April 1988 Table of Contents

Features Bridges and Culverts Shotcreted over Inflated Forms

The use of inflated forms has grown steadily. A single form can be adjusted to build many sizes of culvert arch or other structures such as large-diameter concrete pipe, tunnel linings, and water tanks as well as earth-sheltered buildings. Read more

Features Post-Tensioned Dome Shotcreted from Outside an Inflated Form

Post-tensioned domes designed to support stored materials can be built using inflated forms. Read more

Features Inflated Forms for Chimney Lining

Every chimney that lacks a masonry liner or has a cracked liner, that has loose mortar joints or damaged brickwork, or shows signs of creosote staining can be viewed as a potential fire hazard. A new refractory concrete lining of the proper size can provide a smooth, seamless acid-resistant flue surface to remedy many of the problems cited. Read more

Features Earth-Sheltered Residences Built Over Inflated Forms

Inflated forming techniques coupled with a better understanding of ground temperature control are responsible for a new generation of earth-sheltered buildings. Read more

Features Inflated Forming for 50-Foot Shells Without Steel

Concrete shells 50 feet or more in diameter can be built at low cost by two persons having only limited construction skills. This method requires no steel reinforcement and is simpler than shotcreting methods. Read more

Features Rebar and Fresh Concrete Lifted and Shaped by Inflating a Form

In the 1960s the first successful attempt was made to use low air pressure to lift and shape in a single operation all of the concrete and steel needed for a 300,000-cubic-foot dome large enough to contain an entire gymnasium. Refinements since then result in the construction steps shown. Read more

Features How to Choose a Concrete Framing System

Preliminary design of a reinforced concrete structure involves the selection and representation of a framing scheme, showing size and shape of beams, columns, and slabs. Read more

Features Formwork for Cone, Funnel, and Cylindrical Structures

A system developed in Austria for forming axially symmetrical curved structures such as funnels, cones, shafts, sewage digestion tanks, and water towers permits continuous placement of concrete without form ties. Read more

Features Better Bubbles

Commonly used air-entraining agents, whether vinsol resins or multicomponent organic materials, usually reduce concrete strength. Read more

Features Whitetopping Costs Based on Pavement Area and Concrete Volume

A payment method used on one Medina County, Ohio, whitetopping takes some of the guesswork out of estimating and bidding concrete overlays. Read more

Features Shotcrete and Urethane Layered Inside Inflated Form

Spray a shell structure onto the inside of an inflated balloon--first some layers of urethane foam, then some layers of shotcrete. Read more

Features Booms and Power Lines: a Deadly Combination

Operating boomed vehicles close to overhead power lines puts operators and nearby workers at risk of electrocution. Read more

Features Formwork: a Big Balloon

Air forms may be full or partial spheres, ellipsoids, cylinders, and varied mix-or-match combinations of these shapes. Irregular or free-form shapes also can be used. Read more

Features Inflated Forms: Why and How?

Building with inflated forms offers the contractor varied opportunities. Read more

Problem Clinic When to Test for Chloride Ion?

The specification for our parking structure job says chloride ion content of the concrete should not be more than 0.15 percent by weight of the cement. Read more

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