cikin fig.3ma’ana don haɗa maɗauran maɗaukakin gada ɗaya, dangane da girman ƙarfin juzu’i, an yi amfani da ƙwanƙwasa masu walƙiya a kai tsaye don ƙuƙumman, da kuma ƙwanƙwasa kai tsaye don bel na sama tare da ginshiƙai na musamman. A cikin yanayin dogayen motsa jiki, za a iya yin welded ɗin a sassa daban-daban, fig.4a. A cikin fig.4b yana nuna mafita tare da ɓacin rai.

Hoto3- Giciye katako na gada daya

Hoto4- Kwakwalwa tare da motsa jiki

A cikin gine-gine, ana amfani da maƙarƙashiya mai tsauri tare da masu tayar da hankali ko kawai masu motsa jiki, amma ana samun mafita tare da masu laushi masu laushi, irin su sasanninta. Don dalilai na tattalin arziki, ana amfani da anka mai haɗin kai, waɗanda aka haɗa su da goyan bayan karfe, sau da yawa (fig.5a), ko hutawa a kan goyan baya tare da lanƙwasawa ɗaya (fig.5b). A cikin fig.5c yana nuna madaidaicin bayani tare da ƙugiya masu ƙaura. A cikin fig.6an nuna bayani na al’ada na goyon bayan rufi a cikin ginin gine-gine, wato a) goyon baya guda biyu da aka yi da I-beams, b) wanda aka yi da T-beams, wanda aka halicce shi ta hanyar yanke I-beams. A ƙarshen goyan bayan, musamman maƙarƙashiya mai ƙarfi ya kamata koyaushe a ba da ita (fig.7). Ana amfani da anchors masu ƙima don gabatar da damuwa daga raguwa da zafin jiki a cikin katako.

*Hoto5- Anchors masu haɗawa *

Hoto6- Taimakon tsarin mezzanine

Ana aiwatar da girman hanyoyin haɗin gwiwa bisa ga ka’idodin farko. Hannun daidaikun mutane yakamata su sami ƙarfi mai ƙarfi daidai da tazarar su. Lokacin da ake ƙididdige haɗin welded na kwakwalwa, ya kamata a yi la’akari da lokacin jujjuyawa.

Hoto7- a) Ƙarshen ƙwaƙwalwa tare da anga; b) atamfa

Haɗin kai na roba

Abubuwan gabatarwa da suka gabata sun yi magana game da rigid coupling, inda matsugunin dangi tsakanin tallafin karfe da farantin ya yi daidai da sifili, kuma haɗin kai yana nufin yin aiki akai-akai. Ƙarƙashin haɗin kai yana nufin, lalacewar gida na simintin da goyon bayan karfe an yi watsi da su.

Hoto8- Bracket tare da haɗin gwiwa na roba

Karkashin zato na tsattsauran ra’ayi, sojojin da ake watsa ta hanyar haɗin kai ɗaya daidai suke da ƙarfin juzu’i da tazarar kwakwalwa. Idan gagarumin motsi na dangi tsakanin tallafin karfe da simintin simintin ya faru a wasu wurare, wannan yana haifar da tsattsauran ra’ayi na sake tara sojoji. Kankare na iya ɗan dakatar da aiki azaman farantin matsi na katako mai haɗe-haɗe, ta yadda matsakaicin ƙimar ƙarfin ƙarfi ya ragu sosai. A cikin fig.8An ba da misali na wani gini tare da haɗin gwiwa na roba, kama da na gadar da ke kan Rhine, Koln-Rodenkirchen. A cikin fig.9Ana nuna tasirin haɗin gwiwa na roba a kan ci gaba da goyon baya, don ƙarfin da aka tattara da kuma cikakken nauyin da aka rarraba. Matsar da ψ, wanda shine ma’auni na taurin haɗin kai don karɓar shear, an bayyana shi a cikin fig.8. Saboda haka tasirin haɗin gwiwa na roba yana da girma sosai, idan an zaɓi halayen haɗin gwiwa da gangan don karɓar shear.

Hoto9- Misali ga gada tare da haɗin gwiwa na roba

Lissafin gine-ginen guda biyu

A ka’ida, yana da tattalin arziki cewa kauri na shinge na kankare ya kamata ya zama ƙananan kamar yadda zai yiwu, yayin da ƙananan ƙananan ƙayyadaddun ƙayyadaddun ƙa’idodi ya kamata a bi.

Tsarukan da aka ƙaddara a tsaye

A cikin yanayin ƙayyadaddun ƙayyadaddun gine-gine (misali katako mai sauƙi), tasirin tasiri a cikin sashe na gama gari don takamaiman kaya na dindindin ne, ko masu zaman kansu na lokaci. Lokacin lanƙwasawa kawai da ƙarfin al’ada a wasu sassa na sashin suna canzawa saboda tasirin kwarara da raguwa.

Ana iya wakilta tasirin raguwa a matsayin bambancin zafin jiki mai dacewa tsakanin karfen karfe da shingen kankare. Sakamakon raguwar kankare, damuwa na ciki ya bayyana a cikin sashin da aka haɗa, wato damuwa mai ƙarfi daga raguwa a cikin simintin, wanda aka hana shi ta hanyar tasirin tallafin karfe (da kuma ƙarfafawa kanta), yayin da matsalolin matsawa masu dacewa suna faruwa a cikin sashin karfe (Fig.10). Ƙunƙasa yana ƙaruwa tare da lokaci zuwa ƙimar ƙarshe bisa ga aikin juzu’i ɗaya. Tun da damuwa na raguwa kuma yana ƙaruwa tare da raguwar lalacewa, wannan yana haifar da abin da ake kira shrinkage flow.

*Hoto10- a) Raunin farantin kyauta ba tare da haɗuwa ba; b) damuwa saboda raguwa a cikin tallafi guda biyu *

Dangane da tsarin tsarin da ke ɗaukar nauyin nauyin kai na shinge na kankare, ya bambanta: haɗawa kawai don nauyin motsi (kawai tallafin karfe yana ɗaukar nauyin kansa, kuma tsarin da aka haɗa yana karɓar nauyin nauyin da ke aiki akan tsarin da aka gama), haɗuwa don nauyin kansa da nauyin motsi (dukan nauyin kai da nauyin motsi yana aiki akan tsarin da aka haɗa).

Halin farko yana faruwa ne lokacin da ginshiƙan ƙarfe ke aiki a matsayin girders na formwork, ba tare da an tallafa musu ba, kuma yayin haɗakarwa, suna iya tanƙwara a filin (fig.11a). A wannan yanayin, tallafin ƙarfe da kansa yana ɗaukar nauyin siminti da tsari. Haɗin kai yana faruwa ne kawai lokacin da kankare ya yi ƙarfi sosai (Fig.11b), kuma ba dole ba ne a ɗora nauyin tallafin nan da nan bayan an haɗa shi, don guje wa lalacewa ko kwararar siminti.

A cikin shari’a ta biyu, lokacin da tsarin da aka haɗe ya karɓi nauyin kansa na shingen kankare (Fig11c), an ɗauka cewa ana tallafawa tallafin ƙarfe yayin yin gyare-gyare a isassun wurare, don kada ya sami lokacin lanƙwasawa mai mahimmanci. Ana nuna rarraba wutar lantarki bayan cire ɓangarorin a cikin fig.11d.

*Hoto11- Haɗin kai don motsi da ɗaukar nauyin kai, tare da rarraba wutar lantarki kafin da bayan cire ɓangarorin *

Preload

A cikin yanayin ƙananan katako, ƙananan ƙananan damuwa suna faruwa a cikin kankare kawai saboda raguwa da bambance-bambancen zafin jiki. Matsananciyar damuwa mai ƙarfi yana faruwa a cikin filayen katako, ci gaba da girders da sauran sifofi, kuma waɗannan na iya haifar da tsagewa a cikin siminti. Idan fashe ya bayyana a cikin yanki na lokuta mara kyau, tasirin haɗuwa ya ɓace. Sabili da haka, yana da amfani don haifar da ƙananan matsalolin matsawa a cikin simintin simintin a gaba don guje wa samuwar fashe saboda raguwar kankare. Za’a iya rage yawan damuwa a cikin simintin simintin katako na katako guda biyu:

1. Ta hanyar madaidaicin preloading mara kyau na ginshiƙan ƙarfe (ƙirar saman gefen). Har ila yau, ya kamata a yi nazari a hankali a kan jerin abubuwan da ake yi na concreting.

2. Ta hanyar haɓakawa da raguwar tallafi na tsakiya na ci gaba da tallafi. Ta haka, tare da hanyar da ta dace, za a iya haifar da matsananciyar damuwa a cikin shingen kankare na goyon bayan haɗe-haɗe.

3. By prestressing. Mafi sauƙaƙan yanayin shine lokacin da aka riga aka rigaya bel ɗin kankare kyauta, kuma daga baya an haɗa shi da tallafin ƙarfe. Amfanin wannan hanya shine ƙananan ƙananan ƙarfin prestressing, tun lokacin da bel ɗin da aka matsa na goyon bayan karfe ba a rigaya ba. Wannan girdar yana karɓar lokacin lanƙwasawa kawai saboda kwarara da raguwar shingen kankare, don haka ya kasance madaidaiciya saboda ƙarfin da aka rigaya. A cikin fig.12kuma ana nuna rarraba damuwa don wannan yanayin na prestress (t=0), kuma cikin fig.12b yanayin ƙarshe a ƙarshen kwarara (t=tE) kuma a cikin fig.12c lankwasawa saboda ɗan gajeren lokacin lodawa (t=a). A cikin fig.12d yana nuna rarraba wutar lantarki don t=0 a yanayin yin prestressing ɗin da aka ɗaure.

Hoto12- Ƙaddamar da shingen kankare mai kyauta tare da haɗin gwiwa na gaba

Gine-ginen da ba a tantance ba a tsaye

Ci gaba da girders da makamantansu suna karɓar lokacin lanƙwasa mara kyau, wanda galibi yana haifar da damuwa mai ƙarfi a cikin shingen kankare da aka ƙarfafa. Cracks ba a so, musamman a gadoji, la’akari da rayuwar sabis na ma’auratan da aka haɗa da kuma tasirin notches a kan raguwa. Ana ƙididdige tsarin tsarin da ba a tantance ba don ɗaukar nauyi na ɗan lokaci (moving loads) bisa ga hanyoyin da aka saba na ƙididdiga don tsarin da ba ya canzawa. Matsakaicin madaidaicin adadi da nakasawa iri ɗaya ne da a cikin ingantaccen tsarin roba. Ƙarƙashin tasirin ɗorawa akai-akai, musamman maɗaukakin prestressing, babban kwarara yana faruwa koyaushe. Lokacin da aka ƙayyade ƙarfin prestressing, ya kamata a yi la’akari da gogayya na abubuwan da aka lanƙwasa. A yayin ginin, ya kamata a zaɓi overhangar gadoji guda biyu a hankali. Tallace-tallacen da aka yi da shirye-shiryen haɗin gwiwa suna da ƙarfi sosai, don haka kusan ba zai yuwu a yi gyare-gyare na gaba na matsayi mai tsayi ba. Ana samun matakin ƙarshe ne kawai bayan shekaru da yawa, la’akari da kwarara. Wannan matakin ba shi da tabbas har zuwa wani lokaci, tun da tasirin raguwa da kwararar ruwa suna canzawa, ya danganta da yanayin yanayin da ba za a iya annabta ba.

Kammalawa

Aikace-aikacen haɗakarwa ba’a iyakance ga katakon ƙarfe ba, amma kuma yana iya haɗawa da goyan bayan ƙulla katako na Langer, gadoji na dakatarwa, da sauransu. Lattice gadoji - matsananciyar damuwa yana faruwa a cikin shingen titin kusa da titin da ke ƙasa, tunda waɗannan slabs ɗin dole ne su bi zuwa babba ko ƙarami haɓakar bel ɗin da ke da ƙarfi na babban girder. Ana buƙatar isassun prestressing na tsaye don guje wa fasa. A cikin fig.13akwai shari’ar kan iyaka wanda grid ɗin karfe ba ya da ƙaramin bel kwata-kwata, kuma aikinsa yana ɗauka gabaɗaya ta hanyar ƙwanƙwasa ƙwanƙwasa da aka riga aka kayyade ta bangarorin biyu. A cikin fig.13b magudanar ruwa na sashin suna bayyane60x180mm a cikin goyon bayan kanta.

Hoto13- Gahle gada: a) sashe; b) mahadar ƙananan bel, hagu a babban tashar, dama a Vešaljka