N.Y.C. Admin. Code § EBC H103: Section EBC H103: Historic Material Properties

H103.1 Historic material properties.

Historic material properties may be determined in accordance with Section H101.2.1 and using the information in Sections H103.2 through H103.8, as appropriate.

H103.2 Structural steel.

The dates below indicate the year when codes, specifications, and standards were published. The possibility that back-stock materials were used at later dates shall be taken into account when determining historic material properties. Sampling and testing are recommended as appropriate, particularly for material manufactured before 1900.

Table H103.2 Steel Stresses: Shapes, Plates, and Eyebars

Years

Yield Stress (ksi)

Ultimate Tensile Stress (ksi)

1880-1899

20

40

1900-1931

27.5

55

1932-1961

33

60

After 1961

36

58

Table H103.2.1 Steel Stresses: Rivets

Years

Allowable Stress (ksi)

Load Type

1899-1923

5

Tension

8

Shear

1924-1936

7

Tension

10

Shear

1937-1946

15

Tension

15

Shear

1947-1961

20

Tension

15

Shear

Notes: ASTM A141 for rivets published in 1933.

Table H103.2.2 Steel Stresses: Carbon Steel Bolts

Years

Allowable Stress (ksi)

Load Type

1899-1923

5

Tension

7

Shear

1924-1941

7

Tension

10

Shear

1942-1961

12

Tension

10

Shear

Notes:

(a) capacities are based on nominal diameter of fastener.

(b) threads need not be excluded from shear plane.

(c) ASTM A307 published in 1947.

Table H103.2.3 Steel Strength: Weld Material

Year

W

eld electrode tensile strength (ksi)

1934-1945

40

1946-1961

60

H103.3 Cast iron.

For cast iron, see the allowable working stress in Table H103.3.

Table H103.3 Cast Iron Allowable Working Stress

Stress Type

Allowable Working Stress (psi)

Tension

2,500

Shear

2,500

Flexural compression

16,000

Flexural tension

2,500

Compression on columns

F

a

= F

cr

 / W

W = 2.3

F

cr

= 17000 for L/r £ 108

F

cr

= (198.3 × 10^6) / (L/r)^2 for L/r > 108

where L is the unbraced column length, r is the least radius of gyration for the column section, W is the ASD safety factor, F

a

is the allowable stress, and F

cr

is critical stress in psi.

H103.4 Structural concrete and reinforcing steel.

For structural concrete and reinforcing steel, see the compressive strength values in Table H103.4.

Table H103.4 Minimum Concrete Compressive Strengths (psi)

Year

Footings

Beams

Slabs

Columns

Walls

Prior to 1900

900

900

900

900

900

1900-1919

1,000

2,000

1,500

2,000

2,000

1920-1938

1,500

2,000

2,000

2,000

2,000

1938-1949

2,000

2,000

2,000

2,000

2,000

1950-1969

2,500

3,000

3,000

3,000

2,500

1970-Present

3,000

3,000

3,000

3,000

3,000

Note: Cinder concrete when found shall have 0 psi value for reinforced-concrete analysis.

Table H103.4.1 Minimum Reinforcing Bar Stresses

Year

Yield Stress (ksi)

Tensile Stress (ksi)

1904-1966

33

55

1967-Present

40

70

H103.5 Masonry.

For brick and block walls, the maximum allowable working stress in compression indicated below may be interpreted as 0.25 × f''m for use with the New York City Building Code and its reference standard TMS 402.

Table H103.5 Maximum Allowable Working Stress on Undamaged Solid Brick Masonry Walls (Full Mortar Joints) (psi)

Year

Conditions for use

Mortar

Compression

Flexural Tension perpendicular to bed joints (Note 3)

Pre 1900

Lime

100

0

Pre 1900

Probed as per note 1

cement-lime

150

5

Pre-1900

See note 2

Natural or Portland cement

200

5

Post 1900

Lime

110

5

1900 -1938

Cement-lime

160

15

Post 1938

Cement-lime

250

15

1900 -1938

Cement

250

25

Post 1938

Cement

325

25

Maximum Allowable Working Stress on Undamaged Hollow Walls of Solid Brick Masonry Walls (full mortar joints) (psi)

Post 1938

Cement

150

25

Cement-lime

125

15

Lime

50

15

Note 1

Cement particles visually observed in mortar by removing a brick (2 locations) and documented in condition survey.

Note 2

See Section H101.2 for testing requirements.

Note 3

Allowable shear shall be 1.4 times the given allowable tension.

Maximum Allowable Working Stress on Undamaged Concrete Block Walls (full mortar joints on bedding area with hollow or solid units) on net area unless otherwise noted (psi)

Pre 1968

58 (stress on gross area)

5

1968-1991

140

5

Post 1991

250

9

Maximum Allowable Working Stress on Undamaged Rubble Masonry Walls (full mortar joints) (psi)

Any

Lime

75

0

Any

Cement

110

0

Maximum Allowable Working Stress on Undamaged Terra Cotta Masonry Walls (full mortar joints) (psi)

Any

Cells oriented vertically.

Cement

70 on gross area

0

Any

Cells oriented horizontally

Cement

70 on gross area

0

H103.6 Timber.

For timber construction, see Sections H103.6.1 and H103.6.2.

H103.6.1 Buildings erected on or before 1938.

Buildings erected on or before 1938 with wood-framed construction not having grade mark stamps use the allowable stresses from Table H103.6.1 if the wood species is known:

Table H103.6.1 Timber Allowable Stresses

Wood Species

Compression (psi)

Tension (psi)

Shear (psi)

Bending (psi)

Elastic Modulus (psi)

Yellow Pine, Longleaf

With grain: 1,600 Across grain: 1,000

1,200

With grain: 150 Across grain: 1,000

1,600

1,600,000

Douglas Fir

With grain: 1,200 Across grain: 800

800

With grain: 100 Across grain: 1,000

1,200

1,200,000

Yellow Pine, Shortleaf

With grain: 1,000 Across grain: 800

900

With grain: 100 Across grain: 1,000

1,000

1,000,000

Spruce

With grain: 1,200 Across grain: 800

800

With grain: 100 Across grain: 500

1,000

1,000,000

H103.6.1.1 Species not otherwise known.

The wood species shall be taken as spruce from Table H103.6.1 where not otherwise known.

H103.6.2 Building erected after 1938.

Buildings erected after 1938 in with wood-framed construction and having grade mark stamps, shall follow the current National Design Specifications.

H103.7 Cold-formed steel.

For cold-formed steel, use the strength values in Table H103.7.

Table H103.7 Cold-Formed Steel Strength

Date

Tensile Strength (ksi)

Yield Strength (ksi)

Prior to 1991

42

25

1991 and after

45

33

H103.8 Wrought iron.

For wrought iron, use the stress values in Table H103.8.

Table H103.8 Wrought Iron Allowable Stresses

Element

Stress Type

Allowable Working Stress (ksi)

Shapes and plates

Direct compression

12

Shapes and plates

Tension

12

Shapes and plates

Shear

6

Rivets

Shear

6

Bolts

Shear

5.5