Reinforcement Properties
Description
Definition of the material properties for a section or beam is a three step process:
- Add the material type (concrete / reinforcing steel / etc.)
- Define a set of properties for that material type (characteristic strength etc.)
- Allocate the material properties defined in 1 & 2 to the relevant parts of the section or beam section component.
This form performs the second of these 3 stages for reinforcement. As data is entered the program checks that values are within the expected range for steel. This check will highlight any values in error by a factor of 10 more. The displays for Ultimate Limit State and Servicability Limit State are to the same scale, and are updated as the values in the fields are changed.
Form Graphic
Field Help
Characteristic strength fy
Enter the characteristic strength of the reinforcement. A warning will be issued if the value entered is unrealistic, but the value will not be rejected.
Material partial factor γm
Enter the partial safety factor for strength. Values not between 1 and 2 will be rejected.
BS 5400 Part 4 specifies 1.15 in clause 4.3.3.3.
BS 8110 Part 1 specifies 1.05 in Table 2.2.
CS 455 Table 2.13a specifies:
1.15 for use with the characteristic strength (may be reduced to 1.05 for grade 460 steel),
1.10 for use with the worst credible strength (may be reduced to 1.05 for grade 460 steel or for any steel grade if measured steel depths are used in addition to the worst credible steel strength).
Modulus of Elasticity
Enter the modulus of elasticity of the reinforcement. The default value is 200kN/mm2 as suggested in clause 4.3.2.2 of BS 5400 Part 4, and clause 2.5.4 of BS 8110 Part 1.
Stress limitation factor
Enter the stress limitation factor for reinforcement in tension and compression.
For BS 5400 refer to BS 5400 Part 4 clause 4.1.1.3 and Table 2 for suitable values. The following gives an aide memoir:
| reinforced | prestressed | |
|---|---|---|
| compression | 0.75 | n/a |
| tension | 0.75 | n/a |
For BS 8110 a value of 0.8 is given in clause 3.8.3.
Density
Enter the density of the reinforcement.
Property name
The program will supply a reference name which provides an identifier to the material property set which is usually unique. This value may be edited to give a more readily recognisable name if required.