Shape Selection Report

8/8/2019 Shape Selection Report

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SHAPES OF PRESTRESSED STRUCTURES

The common shapes of prestressed structural members are;

1. DOUBLE TEE is considered the most widely used section for prestressedconstruction with a flat surface having a width that ranges from 120 to 240centimeters wide. The thickness depends upon the requirements while the spancan extend up to 18 meters.


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APPLICATION

Flat, solid decks in a variety of applications and finishes. Double tee decks for most applications. Up to 130' clear spans are

available. (We do not produce hollow-core slabs.)


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Flat Walls in both solid and integral insulated configurations. These wallscan be produced with either standard structural finishes orarchitectural finishes.

Double tee walls in both solid and integral insulated configurations.Custom wall shapes or cross sections.

2. SINGLE TEE is normally used for longer span up to 36 meters with heavier loads.


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APPLICATION

3. I-SECTION is widely used for bridges, roof, girders up to 36 meters span.


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APPLICATION

To minimize fill requirements and to maintain the necessary under clearance, four 54-inch U-beams were selected in lieu of five 63-inch I-beams for the typical span of 105 feet 8 inches.Judicious use of high strength, high performance concrete, prestressing strands in the topflanges of the beams, spread footings, and semi-integral abutments resulted in economical,

durable, and pleasing structures

4. CHANNEL SLAB is used on bridges of intermediate and major span.

APPLICATION


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The bridge is 1224 feet long and crosses approximately 85 feet above the Ashtabula River in Ohio andits floodplain. Originally designed as an eight-span, steel plate girder bridge the bridge was re-designedas a nine-span, prestressed concrete girder bridge through a Value Engineering Change Proposals(VECP) without sacrificing functionality, durability, or aesthetics. The VECP resulted in savings of approximately $900,000 on the project.

Piers were positioned to avoid the main river channel, wetlands, and a roadway under span 1.

Maximum spans are 147 ft. with the first four spans passing through a horizontal curve

Innovative corrosion resistant features include a link slab between spans 1 and 2 and redundantexpansion joint seals over pier 6. A link slab eliminates the need for an expansion joint between spanones 45 deep type III PCI beams and the 78 deep PCI beams in the remaining eight spans.

Additionally, by relocating expansion joints and thermal neutral points, modular expansion dams werereplaced with more economical strip seals.

Precast prestressedsolid floor and roof slabs can be

produced to anyworkable size or shape which bestsuits the job


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5. INVERTED TEE SECTION provides a bearing ledge to carry the precast deck members having a perpendicular direction of span.


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Andrews Prestressed Concrete has the capability toproduce Multiple sizes of Inverted Tee Beams for any

application


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Our modern adjustable Inverted Tee Beam formsallow more flexibility than a fixed type of form

Prestressed Concrete Beam

Advantages:

Speed - Minimal formwork requirements Safety - Immediately after placement provides a secure work platform Quality - Prestressed concrete is designed to prevent cracking Design - Shallow structural depth


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Shape Selection Report

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