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Jembatan Chesapeake Bay (Tunnel)
The Chesapeake Bay Bridge–Tunnel (CBBT) is a 23-mile-long (37 km) fixed link crossing the mouth of the United States' Chesapeake Bay and connecting the Delmarva Peninsula's Eastern Shore of the state of Virginia with Virginia Beach and the metropolitan area of Hampton Roads, Virginia.
The bridge–tunnel originally combined 12 miles (19 km) of trestle, two 1-mile-long (1.6 km) tunnels, four artificial islands, four high-level bridges, approximately 2 miles (3.2 km) of causeway, and 5.5 miles (8.9 km) of approach roads—crossing the Chesapeake Bay and preserving traffic on the Thimble Shoals and Chesapeake shipping channels. It replaced vehicle ferry services which operated from South Hampton Roads and from the Virginia Peninsula from the 1930s until completion of the bridge–tunnel in 1964. The system remains one of only ten bridge–tunnel systems in the world, three of which are located in Hampton Roads, Virginia.
Since it opened, the Chesapeake Bay Bridge–Tunnel has been crossed by more than 100 million vehicles.[2] The CBBT complex carries U.S. Route 13, the main north–south highway on Virginia's Eastern Shore, and, as part of the East Coast's longstanding Ocean Highway, provides the only direct link between the Eastern Shore and South Hampton Roads regions, as well as an alternate route to link the Northeast and points in between with Norfolk and the Carolinas. The bridge–tunnel saves motorists 95 miles (153 km) and 1½ hours on a trip between Virginia Beach/Norfolk and points north and east of the Delaware Valley without going through the traffic congestion in the Baltimore–Washington Metropolitan Area. The $13 toll is partially offset by some savings of tolls in Maryland and Delaware on I-95.
Financed by toll revenue bonds, the bridge–tunnel was opened on April 15, 1964.[1] It was officially named the Lucius J. Kellam Jr. Bridge–Tunnel in August 1987 after one of the civic leaders who had long worked for its development and operation. However, it continues to be best known as the Chesapeake Bay Bridge–Tunnel. From 1995 to 1999, at a cost of almost $200 million, the capacity of the above-water portion was increased to four lanes. An upgrade of the two-lane tunnels was proposed but has not been carried out.
The CBBT was built by and is operated by the Chesapeake Bay Bridge and Tunnel District, a political subdivision of the Commonwealth of Virginia governed by the Chesapeake Bay Bridge and Tunnel Commission. The CBBT's costs are recovered through toll collections. In 2002, a Joint Legislative Audit and Review Commission (JLARC) study commissioned by the Virginia General Assembly concluded that "given the inability of the state to fund future capital requirements of the CBBT, the District and Commission should be retained to operate and maintain the Bridge–Tunnel as a toll facility in perpetuity."
History
Geographic background
In December 1606, the Virginia Company of London sent an expedition to North America to establish a settlement in the Colony of Virginia. After sailing across the Atlantic Ocean from England, they reached the New World at the southern edge of the mouth of what is now known as the Chesapeake Bay.[3] They named the Virginia capes after the sons of their king, the southern Cape Henry, for Henry Frederick, Prince of Wales, and the northern Cape Charles, for his younger brother, Charles, Duke of York. A few weeks later they established their first permanent settlement on the southern, mainland, side of the bay, along the James River at Jamestown.
Across the bay, the area north of Cape Charles was located along what became known later as the Delmarva Peninsula. As it bordered the bay to its east, the region became known as Virginia's Eastern Shore. As the entire colony grew, the bay was a formidable transportation obstacle for exchanges with the Virginia mainland. One of the eight original shires of Virginia was established there in 1634, eventually becoming the two counties of modern times. However, in comparison to mainland regions, commerce and growth was limited by the need to cross the bay. Consequently, little industrial base grew there, and most residents made their living by farming and working as watermen, both on the Bay (locally known as the "bay side") and in the Atlantic Ocean ("sea side").
Ferry system
For the first 350 years, ships and ferry systems provided the primary transportation.
From the early 1930s to 1954, Virginia Ferry Corporation, a privately owned public service company managed a scheduled vehicular (car, bus, truck) and passenger ferry service between the Virginia Eastern Shore and Princess Anne County (now part of Virginia Beach) in the South Hampton Roads area. This system, a portion of U.S. Route 13, was known as the Little Creek-Cape Charles Ferry. In 1951, the Northern terminus was relocated to a location now within Kiptopeke State Park.
Despite an expanded fleet of large and modern ships eventually capable of as many as 90 one-way trips each day, the lengthy crossing suffered delays due to heavy traffic and inclement weather.
In 1954, the Virginia General Assembly (state legislature) created a political subdivision, the Chesapeake Bay Ferry District and its governing body, the Chesapeake Bay Ferry Commission. The Commission was authorized to acquire the private ferry corporation through bond financing, to improve the existing ferry service.
Once the bridge–tunnel was built, much of the ferry equipment used by the Little Creek-Cape Charles Ferry service was then sold and redeployed to start the Cape May-Lewes Ferry across the 17-mile (27 km) mouth of the Delaware Bay between Cape May, New Jersey and Lewes, Delaware.[4]
Studying a fixed crossing
In 1956, the General Assembly authorized the Ferry Commission to conduct feasibility studies for the construction of a fixed crossing. The conclusion of the study indicated that a vehicular crossing was feasible.[citation needed]
Consideration was given to service between the Eastern Shore and both the Peninsula and South Hampton Roads. Eventually, the shortest route, extending between the Eastern Shore and a point in Princess Anne County at Chesapeake Beach (east of Little Creek, west of Lynnhaven Inlet), was selected. An option to also provide a fixed crossing link to Hampton and the Peninsula was not pursued.[5]
To address these concerns, the engineers recommended a series of bridges and tunnels known as a bridge–tunnel, similar in design to the Hampton Roads Bridge–Tunnel, which had been completed in 1957, but a considerably longer and larger facility. The tunnel portions, anchored by four man-made islands of approximately 5 acres (2.0 ha) each, would be extended under the two main shipping channels. The CBBT was designed by the engineering firm Sverdrup & Parcel of St. Louis, Missouri, who also served as the construction manager for the project.[citation needed]
Construction
In the summer of 1960, the Chesapeake Bay Ferry Commission sold $200 million in toll revenue bonds to private investors, and the proceeds were used to finance the construction of the bridge–tunnel. Funds collected by future tolls were pledged to pay the principal and interest on the bonds. No local, state, or federal tax funds were used in the construction of the project.
Construction contracts were awarded to a consortium of Tidewater Construction Corporation and Merritt-Chapman & Scott Corporation. The steel superstructure for the high-level bridges near the north end of the crossing were fabricated by the American Bridge Division of United States Steel Corporation. Construction of the bridge–tunnel began in October 1960 after a six-month process of assembling necessary equipment from worldwide sources.
The tunnels were constructed using the technique refined by Ole Singstad with the Baltimore Harbor Tunnel, whereby a large ditch was first dug for each tunnel, into which was lowered pre-fabricated tunnel sections cable-suspended from overhead barges. Interior chambers were filled with water to lower the sections, the sections then aligned, bolted together by divers, the water pumped out, and the tunnels finally covered with earth.
The construction was accomplished under the severe conditions imposed by nor'easters, hurricanes, and the unpredictable Atlantic Ocean. During the Ash Wednesday Storm of 1962, much of the partially completed work and a major piece of custom-built pile driver barge called "The Big D" were destroyed. Seven workers were killed at various times during the construction. In April 1964, 42 months after construction began, the Chesapeake Bay Bridge–Tunnel opened to traffic and the ferry service discontinued.
CBBT and Lucius J. Kellam Jr.
The Ferry Commission and transportation district it oversees, created in 1954, were later renamed for the revised mission of building and operating the Chesapeake Bay Bridge–Tunnel. The CBBT district is a public agency and it is a legal subdivision of the Commonwealth of Virginia. However, the bridge–tunnel is supported financially by the tolls collected from the motorists who use the facility.
Eastern Shore native, businessman, and civic leader Lucius J. Kellam Jr. (1911–1995) was the original Commission's first chairman. In a commentary at the time of his death in 1995, the Norfolk-based Virginian-Pilot newspaper recalled that Kellam had been involved in bringing the multi-million-dollar bridge–tunnel project from dream to reality.
Before it was built, Kellam handled a political fight over the location, and addressed concerns of the U.S. Navy about prospective hazards to navigation to and from the Norfolk Navy Base at Sewell's Point.
Kellam was also directly involved in the negotiations to finance the ambitious crossing with bonds. According to the newspaper article, "there were not-unfounded fears that (1) storm-driven seas and drifting or off-course vessels could damage, if not destroy, the span and (2) traffic might not be sufficient to service the entire debt in an orderly way. Sure enough, bridge portions of the crossing have occasionally been damaged by vessels, and there was a long period when holders of the riskiest bonds received no interest on their investment."
An icon of eastern Virginia politics, Kellam remained chairman and champion of the CBBT throughout the hard times, and the bondholders were eventually paid as toll revenues caught up with expenses. He continued to serve until he was over 80 years old, finally retiring in 1993. He had held the post for 39 years.
The facility was renamed in his honor in 1987, over 20 years after it was first opened to traffic.
One of the Seven Engineering Wonders of the Modern World
Following the CBBT's opening in 1964, it was selected by the American Society of Civil Engineers (ASCE) as "One of the Seven Engineering Wonders of the Modern World" in a worldwide competition that included more than one hundred major projects.
The individual components of the bridge–tunnel are not the longest or the largest ever built. However, the total project was unique in the number and different types of major structures included in one crossing – including trestles, tunnels, artificial islands, bridges, causeway, and approach roads – and that it was built under adverse conditions and for adverse conditions.
The CBBT is no longer on the ASCE list, having been replaced by a more recent engineering wonder.
Dimensions
Among the key features of the Chesapeake Bay Bridge Tunnel are two 1-mile (1.6 km) tunnels beneath Thimble Shoals and Chesapeake navigation channels and two pairs of side-by-side high-level bridges over two other navigation channels: North Channel Bridge (75 ft or 22.9 m clearance) and Fisherman Inlet Bridge (40 ft or 12.2 m clearance). The remaining portion comprises 12 miles (19 km) of low-level trestle, 2 miles (3.2 km) of causeway, and four man-made islands.
The CBBT is 17.6 miles (28.3 km) long from shore to shore, crossing what is essentially an ocean strait. Including land-approach highways, the overall facility is 23 miles (37 km) long (20 miles or 32 kilometres from toll-plaza to toll-plaza)[1] and despite its length, there is only a height difference of 6 inches (152 mm) from the south to north end of the bridge–tunnel.
Man-made islands, each approximately 5.25 acres (2.12 ha) in size, are located at each end of the two tunnels. Between North Channel and Fisherman Inlet, the facility crosses at-grade over Fisherman Island, a barrier island which is part of the Eastern Shore of Virginia National Wildlife Refuge administered by the U.S. Fish and Wildlife Service.
Sumber :
http://en.wikipedia.org/wiki/Chesapeake_Bay_Bridge-Tunnel
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