Kev nthuav qhia yeej tsis muaj neeg txawv rau peb. Peb feem ntau dhau ntawm txoj kev loj thaum peb mus ncig, mus ua lag luam, thiab mus ntsib cov txheeb ze thiab phooj ywg. Cov tsheb uas tuaj thiab mus ntawm txoj kev, hla cov neeg suav tsis txheeb, yog lub cim ntawm lub nroog tsis khoom. Cov choj txuas ntau txoj kev ntug hiav txwv kuj dais lub siab ntawm tag nrho lub nroog.
The same goes for Canada's "TransCanada Highway", a system of highways that runs through 10 Canadian provinces. Thousands of passengers rely on this highway system to travel. Like many highways, TransCanada also has many reinforced concrete bridges connecting the various highways. However, after prolonged exposure to the sun and rain, the steel structure is corroded, and the bridge will be left with serious durability problems, resulting in structural degradation and expensive repair costs. In 2013, the Ontario Ministry of Transportation (MTO) launched a 106 million project to replace the Nipigon Riverbridge with two flat-span, four-lane bridges that demonstrated composite fiberglass reinforcement Can replace threaded rebar.
The Nipigon River Bridge is a cable-stayed bridge for Ontario's highway system and the world's first cable-stayed bridge using glass fiber reinforced polymer reinforced concrete (GFRP-RC) decks. This kind of GFRP is composed of vinyl ester resin and boron-free E glass fiber.
Txawm li cas los xij, los ntawm qhov kev xav ntawm engineering, cables - nyob txuas txuas yog qhov nyuaj dua rau kev tsim dua li cov choj ib txwm siv vim tias lawv raug kev nyuaj siab txog li 9000 psi (pounds ib square inch). Benmokrane tau hais tias nws tsis yooj yim sua kom kho lub lawj ntawm lub cable - nyob twj ywm thaum lub pob zeb pib deteriorate.
It was very important for the MTO to approve a design with a structural component like GFRP that would prove to be very durable as it would not require any major repairs for over 100 years. "Even if there's nothing wrong with GFRP, the tilt could come from the concrete itself," Benmokrane said.
"So you really have to choose composites!"
Benmokrane and his team researched, built eight panels—six GFRP-RC panels and two rebar panels—and tested them for cracks. The 220 mm wide ultra-high performance fiber reinforced concrete (UHPFRC) connected GFRP bars have high tensile strength and elastic modulus without obvious cracks.
Ua haujlwm nrog MTO, MMMGroup (tam sim no hu ua WSP) thiab Buckland Taylor, Benmokrane tsim 480 GFRP-RC panels ntsuas 3 x 7 meters, nrog rau 15 thiab 20 mm tuab GFRP-RC txoj kev txhawb nqa. Tag nrho txog 350, 000 meters ntawm GFRP tuav tau siv rau ntawm lub lawj.
Two construction companies, BotConstruction and FerrovialAgroman, accelerated the construction process by precasting the panels within the tower and connecting them with UHPFRC. After building the bridge deck, Bot and Ferrovial drove a total of 182 steel piles 50 to 70 meters deep for the cast-in-place substructure, which is 75 meters high, measured from the bridge's foundation base. They then placed a prefabricated multi-beam center pier about 51 meters above the deck. The beams are connected to the bridge by 66 steel cables.
Tus choj tau ua ob ntu.
He believes the bridge is a landmark achievement for the composites industry as it promises to further expand composites into the infrastructure market. At the International Bridge Conference in National Harbor, Maryland, Benmokrane presented the bridge's design and the benefits of FRP. He said he was delighted, "Based on the feedback I got, I really hope that in the future we will see more bridges around the world using this type of reinforcement," Benmokrane said. "These bridges are very economical, elegant, and have a high aesthetic value," and is optimistic that applications like the Nipigon River Bridge could open doors for many composite companies.
Tus nqi pib ntawm lub pob zeb txuas ntxiv nrog GFRP tuav yuav luag zoo ib yam li tus choj txuas ntxiv nrog epoxy-coated lossis galvanized steel tuav, nws hais. Tus nqi ntawm stainless hlau rebar kuj yog 2 mus rau 4 npaug ntawm GFRP rebar.
Pulwell tau cog lus rau kev sib txuas lus hauv online ntawm iav fiber reinforcement kev lag luam, muab khoom thiab kev thov ntawm GFRP / FRP rebar, cov khoom tshiab nce qib, cov ntaub ntawv kev lag luam, kev lag luam tsom xam, nqe siv thiab lwm yam kev pab dawb. Cov duab thiab cov ntawv tau muab los ntawm Is Taws Nem; Yog tias muaj kev cuam tshuam txog kev cai lij choj, thov qhia rau peb paub, peb nyob nruab nrab ntawm cov kev xav hauv cov ntawv nyeem.
