California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 4 - Construction Safety Orders › Article 6 - Excavations › Appendix D - Aluminum Hydraulic Shoring for Trenches

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Scope. This appendix contains information that can be
						used when aluminum hydraulic shoring is provided as a method of protection
						against cave-ins in trenches that do not exceed 20 feet in depth. This appendix
						must be used when design of the aluminum hydraulic protective system cannot be
						performed in accordance with Section
						1541.1(c)(2).
(b) Soil Classification. In order to use data presented
						in this appendix, the soil type or types in which the excavation is made must
						first be determined using the soil classification method set forth in Appendix
						A of this Article.
(c) Presentation of Information. Information is presented
						in several forms as follows:
(1) Information is presented in tabular form in Tables
						D-1.1, D-1.2, D-1.3 and D-1.4. Each table presents the maximum vertical and
						horizontal spacings that may be used with various aluminum member sizes and
						various hydraulic cylinder sizes. Each table contains data only for the
						particular soil type in which the excavation or portion of the excavation is
						made. Tables D-1.1 and D-1.2 are for vertical shores in Types A and B soil.
						Tables D-1.3 and D-1.4 are for horizontal waler systems in Types B and C
						soil.
(2) Information concerning the basis of the tabular data
						and the limitations of the data is presented in Section (d) of this
						appendix.
(3) Information explaining the use of the tabular data is
						presented in Section (e) of this appendix.
(4) Information illustrating the use of the tabular data
						is presented in Section (f) of this appendix.
(5) Miscellaneous notations (footnotes) regarding Table
						D-1.1 through D-1.4 are presented in Section (g) of this appendix.
(6) Figures, illustrating typical installations of
						hydraulic shoring, are included just prior to the Tables. The illustrations
						page is entitled "Aluminum Hydraulic Shoring: Typical Installations."
(d) Basis and limitations of the data.
(1) Vertical shore rails and horizontal wales are those
						that meet the Section Modulus requirements in the D-1 Tables. Aluminum material
						is 6061-T6 or material of equivalent strength and properties.
(2) Hydraulic cylinders specifications.
(A) 2-inch cylinders shall be a minimum 2-inch inside
						diameter with a minimum safe working capacity of no less than 18,000 pounds
						axial compressive load at maximum extension. Maximum extension is to include
						full range of cylinder extensions as recommended by product
						manufacturer.
(B) 3-inch cylinders shall be minimum 3-inch inside
						diameter with a safe working capacity of not less than 30,000 pounds axial
						compressive load at extensions as recommended by product manufacturer.
(3) Limitation of application.
(A) It is not intended that the aluminum hydraulic
						specification apply to every situation that may be experienced in the field.
						These data were developed to apply to the situations that are most commonly
						experienced in current trenching practice. Shoring systems for use in
						situations that are not covered by the data in this appendix must be otherwise
						designed as specified in Section
						1541.1(c).
(B) When any of the following conditions are present, the
						members specified in the Tables are no considered adequate. In this case, an
						alternative aluminum hydraulic shoring system or other type of protective
						system must be designed in accordance with Section
						1541.1.
1. When vertical loads imposed on crossbraces exceed a
						100 pound gravity load distributed on a one foot section of the center of the
						hydraulic cylinder.
2. When surcharge loads are present from equipment
						weighing in excess of 20,000 pounds.
3. When only the lower portion of a trench is shored and
						the remaining portion of the trench is sloped or benched unless: The sloped
						portion is sloped at an angle less steep than three horizontal to one vertical;
						or the members are selected from the tables for use at a depth which is
						determined from the top of the overall trench, and not from the toe of the
						sloped portion.
(e) Use of Tables D-1.1, D-1.2, D-1.3 and D-1.4. The
						members of the shoring system that are to be selected using this information
						are the hydraulic cylinders, and either the vertical shores or the horizontal
						wales. When a waler system is used the vertical timber sheeting to be used is
						also selected from these tables. The Tables D-1.1 and D-1.2 for vertical shores
						are used in Type A and B soils that do not require sheeting. Type B soils that
						may require sheeting, and Type C soils that always require sheeting, are found
						in the horizontal wale Tables D-1.3 and D-1.4. The soil type must first be
						determined in accordance with the soil classification system described in
						Appendix A to Section
						1541.1. Using the appropriate
						table, the selection of the size and spacing of the members is made. The
						selection is based on the depth and width of the trench where the members are
						to be installed. In these tables the vertical spacing is held constant at four
						feet on center. The tables show the maximum horizontal spacing of cylinders
						allowed for each size of wale in the waler system tables, and in the vertical
						shore tables, the hydraulic cylinder horizontal spacing is the same as the
						vertical shore spacing.
(f) Example to Illustrate the Use of the Tables:
(1) Example 1.
A trench dug in Type A soil is 6 feet deep and 3 feet
						wide. From Table D-1.1: Find vertical shores and 2 inch diameter cylinders
						spaced 8 feet on center (o.c.) horizontally and 4 feet on center (o.c.)
						vertically. (See Figures 1 & 3 for typical installations.)
(2) Example 2:
A trench is dug in Type B soil that does not require
						sheeting, 13 feet deep and 5 feet wide. From Table D-1.2: Find vertical shores
						and 2 inch diameter cylinders spaced 6.5 feet o.c. horizontally and 4 feet o.c.
						vertically. (See Figures 1 & 3 for typical installations.)
(3) Example 3:
A trench is dug in Type B soil that does not require
						sheeting, but does experience some minor raveling of the trench face. The
						trench is 16 feet deep and 9 feet wide. From Table D-1.2: Find vertical shores
						and 2 inch diameter cylinder (with special oversleeves as designated by
						footnote #2) spaced 5.5 feet o.c. horizontally and 4 feet o.c. vertically.
						Plywood (per footnote (g)(7) to the D-1 Table) should be used behind the
						shores. (See Figures 2 & 3 for typical installations.)
(4) Example 4:
A trench is dug in previously disturbed Type B soil, with
						characteristics of a Type C soil, and will require sheeting. The trench is 18
						feet deep, and 12 feet wide. 8 foot horizontal spacing between cylinders is
						desired for working space. From Table D-1.3: Find horizontal wale with a
						section modulus of 14.0 spaced at 4 feet o.c. vertically and 3 inch diameter
						cylinder spaced at 9 feet maximum o.c. horizontally, 3 x 12 timber sheeting is
						required at close spacing vertically. (See Figure 4 for typical
						installation.)
(5) Example 5:
A trench is dug in Type C soil, 9 feet deep and 4 feet
						wide. Horizontal cylinder spacing in excess of 6 feet is desired for working
						space. From Table D-1.4: Find horizontal wale with a section modulus of 7.0 and
						2 inch diameter cylinders spaced at 6.5 feet o.c. horizontally. Or, find
						horizontal wale with a 14.0 section modulus and 3 inch diameter cylinder spaced
						at 10 feet o.c. horizontally. Both wales are spaced 4 feet o.c. vertically,
						3x12 timber sheeting is required at close spacing vertically. (See Figure 4 for
						typical installation.)
(g) Footnotes, and general notes, for Tables D-1.1,
						D-1.2, D-1.3, and D-1.4.
(1) For applications other than those listed in the
						tables, refer to Section
						1541.1(c)(2) for
						use of manufacturer's tabulated data. For trench depths in excess of 20 feet,
						refer to Section
						1541.1(c)(2) and
						1541.1(c)(3).
(2) 2-inch diameter cylinders, at this width, shall have
						structural steel tube (3.5 x 3.5 x 0.1875) oversleeves, or structural
						oversleeves of manufacturer's specification, extending the full, collapsed
						length.
(3) Hydraulic cylinders capacities.
(A) 2-inch cylinders shall be a minimum 2-inch inside
						diameter with a safe working capacity of not less than 18,000 pounds axial
						compressive load at maximum extension. Maximum extension is to include full
						range of cylinder extensions as recommended by product manufacturer.
(B) 3-inch cylinders shall be a minimum 3-inch inside
						diameter with a safe work capacity of not less than 30,000 pounds axial
						compressive load at maximum extension. Maximum extension is to include full
						range of cylinder extensions as recommended by product manufacturer.
(4) All spacing indicated is measured center to
						center.
(5) Vertical shoring rails shall have a minimum section
						modulus of 0.40 inch.
(6) When vertical shores are used, there must be a
						minimum of three shores spaced equally, horizontally, in a group.
(7) Plywood shall be 1.125 inches thick of wood or 0.75
						inch thick, 14 ply, arctic white birch (Finland form). Please note that plywood
						is not intended as a structural member, but only for prevention of local
						raveling (sloughing of the trench face) between shores. Equivalent material may
						be used if it has been approved in accordance with Section
						1505(a).
(8) See Appendix C for timber specifications.
(9) Wales are calculated for simple span
						conditions.
(10) See Appendix D, Section (d), for basis and
						limitations of the data.
ALUMINUM HYDRAULIC SHORING TYPICAL
						INSTALLATIONS
FIGURE NO. 1
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ALUMINUM HYDRAULIC SHORING TYPICAL
						INSTALLATIONS
FIGURE NO. 2
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ALUMINUM HYDRAULIC SHORING TYPICAL
						INSTALLATIONS
FIGURE NO. 3
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ALUMINUM HYDRAULIC SHORING TYPICAL
						INSTALLATIONS
FIGURE NO. 4
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Note: Authority cited: Section
						  142.3, Labor
						  Code. Reference: Section
						  142.3, Labor
						  Code.