HOME

TheInfoList



OR:

The High Five Interchange is one of the first five-level
stack interchange A directional interchange, colloquially known as a stack interchange, is a type of grade-separated junction between two controlled-access highways that allows for free-flowing movement to and from all directions of traffic. These interchanges e ...
s built in
Dallas Dallas () is a city in the U.S. state of Texas and the most populous city in the Dallas–Fort Worth metroplex, the List of Texas metropolitan areas, most populous metropolitan area in Texas and the Metropolitan statistical area, fourth-most ...
,
Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
. Located at the junction of the Lyndon B. Johnson Freeway ( Interstate 635, or I-635) and the Central Expressway ( U.S. Highway 75, or US 75), it replaces an antiquated combination interchange constructed in the 1960s. The $261 million (equivalent to $ in ) project was started in 2002 and completed in December 2005; 13 months ahead of schedule. It was designed by
HNTB HNTB Corporation is an American infrastructure design firm. Founded in 1914 in Kansas City, Missouri, HNTB began with the partnership made by Ernest Emmanuel Howard with the firm Waddell & Harrington, founded in 1907. One of the most trusted U. ...
and built by Zachry Construction Corporation. The interchange is considered by ''
Popular Mechanics ''Popular Mechanics'' (often abbreviated as ''PM'' or ''PopMech'') is a magazine of popular science and technology, featuring automotive, home, outdoor, electronics, science, do it yourself, and technology topics. Military topics, aviation an ...
'' to be one of "The World's 18 Strangest Roadways" because of its height (as high as a 12-story building), its 43 permanent bridges, and other unusual design and construction features. In 2006, the American Public Works Association (APWA) named the High Five Interchange as "Public Works Projects of the Year".


Description

The High Five Interchange, north of downtown in
Dallas, Texas Dallas () is a city in the U.S. state of Texas and the most populous city in the Dallas–Fort Worth metroplex, the List of Texas metropolitan areas, most populous metropolitan area in Texas and the Metropolitan statistical area, fourth-most ...
, is a massive five-level
freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms ...
interchange. It is the junction of two major highways carrying heavy rush-hour traffic, the Lyndon B. Johnson Freeway ( I-635) and the Central Expressway ( US 75), and is the first five-level
stack interchange A directional interchange, colloquially known as a stack interchange, is a type of grade-separated junction between two controlled-access highways that allows for free-flowing movement to and from all directions of traffic. These interchanges e ...
to be built in the city. It replaces the antiquated three-level modified
cloverleaf interchange A cloverleaf interchange is a two-level interchange (road), interchange in which all turns are handled by slip roads. To go left (in right-hand traffic; reverse directions in left-driving regions), vehicles first continue as one road passe ...
built in the 1960s, which caused a severe
bottleneck Bottleneck may refer to: * the narrowed portion (neck) of a bottle Science and technology * Bottleneck (engineering), where the performance of an entire system is limited by a single component * Bottleneck (network), in a communication network * ...
by narrowing US 75 down to two lanes at the junction of the two highways. The looped ramps of the cloverleaf forced motorists to slow down drastically, backing up traffic. Left-hand exits contributed to the congestion. Further, its two
frontage road A frontage road (also known as an access road, outer road, service road, feeder road, or parallel road) is a local road running parallel to a higher-speed, limited-access road. Where parallel high-speed roads are provided as part of a maj ...
s were not directly connected to each other, making local access difficult. Alluding to the celebratory gesture, the "High Five" name refers to the five flyover ramps that tower over the landscape, handling the left-turn movements. The interchange is as high as a 12-story building and includes 43 bridges spread across five levels (the "High Five"), 710 support tiers, and of additional highway lanes. The highest ramps are above ground. The lanes of US 75, which are on the bottom level, are below ground level, giving the structure a total height of from bottom to top. As part of the project, I-635 was widened to include four dedicated
high-occupancy vehicle lane A high-occupancy vehicle lane (also known as an HOV lane, carpool lane, diamond lane, 2+ lane, and transit lane or T2 or T3 lanes) is a restricted traffic lane reserved for the exclusive use of vehicles with a driver and at least one passenger, ...
s (HOV lanes) that are barrier-separated and reversible. The new lanes for regular traffic were built on the outer vacant right-of-way, while the HOV lanes were built in the
median The median of a set of numbers is the value separating the higher half from the lower half of a Sample (statistics), data sample, a statistical population, population, or a probability distribution. For a data set, it may be thought of as the “ ...
. The original I-635 lanes that passed through the former interchange, now demolished, were relocated between the new regular and HOV lanes. From bottom to top, the roads on the five levels are: * Level I: US 75, a six-lane highway, three lanes going each way * Level II: The junction of the two six-lane frontage roads, each having three through lanes in each direction, left-turn lanes, and turnarounds, and easy access to US 75 and I-635 * Level III: I-635, 10 regular lanes, five going each way, and four HOV lanes (two going each way) separated by barriers * Levels IV and V: Direct connection ramps (two levels), eliminating the left exits of the modified cloverleaf The interchange is decorated with etchings on
precast concrete Precast concrete is a construction product produced by casting concrete in a reusable molding (process), mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples i ...
elements, along with coloration specified by the
Texas Department of Transportation The Texas Department of Transportation (TxDOT ) is a Texas state government agency responsible for construction and maintenance of the state's immense Texas state highway system, state highway system and the support of the state's maritime trans ...
(TxDOT). The High Five Interchange also incorporates a hiking and bike trail, named the Cottonwood Trail, which runs under all levels of the interchange. The section of the trail passing beneath the interchange was constructed as part of the High Five Interchange project by TxDOT.


History

The High Five Interchange project was planned as a replacement for the existing antiquated interchange, which accommodated 500,000 vehicles daily and was located in one of the most intensely developed commercial zones in Dallas. It was a collaborative project between the TxDOT, affected motorists and property owners, and the primary contractor, Zachry Construction. An essential consideration was to complete the project with as little disruption to the
traffic flow In transportation engineering, traffic flow is the study of interactions between travellers (including pedestrians, cyclists, drivers, and their vehicles) and infrastructure (including highways, signage, and traffic control devices), with the ai ...
as possible. Reasons for upgrading the interchange, in addition to the need to increase traffic flow and reduce congestion, were to improve air quality, safety, and local access. Zachry Construction Corporation submitted the lowest bid and was awarded the $261 million (equivalent to $ in ) contract by TxDOT, the largest ever by that agency. The construction contract for the High Five Interchange was unique in that it contained elements not found in other construction project contracts. For example, it specified the concrete maturity method to be used to ensure the concrete's strength (the first time TxDOT had ever done so) and contained an early-completion bonus, a sliding scale of up to $11 million (equivalent to $ in ) if the company completed the contract within four years. Also built into the construction contract was a provision that Zachry be charged for "lane rentals" by TxDOT for time they closed down traffic lanes—fees based on hourly assessments and the time of day the lane was closed. The fees ranged from $50 to a high of $110,000 for rush hours (equivalent to $ to $ in ). In order not to interfere with traffic flow during construction, the new interchange was designed largely as elevated flyover ramps and viaducts so they could be built high over the existing junction lanes; once traffic was transferred to the new structures, the old lanes could simply be closed off and removed. Little of the original interchange remained when the project was finished. To save time and money, innovative construction methods were employed. The original plans called for the segments of the long ramps and spans (used to direct-connect roads) to be made of steel, but, because building with steel would interfere with heavy traffic flow during construction, cast-in-place segmental concrete was substituted in the plans. Zachry decided, however, to use
precast concrete Precast concrete is a construction product produced by casting concrete in a reusable molding (process), mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples i ...
segmental bridges, rather than casting the bridge elements in place, and used a unique machine, designed and constructed by Deal S.R.L. of Italy and costing about $1 million (equivalent to $ in ), to move the pieces into place. During the construction, of earthwork was used, of concrete was mixed on site, and of
retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...
s were built. Additionally, of drilled shafts and of drainage pipe were completed. In addition to the construction of 43 permanent bridges, six temporary bridges were built, resulting in of
bridge deck A deck is the surface of a bridge. A structural element of its superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildin ...
. The project was designed by
HNTB HNTB Corporation is an American infrastructure design firm. Founded in 1914 in Kansas City, Missouri, HNTB began with the partnership made by Ernest Emmanuel Howard with the firm Waddell & Harrington, founded in 1907. One of the most trusted U. ...
, who provided professional engineering consultation throughout the construction, which had begun in 2002 and was completed in December 2005, more than 13 months earlier than planned.


Recognition

In 2006, APWA named the High Five "Public Works Project of the Year" for its massive size, its innovative design, the complexity and rapidity of its construction, and the need it fulfilled for the community. TxDOT as the managing agency, Zachry Construction Corporation as the primary contractor, and HNTB as the primary consultant received the award in recognition of their cooperative alliance in completing the project. The interchange is ranked by ''
Popular Mechanics ''Popular Mechanics'' (often abbreviated as ''PM'' or ''PopMech'') is a magazine of popular science and technology, featuring automotive, home, outdoor, electronics, science, do it yourself, and technology topics. Military topics, aviation an ...
'' as one of "The World's 18 Strangest Roadways", which called it a "labyrinth of lanes" and a "five-level marvel of engineering" because of its height, the number of its bridges, and other unusual design and construction features.


See also

* *


References


External links

{{Commons category, High Five Interchange, Dallas
Google Maps Satellite View

Texas Freeway, includes picture of the old interchange

Alternate view of old interchange

Another view of the old interchange

Dallas High Five Construction Photos, Feb.-May 2004

Dallas High Five Interchange Tour Dallas, TX
ScrewdUPClickV2 State highways in Texas Highways in Dallas Road interchanges in the United States U.S. Route 75