February 1998 Table of Contents

Features Cable-Stayed Bridge Rotated Over Freeway

Bridge a 10-lane freeway without disrupting traffic. That was the extraordinary challenge presented by the South African Department of Transport when it prohibited lane closures during construction of a bridge to take Harper Road over the N12 freeway in Germiston. The N12 carries 230,000 vehicles daily on its 10 lanes. Read more

Features Diagnosing Slab Delaminations

Article discusses jobsite factors that can have a pronounced effect on the bleeding characteristics that can lead to delaminations in concrete slabs. For years, the absence of a bleedwater sheen on the surface of a concrete slab has been used as an indicator that the slab is ready for floating and troweling. If premature finishing seals the surface before bleeding has ceased, delaminations may occur. But the absence of bleedwater on a surface isn't a foolproof indicator that bleeding has ceased. If the evaporation rate exceeds the bleeding rate, concrete still can be bleeding even though no water is on the surface. Read more

Features Superflat Floor Meets Warehouse Needs

When Eaton Steel Corp., Taylor, Mich., decided to modernize existing warehouse storage, the company needed a heavy-duty superflat concrete floor with no transverse joints and minimal cracking. Transverse joints were undesirable because they would create bumps in the wheel paths of the warehouse's high-reach forklift traffic. And over time, joint spalling could hinder lift-truck efficiency and require extra maintenance. Read more

Features Bridge Piers Placed by Tremie

For a new bridge spanning the Ottawa River between Hawkesbury, Ontario, and Grenville, Quebec, contractor Dufferin Construction Co. moved pier forms into place using a special marine railway and gantry barge and eliminated cofferdams by placing pier concrete by tremie. The bridge will replace the deteriorating Perley Bridge, which was built in 1931, 80 feet downstream from the new site. Read more

Features Building a Bridge in Five Days

Each day during the construction season, Stoneco Quarries sends up to 400 trucks loaded with limestone aggregate across a bridge on Sterns Road in Monroe County, Mich. Early in 1997, however, county officials notified quarry owners that the load rating for the old steel bridge would have to be lowered because of deterioration during the last several years. Furthermore, it would be five years before Monroe County could schedule bridge replacement. Read more

Features Bridge Deck Forms Bear the Weight

A Tampa, Fla., contractor cut the time and cost of building a low-profile bridge by using a custom flying deck-forming system that remained rigid under extreme loads and long spans. The 650-foot-long, 90-foot-wide bridge—located on Blind Pass Road (State Road 699) in St. Pete Beach, Fla.—has an 18-inch-thick solid-concrete deck with 40-foot-long spans and no supporting girders. The deck-form panels were designed to support a full bridge span without intermediate supports, eliminating the need for midspan crutch bents. Read more

Products Solving Problems Flashing for Bridge-Deck Joints

Bridge decks need joints. Without them, decks are vulnerable to thermal stresses that will induce cracking and, ultimately, failure. But if the seals fail, the joints give water, deicing chemicals and debris a path to attack the underlying structure. Read more

Problem Clinic Curving Plywood Forms

How much can we bend 3/8-inch plywood forms? Read more

Problem Clinic Coloring Flatwork After It's in Place

We wrote a job specification calling for application of a colored dry shake to 50,000 square feet of concrete floor. The contractor didn't read the specification and finished the concrete without applying the colored dry shake. Workers applied a membrane Read more

Problem Clinic Recommended Floor Slope and Tolerance

We're designing the concrete floor for an auto dealership's service department. Read more

Problem Clinic Bug Holes on Rubber-Lined Wall Forms

We have a problem with too many bug holes on wall surfaces formed with rubber-lined wall forms. Are there ways to achieve the same smooth surface we can get with bare medium-density-overlaid plywood wall forms? Read more

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