Floor Load Capacity Testing

The bearing capacity of the floor is related to many factors. First, it is necessary to inspect and understand the span in both directions of the floor, the grade of the concrete used in the floor, the reinforcement configuration of the floor, the thickness of the floor slab, and the possible loading forms on the floor.(Uniform distribution, concentrated force, linear load). Then, considering the uniform load it can bear, the PKPM software is used to build a model and perform calculations on its bearing capacity and load analysis.

What should be done when the load-bearing capacity of the floor does not meet the requirements after the calculation??

The majority of reasons for insufficient floor bearing capacity are insufficient floor thickness, inadequate steel reinforcement in the floor, and insufficient steel reinforcement in the load-bearing beams. In such a situation, what should be done??

1. Reinforcement Methods for Insufficient Panel Thickness:

(1) Chisel the surface of areas with insufficient floor thickness and wash with water until clean.

(2) At a distance of 10mm from the existing panel surface on all four sides, prestressed steel wires are placed every 200mm, forming a prestressed steel wire mesh.

(3) Cast fine aggregate concrete with a strength grade higher than that of the original slab surface, and cure according to standard procedures.

2. Handling insufficient board thickness:

(1) Cause: Inadequate control of elevation during concrete pouring.

(2) Method of Treatment: Since the main construction is fully completed, redoing the work would incur significant economic losses. Adding more concrete thickness to the top of the slab would be difficult to effectively bond with the completed concrete, making it hard to achieve the reinforcement effect. By increasing the tensile strength at the bottom of the existing slab thickness, we can enhance the cracking bending moment in the elastic working stage and the bearing capacity for continued crack development in the cracked working stage, thereby increasing the area of the compressive working surface and improving the bearing capacity of the slab. The specific operational steps are: carbon fiber reinforcement – treatment of concrete slab bottom → apply primer → repair defects with epoxy putty → paste carbon fiber sheets → cure → paint → complete inspection and acceptance.

What to do if the reinforcement of the floor slab surface is insufficient??

Chapter1. Perform bending moment amplitude adjustment.

Section2. Calculate the bending moment to the edge of the support (using total bending moment minus shear force multiplied by support/2). This will reduce the total support bending moment by over 40%. Also, carefully verifying the calculated loads will yield positive results.

1. This is the case with separated reinforcement, and there's also the double-layer bidirectional reinforcement method where the upper part is continuously reinforced.

2. Reinforcement is required on both sides of the floor, double-layered in every location. If there are no tensile steel bars, distributed steel bars are used to supplement. Therefore, if there are tensile steel bars, distributed steel bars are not needed. In some cases, the lower part of certain floor slabs may lack tensile steel bars, such as in one-way slabs or cantilever slabs. In such instances, distributed steel bars are necessary for the lower section.

3. If there's non-through reinforcement, there must be distribution reinforcement, as explained in response 2. The layout method is to form a grid with the distribution reinforcement and lay it over the areas without the main reinforcement.

4. It is marked only for the tension reinforcement.

5. That means that, although the beam is the same, different sections of this beam support different panels, typically with different spans requiring different reinforcing steel.

Testing Method for Floor Load-Bearing Capacity

Method 1: Load Test

1. Tentatively, two deflection measurement points will be placed at the center bottom of the tested floor. Deflection measurement points can also be arranged around the four edges of the floor bottom based on the actual site conditions. Measurement will be done using a dial gauge, and the positions and number of deflection measurement points can be adjusted according to the site situation.

2. Test Load:

Test load calculation valuesLarge load value is considered according to relevant formulas, or may be provided by the entrusting party with test loads.High load value.

3. Graded Loading

Load according to specifications, monitor deflection and cracking development, thereby determining the floor-bearing capacity.

Method Two: Calculation Analysis Method

1. On-site Survey

Structural arrangement of the on-site buildings, axis grid dimensions, component cross-sectional dimensions, floor thickness and reinforcement conditions, concrete strength, and carbonation depth testing.

2. Calculation and Analysis

Based on on-site testing results, in accordance with the National Standard "Code for Load of Building Structures"(GB50009-2012), "Code for Design of Concrete Structures" (GB 50010-2010), the auxiliary structural design software PKPM compiled by the Chinese Academy of Building Research is used for the calculation of the load-bearing capacity of the building floor slabs.

Floor bearing capacity should be tested and calculated.?

The "Code for Load Design of Building Structures" stipulates that the live load for general civil buildings is taken...2.0 kN/m^2, which means a live load of 200 kg per square meter. When calculating the floor's bearing capacity, this load must be multiplied by a load factor, typically 1.4.