qtoConstruction - Calculation Of The Load Bearing Capacity Of Reinforced Cement Concrete (2024)

FAQs

What is the bearing capacity of reinforced concrete? ›

Bearing capacity of a foundation is the maximum load that can be applied on a foundation, before failure or uncontrolled deformations occur. Imposed loads varies from approximately 1.5 kN/m2 (153 kg/m2) in domestic buildings to approximately 10 kN/m2 (1053 kg/m2) in heavy industrial areas.

Step 1 - Find out the no. Of bars and their dimensions in one meter span of slab in shorter direction. Step 2 - find out the grade of concrete. Step 3 - using the IS 456 page 90 formula, calculate the area of steel present in temaion and the thickness of slab and thereafter find the moment of resistance of slab.

The bearing strength of concrete is simply the compressive strength of the concrete and the ratio of the total surface area to the load bearing area (known as bearing ratio).

It represents the load under which the bearing can operate for one million revolutions without experiencing failure. Use the formula C0 = (P0 / F0) x C to calculate the static load carrying capacity, C0, of the bearing.

Allowable bearing capacity is the maximum pressure that can be applied to the soil, considering factors such as safety against shear failure and excessive settlement. It is calculated by dividing the ultimate bearing capacity by a factor of safety.

Another example is calculating the bearing between two points with given latitude and longitude. The formula for this is: β = atan2(X,Y), where X and Y are two quantities that can be calculated based on the given latitude and longitude.

Net ultimate bearing capacity q_αστ or q_ult: is the net stress that causes shear failure in the foundation soil. Net allowable pressure q_επ: is the net ultimate bearing capacity divided by a factor of safety F, q_επ = q_αστ/F = (q'_αστ - γD_f)/F.

Bearing calculation

The Computation of Bearing Loads is simplified as follows: R= Radial load – loads that are perpendicular to the shaft. T= Thrust load – loads that are parallel to the axis of the bearing. C= Combined load is a result of calculating both Radial and Thrust loads using the combined load calculations.

Take the total load, and divide by the overall recommended load to get the percentage. For example, if the total load is up to 800 watts and this is a 20 amp circuit, then the load usage is 800 watts divided by 1920 watts equal to 0.416 or 42%.

What determines the load capacity of a bearing? ›

A bearing's ability to withstand a load is determined by how close the Hertzian contact pressure is to the stress limit of the bearing. The closer it is to the bearing's stress limit, the less time it will take for the bearing to experience plastic deformation.

Net ultimate bearing capacity (qₙᵤ): the net pressure increase at the foundation base that will result in shear failure of the soil. It is calculated by subtracting the weight of the soil (𝝲) multiplied by the foundation depth (D) from the ultimate bearing capacity (qᵤ).

The allowable bearing capacity (q_a) is the maximum bearing stress that can be applied to the foundation such that it is safe against instability due to shear failure and the maximum tolerable settlement is not exceeded.

To summarize: A 4-inch concrete driveway can support weights up to approximately 6,000 pounds. A 5-inch concrete driveway can support weights up to approximately 10,000 pounds. A 6-inch concrete driveway can support weights exceeding 12,000 pounds, depending on the specific design and construction.

With natural strength, even a standard concrete with minimal thickness has impressive load bearing capabilities. 3000 psi is the standard of compressive strength on a concrete slab.

The maximum bearing pressure should not exceed the bearing strength equal to 0.6 f_ck, where f_ck is the smaller characteristic cube strength of concrete or bedding material.