Characteristic and Design Values and Partial Safety Factors

35.1 Characteristic Strength of Materials

The term ‘characteristic strength’ means that value of the strength of the material below which not more than 5 percent of the test results are expected to fall. The characteristic strength for concrete shall be in accordance with Table 2. Until the relevant Indian Standard Specifications for reinforcing steel are modified to include the concept of characteristic strength, the characteristic value shall be assumed as the minimum yield stress/0.2 percent proof stress specified in the relevant Indian Standard Specifications.

35.2 Characteristic Loads

The term ‘characteristic load’ means that value of load which has a 95 percent probability of not being exceeded during the life of the structure. Since data are not available to express loads in statistical terms, for the purpose of this standard, dead loads, imposed loads, wind loads, snow load and seismic forces in accordance with Part 6 ‘Structural Design, Section 1 Loads, Forces and Effects’ of the Code shall be assumed as the characteristic loads.

PART 6 STRUCTURAL DESIGN — SECTION 5 CONCRETE: 5A PLAIN AND REINFORCED CONCRETE

35.3 Design Values

35.3.1 Materials

The design strength of the materials, $f_{\mathrm{d}}$ is given by:

f _ {\mathrm{d}} = \frac {f}{\gamma_ {\mathrm{m}}}

35.4 Partial Safety Factors

35.4.1 Partial Safety Factor $gamma\{mathrm\{f\}\}$ for Loads

The values $\gamma_{\mathrm{f}}$ given in Table 18 shall normally be used.

Table 18 Values of Partial Safety Factor $\gamma_{\mathrm{f}}$ for Loads

Sl No.	Load Combination	Limit State of Collapse			Limit States of Serviceability
Sl No.	Load Combination	DL(3)	IL(4)	WL(5)	DL(6)	IL(7)	WL(8)
i)	$DL+IL$	1.5	1.5	-	1.0	1.0	-
ii)	$DL+WL$	$1.5 or 0.9^{1)}$	-	1.5	1.0	-	1.0
iii)	$DL+IL+WL$	1.2	1.2	1.2	1.0	0.8	0.8

Chapter 35Characteristic and Design Values and Partial Safety Factors

35.1 Characteristic Strength of Materials

35.2 Characteristic Loads

35.3 Design Values

35.3.1 Materials

35.4 Partial Safety Factors

35.4.1 Partial Safety Factor $gamma\{mathrm\{f\}\}$ for Loads

35.3.2 Loads

35.3.3 Consequences of Attaining Limit State

35.4.2 Partial Safety Factor $gamma\{mathrm\{m\}\}$ for Material Strength

35.1 Characteristic Strength of Materials

35.2 Characteristic Loads

35.3 Design Values

35.3.1 Materials

35.4 Partial Safety Factors

35.4.1 Partial Safety Factor gamma{mathrm{f}}gamma\{mathrm\{f\}\}gamma{mathrm{f}} for Loads

35.3.2 Loads

35.3.3 Consequences of Attaining Limit State

35.4.2 Partial Safety Factor gamma{mathrm{m}}gamma\{mathrm\{m\}\}gamma{mathrm{m}} for Material Strength

35.4.1 Partial Safety Factor $gamma\{mathrm\{f\}\}$ for Loads

35.4.2 Partial Safety Factor $gamma\{mathrm\{m\}\}$ for Material Strength