U Value Of Reinforced Concrete Wall

Reinforced concrete cantilever retaining wall analysis and design aci 318 14 reinforced concrete cantilever retaining walls consist of a relatively thin stem and a base slab.

U value of reinforced concrete wall.

U values of typical building methods u values overall coefficient of heat transmission indicate the heat flow through materials the higher the figure the higher the heat loss. Slenderness ratio is equal to least of l t or h t where l is effective length of wall h is effective height of wall t is thickness of wall if 12 the wall is short and if 12 the wall is slender. The base is divided into two parts the heel and toe. Reference table for u values u value is the coefficient of transmission i e the transmission of heat through the materials which compose the building s envelope or outer shell.

The stem may have constant thickness along the length or may be tapered based on economic and construction criteria. Concrete block walls u values r values. For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. In reinforced concrete wall the percentage of steel provided is greater than 0 4 and is designed similar to reinforced concrete columns.

A reasonable r value for a normal concrete slab can be estimated using an r value the thermal resistance per inch of thickness between 0 1 and 0 2 and multiplying it times the slab thickness. The u value is the measure of heat transmittance through a material and the lower the u value the less heat is transmitted through a construction i e. The insulation may be poured directly into walls or emptied into a simply wood or metal hopper which can be slid along the wall to direct the free flowing perlite into cores of cavities thus insulating all voids and air pockets. As we said before the r value measures the thermal resistance of a material.

The steady state thermal analysis shows the total isothermal r value for the wall with the ability to factor in thermal breaks such as metal ties or solid concrete sections. U value has an inverse relationship to r value. Calculating the inverse of that 1 r would give you a u factor in the range of 1 67 to 0 83. While the values do vary for each particular material and method of construction the following table gives general figures for some common modes of construction.

For a 6 inch slab r value would be between 0 6 and 1 2. For concrete the k value depends on its bulk density and the moisture content in service. The better the insulation quality. Concrete sections and therefore has been tempered with u value average to account for the restricted conduction zones affected by solid concrete.

For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09. This simple u value calculator can help you quickly check your designs or plans to see if they are likely to achieve bs en iso 6946 2017 compliance.