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Presentation on theme: "1 29 CFR 1926 SUBPART Q CONCRETE AND MASONRY CONSTRUCTION."— Presentation transcript:


2 2 w 51 killed w 170 feet above ground w Entire form peeled away from newly placed concrete Cooling Tower St. Mary’s West Virginia 1978

3 3 What the St. Mary’s West Virginia tower would have looked like if it had been completed.

4 4 Jump forms atop the St. Mary’s structure tore loose, pulling work platforms and concrete down inside the tower.

5 5 Wreckage 168 feet below the top of the St. Mary’s tower being picked apart by investigators looking for clues. The state of West Virginia objected to the site being cleaned before it could make its own full investigation.

6 6 Part 1926 Subpart Q Concrete and Masonry Construction w 1926.700 - Scope, application, and definitions applicable to this subpart. w 1926.701 - General requirements w 1926.702 - Requirements for equipment and tools. w 1926.703 - Requirements for cast- in-place Concrete. w 1926.703 App - General Requirements for Formwork w 1926.704 - Requirements for precast concrete. w 1926.705 - Requirements for lift- slab operations. w 1926.705 App - Lift Slab Operations w 1926.706 - Requirements for masonry construction.

7 7 w "Bull float" w "Formwork" w "Lift slab" w "Limited access zone" w "Precast concrete" w "Reshoring" w "Shore" w "Vertical slip forms" w “Jacking operation” 29 CFR 1926 700 Scope, application, and definitions applicable to this subpart.

8 8 w (a) Construction loads. w (b) Reinforcing steel. w (c) Post-tensioning operations. w (d) Riding concrete buckets. w (e) Working under loads. w (f) Personal protective equipment. 29 CFR 1926.701 General requirements

9 9 1926.701(b) All protruding reinforcing steel, onto and into which employees could fall,shall be guarded to eliminate the hazard of impalement.

10 10 Rebar protection

11 11 1926.701(c) - Post-tensioning operations No employee (except those essential to the post-tensioning operations) shall be permitted to be behind the jack during tensioning operations

12 12 Jack

13 13 Cutting bars

14 14 1926.701(d) Riding concrete buckets No employee shall be permitted to ride concrete buckets.

15 15 w (a) Bulk cement storage. w (b) Concrete mixers. w (c) Power concrete trowels. w (d) Concrete buggies. w (e) Concrete pumping systems. w (f) Concrete buckets. w (g) Tremies. w (h) Bull floats. w (i) Masonry saws. w (j) Lockout/Tagout procedures. 702 Equipment and Tools.

16 16 w 1926.702 (b) Concrete mixers with one cubic yard or larger loading shall be equipped with: A mechanical device to clear the skip of materials Guardrails installed on each side of the skip

17 17 1926.702(e) (1) Concrete pumping systems shall be provided with pipe supports designed for 100 percent overload. (2) Air hoses shall be provided with positive fail-safe joint connectors. Pumping System

18 18 1926.702(g) Tremies. Sections of tremies and similar concrete conveyances shall be secured with wire rope (or equivalent materials) in addition to the regular couplings or connections.

19 19 Concrete piping system connection point

20 20 1926.702 (f) Concrete buckets (1) Concrete buckets equipped with pneumatic gates shall have positive safety latches or similar safety devices installed to prevent premature or accidental dumping. (2) Concrete buckets shall be designed to prevent concrete from hanging up on top and the sides.

21 21 1926.702 Power-concrete trowels Shall be equipped with a control switch that will automatically shut off the power whenever the hands of the operator are removed from the equipment handle.

22 22 1926.702(d) Concrete buggy handles shall not extend beyond the wheels on either side of the buggy

23 23 1926.702(i) (1)Masonry saws shall be guarded with a semicircular enclosure over the blade (2)A method of retaining blade fragments shall be incorporated in the design of the semicircular enclosure.

24 24 1926.702(h) Bull floats - Electrocution - Handles

25 25 w (a) General requirements for formwork. w (b) Shoring and reshoring. w (c) Vertical slip forms. w (d) Reinforcing steel. w (e) Removal of formwork. 29 CFR 1926.703 Cast-in-place Concrete.

26 26 Form work operations fall protection

27 27 Cast in-place concrete work

28 28 Form work



31 31 1926.703 Shoring & re-shoring Inspected prior to erection Damaged equipment shall not be used Inspected immediately prior to, during, and immediately after concrete placement.

32 32 1926.703 (b) Shoring & re-shoring Equipment found to be damaged or weakened, shall be immediately reinforced. Sills shall be sound, rigid, and capable of carrying maximum intended load. 1926.703(b)(6) All base plates, shore heads, extension devices, and adjustment screws shall be in firm contact, and secured when necessary, with the foundation and form.

33 33 1926.703(b)(8) Single post shores Design prepared by qualified designer Vertically aligned Spliced to prevent movement Braced in two mutually perpendicular directions at splice level Each tier diagonally braced in the same two directions

34 34 Ellis shoring system

35 1926.703(c) Vertical slip forms Jack rod Jack Yoke assembly Working deck Wales Bracing for Wales Slight batter of sheathing Sheathing Splash board Thin pipe around jack rod

36 36 Vertical slip-form operation

37 37 1926.703(d) Vertical slip form Steel rods or pipes on which jacks climb shall be designed for that purpose and adequately braced when not encased in concrete. Designed to prevent excessive distortion during jacking Provided with scaffolds or work platform where employees required to pass Jacks and lifting devices provided with mechanical dogs or other automatic holding devices Form structure maintained within all design tolerances - for plumpness during jacking operations

38 38 1926.703 (e) Removal of formwork Shall not be removed until employer determines concrete has gained sufficient strength to support its weight and super imposed loads: Plans and specifications which stipulate conditions for removal of forms and shores; Concrete had been properly tested.

39 39 Flying forms

40 40

41 41 w (a) Adequate support of wall units, structural framing, and tilt-up panels w (b) Capability of inserts w (c) Imbedded inserts w (d) Lifting hardware w (e) No employee under pre-cast concrete members being lifted or tilted into position except those employees required for the erection of those members 1926.704 Pre-cast Concrete.

42 42 Pre-cast concrete operation

43 43

44 44 Un pre-stressed slab Prestressed slab - unloaded Prestressed slab - loaded

45 45 29 CFR 1926.705 lift-slab operations.

46 46 w (a) Lift-slab operations shall be designed and planned by a registered professional engineer w (b) Jacks/lifting units shall be marked w (c) Jacks/lifting units shall not be loaded beyond their rated capacity w (d) Jacking equipment shall not be overloaded w (e) Design and installation of jack lifting units 29 CFR 1926.705 lift-slab operations.

47 47 w (f) Jacks/lifting units shall have a safety device installed w (g) Jacking operations shall be synchronized w (h) Automatic controlled leveling w (i) Manually controlled leveling w (j) Maximum number of manually controlled jacks/lifting units w (k) Number of employees allowed in the building 29 CFR 1926.705 lift-slab operations. (continued)

48 48 w (l) Temporary connections w (m) Welding on temporary and permanent connections w (n) Load transfer from jacks/lifting units to building columns w (o) Securing Jacks/lifting units w (p) Prevention of components from disengaging during lifting operations. 29 CFR 1926.705 lift-slab operations. (continued)

49 49 Jack rod Lifting angle Seal block Spearhead frame cast in floor slab Wedge Wedge block

50 50 1926.705(a) Lift-slab operations shall be designed by a registered professional engineer who has experience in lift-slab construction.

51 Lift slab operation

52 52 1926.705 Jack lifting unit (b) Marked to indicate rated capacity (c) Not loaded beyond capacity (d) Two and 1/2 times the load (e) Designed so they neither lift nor continue to lift when they are loaded in excess to rated capacity (f) Synchronized lifting to ensure uniform lifting (g) Leveling device installed ( all points 1/2 inch tolerance) (h) Stop device (exceeds 1/2 inch tolerance) (i) Manual controls located in central location - attended by competent person (must be experienced) (j) Maximum number of annually controlled units

53 53 Closure strip

54 54 1926.705 (k) No employee permitted in the building structure while jacking operation taking place - unless reinforced sufficiently to ensure integrity during erection

55 55 1926.705(K)(2) Under no circumstance, shall any employee who is not essential to the jacking operation be permitted immediately beneath a slab being lifted

56 56 1926.705(i) Manual lifting controls shall be centrally located

57 57 29 CFR 1926.706 Masonry construction.

58 58 w a) Limited access zone prior to the start of construction of the wall equal to the height of the wall to reconstructed plus four feet, and shall run the entire length of the wall on the side of the wall which will be un- scaffolded restricted to entry by employees actively engaged in constructing the wall shall remain in place until the wall is adequately supported w (b) All masonry walls over eight feet in height shall be adequately braced 29 CFR 1926.706 Masonry construction.

59 59 1926.706(a) Limited access zone Established prior to the start of construction Equal to the height of the wall plus four feet Unscaffolded side of wall Remain until adequately supported Masonry walls over 8 feet adequately braced


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