What are the design criteria for the shelf load of compact shelves?
Release Time : 2025-12-18
The load-bearing design of compact shelves requires a comprehensive consideration of multiple factors, including material properties, mechanical principles, structural optimization, and environmental adaptability. The core logic lies in ensuring, through scientific calculations and engineering verification, that the shelves can both bear the target load and maintain structural stability during long-term use.
As the primary material for the shelves, the mechanical properties of compact shelves directly affect their load-bearing capacity. Cold rolling processes enhance the strength and hardness of the steel plate through work hardening, resulting in a significantly higher yield strength than hot-rolled steel plates. For example, Q235B compact shelves have a yield strength of up to 235 MPa, while Q355B compact shelves achieve 355 MPa, providing a foundation for the shelves to bear higher loads. Simultaneously, the choice of steel plate thickness must balance strength and cost; thicker steel plates increase load-bearing capacity but also increase material usage and the shelf's weight. In practical design, shelf thickness is typically determined using mechanical formulas based on load requirements. For example, in one case, a 1.2mm thick compact shelf can safely support 150kg across an 800mm span, while a 2.0mm thick steel plate can support up to 300kg.
Shelf load design must adhere to mechanical principles to ensure structural stability under load. Beam deflection (bending deformation) is a critical indicator; industry standards require that deflection not exceed 1/200th of the beam length. For instance, if the beam length is 2.7 meters, the maximum allowable deflection is 13.5mm; exceeding this value may cause the shelf to tilt or even collapse. Furthermore, the connection method between the shelf and the beam also affects load distribution. Bolted or welded connections must ensure sufficient rigidity at the joints to prevent localized stress concentration and subsequent damage.
Structural optimization is an effective means of improving shelf load capacity. By rationally designing the shelf shape and support structure, loads can be distributed and stress concentration reduced. For example, using corrugated or stiffened panels can enhance the bending resistance of shelves, allowing them to bear higher weights at the same thickness. Simultaneously, the span of the shelves must match the overall structure of the racking to avoid deformation due to excessive span. For instance, an automated warehouse case study shows that by designing the bottom layer to bear 2000kg and the top layer 800kg, the storage requirements for heavy parts were met while reducing steel usage by 30%.
Dynamic load is a key factor to consider in shelf design. Dynamic impacts from forklift operations and AGV movement generate forces far exceeding static loads, typically requiring a safety factor of 1.5-2.0 times. For example, tests in a cold chain warehouse showed that when a forklift travels at 5km/h, the impact force on the racking is 1.8 times that of a static load. Therefore, shelf design needs to be verified through dynamic simulation testing to ensure structural integrity under frequent picking operations.
Environmental factors also significantly impact the load-bearing capacity of shelves. Temperature changes can reduce the toughness of steel. For example, a cold storage environment (-25℃) can reduce the toughness of steel by 15%, necessitating the use of low-temperature steel. High humidity accelerates steel corrosion. Data from a warehouse in southern China shows that untreated shelving has a 40% shorter lifespan, thus requiring galvanizing or powder coating to improve rust resistance. Furthermore, ground conditions must be considered. Insufficient foundation bearing capacity can lead to shelving settlement. In one case, foundation settlement caused the shelving to tilt at a 0.3° angle, resulting in goods slipping.
Shelf load design must comply with relevant standards and specifications to ensure safety and compliance. Routine inspections and annual checks are also crucial for ensuring shelving safety, focusing on checking the bending of uprights, looseness of beam connections, and weld defects.