Wall Form Design 191

7.2.2 Horizontal Loads

Braces should be designed to resist all foreseeable horizontalloads, such as seismic forces, wind, cable tension, inclined sup-ports, dumping of concrete, etc.

Wall form bracing must be designed to meet the minimumwind load requirements of ANSI A58.1 or the local design buildingcode, whichever is more stringent. For exposed wall, the minimumwind design load should not be less than 15 psf. Bracing for wallforms should be designed for a horizontal load of at least 100 lbper lineal foot of the wall, applied at the top.

7.3 METHOD OF ANALYSIS

Step 1: The procedure for applying equations of Tables 3.15and 3.16 to the design of a sheathing is to considera strip of 1 ft depth (consider the lower 1 ft of sheath-ing where concrete lateral pressure is maximum).Determine the maximum allowable span based onthe allowable values of bending stress, shear stress,and deection. The lowest value will determine themaximum spacing of studs.

Step 2: Based on the selected stud spacing, the stud itselfis analyzed to determine its maximum allowablespacing. The studs are subject to uniform pressureresulting from the fresh concrete. This pressure isresisted rst by the sheathing which in turn transferthe loads to studs. The selected stud span will bethe spacing of the wales.

Step 3: Based on the selected stud spacing, the maximumwale spacing (distance between horizontal supportsor ties) can be determined using the same proce-dure. For simplicity and economy of design, thismaximum span value is usually rounded down to thenext lower integer or modular value when selectingthe spacing.

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