When designing an automated three-dimensional warehouse, it is necessary to provide the civil engineering design institute with the load requirements of the shelves on the ground. There are some people don’t know how to calculate when they encounter this problem, and often turn to manufacturers for help. Although most reliable shelf manufacturers can provide corresponding data, the response speed is relatively slow, and they cannot answer the owner’s questions in a timely manner. Besides, if you don’t know the calculation method, you can’t judge whether there is any problem with the data you get, and you still have no idea. Here is a simple calculation method that only needs a calculator.
In general, it is necessary to propose that the load of the shelf on the ground has two items: concentrated load and average load: concentrated load refers to the concentrated force of each column on the ground, and the general unit is expressed in tons; average load refers to the unit area of the shelf area. Bearing capacity is generally expressed in tons per square meter. The following is an example of the most common beam-type shelves. The pallet goods are arranged on the shelves as shown in the figure below:
For easing understanding, the figure captures the layout of two adjacent compartments on one of the shelves, and each compartment holds two pallets of goods. The weight of the unit pallet is represented by D, and the weight of two pallets is D*2. Taking the cargo grid on the left as an example, the weight of the two pallets of goods is evenly distributed on the four columns 1, 2, 3, and 4, so the weight shared by each column is D*2/4=0.5D, and then we use Take the No. 3 column as an example. In addition to the left cargo compartment, the No. 3 column, together with 4, 5, and 6, also needs to share the weight of the two pallets on the right compartment equally. The calculation method is the same as that of the left compartment, and the shared weight is also 0.5 D, so the load of No. 3 column on this layer can be simplified to the weight of a pallet. Then count how many layers the shelf has. Multiply the weight of a single pallet by the number of layers to get the concentrated load of the shelf column.
In addition, in addition to the weight of the goods, the shelf itself also has a certain weight, which can be estimated based on empirical values. Generally, the standard pallet rack can be estimated according to 40kg for each cargo space. The calculation formula is to use the weight of a single pallet plus the self-weight of a single cargo rack and then multiply it by the number of layers. For example, the unit cargo weighs 700kg, and there are 9 layers of shelves in total, so the concentrated load of each column is (700+40)*9/1000=6.66t.
After introducing the concentrated load, let’s look at the average load. We delineate the projection area of a certain cargo cell as shown in the figure below, and the length and width of the area are represented by L and W respectively.
There are two pallets of goods on each shelf within the projected area, and considering the weight of the shelf itself, the average load can be multiplied by the weight of two pallets plus the self-weight of the two shelves , and then divide by the projected area. Still taking the unit cargo of 700kg and 9 shelves as an example, the length L of the projected area in the figure is calculated as 2.4m and W as 1.2m, then the average load is ((700+40)*2*9/1000)/(2.4*1.2 )=4.625t/m2.
Post time: May-18-2023
