Thaum tom qab tensioning, cov leeg tau muab rau hauv cov kav dej ntawm cov tswv cuab precast. Yog li qhov poob hauv prestress tshwm sim vim kev sib txhuam ntawm cov pob zeb nto thiab cov leeg hauv cov txheej txheem ntawm tensioningQhov poob ntawm kev sib txhuam kuj yog nrog cov nyhuv wobble.
Vim li cas thiaj muaj kev poob siab?
2.1.1 Prestress losses
Instantaneous poob xws li kev sib txhuam, elastic shortening (ES) thiab zaum poob los yog anchorage slip. Kev poob lub sij hawm ntev tshwm sim nyob rau lub sijhawm. Lawv suav nrog kev poob hauv prestress vim yog pob zeb creep (CR), shrinkage (SH) thiab so ntawm prestressing strands (RE)
Vim li cas qee qhov kev poob raug txiav txim siab hauv kev tsim cov tswv cuab prestressed?
Prestressing a cov tswvcuab ua tau zoo siv lub zog axial ntau heev rau cov tswvcuab uas nyob hauv qhov chaw rau nws lub neej kev pabcuam tag nrho. … Qhov kev txo qis hauv kev quab yuam no raug xa mus rau qhov kev poob qis ib nrab thiab raug hais raws li ib feem ntawm kev tsim cov tswv cuab prestressed.
Vim li cas kev poob siab ua rau lub luag haujlwm tseem ceeb ntawm kev ua haujlwm ntawm cov tswv cuab prestress?
Qhov tseeb, lub zog prestressing yog siv los tswj cov kab nrib pleb, kom txo qis deflections thiab ua kom ib nrab counterbalance cov nyhuv ntawm cov tuag thiab nyob loads. Raws li qhov tshwm sim, kev poob siab ntau dhau tuaj yeem ua rau muaj kev puas tsuaj rau kev ua haujlwm ntawm PRC cov ntsiab lus, tshwj xeeb tshaj yog nyob rau hauv cov qauv kev laus uas twb muaj lawm.
Yuav ua li cas koj thiaj li txo qhov poob hauv kev ntxhov siab?
Yog tias qhov kev ntxhov siab thawj zaug hauv cov hlau paub, qhov feem pua ntawm kev ntxhov siab vim qhov elastic deformation ntawm cov pob zeb tuaj yeem suav tau. thiab the methowd ntawm kev kho siv cov pob zeb muaj zog siab nrog cov dej cement qis ua rau txo qis thiab ua rau poob ntawm prestress.
