513 EM 385-1-1 Chapters 23-29

Sections

25-8. General Requirements.

Support Systems, Shoring, and Shielding

Follow one of the prescribed systems for support systems, including shield systems and other protective systems.
Adhere to designs based on manufacturer's tabulated data, other tabulated data, or those designed by an RPE, maintaining necessary documentation at the jobsite during excavation.
Ensure materials and equipment are damage-free and maintain them according to manufacturer recommendations, with a Competent Person (CP) evaluating any damaged materials or equipment.

Installation and Removal of Support Systems

Install support systems safely, coordinating with excavation processes and ensuring protection against cave-ins and structural collapses.
Do not excavate to a level more than 2 feet (0.6 m) below the bottom of the members of a support system unless the system is designed for full trench depth and no soil loss is observed.
Remove support system members cautiously, starting from the bottom, and backfill concurrently to ensure stability and employee safety.
All excavations which have vertically sided lower portions must be shielded or supported to a height at least 18 inches (45.7 cm) above the top of the vertical side. (See Figure 25-3)

Shield Systems

Install shields to prevent lateral movement and protect employees from cave-ins when entering or exiting shield-protected areas.
Forbid employee presence inside shields during installation, removal, or movement.

Cofferdams

Design cofferdams with controlled flooding provisions, if overtopping by high water is possible.
Equip cofferdams with standard guard railings, walkways, and two rapid exit means for personnel and equipment, adhering to specified chapters for guardrails.
Develop and post evacuation procedures at the jobsite, including warning signals for emergencies and controlled flooding, and protect cofferdams from nearby shipping channels.

25-9. Figures and Tables.

See Figures/Tables Checklists/Forms

25-10. Checklists and Forms.

Not Applicable.

Knowledge Check Choose the best answer for the question.

25-9. Generally, the excavation of material below the bottom of the members of a support system is limited to _____.

4 feet

3 feet

2 feet

1 foot

You forgot to answer the question!

EM 385-1-1 Paragraph 25-8 (j.–k.).

25-8. General Requirements. (j.–k.).

j.  Support Systems, Shoring, and Shielding.  Support systems, including shield systems and other protective systems, must follow one of the following systems:
(25-8.j)

(1)  Designs using manufacturer’s tabulated data.  Implement designs based on manufacturer's tabulated data.  Follow all specifications, limitations, and recommendations issued or made by the manufacturer.

(a)  Deviation from the specifications, recommendations, and limitations are only allowed after the manufacturer issues specific written approval.

(b)  Maintain a written copy of the manufacturer's specifications, recommendations, and limitations, and the manufacturer's approval to deviate from these, if required, at the jobsite during excavation.

(2)  Designs using other tabulated data.  Select the design from and according to written tabulated data, such as charts and tables approved by an RPE.  Maintain at least one copy of the tabulated data at the jobsite during excavation.  The tabulated data must include the following:

(a)  Identification of the parameters that affect the selection of the protective system drawn from such data.

(b)  Identification of the limits of use of the data.

(c)  Explanatory information as may be necessary to aid the user in correctly selecting a protective system from the data.

(d)  The identity of the RPE who approved the data to include name and contact information.

(3)  Designed by an RPE.  Implement support systems, shoring, or shielding based on designs prepared by an RPE.  Maintain at least one copy of the designs at the jobsite during excavation.  Designs must be in writing and include the following:

(a)  A plan indicating the sizes, types, and configurations of the materials to be used in the protective system.

(b) The identity of the RPE who designed the support system to include name and contact information.

(4)  Materials and Equipment Used for Support Systems.

(a)  Materials and equipment must be free from damage or defects that might impair their proper function.

(b)  Use and maintain manufactured materials and equipment in a manner consistent with the recommendations of the manufacturer and in a manner that will prevent employee exposure to hazards.

(c)  When material or equipment is damaged, a CP must examine the material or equipment and evaluate its suitability for continued use.

(5)  Installation and Removal of Support Systems.

(a)  Support excavations less than 20 feet (6.1 m) in depth which have vertically lowered portions to a height at least 18 inches (45.7 cm) above the top of the vertical side (see figure 25-3).

(b)  Do not excavate to a level more than 2 feet (0.6 m) below the bottom of the members of a support system.  Excavation of material to a level of 2 feet (0.6 m) below the bottom of the members of a support system is only permitted if the system is designed to resist the forces calculated for the full depth of the trench, and there are no indications while the trench is open of a possible loss of soil from behind or below the bottom of the support system.

(d)  Install and remove support systems in manners that protect employees from cave-ins, structural collapses, or from being struck by members of the support system.

(e)  Do not subject individual members of a support system to loads exceeding those for which they were designed to withstand.

(f)  Securely connect the support system members to prevent sliding, falling, kickouts, or other predicable failure.

(g)  Before temporary removal of individual members, take additional precautions to ensure the safety of employees (for example, installing other structural members to carry the loads imposed on the support system).

(h)  Begin removal at, and progress from, the bottom of the excavation.  Slowly release members to allow notice of any indication of possible failure of the remaining members or possible cave-in of the sides of the excavation.  In unstable soil, use ropes to pull out the jacks or braces from above after personnel have cleared the trench.

(i)  Backfilling must progress together with the removal of support systems from excavations.

(j)  Shield Systems.

(j-1)  Install shields in a manner to restrict lateral or other hazardous movement of the shield in the event of the application of sudden lateral loads.

(j-2)  Protect employees from the hazard of cave-ins when entering or exiting the area protected by shields.

(j-3)  Do not allow employees inside shields when shields are being installed, removed, or moved.

k.  Cofferdams.  (25-8.k)

(1)  If overtopping of the cofferdams by high water is possible, design must include provisions for controlled flooding of the work area (see para 25-7.h).

(2)  If personnel or equipment are required or permitted on cofferdams, provide standard guard railings, or equivalent protection according to chapter 21.

(3)  Provide walkways, bridges, or ramps with at least two means of rapid exit for personnel and equipment working on cofferdams.  Equip these means of egress with standard guardrails according to chapter 21.

(4)  Develop evacuation procedures that includes warning signals for evacuation of personnel and equipment in case of emergency and for controlled flooding (see para
    25-7.h). Post the procedures at the jobsite.

(5)  Protect cofferdams located close to navigable shipping channels from vessels in transit.