Heavy-duty Rack Testing

Heavy-duty rack inspection mainly conducts scientific testing and analysis on the structural integrity testing, dimension and verticality testing, surface coating quality testing, safety accessory and marking inspection, load-bearing capacity verification testing and seismic and impact resistance property testing, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Structural integrity testing: The rack main structures are checked, including the main load-bearing components such as the upright frames, beams and support beams, whether there are the defects such as the cracks, deformations, rust and corrosion. The firmness of the welding or bolted connection parts is emphatically evaluated, ensuring the stability and safety of the overall structures under the rated loads.

Dimension and verticality testing: The overall and key component dimensions of the racks are measured, such as the upright frame spacings, beam elevations and shelf heights. The tools such as the laser levels or plumb lines are used to detect the verticality deviations of the racks, ensuring that their installation meets the design requirements, avoiding the stress concentration and instability risks caused by the tilting.

Surface coating quality testing: The qualities of the anti-corrosion coatings on the rack surfaces are evaluated, including the coating thicknesses (measured with the coating thickness gauges), adhesion (cross-cut testing), uniformity, and whether the defects such as the peeling, blistering and missing coating exist. The good coatings are the key to guaranteeing the long-term corrosion resistance of the racks in the storage environments.

Safety accessory and marking inspection: Whether the safety protection devices of the racks, such as the beam safety pins, upright frame protective skirts and anti-collision guardrails, are complete and effective is checked. At the same time, whether the markings on the racks such as the rated loads and safety warnings are inspected, complete and correct is verified. This is the important basis of the daily use and management.

Load-bearing capacity verification testing: Through the static load or dynamic load testing, the actual storage working conditions are simulated, verifying the load-bearing performances of the racks under the rated loads and possible overload conditions. During the testing, the stresses, strains and overall deformations of the key parts are monitored, evaluating whether they meet the safety margin requirements of the design and relevant standards.

Seismic and impact resistance property testing: The impact resistance of the racks when subjected to the seismic forces or accidental collisions of the equipment such as the forklifts is evaluated. Through the simulation analysis or specific testing, the responses of the structures under the dynamic loads are checked, ensuring that they have the sufficient toughness and anti-tilting abilities, preventing the progressive collapse.

Foundation and anchor bolt inspection: Whether the load-bearing surfaces of the rack foundations are flat and firm, without the settlement or cracking phenomena, is checked. At the same time, whether the specifications, pretension forces and anti-loosening measures of the anchor bolts are in place is checked, ensuring that the racks are reliably connected to the ground. This is the root of the overall structural stability.

Testing Scope

Beam-type heavy-duty racks: This is the most common heavy-duty rack form. The testing emphases are the connection nodes between the upright frames and beams, beam deflections, locking states of the safety pins, and the load-bearing uniformity of the beams at the various levels. Usually applied to the palletized warehousing.

Drive-in heavy-duty racks: As the high-density storage racks, their testing needs to particularly pay attention to the straightness and levelness of the guide rails, load-bearing strengths of the cantilever supports, and the lateral force effects on the structures caused by the goods access. The overall stability during the high-position storage needs to be evaluated.

Narrow aisle heavy-duty racks: This type of rack usually has the higher heights and narrower aisles. The testing scope needs to strengthen the inspection of the overall verticality, free end heights of the upright frame tops, as well as the connection parts between the aisle guide rails and rack structures, ensuring the compatibility and safety with the dedicated forklifts.

Cantilever heavy-duty racks: Mainly used to store the long materials. The testing core is the root connection strengths of the cantilever arms, vertical and horizontal deformations of the cantilever arms, as well as the torsional resistance of the upright frames when bearing the asymmetric loads, preventing the cantilever sagging or falling off.

Mezzanine heavy-duty racks: As the multi-layer structures, the testing scope includes the load-bearing capacities of the upper floor panels, vertical loads and stability of the support upright frames, and firmness of the stairs and safety guardrails. The safety re-verification of the overall structures needs to be carried out.

Periodic testing of the racks already in use: For the racks in use, the testing scope needs to add the evaluation of the daily wear and tear, such as the component damages caused by the forklift collisions, accumulation of the plastic deformations under the long-term loads, as well as the coating aging and rust expansion caused by the environments.

Acceptance testing of the newly installed racks: Carried out after the initial installation of the racks, the testing scope covers the conformity of all the design specifications, installation qualities, as well as the structural geometric tolerances under the empty-load states, ensuring that they reach the basic safety conditions for the delivery and use.

Testing Methods

Visual inspection method: The most basic testing method. The professional testing personnel carry out the systematic visual inspection on the racks. Emphatically finding the intuitive defects such as the obvious structural damages, severe deformations, rust, coating peeling, missing or damaged connectors, and making the detailed records.

Dimension and geometric measurement method: The tools such as the tapes, laser distance meters, levels, plumb lines and total stations are used to precisely measure the geometric dimensions, levelness, verticality and diagonal deviations of the racks. The measurement results are compared with the design drawings or the relevant installation standards (such as the SEMA and RMI standards).

Non-destructive testing technology: For the key load-bearing welds or the parts suspected of having the internal defects, the magnetic particle testing (MT) or penetrant testing (PT) can be used to find the surface and near-surface cracks; for the important components, the ultrasonic testing (UT) can be used to evaluate the internal qualities when necessary.

Load testing method: Including the static load testing and dynamic load testing. The static load testing places the standard loads (usually 1.25 times the rated loads or above) for the specified times, observing the deformations and recovery conditions; the dynamic load testing simulates the forklift goods access processes, evaluating the dynamic responses and fatigue characteristics of the structures.

Instrument monitoring method: The resistance strain gauges are pasted on the key parts (such as the upright frame bottoms, beam mid-spans and connection nodes), and the stress and strain distributions during the loading processes are measured through the static or dynamic strain instruments, scientifically evaluating the stressed states and safety factors of the structures.

Three-dimensional laser scanning method: The three-dimensional laser scanners are used for the fast and high-precision scanning of the whole racks, generating the point cloud models. Through the comparison with the original design models, the overall deformations, tilting and component damage conditions of the racks can be comprehensively and intuitively analysed.

Standard-based technical evaluation: According to the testing processes and acceptance criteria specified in the domestic and international standards (such as the Chinese GB/T 30675, Design calculations for industrial racks, the EU EN 15635, Steel static storage systems — Application and maintenance of storage equipment, and the American ANSI MH16.1), the systematic and standardized technical conformity evaluation is carried out.

Testing Standards

Domestic Standards:

1. GB/T 30675, Design calculations for industrial racks

International Standards:

1. EN 15635, Steel static storage systems — Application and maintenance of storage equipment

2. ANSI MH16.1, Specification for the design, testing and utilization of industrial steel storage racks

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Laser distance meter and total station: Used to efficiently and precisely measure the overall dimensions, shelf heights, aisle widths and key point coordinates of the racks. The total stations are especially suitable for the three-dimensional spatial measurement of the verticality and geometric tolerances of the large and high racks.

Electronic level and laser line projector: Used to detect the levelness of the beams at the various levels of the racks, verticality of the upright frames and flatness of the installation foundations. The laser line projectors can provide the intuitive horizontal and vertical reference lines, convenient for the fast comparison.

Coating thickness gauge: Adopting the magnetic measurement method or eddy current measurement method, non-destructively measuring the thicknesses of the anti-corrosion coatings (such as the paints and galvanized layers) on the rack steel surfaces, judging whether they reach the anti-corrosion grades required by the design or standards.

Static resistance strain instrument and strain gauges: The core equipment of the stress and strain analysis. The strain gauges are pasted on the surfaces of the tested components, and the micro-strain data of the components under the loads are collected through the strain instruments, thereby calculating the stresses and evaluating their load-bearing capacities and safety margins.

Non-destructive testing equipment: Including the magnetic particle flaw detection machines, penetrant testing reagent kits and ultrasonic flaw detectors, etc. Used to find the potential defects such as the cracks, lack of fusion and slag inclusions in the rack welds and base materials, evaluating the internal integrity of the structures.

Torque wrench: Used to check and verify whether the pretension torques of the rack anchor bolts and structural connection bolts reach the design requirements, ensuring the fastening reliability of the connection points, preventing the structural instability caused by the bolt loosening.

Three-dimensional laser scanner: The advanced geometric dimension and deformation measurement equipment. It can quickly obtain the massive point cloud data of the whole racks, and through the professional software for the three-dimensional modeling and comparative analysis, comprehensively evaluate the structural states and generate the digital testing reports.