January 1990 Table of Contents

Features Forming the World's Largest Concrete-Frame Building

The 967-foot tower at 311 South Wacker Drive is the world's largest concrete building. Most of the 70 stories were formed with truss-supported flying deck units custom fabricated for the job. Work for the forming contractor began in a steel shell placed above each of the 44 column cassions of the tower foundation. The core wall area was excavated, braced, and formed conventionally, from the mat foundation to the core level. Once the core walls and columns had been poured to grade level and cured, the forms were removed. Top-down construction made it possible to get an earlier start on the tower forming. Read more

Features High-Volume Polypropylene Reinforcement for Shotcrete

Although shotcrete reinforced with polypropylene fiber was first used in Europe in 1968, it was not until 1988 that a high volume of polypropylene fiber was successfully used in a shotcrete application. Conditions related to crack resistance and rebounding had resulted in a compromise on steel fiber length, making the mid-range length most commonly specified. Because of the low modulus or flexible nature of the polypropylene fibers, it was hoped that longer fibers and higher volumes could be used without causing problems of manageability in the field. Read more

Features Planning for Success Brings Success to an Indiana Contractor

Travis Gloyd Construction, Inc., (TGC) near Ft. Wayne, Indiana, has grown from a small business doing mostly residential work to a growing company whose profits come largely from commercial jobs. Looking back on the 20 years it has taken Gloyd to build TGC, he points out key areas underpinning his company's success. Read more

Features Someone Still Has to Pay When Building Components Don't Fit Even If Tolerances Are Met

When building components won't fit because of dimensional variations in cast-in-place concrete, concrete products, and other materials, someone has to pay for correcting the interferences. Concrete constructors and material fabricators will probably have to pay if their products are not within specified tolerances. If all materials are within specified tolerances but the variations still cause an interference, the architect or engineer may have to pay for the correction. Ambiguous situations or situations not covered by specified tolerances may become a free-for-all of claims and counterclaims. Read more

Features Concrete Giant Rises on Chicago Skyline

The world's tallest concrete building makes its home at 311 South Wacker Drive, Chicago. The 70-story tower rises 967 feet high and just so happens to be right across the street from the Sears Tower, the world's tallest steel-frame building. The view from the street in front of the tower allows observers to notice the flame-finished rose granite below the Gothic-styled glass section at the top and the polished banding weaving through the tower's strong vertical planes. The building's floor plan - six-sided at ground level - changes as it rises. Read more

Features Prestressed Concrete Sludge Digesters

Four giant eggs, 149 feet tall and 92 feet in diameter at the midsection, are part of a major wastewater treatment project in Bottrop, Germany. Each tank is an air-free chamber for the digestion of sludge coming from several nearby wastewater treatment plants. The prestressed egg-shaped digesters offer operational advantages such as minimum water surface area for scum buildup and steep cone floors to maximize sludge drawoff and eliminate the need for cleaning. The digesters are prestressed both horizontally and vertically to assure a water-tight structure. Read more

Features Precast Pedestrian Bridges Keep Park Picturesque

In 1988, the City of Winnipeg, Manitoba, Canada, used architectural precast concrete to build three multispan pedestrian bridges spanning a retention pond in Kil-Cona Park. The 12 arch panels required for the three bridges were cast from one form. The three bridges' superstructures use 39 precast concrete components: arch span panels, end span panels, and diaphragms. The foundations use 42 precast concrete piles. Precast erection of the three bridges took just 3 days. Read more

Features Concrete Pavements Save Truck Fuel

Results of a 1982 study published by the Federal Highway Administration (FHWA) show that trucks can save as much as 2 miles per gallon by driving on concrete instead of asphalt pavements, even when the pavement surfaces are similar in roughness. The study was prepared for FHWA by John P. Zaniewski, assistant professor of engineering at Arizona State University, to analyze the relationship between highway design and vehicle operating costs. The study focused on concrete and asphalt pavements with intermediate to smooth riding qualities typical of most major highways in the United States. Vehicles were driven on the test pavements at constant speeds of 10, 20, 30, 40, 50, 60, and 70 mph while fuel consumption, speed, and other factors were monitored. Read more

Features Leave Existing Manholes in Place -- Install Movable Curbs

"Moving manholes because of new curb lines can cost up to 50,000 dollars each," says James Pitts, an engineer for Ohio Bell. To eliminate this costly and time-consuming work, Pitts and co-worker Richard Taus designed an innovative device that allows new curb lines to be placed right over existing manholes. The device is a movable steel curb attached to a cast-in-place frame. Utility workers can easily remove the curb to gain access to the manhole and then replace it when their work is done. Cost of the curb, including installation, is about 2,000 dollars. That's 25 times less than the cost of relocating a manhole. Read more

Problem Clinic Bracing for Column Forms

When renting or purchasing prefabricated column forms, we frequently see the note, "Brace according to industry standards," or similar wording. What are these industry standards, and who sets them up? Read more

Problem Clinic Joint Detail Where Asphalt Pavement Meets a Concrete Slab

I'm designing a new fleet shop for the company where I work. Tractor trailers will drive out of the fleet shop, which has a concrete floor, onto an asphalt parking area. My concern is load transfer from the concrete to the asphalt. Should the asphalt be t Read more

Problem Clinic Yield Loss in High Walls

I've heard of yield loss in high walls caused by loss of air due to vibration and compression of air because of concrete pressure before it sets. Could this explain an underyield of 10%? Read more

Problem Clinic Blistering in Heated Enclosure

Would a natural gas heater 3 feet above the floor cause blistering? We supplied concrete for a garage floor and the flatwork contractor had trouble finishing it in the vicinity of the heater. He said concrete near the heater felt like bread dough during f Read more

Close X