Articles and Technical Papers

Expanding the Use of Post-Tensioning in Buildings (PDF)

Structure, January 2008

For more than 40 years, post-tensioned concrete has been used in buildings. It is widely accepted by structural engineers for offices, parking garages, condominiums and apartments.

Post-Tensioning Revisited

Structure Magazine, July 2007

Post-tensioned concrete has been used for more than 40 years in the United States in a wide variety of construction projects. First used primarily in bridge construction, applications for post-tensioning now extend far beyond bridges to include tanks, office buildings, condominiums, hotels, parking structures, pavement, masonry, seismic walls, single-family homes and more.

Corrosion Conundrum

Bridges, Jan/Feb 2007

When corrosion occurs in the post-tensioning for bridges and other structures, effects can be disastrous. Following random inspections of Florida bridges that revealed corrosion in a few of the structures' post-tensioning, the Florida Department of Transportation (FDOT) called for a full investigation in late 2000 to determine the degree of corrosion in all FDOT bridges reinforced with post-tensioning.

Renovating Resorts Atlantic City (PDF)

Concrete International, November 2006

The adage "time is money" is certainly relevant to many industries, but is particularly relevant to building renovations and the costs of downtime, interruptions to services, or inconveniences to customers. To the casino industry, the phrase is even more literal.

Bridges, September/October 2006

The Four Bears Bridge is the only crossing of the 150-mile-long Lake Sakakawea on the Fort Berthold Indian Reservation. It is the first post-tensioned precast segmental bridge in the state and resulted in North Dakota and the Tribes embracing a new landmark that celebrates the past and the future.

Why Construction Safety is Important

Facilities Manager, July/August 2006

Today’s owners face a variety of risks when they undertake a construction project. Not only must owners be concerned with potential risks to their employees, tenants, or property, but they must also be concerned about the risks that the contractor bears.

Blast Mitigation of Concrete Structures

The Construction Specifier, March 2006

Although recent concerns about terrorism have generated a wider knowledge of the consequences of bombing, the majority of public, federal, and corporate buildings still has minimal blast-resistance capacities and may not be able to survive the destructive effects of such attacks.

Structural Engineer, July 2005

Bonded post-tensioning system minimizes life-cycle maintenance costs.

Post-Tensioning Update

Associated Construction Publications, June 15, 2005

Although post-tensioning has been a proven solution in the marketplace for almost five decades, older systems focused more on obtaining the desired prestress force and less on durability. Today, however, the industry has evolved to offer systems that deliver the desired prestress force while providing improved protection for the prestressing steel.

Water & Wastewater International, May 2004

The water and wastewater industry is undergoing tremendous changes due to population growth, aging infrastructure, security concerns and water quality regulation. All of these factors have contributed to industry growth, which calls for the construction of new storage and process tanks that reduce long-term maintenance costs.

Concrete Under Stress

Structural Engineer, April 2005

There is little argument that today's owners have a vested interest in using innovative techniques that not only provide efficient and cost-effective construction solutions, but also provide long-term value in terms of life-cycle cost. One growing solution — the VSLAB post-tensioning system — has proven to be a leading means of minimizing maintenance costs of concrete structures.

WaterWorld, March 2005

With a basic understanding of prestressed, post-tensioned concrete and recently enhanced multistrand and monostrand systems, industry professionals can select the optimal solution for their next water storage or process tank.

Concrete Products, September, 2004

A proprietary innovation in blast-resistance is based on a familiar technology. Steel-belted radial tires incorporate the same wire metallurgy as Hardwire, a family of high-tensile-steel reinforcement products said by the manufacturer to have been successfully implemented as blast-resistance and blast-mitigation retrofit solutions on a variety of structures and infrastructure components.

Engineering News-Record, Aug 30/Sept 6, 2004 Issue

Some call it "steel-belted duct tape." Inspired by a rebar cage, an inventor in 2000 began tinkering in his garage with ultrahigh-strength twisted steel wires, attempting to replicate the structure in miniature. The material, called Hardwire, comes in various configurations, but all resemble duct tape in being thin and shipped on a spool.

Business Wire, August 17, 2004

Hardwire, LLC has announced that their proprietary high-tensile steel reinforcement products -- based on steel-belted technology commonly found in tires -- have been successfully implemented as solutions for structures and other infrastructure components seeking blast-resistance and blast-mitigation retrofit.

Structural Engineer, July 2004

Determining design parameters is the first and most important step into achieving adequate and durable strengthening solution. In addition to strength and serviceability, design parameters should address environmental exposure and fire rating issues.

Concrete Products, March 2004

According to industry associations, it costs about $10,000 to $12,000 per space to build a new multi-level garage. Even more staggering is the estimated $650-per-year cost of simply operating the structure — including lighting, cleaning, employees, elevators and gate equipment.

PTI Structure Awards Competition (PDF)

Concrete International, January 2004

The Post-Tensioning Institute (PTI), Phoenix, AZ, reinstated its Structure Awards Competition in 2003— the first one PTI has held since 1987—with plans to continue the program as an annual event. Winners are chosen in five categories and seven projects received honorable mention.

Better Roads, November 2003

The Vietnam Veterans Memorial Bridge, which crosses the James River directly downstream of the Port of Richmond, is the gem among the 15 bridges along the new 8.8-mile Route 895 Connector, known as the Pocahontas Parkway. The new toll road was planned to alleviate congestion and traffic delays by linking I-95 in Chesterfield County to I-295 in Henrico County.

Engineering News-Record, October 6, 2003

A new strengthening product offering from VSL is set to change the landscape of concrete reinforcing materials. Hardwire is a steel-reinforced polymer (SRP) composite that is bonded externally to structural elements, allowing end users to incorporate ultra high tensile strength fibers inside or outside almost any material.

Engineering News-Record, October 13, 2003

For decades, storage tanks have been the primary resource to store municipal water and wastewater. Yet today's technology is making them tougher.

Concrete International,, May 2003

When selected by the Maryland Aviation Administration (MAA) to provide design services for the new Baltimore Washington International Airport (BWI) Consolidated Parking Garage, Walker Parking Consultants and Michael Baker Architects opted to use the most advanced techniques and materials possible.

Engineering News-Record, April 14th, 2003

The William H. Harsha Bridge uses a VSL Monostrand Stay Cable System. It is the first cable-stayed bridge in the U.S. to use co-extruded stay pipe and strand-by-strand installation.

Concrete International, April 2003

When selected by the Western Pennsylvania Conservancy to renovate Fallingwater - one of Frank Lloyd Wright's most famous designs - VSL (a post-tensioning contractor) became part of a team focused on saving the ailing structure.

Saving Fallingwater

This Old House Magazine, January/February 2003

Fallingwater, Frank Lloyd Wright"s masterpiece, has been featured on a U.S. postage stamp, on the cover of Time magazine, and in perhaps a shelf-full of coffee table books. Too bad it wasn"t built properly.

Concrete International, January 2003

Post-tensioned masonry combines an advanced construction technique with an old building material almost forgotten in the education of civil engineers. The major advantages of masonry have always been the overall availability of its raw materials, it's easy and economical construction, and its natural beauty and durability.

Third Middle East Symposium On Structural Composites for Infrastructure Applications, December, 2002

This article explores a case study for the upgrade and full-scale load testing of a parking garage for a commercial office rental property. Carbon fiber reinforced polymer (CFRP) reinforcement was considered for flexural strengthening and the performance was verified by full-scale in-situ load testing of typical bays before and after strengthening.

Fallingwater, Standing Still

Architecture, September 10, 2002

Inspired as much by the rocky earth as by De Stijl, Bauhaus, and Richard Neutra, Frank Lloyd Wright emerged from a decade of near-dormancy in 1935 to design Fallingwater, a home in rural Mill Run, Pennsylvania. It was worth the wait; the icon of American design would produce what is arguably the most important and recognizable private residence in the world.

New Life for Bridges and Budgets

Bridge Builder, September/October 2002

A recent survey conducted by the National Cooperative Highway Research Program (NCHRP, Synthesis 249) indicated that sixty-three percent of the North American transportation agencies expect to see the need to increase the live load capacity of existing highway bridges grow as the infrastructure continues to age.

Concrete Repair Bulliten, May/June 2002

The future growth of nations and their economical prosperity is closely related to the potency of its transportation infrastructure. Bridges, in particular, are one of the most important components of this infrastructure.

ENR, March 25, 2002

First, the leaning tower of Pisa is rescued. Then, Fallingwater – the sagging house of Pennsylvania. Workers are completing a post-tensioning procedure designed to put a stop to the historic sagging of the hallmark-cantilevered portion of the 64-year-old Fallingwater, designed by Frank Lloyd-Wright.

Structural Engineer, March 2002

State Route 29 snakes its way through Trenton, New Jersey, along the Delaware River. Just south of downtown, it veers away from the river and proceeds through a residential area. Over the years, increased vehicular traffic on this major artery has contributed to mounting traffic congestion, causing problems for local residents as well as headaches for commuters.

The Business Monthly, March 2002

One of the most well known by architect Frank Lloyd Wright is undergoing a one-of-a-kind overhaul by a Hanover company. Without the structural repairs, Fallingwater would end up in the very steam it was designed to embody.

Civil Engineering, February 2002

The scope of the structural rehabilitation of Fallingwater, Frank Lloyd Wright"s architectural masterpiece in rural western Pennsylvania, has been expanded because of the deteriorated condition of the substructure beneath the floor of the living room.

Fallingwater Gets a Facelift

Pennsylvania Business Central, February 2002

Fallingwater, one of Frank Lloyd Wright"s most distinctive accomplishments and one of the most unique houses ever built in America, is getting a new lease on life with the help of some much needed renovations.

Load Checks Get Easier, Cheaper

ENR: Engineering News-Record, October 6, 1997

The practice and popularity of checking load capacity of repairs on structures may be turned on its head if a test method recently brought over from Europe finds widespread acceptance in the U.S. Rather than spending days using traditional tools such as large water-filled bladders or educated guesses, testers use off-the-shelf electronics and hydraulic equipment to apply and measure loads in hours.