An inspiring new way of life is taking shape in the southern foothills of Las Vegas Valley, Nev..  The City of Henderson, located five miles southeast of Las Vegas, forms the southern edge for one of the fastest growing metropolitan areas in the U.S.  Dubbed as the gateway between the mountains and the desert, Henderson remains the second largest city in Nevada, second only to Las Vegas, and remains one of the top five fastest growing cities in the nation today.

Regional growth has generated a sizeable number of developer and construction projects requiring new infrastructure to keep pace with the development in and around the city.  Many developers fund water, sewer, roads and other infrastructure through Limited Improvement Districts.  The costs for this infrastructure and amenities are included in the sale price of the homes.

One such development is the master-planned community, Inspirada, formerly known as South Edge, which was a collaboration between the Henderson city officials and a consortium of nationally-known builders and developers.  Inspirada will be an example of “new urbanism” living at its best with the character of modern master-planned living combined with the convenience, charm and timeless principles of a bygone era.  The project will encompass nearly 2,000 acres and will be comprised of more than 11,000 homes for an estimated 26,000 residents.

This development will require a sufficient amount of water storage to be in place before construction begins. In order  to meet this requirement, the City of Henderson, the project owner; South Edge LLC and its affiliates, collectively Inspirada (Las Vegas), the developer; Landtek (Las Vegas), construction manager; and Stanley Consultants, Inc. (Las Vegas), consulting engineer; completed one 3.5 MG water storage tank and are currently constructing a second one to help meet the water needs of the new development.  The water storage has to be implemented and on line before work on the homes can begin, so the tanks are a crucial element for the Inspirada development.

After careful consideration of the long-term benefits, it was determined that prestressed concrete would offer the highest quality, longest lasting and lowest maintenance water storage structures for this project.  The floors, footings, columns, walls and roofs are all designed and constructed with concrete.  Each tank has an inside diameter of 172 feet and a wall height of 21.5 feet.  All construction joints incorporate PVC waterstops to ensure a watertight structure.  A 9 inch thick, cast-in-place, flat concrete roof is supported by 52 concrete columns, each 18 inches in diameter.  The 10 foot thick walls of the tanks are both circumferentially and vertically prestressed by DYK Incorporated of El Cajon, Calif., who is the general contractor and tank prestressor.  Vertical post-tensioning is achieved with 132 1-1/4 inch diameter vertical tendons.  Circumferential prestressing is completed with 7-wire galvanized strand and protected with several coats of automatically applied shotcrete.

The entire prestressing and shotcreting operation is completed using one of the world’s most technologically advanced, fully automated machines to ensure that the necessary quality control is consistently maintained. DYK’s prestressing machine continuously and electronically monitors the applied stressing force on the strand as it is applied.  The project is made more economical by the use of prestressed concrete tanks to accomplish both structural and environmental design needs, achieving a high strength, low maintenance, watertight structure.

The tank’s design is able to integrate several design considerations that enable them to perform more effectively.  One of these is the design and construction of a large 40 foot long by five feet wide weir box, rather than an overflow pipe, to accommodate the overflow of water in a worst case scenario.  The side wall penetration weir box allows a greater volume of water to flow through two – 24 inch pipes rather than the amount that would pour through a small cone-shaped overflow pipe.  

Both tanks are located in a remote, rural area and upon completion will be painted a dark tan to echo the colors in the desert.  The second tank, 3.5 MG “2780 R-37”  is being constructed about 1 ½ miles from the first 3.5 MG “2780 R-36” tank and construction is under way, with an expected completion date of April 2008.

Henderson’s master planned communities are looked at as models throughout the southwestern United States and this project is no exception. SLDT