Crane Load Test Methods and Acceptance Criteria per GB/T 5905-2011
💡 GB/T 5905-2011 "Cranes — Test Code and Procedures" is the general national standard for crane load testing in China. The standard specifies the methods and requirements for static load tests, dynamic load tests, and stability tests on cranes. Factory acceptance tests and type tests for overhead, gantry, tower, and mobile cranes are all conducted in accordance with this standard. This article provides a detailed breakdown of the test procedures, load factors, and acceptance criteria.
GB/T 5905-2011 "Cranes — Test Code and Procedures" is an equivalent adoption of ISO 4310:2009 and serves as the general technical specification for testing all crane types. The standard defines three fundamental test categories — static load test, dynamic load test, and stability test — along with the corresponding load factors, test procedures, and acceptance criteria for each. Kelude Heavy Industry performs routine factory tests on its overhead and gantry cranes in strict accordance with this standard.
Static Load Test Procedure and Requirements
The static load test verifies the load-bearing capacity of the crane's metal structure and load-carrying system. The test load is set at 1.25 times the rated load, and the procedure is as follows:
Test procedure: The test load is smoothly lifted to approximately 100 mm above the ground and held in suspension for 10 minutes. After unloading, the main girders, outriggers, and other primary structural components are inspected for permanent deformation and cracks. For overhead cranes, particular attention is paid to the mid-span deflection of the main girder. For gantry cranes, the outrigger connection points are also checked in addition to the main girder.
Acceptance criteria: After unloading, the deflection of the bridge girder must not exceed 1/2000 of the span, and no permanent deformation or cracks are permitted in the structure or weld seams. No relative displacement is allowed at structural connection points. Note that the 1/2000 limit applies to residual deformation after unloading — this is a different indicator from the elastic deflection of 1/700 to 1/800 measured under full load.
Test weights: Test loads typically consist of calibrated test weights, heavy objects, or purpose-built water tanks for load testing. The mass of the test load must be verified through calibration, with a tolerance of no more than ±1%. When using water tanks, the tank volume is calculated based on a water density of 1 t/m³, and the water level gauge should be marked in advance.
Dynamic Load Test Procedure and Requirements
The dynamic load test verifies the working capability of all crane mechanisms under overload conditions. The test load is set at 1.1 times the rated load.
Test procedure: The hoisting, long travel (bridge travel), and cross travel (trolley travel) mechanisms — or luffing and slewing mechanisms where applicable — are operated simultaneously or sequentially for no fewer than three complete round trips. Each mechanism must operate within its rated speed range, covering the full cycle of starting, running, and braking. The hoisting mechanism should perform three full-stroke lifts and three full-stroke lowerings.
Acceptance criteria: During the test, all mechanisms must operate normally without abnormal vibration or noise. Brakes must engage reliably, and the load's descent distance after braking must not exceed the value specified in the standard. Motors, gearboxes, and couplings in all mechanisms must not exhibit overheating or abnormal temperature rise. No significant friction marks should appear on the wheel flanges or crane rails.
Stability Test for Overturning Resistance
The stability test applies to crane types with overturning risk, including gantry cranes, tower cranes, and mobile cranes. Overhead cranes are generally exempt from this test because they operate on rails and have a low center of gravity.
Gantry crane stability test: A load equal to 1.25 times the rated load is applied at the maximum working radius (the farthest point of the cantilever end), and the outriggers are checked to ensure they do not lift off the rail surface. No lifting of any outrigger is permitted. A horizontal force is also applied to simulate wind load, calculated according to the wind load formula in GB/T 3811 Crane Design Standard.
Acceptance criteria: No outrigger may lift off the rail or foundation surface. The anti-overturning stability factor must meet the standard requirements (≥1.5 without wind, ≥1.33 with working wind, ≥1.15 with non-working wind).
Comparison of the Three Test Methods
| Test Type | Test Load | Key Inspection Points | Acceptance Criteria |
|---|---|---|---|
| Static Load Test | 1.25 × rated load | Permanent deformation of main girder, outriggers, and weld seams; mid-span deflection | Residual deflection ≤ 1/2000 of span; no permanent deformation or cracks |
| Dynamic Load Test | 1.1 × rated load | Hoisting, long travel, and cross-travel mechanisms; braking performance; temperature rise in motors and gearboxes | Normal operation without abnormal vibration or noise; reliable braking; no overheating |
| Stability Test | 1.25 × rated load at max working radius | Outrigger lift-off; anti-overturning stability factor under wind load conditions | No outrigger lift-off; stability factor ≥1.5 (no wind), ≥1.33 (working wind), ≥1.15 (non-working wind) |
| Test Type | Load Coefficient | Test Time | Detection Item | Acceptance Criteria |
|---|---|---|---|---|
| Static load test | 1.25Parts of Line | Hover10min | main girder deflection, structure Deformation, Crack | Residual deformation≤S/2000 |
| Dynamic Load Test | 1.1Parts of Line | Round Trip≥3Cycle | mechanism Operation, Braking, temperature rise, Noise | No Abnormalitiesvibrationandtemperature rise |
| stability test | 1.25Parts of Line+wind load | Continuous Loading | Outrigger Lift-Off, overturning moment | Outrigger No Lift-Off stability factor Compliant |
| Crowd Standard | factory100%Performstatic load+Dynamic Load Test, Provide Official Test Report | |||
Frequently Asked Questions
Q: Why is the static load test set at 1.25 times the rated load instead of 1.5 times?
A: The 1.25 factor is the characteristic value specified in ISO 4310 and GB/T 5905, which accounts for the safety margin between material yield strength and design stress. Crane design per GB/T 3811 already incorporates a 1.5 safety factor. The 1.25 static load represents the maximum probable load during service and is intended to verify the structure's elastic behavior under extreme operating conditions—not to induce failure.
Q: What is the difference between a type test and a routine test?
A: A routine test is performed on every crane unit by unit before delivery and includes a no-load test run, static load test, and dynamic load test. A type test is a comprehensive inspection conducted when a new product is being certified or when a significant design change is made. In addition to load testing, it covers structural strength testing, material verification, and endurance tests. Type tests are carried out by nationally accredited testing bodies, whereas routine tests are completed by the manufacturer.
Q: Do I need to repeat load testing after on-site installation?
A: Yes. Per TSG 51-2023 Crane Safety Technical Supervision Regulation, a load test must be performed on site after installation, including a 1.25 static load test and a 1.1 dynamic load test. The purpose is to verify that installation quality—such as rail straightness and crane wheel installation accuracy—meets design requirements. Kelude Heavy Industry includes on-site load testing as part of delivery and provides an Installation Acceptance Report.
Q: How often should load testing be performed on cranes in service?
A: Load testing for cranes in service falls into two categories: load tests during periodic inspection (every 2 years per TSG 51) and load tests after major repairs (mandatory after replacing critical components such as the main girder or hoisting mechanism). For cranes rated at A6 or higher, a dynamic load test is recommended every 4 years and a static load test every 6 years.
