Understanding Spacings

Many ProStructures tools allow you to enter spacing values, either for rebar or for other elements, such as cast-in inserts on panels.

Basic Format

The basic format for spacings is:

NumberOfBars * Spacing

If offsets are required, the format is:

LeftOffset , NumberOfBars * Spacing , RightOffset

Example 1: 100,8*600,100

100 mm left offset, then 8 bars spaced at 600 mm, then a 100 mm right offset.
Additional spacings and bars in the series follow the same pattern.

Example 2: 100,8*600,350,2*350,100

100 mm left offset, then 8 bars spaced at 600 mm, then a 350 mm space, then 2 bars spaced at 350 mm, then a 100 mm right offset.

Alignment Layout Options

When the spacing values you enter do not divide evenly into the span (total length), then the program uses alignment layout options, where applicable, to determine how the "odd" bars are placed.

In the following examples, the entered values are:

Length/span: 3000 mm
Left offset: 100 mm
Spacing: 600 mm
Right offset: 100 mm

Using these values, the examples below show how bars are distributed when you select the various alignment layout options:

Setting	Description
Left Aligned	Bars are spaced based on the values you enter on the left side of the span. To accommodate for spacings that do not divide evenly, extra bars and spaces are placed toward the right end of the span. Example: 100,4600,500,2500,100 The "extra" spacings and bars (500,2*500) are placed toward the right end of the span.
Right Aligned	Bars are spaced based on the values you enter on the right side of the span. To accommodate for spacings that do not divide evenly, extra bars and spaces are placed toward the left end of the span. Example: 100,3500,600,3600,100 The "extra" spacings and bars (3*500) are placed toward the left end of the span.
Center Half Aligned	Bars are spaced based on the values you enter toward the center of the span. To accommodate for spacings that do not divide evenly, extra bars and spaces are placed toward the outside of the span. Example: 100,3550,600,1600,550,2550,100 The "extra" spacings and bars (3550 and 550,2*550) are placed toward the outside of the span.
Center Aligned	Bars are spaced based on the values you enter toward the center of the span. To accommodate for spacings that do not divide evenly, extra bars and spaces are placed toward the outside of the span. Example: 100,3400,600,2600,400,2400,100 The "extra" spacings and bars (3400 and 400,2*400) are placed toward the outside of the span.
Round Up	Bars are spaced evenly. To achieve the even spacing, the program rounds up the number of bars required, resulting in an actual spacing that is slightly less than the entered spacing. Example: 100,6*560,100 Bars required are rounded up and spaced evenly at 560 mm.
Round Down	Bars are spaced evenly. To achieve the even spacing, the program rounds down the number of bars required, resulting in an actual spacing that is slightly greater than the entered spacing. Example: 100,5*700,100 Bars required are rounded down and spaced evenly at 700 mm.