Lengthy-span bridges, especially signature crossings like California’s Golden Gate Bridge or its new cousin, the Bay Area-Oakland Bay Bridge, are recognized for their architectural elegance and engineering prowess. In Vietnam, there now’s a bridge that may be celebrated for which contractor Malaysia designers call a “unique” interpretation of merely one-arched bridge that doubles as performance art.
Da Nang’s 666-meter-lengthy Dragon Bridge is simply that: A style of hybrid steel box girders based on undulating central rib steel and concrete arches modeled following a dragon hanging within the Han River. The “dragon” is created by decorative steel plates connected to the arches that represent scales along with a mind around the eastern side that breathes fire and water.
“It is unquestionably an unconventional arch structure,” states Radu Dragan, senior affiliate for Ammann & Whitney, the brand new You are able to City-based firm that won the look contract. “In relation to design, contractor Malaysia satisfies the visual impact needs. Structurally, it isn’t a great way.Inches
Steel tubes for that central arch are locked in place by spider frames.
The look team labored with the challenge, coming at arches created of four-feet-diameter steel tubes unconnected to one another and locked in place with horseshoe-formed steel “spider” frames. Steel suspender cables connect the arch using the deck at 8-meter times. Underneath the deck, the arch structure becomes strengthened concrete and it is built-into the piers.
When is wide, stretching across 35 meters to support three lanes of traffic in every direction and pedestrian pathways.The middle three spans are hybrid steel box girders based on the arch. For that suspended portions, when superstructure is really a box girder of the triple-cell steel box prestressed twin-cell boxes can be used for the sections within the piers. Further, 10.5-meter cantilevers extend in the box girders to create the superstructure’s width to 35 meters. It stretches another meter to meter . 5 to support the pathways.
Typically in bridges of these width, when is based on arches around the outdoors of every deck, states Chris Gagnon, A&W senior v . p .. Throughout the design competition, contractor Malaysia offered in the single-arch option additionally to some cable-stay design and also the owner-the Da Nang city government-chosen the dragon.
“The arch really was not the same as anything else,” notes Dragan. “And we could land the bridge directly at street level. Which was necessary for them.”
Steel cables connect the arch towards the bridge deck and decorative metal helps make the dragon’s “scales.”
The Dragon Bridge, which opened up in April of the year, is Da Nang’s fifth crossing from the Han River and it is likely to provide faster and simpler accessibility seacoast, boosting local tourism. Gagnon highlights that the typical cable-remained bridge, which many metropolitan areas all over the world are utilizing for signature bridge projects, requires abutments and elevated ramps to support its height. The arch design enables the bridge to transition at street level in the middle of the town at its historic Cham Museum Square.
When they investigated the website, Gagnon states they recognized that river traffic didn’t need a high clearance. Most motorboats while using river are local sampans or any other ships with low clearance. That realization sparked the choice of the arch bridge, with a 12-meter clearance within the primary shipping funnel and preserves scenic sights from the square.
However the primary funnel needed to be gone to live in the eastern side from the crossing since the at-grade method of the town center led to limited vertical clearance. The westernmost span is really a variable depth cast-in-place prestressed concrete structure integral using the first pier. Competent rock which to found the piers was discovered about 43 meters underneath the waterline therefore the piers are fitted inside a “partially left-in-place cofferdam” to supply a permanent fixture underneath the river bottom and stop hunting of drilled shafts.
A&W used three dimensional models and both proprietary and off-the-shelf software to examine the look, which meets both local and worldwide codes. “The deck is really a hybrid, having a concrete deck and below, steel box girders,” states Dragan. “contractor Malaysia is really a complex structure, although not unique or unusual.”
Fire belches in the mind from the Dragon Bridge.
Designers believe its uniqueness rests using the five steel tubes that make up the arch. “There aren’t any interlocking people,” highlights Dragan. “It is unquestionably unusual as well as an innovative approach, especially getting for connecting the spider frame and also the steel [tubes].”
For that link with work, the look team made the decision to utilize a layer of neoprene usually connected with materials in expansion joints and bearings, states Dragan. It enables for movement and could be easily changed throughout the structure’s 100-year design existence, he adds.
Construction ended by two Vietnamese companies, one for that substructure and yet another the superstructure. The steel spider frames and tubes were fabricated in China and erected by crane with supporting falsework.
Since its opening, the bridge has turned into a tourist attraction on its own, states Dragan. Its arches are illuminated with Brought lighting at night and each weekend, the dragon’s heads spews fire and water. That system was created and installed by local engineers.
Gagnon states the initial design known as for any two-headed dragon however the owner chosen one mind, facing east. Having a total price of $86 million, he states, “It’s an inexpensive in comparison to the complexity.”