Prestressed Roof Plank Design Example

Load balancing is used a portion of the load on slab is balanced by the transverse forces imposed by the draped tendons in each direction.

Prestressed roof plank design example.

Where voids stairs and other features prevent the slabs from spanning between walls slabs spanning perpendicularly are provided supported by the. High strength prestressing strands are cast into the plank at the spacing and. General after making an initial selection of the slab thickness the second step in slab design is to determine the amount and distribution of prestress. The design is in accordance with as 3600.

The example in section 10 2 provides design parameters used in this example. Geometric and data given by the manufacturer are as follows. The example in section 8 4 shows a partial example for the design of a special moment frame constructed using precast concrete per aci 318 section 21 8. The plank is manufactured on 500 foot long beds in a standard width of 48 inches and thicknesses of 8 10 and 12 inches.

A c 135 2103 mm2 i 678 106 mm4 y t 99 mm f ck. Take the final long term losses as 24. The floors and roofs of these buildings are to be untopped 8 inch thick hollow core precast prestressed concrete plank. Design steel plank support headers at openings when headers are determined necessary by the manufacturer s engineer.

8 1 1 1 general design requirements. Plank is cut to length for each project. This article deals with the design of prestressed precast elements with pretensioned tendons according to ec2. In spancrete hollowcore plank such loads may be distributed over several slabs.

Instructional material complementing fema 752 design examples precast concrete 5. Some of the images and calculations included in this article were taken from the worked example of prestressed concrete girders according to eurocode 2 published by the fachvereinigung deutscher betonfertigteilbau e. Prestressed solid composite planks comprises a wet cast prestressed concrete element combined with insitu concrete structural topping to give an overall solid composite slab. Please see the appropriate design information in the research notes under the research heading.

Example 1 calculate m sr for the 203 mm deep prestressed hcu shown below. Design calculations shall be performed by an engineer registered in the state that the project is located in and be experienced in precast prestressed concrete design. Figure 10 2 1 shows the typical floor plan of the diaphragms. 3 6 a floor system alternate 1 prestressed plank and half slab floor system this precast floor system refer to figure 3 12 comprises prestressed planks spanning between load bearing walls.

The initial prestressing force may be taken as 70 of characteristics strength of the standard 7 wire helical strand.