In regions with low seismicity such as Europe and parts of the US, many bridge superstructures borrow ideas from Lego blocks in that segments are pre-cast and assembled at the final construction site.
Now the technique has been modified and could be applied in earthquake-prone Taiwan, the National Center for Research on Earthquake Engineering announced yesterday.
The new technique will be used for the first time in Taichung, where two bridges will be built to connect the Formosa Freeway (Freeway No. 3) with Taichung City's expressway system, with construction beginning as early as May.
PHOTO: COURTESY OF NATIONAL APPLIED RESEARCH LABORATORIES
"Building pre-cast segmental bridges offers several advantages," said project leader Chang Kuo-chun (張國鎮), professor and chairman of the National Taiwan University Department of Civil Engineering.
Because pre-cast bridge segments are fabricated in factories, they are solid in quality when compared with bridges that are constructed on-site, Chang said, adding that while traditional bridges average a 50-year lifespan, the pre-cast segmental bridges may last up to 75 years.
"The bridges have accelerated construction time and better work environments for workers because less construction occurs in high-rise settings. Also, there is less traffic disruption because of the shorter construction time," he said.
But one of the biggest advantages of pre-cast segmental bridges is that because they are only assembled on-site, less land is required for construction, so the bridges create a reduced environmental impact, he said.
As a result, pre-cast segmental bridges abroad are mostly built in environmentally sensitive regions, such as the famous Linn Cove viaduct in North Carolina in the US, where the bridge blocks were suspended in a top-down style and the bridge hugs the belt of the cove loosely to preserve the original beauty of the scenic area, he said.
The key to making pre-cast segment bridges work in Taiwan lies in padding them with complementary seismic isolation systems, or threading energy dissipating (ED) reinforcement steel rods through the blocks after assembly, Chang said.
"We have made three types of bridge columns: one with no ED rods, one with moderate ED rods and one with high ED rods," he said.
A computerized earthquake test revealed that the third type with high ED rods demonstrated the best seismicity resistance, Chang said, adding that whether the second type or third type better suits the needs of Taiwan required more research and experimentation.
"However, the first type of columns [no ED rod] can be built in the least amount of time, which is good for places where construction time needs to be tightened, like when bridges are built in urban areas with heavy traffic," Chang said, adding that such columns would need to be fitted with seismic isolation systems.
The new bridges to connect the Formosa Freeway and the Taichung City expressway system will use exactly that, said deputy director of the Taiwan Area National Expressway Engineering Bureau design division Chen Kuo-long (
Asked whether the Suhua Freeway construction team might consider the newest technique, Chen said the change would "require a whole new drafting of the construction plan."
"However, it is true that this technique is good for environmentally sensitive regions," he said.
An essay competition jointly organized by a local writing society and a publisher affiliated with the Chinese Communist Party (CCP) might have contravened the Act Governing Relations Between the People of the Taiwan Area and the Mainland Area (臺灣地區與大陸地區人民關係條例), the Mainland Affairs Council (MAC) said on Thursday. “In this case, the partner organization is clearly an agency under the CCP’s Fujian Provincial Committee,” MAC Deputy Minister and spokesperson Liang Wen-chieh (梁文傑) said at a news briefing in Taipei. “It also involves bringing Taiwanese students to China with all-expenses-paid arrangements to attend award ceremonies and camps,” Liang said. Those two “characteristics” are typically sufficient
A magnitude 5.9 earthquake that struck about 33km off the coast of Hualien City was the "main shock" in a series of quakes in the area, with aftershocks expected over the next three days, the Central Weather Administration (CWA) said yesterday. Prior to the magnitude 5.9 quake shaking most of Taiwan at 6:53pm yesterday, six other earthquakes stronger than a magnitude of 4, starting with a magnitude 5.5 quake at 6:09pm, occurred in the area. CWA Seismological Center Director Wu Chien-fu (吳健富) confirmed that the quakes were all part of the same series and that the magnitude 5.5 temblor was
The brilliant blue waters, thick foliage and bucolic atmosphere on this seemingly idyllic archipelago deep in the Pacific Ocean belie the key role it now plays in a titanic geopolitical struggle. Palau is again on the front line as China, and the US and its allies prepare their forces in an intensifying contest for control over the Asia-Pacific region. The democratic nation of just 17,000 people hosts US-controlled airstrips and soon-to-be-completed radar installations that the US military describes as “critical” to monitoring vast swathes of water and airspace. It is also a key piece of the second island chain, a string of
The Central Weather Administration has issued a heat alert for southeastern Taiwan, warning of temperatures as high as 36°C today, while alerting some coastal areas of strong winds later in the day. Kaohsiung’s Neimen District (內門) and Pingtung County’s Neipu Township (內埔) are under an orange heat alert, which warns of temperatures as high as 36°C for three consecutive days, the CWA said, citing southwest winds. The heat would also extend to Tainan’s Nansi (楠西) and Yujing (玉井) districts, as well as Pingtung’s Gaoshu (高樹), Yanpu (鹽埔) and Majia (瑪家) townships, it said, forecasting highs of up to 36°C in those areas
RSS