Presentation on theme: "Steel Erection - OSHAs First Negotiated Rule. Subpart R - Steel Erection Issued January 18, 2001 Long overdue updating of the existing standard Addresses."— Presentation transcript:
Subpart R - Steel Erection Issued January 18, 2001 Long overdue updating of the existing standard Addresses hazards associated with: double connections, column stability, falls, hoisting & rigging, joist installation, engineered metal buildings, decking, multiple lifts, structural stability… Effective Date: January 18, 2002… + Phase-in of Component requirements, e.g., bolt holes for joist connections, etc. (permit obtained before, 1/18/01) or steel erection began before 9/16/01
Layout of Subpart R.750 - Scope.751 - Definitions.752 - Site Layout, Site-specific Erection Plan & Construction Sequencing.753 - Hoisting & Rigging.754 - Structural Steel Assembly.755 - Column Anchorage.756 - Beams & Columns.757 - Open Web Steel Joists.758 - Systems- engineered Metal Buildings.759 - Falling Object Protection.760 - Fall Protection.761 - Training Appendices A - H
Scope of Subpart R Subpart R applies to steel erection activities such as, connecting, bolting, plumbing & guying, joist installation, decking, and related work (e.g., hoisting & rigging) that occurs in tiered and non- tiered buildings, bridges, stadiums, and special structures BUT NOT communication and broadcast towers or tanks (e.g., water or fuel tanks)
1926.751 - Definitions Connector - means an employee who, working with hoisting equipment, is placing & connecting structural members and/or components. Hoisting Equipment means a crane or a derrick NOT a come-along!
A come-a-long Mechanical device usually consisting of a chain or cable attached at each end, that is used to facilitate movement of materials through leverage. This is not considered hoisting equipment.
Derrick floor: An elevated floor of a building or structure that has been designated to receive hoisted pieces of steel prior to final placement
Opening A gap or void 12 inches or more in its least dimension in a floor, roof or other walking/working surface. Skylights and smoke domes shall be regarded as openings.
Project structural engineer of record Registered, licensed professional engineer responsible for the design of structural steel framing and whose seal appears on the structural contract documents.
Shear connector Steel bars, steel lugs, headed steel studs, and similar devices which are attached to a structural member for the purpose of achieving composite action with concrete.
Steel joist An open web, secondary load- carrying member of 144 feet or less, designed by the manufacturer, used for the support of floors and roofs. This does not include structural steel trusses or cold-formed joists.
Steel joist girder An open web, primary load- carrying member, designed by a manufacturer, used for the support of floors and roofs.
Systems-engineered metal building Field-assembled building system consisting of framing, roof and wall coverings.
1926.752 Site layout, site-specific erection plan and construction sequence
(a) Approval to begin steel erection ASTM standard test method (concrete must be 75% of the minimum compressive design strength): footings, piers, walls Repairs, replacements and modifications to anchor bolts made in accordance with 1926.755(b) (b) Commencement of Steel Erection –Steel Erector shall not erect steel unless it has received written notification of the requirements of (a) have been met
(c) Site layout (controlling contractor shall provide): Adequate access A firm, properly graded, drained area, readily accessible for the safe storage of materials and the safe operation of equipment
1926.753 - Hoisting & Rigging Crane inspections as per ANSI B30.5- 1994 Qualified operator is in charge of lifts and has final call Qualified rigger OK to use man baskets (1926.550(g)(2) does not apply, rest of.550 does apply) Preplan routes to minimize employee exposure to suspended loads Multiple lift rigging procedures….
Critical lift A lift that (1) exceeds 75 percent of the rated capacity of the crane or derrick, or (2) requires the use of more than one crane or derrick.
(1)Multiple lift shall only be performed if the following are met: multiple lift rigging assembly is used; maximum members is hoisted of five per lift; only structural members are lifted; and employees engaged in the lift have been trained in the procedures in 1926.761 (c)(1) Construction Safety Council
(4)The multiple lift rigging assembly shall be rigged with the members: rigged at least 7 feet apart rigged from the top down attached at their center of gravity and maintained level Construction Safety Council
(2) Components of the multiple lift rigging assembly shall be specifically designed and assembled with a maximum capacity for total assembly and for each individual attachment point. Capacity must be certified by the manufacturer or a qualified rigger and have a 5 to 1 safety factor Construction Safety Council
1926.753(e) (3) The total load shall not exceed: The rated capacity of the hoisting equipment The rigging capacity (4) The multiple lift rigging assembly shall be rigged with the members: –attached at their center of gravity and maintained level; –rigged from the top down; and –rigged at least 7 feet apart (5) The members on the multiple lift rigging assembly shall be set from the bottom up. (6) Controlled load lowering shall be used whenever the load is over the connectors.
A B C D E (shackle) F (hook) H (shackle) I (hook) G Typical Multiple Lift Rigging Assembly What do you need to know? How much does each piece weigh? What size slings? What size and type of hooks? What size of shackles?
1926.754(a) - Structural stability SHALL be maintained at ALL times during the erection process!
1926.754 Structural Steel Assembly (b)(3) - maintain fully planked or decked floor or net 2 stories or 30 ft. below any erection work (c) Walking/working surfaces - trip hazards and slip resistance (SR effective 7/18/06) (d) Plumbing-up - as per competent person (e) Metal decking - (2)(iii) - metal decking holes/openings SHALL not be cut until immediately prior to being filled/used
Metal decking Commercially manufactured, structural grade, cold rolled metal panel formed into a series of parallel ribs; this includes metal floor, and roof decks, standing seam metal roofs, other metal roof systems and other products such as bar gratings, checker plate, expanded metal panels.
Decking hole A gap or void more than 2 inches in its least dimension and less than 12 inches in its greatest dimension in a floor, roof or other walking/working surface.
Framed metal deck openings Must be turned down to allow continuous deck installation except where not allowed by structural design.
Skylights and smoke domes shall be regarded as openings.
1926.755 - Column Anchorage (a) General requirements for erection stability –Columns anchored by a min. of 4 rods (bolts) –Each anchor rod, assembly including base plate and foundation, designed to resist a 300# eccentric load at 18 from the column face
1926.755 - Column Anchorage (a) (continued) –Columns set on level finished floors, pre- grouted leveling plates, leveling nuts, or shim packs –All columns shall be evaluated by a competent person to determine whether guying or bracing is needed
(1) Need approval of the project structural engineer. (2) Prior to column erection, the controlling contractor shall provide written notification to the steel erector if there has been any repair, etc., to the anchor rods (bolts). (b) Repair, Replacement Or Field Modification Construction Safety Council
Prevent Steel Collapse! 4 bolts minimum per column! [.755(a)] Repair, replacement or field modification of anchor bolts must be approved by the structural engineer of record! [.755(b)] New bolt not made!= 2 anchor bolts New bolt not tested!
(a)General. Secured with at least two bolts per connection. Competent person to evaluate. (b)Diagonal bracing. With bracing, secured by at least one bolt per connection. (c)Double connections at columns and/or at beam webs over a column. At least one bolt or similar connection device is present. Construction Safety Council 1926.756 - Beams & Columns
Double connection Attachment method where the connection point is intended for two pieces of steel which share common bolts on either side of a central piece.
In order to make the double connection: the connector has to back out the bolts hold the beam in place with a spud wrench (fig. 1) When second beam arrives, align and hold it with a spud wrench push bolts back through first beam into second beam and secure in place. (old way – no beam seat, flanged or clipped connection used)
1926.756 - Beams & Columns - (c) Double connections at columns and/or at beam webs over a column: At least one bolt or similar connection device must be present (e.g., a beam seat, etc.) Staggered connection Clipped connection
(d)Column splices. Designed to resist a 300# eccentric load located at 18 from column face. (e)Perimeter columns. Must extend a min. of 48 above the finished floor for safety cables. Holes or other attachment device attached to perimeter columns Construction Safety Council
Diagonal bracing Solid web structural members used as diagonal bracing must be secured by at least one bolt per connection drawn up wrench tight or the equivalent as specified by the project structural engineer of record.
1926.757 - Open Web Steel Joists Addresses proper joist end attachment, erection procedures –erection bridging requirements according to Tables A & B (similar to SJI Tables) –Holes in joists/bolting required for joists in 40+ bays Requirements for landing and placing loads on joists Some requirements may be modified through a site-specific erection plan (tandem setting of some 60+ joists and requirements for landing decking bundles)
Bridging terminus point Means a wall, beam,tandem joists (with all bridging installed and horizontal truss in the plane of the top cord) or other element at an end or intermediate point of a line of bridging that provides an anchor point for the steel joist bridging. (Bridging is secured to the wall or beam)
An employee was assigned to connect the X-braces at the end of 40-foot long bar joists. Only one end of the bar joist he was working on had been welded. The employee was sitting on the unwelded end of the bar joist trying to connect the X- braces. He lost his balance, dislodging the bar joist from its end support, and fell approximately 24 feet to his death. Steel Erection Operation
Five iron workers were distributing 90-foot-long open web bar joists on a building under construction. The bar joists were supported by vertical columns spaced 30 feet apart. The steel columns were not framed in at least two directions and the bar joists were not field bolted to the vertical columns to prevent collapse. The bar joists shifted, causing the vertical columns to lean. This caused entire section of columns and pen web bar joists to collapse. Two employees rode the iron down. One was fatally injured and one received serious injuries. Steel Erection Operation
1926.757 - Open Web Steel Joists When columns not framed in 2 directions by beams, Steel joists shall be field-bolted at the column Hoist cables not released until joists are field-bolted and the bottom chord is restrained by stabilizer plate
1926.757 - Open Web Steel Joists (b) Attachment of steel joists and steel girders: K, LH & DLH series joists to be attached by specific welds or equivalent bolts –except for panels, each joist shall be attached to the support structure at least on one end of both sides of the seat immediately upon placement
1926.757 - Open Web Steel Joists (c) Erection of steel joists: as per incorporated SJI tables (d) Erection bridging (e) Landing & placing loads
1926.758 - Systems-Engineered Metal Buildings Specific requirements for metal buildings (e.g., Butler buildings, etc.) including: –4 anchor rods/column –rigid frames to have 50% of bolts or mfg spec. –girt connections –joists and purlins
System-Engineered Metal Buildings Rigid frames will have 50 percent of their bolts or the number of bolts specified by the manufacturer (which ever is greater) installed and tightened before the hoisting equipment is released.
System-Engineered Metal Buildings Minimum of four (4) anchor rods (anchor bolts) per structural columns
Girt Is the Z or C shaped member formed from sheet steel spanning between primary framing and supporting wall materials. (Engineered metal buildings)
§1926.759 Falling Object Protection (does not apply to materials being hoisted) Secure loose items aloft Controlling contractor to bar operations below steel erection unless falling object protection provided (from objects other than hoisted materials)
Falling Object Protection Secure all loose items aloft
§1926.760 Fall Protection All must be protected at heights greater than 2 stories or 30 feet, including connectors and deckers Between 15 and 30 feet: Fall protection required for all with exceptions for: – Deckers in controlled decking zone (CDZ) and – Connectors Connectors must be provided and wear equipment necessary to be able to be tied-off, or be provided with other means of fall protection
Personal fall arrest system Means a system used to arrest an employee in a fall from a working level. System consists of an anchorage, connectors, a body harness and may include a lanyard, deceleration device, lifeline or suitable combination of these.
Positioning device Means a body belt or body harness rigged to allow an employee to be supported on an elevated, vertical surface, such as a wall or column and work with both hands free while leaning. Fall Restraint…? = NO ( I mean ZERO!) Free Fall
1926.760 - Fall protection 1926.760(d)(1)- Fall Protection systems shall meet the requirements of 1926.502!
§1926.760 Fall Protection (cont.) Controlled decking zone: –For leading edge decking work limited access designated boundaries by control lines Work practices for attaching deck: –install safety attachments from leading edge back –no final attachments allowed in CDZ –up to 3000 SF of unsecured decking specific training requirements
Safety deck attachment An initial attachment that is used to secure an initially placed sheet of decking to keep proper alignment and bearing with structural support members.
Warning Line System CDZs Controlled Decking Zones
§1926.760 Fall Protection (cont.) Perimeter cables required –Must be installed as soon as the metal decking has been installed Custody of Fall Protection Equipment: –Controlling contractor must choose to either : accept responsibility for maintaining fall protection equipment left by erector, OR ensure that it is removed (.760(e))
§1926.761 Training Qualified person to train workers in use & operation of fall protection equipment Qualified person to train workers engaged in specific activities: –christmas-treeing – connecting – CDZ procedures