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IS 2408:1963 is the Indian Standard (BIS) for methods of static tests of timber in structural sizes. This standard outlines the methods for conducting static tests on timber members in structural sizes. It is used to evaluate mechanical properties such as flexural strength and compressive strength on full-scale sections, accounting for natural defects (like knots and shakes) that small clear specimens do not capture.
Methods of static tests of timber in structural sizes
! Test specimens must include natural defects typical of their grade to accurately reflect real-world structural capacity.
! Moisture content must be recorded immediately after testing, as the structural strength of timber varies significantly with moisture levels.
! Loading rates must be strictly controlled to ensure static loading conditions, avoiding dynamic or impact effects.
timberwoodstructural timber
International Equivalents
Similar International Standards
ASTM D198-22ASTM International, USA
HighCurrent
Standard Test Methods of Static Tests of Lumber in Structural Sizes
Defines static test methods for structural-sized timber, including bending, compression, and tension.
EN 408:2010+A1:2012CEN (European Committee for Standardization), Europe
HighCurrent
Timber structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties
Specifies test methods for determining physical and mechanical properties of structural timber and glulam.
AS/NZS 4063.1:2010Standards Australia / Standards New Zealand
HighCurrent
Characterisation of structural timber - Part 1: Test methods
Provides methods for testing structural timber to determine characteristic properties like strength and stiffness.
BS 373:1957BSI (British Standards Institution), UK
LowWithdrawn
Methods of testing small clear specimens of timber
Historically relevant but focused on small, clear specimens, not structural sizes like IS 2408.
Key Differences
≠IS 2408:1963 specifies a fixed rate of machine head movement (e.g., 2.5 mm/min in bending), while modern standards like EN 408 specify a loading rate designed to achieve failure within a target time frame (e.g., 300 ± 120 seconds), which is more scientifically robust.
≠Modern standards like ASTM D198 and EN 408 include provisions and calculations for advanced data acquisition and correction for machine deformation, which are absent in the 1963 Indian Standard.
≠EN 408 explicitly covers glued laminated timber (glulam) and other engineered wood products within its scope, whereas IS 2408 is primarily focused on solid sawn timber.
≠The specified geometries for test specimens can differ significantly. For example, the length-to-depth ratio for compression parallel to grain tests in EN 408 is 6, while IS 2408 specifies a range of 2 to 4.
Key Similarities
≈All standards outline methods for the same fundamental mechanical tests: bending (flexure), compression (parallel and perpendicular to grain), tension, and shear.
≈The use of a four-point bending test setup is a common method across all standards for determining the Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) of structural members.
≈All standards recognize the critical influence of moisture content and require or recommend conditioning specimens to a target moisture content, typically around 12%, before testing.
≈The basic physical principles and formulas used to calculate key properties like bending strength (MOR) and stiffness (MOE) from raw load and deflection data are fundamentally the same.
Parameter Comparison
Parameter
IS Value
International
Source
Bending Test: Span-to-Depth Ratio
12 to 24 (14 suggested)
18 ± 1
EN 408:2010
Bending Test: Target Time to Failure
Not specified; loading rate is fixed.
300 ± 120 seconds
EN 408:2010
Compression Parallel to Grain: Length-to-Least-Dimension Ratio
What is the difference between IS 2408 and IS 1708?+
IS 2408 is for testing full structural sizes which include natural defects, while IS 1708 is for testing small, clear specimens devoid of defects.
What are the primary properties evaluated under this code?+
Flexure (bending) characteristics, compression parallel to the grain, and modulus of elasticity for full-size structural members.
Why is moisture content important in this test?+
Timber strength is inversely proportional to its moisture content below the fiber saturation point; thus, testing requires correlating strength to a standard moisture level (usually 12%).