Some useful methods to work out ideal column spacing for pallet racking

While placing warehouse pallet racking, it becomes difficult to adapt building columns. Although the layout drawing is adjusted properly but collapsing of columns in the middle of a drive aisle or in the racking itself can’t be avoided.

In this civil engineering article, you will be familiar with a perfect building column spacing to get rid of this complicated method and increase the number of storage locations inside a building.

Building Columns: These are vertical members which provide support to the facility ceiling. They are available with different types of sizes and designs.

Uprights: These are vertical supports in a pallet racking system. To develop a pallet racking structure, two upright frames are required on each side to support the horizontal beams.

Beams: They provide horizontal weight-bearing supports in a pallet racking system which attaches the upright frames to each other.

Flue Space: These are spaces among back to back rows of pallet racking. These back-to-back rows are attached with row spacers. 12” is the most recommended row spacer length to facilitate minor overhang of the pallets in the back as well as fire suppression if required inside the racks.

This flue space also facilitates the typical building columns (10” x 10”) to be hidden inside the racking devoid of losing any pallet storage locations.

Purpose of building columns: The architects and structural engineers place building columns by keeping 40 or 50 feet distance owing to standard steel mill member lengths. However, when the building is designed around the proposed use and equipment inside, these lengths can be adjusted to obtain the best use of the space investment.

To maximize your pallet rack layout, two things can be done to get rid of the building columns falling outside of the racking and inside fork truck drive aisles:

Place racking properly in order that the building columns land in the flue spaces of the pallet racking as well as inside the racking itself.

If possible, the pallet racking should be placed in order that the building columns fall inside flue spaces to get rid of losing storage locations. Given below the ideal building column spacing for a various single-deep pallet racking designs. Here, 12” x 12” building columns and 48” deep pallets (therefore no pallet overhang) are taken.

To determine the best building column spacing for your preferred rack layout, the following formula should be applied :-

[(Rack Depth x 2) Flue Aisle] x # Bays = Column Spacing

The process is complicated for placing and configuring pallet racking specifically when it is not possible to work with the general contractor to maximize the building column spacing inside your new building, or moving into an existing building.

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Published By
Rajib Dey
www.constructioncost.co
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Reason for damaging & collapsing of concrete buildings

A reinforced concrete building gets damaged and collapses due to several reasons such as sliding of roofs, falling of walls, crushing of columns, short column effects, diagonal cracking, foundation sinking and tilting etc.

Types and Causes for Damage and Collapse of Concrete Buildings.

Given below, the details about the most common types of damages in reinforced concrete buildings:

1. Sliding of Roofs off the Supports: Where the beams are just supported on walls or columns, they are susceptible to slide if the severity of earthquake surpasses the frictional resistance and several times come out of the support and collapse, specifically when the bearing length is minor.

2. Collapsing of Infill Walls: The infill panel walls amid reinforced concrete columns overturn outer the framework when they are not firmly retained or secured with the frames.

3. Crushing of Column Ends and Virtual Hinging: When extreme shaking occurs, the column ends are susceptible to serious eccentric compressive stresses which compel the concrete to get crushed and broke down from the exterior surfaces. In frequent cycles, the damage proceeds interiors, consequently the effective section is shortened significantly. Both the column ends substantially function as pins and the entire framework falls down like a mechanism.

4. Short Column Effect: If infill walls having wide openings are joined to the columns, the sections of the columns to be deformed against lateral seismic loads turn out to be very short with reference to their normal height.

Such short columns develop into much harder as compared to other columns and pull greater shear forces under which they experience extreme diagonal tension which result in collapsing of the column.

5. Diagonal Cracking in the Columns: Columns are exposed to diagonal cracking resulting from large seismic shears occurred under extreme ground shaking. When the building also sustains the twisting action, the crack may change to a spiral form that decreases load bearing strength of the columns significantly.

6. Diagonal Cracking of Column Beam Joint: Several times, diagonal cracking happens through the intersection of the columns with the beams that considerably damages the strength of the frame.

7. Drawing Out of the Reinforcing Bars: Where the anchor length of the column bars or overlaps among the longitudinal bars are insufficient for producing full tensile strength of the bar, they are frequently drawn out because of tensions occurred in the column against reversal of stresses.

8. Collapse of Gable Frames: Reinforced concrete gable frames, frequently applied for school workshops, gymnasia and assembly halls, and cinema halls, may be expanded devoid of secondary resistance obtainable as soon as a joint fails. These are frequently found to fail and collapse if not properly designed and detailed.

9. Foundation Sinking and Tilting: Sinking or tilting of foundations of columns because of seismic shaking happens in loose soft soils and can result in extreme cracking of the superstructure and even fall down.



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Published By
Rajib Dey
www.constructioncost.co
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