New York Codes, Rules and Regulations › Title 12 - DEPARTMENT OF LABOR › Chapter I - Industrial Board Of Appeals › Subchapter A - The Industrial Code › Part 23 - Protection In Construction, Demolition And Excavation Operations › Subpart 23-4 - Excavation Operations › Section 23-4.5 - Use of Tables III and IV

Current through Register Vol. 46, No. 28, July 10, 2024
The use of Tables III and IV shall be subject to the
						following requirements:
(a) The sizes
					 of members shown in Tables III and IV are the minimum requirements for timber
					 bracing systems used in the sheeting and shoring of excavations.
(b) Steel, aluminum or combinations of steel,
					 aluminum and timber bracing systems of equivalent strength and capacity may be
					 used in place of timber bracing systems.
(c) Portable, adjustable-type metal shores
					 for trench bracing systems shall be approved.
(d) Braces shall be so placed that the full
					 cross-sectional areas required by Tables III and IV of this Subpart bear
					 against the stringers.
(e)
					 Stringers shall be placed with their least dimensions flat against the
					 sheeting.
(f) Where any side of an
					 excavation is a combination of an unbraced slope in accordance with Table I of
					 this Subpart near the surface and a braced vertical section near the bottom,
					 the sizes of the bracing members shall be determined from Tables III and IV of
					 this Subpart. In such case, the excavation depth shall be the sum of the depth
					 of the braced section plus one-half the depth of the unbraced sloped
					 section.
(g) The uppermost brace of
					 any bracing system shall be located not more than two feet below the top of the
					 supported material.
(h) The maximum
					 distance between the lowest brace and the bottom of the excavation shall not
					 exceed three feet, except where the sheeting or soldier beam is embedded as
					 stipulated in subdivision (i) below.
TABLE IV
MINIMUM SIZES OF STRINGERS AND BRACES
Wide Trenches-Horizontal Cross-Braces More Than
						Four Feet But Not Longer Than Eight Feet
Trench
									 Depth
Type of
									 Soil
Vertical Spacing
									 of Stringers
Horizontal Spacing
									 of Cross-Braces
4 Feet
6 Feet
Stringers
Braces
Stringers
Braces
Stringers
Braces
Stringers
Braces
5 to 10 ft.
Stiff cohesive
4 ft. max.
4 × 4
4 × 4
6 × 6 or 4 ×8
4 × 6
6 × 6
4 × 6
8 × 8
6 × 6
Noncohesive
Over 4 ft. to 6 ft. max.
6 × 6 or 4 ×8
4 × 6
6 × 6
6 × 6
6 × 8
6 × 8
8 × 10
6 × 8
Soft cohesive and wet flowing
4 ft. max.
6 × 6
6 × 6
6 × 10
6 × 6
8 × 10
6 × 6
10 × 12
8 × 8
Over 10 to 20 ft.
Stiff cohesive and noncohesive
4 ft. max.
4 × 6
4 × 6
6 × 6
6 × 6
8 × 8 or 6 ×10
6 × 6
10 × 10
8 × 8
Soft cohesive and wet flowing
4 ft. max.
6 × 8
6 × 8
8 × 10
6 × 10
10 × 12
8 × 10
*
*
Over 20 ft.
For any trench over 20 feet in depth
								  the sheeting, shoring and bracing system shall be designed by a professional
								  engineer licensed to practice in the State of New York. Such design plan,
								  including design analysis and specifications, shall be submitted to the board
								  for special approval before any work is performed on such excavation.
* Sizes of timber for such conditions become excessive. A
						special structure designed by a professional engineer licensed to practice in
						the State of New York shall be constructed and used for the specific condition
						involved.
Note:
Timber sizes are nominal or trade
						dimensions.
(i) If the
					 bottom of the sheeting or soldier beam is embedded below the bottom of the
					 excavation, the maximum distance between the lowest brace and the bottom of the
					 excavation shall not exceed the vertical spacing for braces allowed in Tables
					 III and IV of this Subpart. The minimum depth of embedment of the sheeting or
					 soldier beam shall be three feet. The actual depth of each such embedment shall
					 be such that there is no significant movement of the bottom of the sheeting or
					 soldier beam.
Exception:
Where the operation being performed, such as laying large
						diameter concrete pipe or reinforced concrete culverts, precludes the placing
						of vertical bracing as specified in subdivisions (h) and (i) above, the
						vertical spacing may be in accordance with a specific design and plans made by
						a professional engineer licensed to practice in the State of New York. Such
						specified bracing system shall be designed so that the sheeting and shoring
						will withstand all the forces intended to be imposed thereon. Copies of the
						design and plans of such sheeting and shoring system shall be kept at the job
						site available for examination by the commissioner.
(j) The bracing or shoring of trenches shall
					 be continued as the excavation progresses in length. No person except workmen
					 fabricating the required sheeting and shoring system shall be allowed inside
					 such excavation until the required sheeting and shoring system has been
					 completed.
(k) Backfilling and
					 removal of trench supports shall progress together from the bottom of the
					 trench. Jacks or braces shall be released slowly and, in unstable soil, ropes
					 shall be used to remove the jacks or braces from above after employees have
					 vacated the trench.
Footnotes
* Sizes of timber for such conditions become excessive. A
						special structure designed by a professional engineer licensed to practice in
						the State of New York shall be constructed and used for the specific condition
						involved.