513 EM 385-1-1 Chapters 23-29

Sections

27-8. General Requirements.

Precast Concrete Operations

Develop a plan specifically for precast concrete placement activities before starting.
Ensure precast concrete members are adequately supported to prevent any overturning or collapse until they are permanently connected.
Verify that lifting inserts and hardware can support the required loads: at least twice the maximum intended load for tilt-up precast concrete members, at least four times for other precast concrete members, and at least five times for lifting devices.

Masonry Construction

Formulate a masonry erection plan before initiating any structural masonry activities.
Establish a limited access zone when constructing a masonry wall, which must be equal to the wall's height plus four feet, extend along the entire wall, and be restricted to actively engaged employees.
For masonry walls over 8 feet, create a restricted zone on both sides of the wall, enforce entry limitations, and ensure evacuation during specific wind conditions as per the guidelines.

Zone and Bracing Regulations

Maintain limited or restricted access zones until the wall is sufficiently supported to prevent any risk of overturning or collapse.
Ensure all masonry walls over 8 feet are properly braced to avoid overturning and collapse, keeping the bracing in place until the permanent structure is established.
Engage a Qualified Person (QP) to determine the restricted zone for multi-story structures.

Wall Maintenance and Safety Protocols

Replace or repair any damaged or weakened braces before permitting work in the affected restricted zone.
Require that wall repairs are designed by a structural engineer and approved by the designated designer before commencement.
Continuously monitor wind speeds during work in the restricted zone and evacuate employees if wind speeds exceed specified limits.

Knowledge Check Choose the best answer for the question.

27-7. When must restricted zones be established on both sides of a masonry wall?

When masonry walls are constructed on uneven surfaces

When masonry wall are properly shored

When masonry walls are over 8 feet high

When masonry walls are not braced

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EM 385-1-1 Paragraph 27-8 (f.–g).

27-8. General Requirements. (f.–g).

f.  Precast Concrete Operations.  (27-8.f)

(1)  Develop a precast concrete plan prior to beginning any precast placement activities (see para 27-7.b).

(2)  Adequately support precast concrete members to prevent overturning or collapse until permanent connections are complete.

(3)  Lifting Inserts and Hardware.

(a)  Lifting inserts which are embedded or otherwise attached to tilt-up precast concrete members must be capable of supporting at least two times the maximum intended load applied or transmitted to them.

(b)  Lifting inserts which are embedded or otherwise attached to precast concrete members, other than tilt-up members, must be capable of supporting at least four times the maximum intended load applied or transmitted to them.

(c)  Lifting hardware must be capable of supporting at least five times the maximum intended load applied or transmitted to the lifting device.
        (4)  Do not allow employee under precast concrete members being lifted or tilted into position except employees required for the erection of those members.

g.  Masonry Construction.  See MCAA Standard Practice for Bracing Masonry Walls Under Construction.  (27-8.g)

(1)  Develop a masonry erection plan prior to beginning any structural masonry activities (see para 27-7.c).

(2)  Establish a limited access zone whenever a masonry wall is being constructed. The limited access zone must:

(a)  Equal the height of the wall plus four feet and run the entire length of the wall.

(b)  Be established on the side of the wall which will be unscaffolded.

(d)  Remain in place until the wall is adequately supported to prevent overturning and to prevent collapse unless the height of wall is over eight feet, in which case, a restricted access zone must be established according to paragraph 27-8.g.

(3)  Establish a restricted zone whenever a masonry wall over 8’ is being constructed. The restricted zone is created to keep masons and other tradesmen away from a wall under construction when winds exceed critical velocities until the wall is completely tied into the rest of the structure.  The restricted zone must:

(a)  Be established on both sides of wall prior to the start of wall construction.

(b)  Be equal to the height of the wall being constructed plus 4 feet (1.2 m) and must run the entire length of the wall plus 4 feet (1.2 m) beyond the ends of the wall.

(c)  Be restricted to entry by individuals who have been trained to recognize the hazards associated with working inside the restricted zone and are actively engaged in constructing the wall.

(d)  Be evacuated during the initial period of wall construction when wind speeds exceed 20 mph (32.1 km/h).

Note.  The initial period is considered the period of time, not to exceed 24 hours, during which the masonry is being laid above its base or highest line of bracing, and at the end of which required bracing is installed.

(e)  Be evacuated during the intermediate period of wall construction when wind speeds exceed 35 mph (56.3 km/h).

Note.  The intermediate period is considered the period of time following the initial period but before the wall is connected to the elements that provide its final lateral support.

(f)  Remain in place until the wall has obtained its final lateral support.

(g)  For multi-story structures, a QP must determine the restricted zone.

(4)  Adequately brace all masonry walls over 8 feet (2.4 m) in height to prevent overturning and to prevent collapse unless the wall is adequately supported so that it will not overturn or collapse.  The bracing must remain in place until permanent supporting elements of the structure are in place.

(5)  Repair or replace any damaged or weakened brace elements before work is permitted in the restricted zone in the vicinity of the damaged brace or weakened brace element.

(6)  Repairs to damaged walls must be designed by a structural engineer, familiar with the work being performed, and approved by the designer of record before starting the repairs.

(7)  Each employer having workers in the restricted zone must monitor the wind speed continuously while the work is in progress and evacuate employees when wind speeds exceed the requirements of paragraphs 27-8.g(3)(d) and 27-8.g(3)(e).

(a)  Wind speeds must be 3-second gust speeds.

(b)  Instrument methods must accurately measure wind speed to +/- 2 mph (+/- 3.2 km/h). Properly maintain the instruments.

(8)  Do not use scaffolds intended for masonry construction workers to provide temporary lateral support of masonry walls.

(9)  Locate cleanouts on the side of the masonry wall opposite to the scaffolding.