Structural Steel Erection, Bolting & Connections

Steel day is the best day on any church project. Concrete guys will argue, but concrete guys argue about everything. When that first column goes vertical and the crane swings the first beam into place, the building stops being lines on paper and starts being a building. There’s a reason ironworkers walk a little taller than everyone else on site — they’re literally building the skeleton that holds everything up.

But steel erection is also where things can go catastrophically wrong if you don’t know what you’re doing. A misaligned anchor bolt is a headache. An under-torqued high-strength bolt is a lawsuit. A column that’s out of plumb by 25 mm at the base becomes 75 mm off at the roof, and suddenly your curtain wall doesn’t fit and someone’s writing a very expensive cheque.

This guide covers the full scope of structural steel work on church projects — from the moment the first truck rolls in with columns on the flatbed to the last shear stud welded on the composite deck. Real procedures, real tolerances, real numbers. The kind of stuff that keeps engineers happy and keeps ironworkers from having to do things twice.

1. Erection Planning & Sequence

Every HCMI steel erection starts with a plan. Not a “we’ll figure it out when the crane gets here” plan — an actual, written, reviewed erection plan per CISC guidelines. This document lives in the site trailer and everyone touching steel has read it.

What the Erection Plan Covers

• Erection sequence: Which bays go up first, which direction the crane walks, where temporary bracing goes. Typical HCMI church projects erect from the back (sanctuary end) forward so the crane can retreat without swinging over erected steel.
• Crane selection: Capacity at maximum radius, boom length, ground bearing pressure. A typical HCMI sanctuary uses a 100–160 ton hydraulic crane; fellowship halls and additions might get away with a 60-tonner.
• Lifting procedures: Pick points on each member, rigging configuration, maximum pick weight. Every lift over 80% of rated capacity requires a critical lift plan per O. Reg. 213/91.
• Temporary bracing: Locations, connection details, removal sequence. Bracing stays until the permanent lateral system (braced frames, moment frames, or diaphragm) is complete and inspected.
• Laydown area: Where trucks unload, how pieces are sorted and shaken out. Steel should arrive in erection sequence — the first piece you need is on top of the last truck.

Crane Selection Basics

You don’t pick a crane based on the heaviest piece alone. You pick it based on the heaviest piece at the farthest radius. A W18×50 beam weighing 2,200 kg at 30 m radius needs a very different crane than the same beam at 15 m. Always work from the crane’s load chart — never from memory, never from “we used the same crane last job.”

2. Column Setting

Columns are the first steel to go vertical, and everything that follows depends on getting them right. A column that’s 5 mm out of position at the base is a column that’s out of position forever. The engineer designed it in one spot; your job is to put it in that spot.

Base Plate Shimming & Grouting

1. Verify anchor bolt positions against the Leica total station layout (see the Survey Layout & Control article). A good standard tolerance for anchor bolt placement is ±3 mm from design. If they’re outside that, stop and call the engineer before trying to make it work.
2. Set levelling nuts on all anchor bolts to the correct elevation. Use the total station or a precise builder’s level to set all nuts to within ±1.5 mm of design bearing elevation.
3. Place steel shim stacks at a minimum of three points per base plate (four for plates larger than 450 mm square). Shims must be full-bearing — no rocking. Maximum shim stack height: 75 mm; if you need more, the concrete is wrong.
4. Fly the column and land it on the shims. Guide it onto the anchor bolts using drift pins if needed.
5. Thread anchor bolt nuts hand-tight, then snug with a wrench. Do not fully torque yet — you’ll need adjustment room for plumbing.
6. Grout after plumbing: Non-shrink grout (Masterflow 928 or equivalent) is placed after the column is plumbed and the anchor bolts are fully tightened. Minimum 25 mm grout bed; maximum 75 mm. Allow 24–48 hours cure before releasing temporary bracing.

Plumbing Columns with Guy Wires

Once the column is standing and initially bolted, it needs to be plumbed — made perfectly vertical in both axes. CSA S16 allows a plumb tolerance of H/500, where H is the column height. For a typical 6 m church column, that’s 12 mm maximum out-of-plumb. Best practice is to target H/1000 so that curtain walls actually fit.

The procedure is straightforward but demands patience:

1. Attach a minimum of two guy wires at approximately 2/3 column height, oriented 90° apart.
2. Anchor the far ends to dead-man weights (minimum 2,000 kg) or cast-in slab anchors.
3. Install turnbuckles in-line on each guy wire.
4. Using the Leica total station in stake-out mode, check the column centre at the top against the design coordinates.
5. Adjust turnbuckles to bring the column into plumb. Work one axis at a time.
6. Re-check with the total station — both axes, both faces. Confirm H/1000 or better.
7. Fully torque anchor bolt nuts. Re-verify plumb — torquing can pull the column slightly.

3. Beam Setting & Connections

Once columns are plumbed and secured, beams start flying. A good connector crew can set and bolt 15–20 beams per hour in an efficient sequence. A bad sequence turns that into five beams per hour with the crane sitting idle half the time. The erection plan dictates the sequence; the connectors execute it.

Connection Types on Church Projects

Fit-Up Procedure

1. Signal the crane to bring the beam into position. The connector on the column guides the beam end into the connection using hand signals (see Section 12 for signals).
2. Drive a drift pin through the first hole to align the bolt pattern. Drift pins go through at least one bolt hole per connection before the crane load is released.
3. Install erection bolts: A minimum of two erection bolts per connection (CISC requirement). Erection bolts must be the same diameter and grade as the final bolts. Snug them tight.
4. Signal the crane to release. Confirm the beam is stable on erection bolts before the choker is pulled.
5. Install remaining bolts and bring all bolts to snug-tight as a minimum. If the connection requires pretensioning, that’s a separate step (Section 4).

4. High-Strength Bolting

This is where a lot of crews get sloppy, and it’s where inspectors spend most of their time. High-strength bolting isn’t just “tighten it until it feels good” — it’s a controlled, inspectable, documented procedure with specific torque values, rotation angles, and verification requirements.

Bolt Grades: The New Naming

The old ASTM A325 and A490 designations have been consolidated under ASTM F3125 (referenced in CSA S16). Same bolts, new name, same arguments about which one to use:

Snug-Tight vs. Pretensioned

Not every bolt needs pretensioning. CSA S16 and the RCSC Specification define when each condition applies:

• Snug-tight: The tightness achieved by a few impacts of an impact wrench or the full effort of one person on a standard spud wrench. Adequate for the majority of shear connections in building frames.
• Pretensioned: Required for slip-critical connections, connections subject to fatigue, connections with oversized or slotted holes, and connections in moment frames. The bolt must achieve a minimum clamping force (70% of the bolt’s tensile strength).

Turn-of-Nut Method — Step by Step

The turn-of-nut method is the most reliable and most commonly used pretensioning method on church projects. Here’s the procedure, exactly as RCSC and CSA S16 require it:

Tension-Control (TC) Bolts

TC bolts (the “twist-off” type) have a splined end that shears off at the calibrated tension. They’re fast and largely foolproof — if the spline snapped off, the bolt is tensioned. That said:

• Always verify with a Skidmore-Wilhelm calibrator: minimum 3 bolts per lot at start of shift.
• TC bolts are one-use only. If you remove one, it goes in the scrap bin.
• Store bolts in sealed containers with desiccant. Lubrication on the threads is factory-applied and critical — rusty TC bolts give false readings.

Skidmore-Wilhelm Testing

The Skidmore is a hydraulic bolt tension calibrator. Before each shift and whenever the bolt lot changes, install 3 representative bolts from the lot into the Skidmore and tighten using the same method (turn-of-nut, TC gun, or calibrated wrench) that will be used in the field. The tension reading must meet or exceed the minimum pretension per CSA S16 Table 3 (e.g., 3/4″ A325 = 125 kN; 7/8″ A325 = 173 kN).

5. Metal Deck Installation

Once the steel frame is up and bolted, the metal deck goes down. Deck serves double duty on most HCMI church projects: it’s the form for the concrete slab and the bottom tension element of the composite floor. Get the installation wrong and you’re either pouring concrete onto the parking lot below or building a floor that deflects like a trampoline.

Deck Types & Gauges

Laying Pattern

Deck sheets are laid perpendicular to the supporting beams, starting from one end of the building and working across. Key rules:

• End bearing: Minimum 50 mm bearing on supports. Deck must land on steel, not on air.
• Side laps: Adjacent sheets overlap by one rib (male-female interlock). Side laps must be fastened at intervals not exceeding 900 mm for composite deck.
• End laps: When sheets don’t span the full bay, provide a 50 mm end lap over a support beam, fastened with two puddle welds or screws per rib.

Fastening Methods

• Puddle welds (deck-to-beam): 19 mm diameter minimum, burned through the deck into the beam flange. Typically spaced at 300 mm on centre at supports. CWB-certified welder required.
• Button punch (side laps): Crimping tool creates a mechanical interlock between overlapping ribs. Fast, no heat. Spaced at 600–900 mm.
• Self-drilling screws: #12 or #14 Tek screws for deck-to-beam attachment where welding is impractical. Minimum 2 screws per rib at each support.
• Side-lap screws: #10 self-drilling screws as an alternative to button punching. Same spacing requirements.

Pour Stops, Closures & Safety Netting

Pour stops are angle or channel sections at slab edges that contain the concrete during the pour. Install them before reinforcing. Deck closures are corrugated filler pieces at beams running parallel to the deck ribs — they prevent concrete from flowing into the flutes at those locations. Safety netting or equivalent fall protection must be installed below open deck areas per O. Reg. 213/91 s. 26.1 before anyone works on the deck.

6. Shear Stud Welding

Shear studs are what make a composite floor composite. Without them, the concrete slab and the steel beam act independently — two separate elements bending under load. With studs, the slab and beam act together as a T-shape, dramatically increasing stiffness and strength. A W16×31 beam with composite action can carry the same load as a W21×44 without it. That’s real money.

Nelson Stud Gun Operation

1. Set the gun parameters: Weld time (typically 0.5–1.0 seconds), lift height (3–5 mm), and plunge depth. These are set based on the stud diameter — 19 mm (¾″) studs are standard on church projects.
2. Load the stud into the chuck and place the ceramic ferrule.
3. Position the gun perpendicular to the beam flange, pressing firmly.
4. Pull the trigger. The gun lifts the stud, strikes an arc, melts the base, and plunges the stud into the weld pool. It happens in under a second.
5. Remove the ferrule by tapping it off. Inspect the 360° weld fillet at the stud base.

Quality: Bend Test & Visual Inspection

Per CSA S16 and the CISC quality manual:

• Visual: Every stud gets a visual inspection. Look for a full 360° flash (weld fillet) around the base. No burn-through, no porosity, no incomplete fusion.
• Bend test: The first two studs of each production run and any stud that looks questionable get a 15° bend test. Using a pipe slipped over the stud, bend it 15° from vertical. If it doesn’t crack at the weld, it passes.
• Stud height: After welding, the stud must project a minimum of 75 mm above the top of the deck rib for standard composite action. The engineer may specify more for deeper slabs. Measure with a ruler — this is not a “looks about right” dimension.

7. Steel Joist Erection

Open-web steel joists (OWSJs) are the workhorses of church roofs. They span long distances at light weight, and they’re economical — which is important when the building committee is counting every dollar. But joists have one critical weakness: they are laterally unstable until bridging is installed. An unbridged joist is a 12-metre-long piece of steel that wants to roll over like a wet noodle.

SJI Standards & CISC Requirements

• All joists must be erected and bridged per the Steel Joist Institute (SJI) Code of Standard Practice and the erector’s procedure.
• Bridging is life-safety. Horizontal bridging and diagonal bracing must be installed before the next joist is set. The SJI is explicit: bridge as you go.
• Maximum bridging spacing is governed by the joist designation and is shown on the joist placement plan (typically 1,500–2,400 mm on centre for K-series joists).
• Bottom chord bracing is required at the same spacing as top chord bridging unless the deck or other elements provide continuous lateral support.

Joist Seat Connections

Joists bear on seats welded to the support beams or on bearing plates on walls. Each seat gets a minimum of two ½″ fillet welds, 50 mm long, or two ¾″ A325 bolts. The joist must not be released from the crane until the seat connection is secured and at least one row of bridging is installed to the adjacent (already-braced) joist.

Joist Girder Seats

Joist girders — the big ones that support the joists — sit on column cap plates. These connections are typically bolted with 4× ¾″ A325 bolts. The girder must be stabilised with a minimum of one joist and its bridging connected before the next girder is set.

8. Miscellaneous Metals

Not everything on a steel project is big and dramatic. A lot of the work is the smaller stuff that makes the building functional — lintels over doors, angle supports for masonry, handrails, guardrails, ladders, and embed plates. It’s less glamorous than swinging beams, but if the lintel is wrong the mason can’t lay block, and if the embed plate is wrong the precast crew is standing around billing you by the hour.

Common Miscellaneous Items

• Lintels: Typically L-angles or WT sections spanning over openings in masonry walls. Minimum bearing: 200 mm per side (or as specified). Verify size, location, and elevation against the architectural and structural drawings.
• Shelf angles: Continuous angles supporting masonry veneer at floor lines. Slotted holes allow vertical adjustment. Shimmed to line and grade, then bolted to the structure with expansion anchors or through-bolts.
• Embed plates: Steel plates cast into concrete to receive future connections. Verify placement with the Leica total station before concrete is placed. Tolerance: ±6 mm position, ±3 mm elevation. Once the concrete is poured, they’re permanent.
• Handrails & guardrails: Must meet OBC 9.8.8 for guards (1,070 mm minimum height, no climbable elements, 100 mm maximum opening for pickets) and be secured per the engineer’s details.
• Roof access ladders: Fixed ladders over 3 m require a cage or fall arrest system per O. Reg. 213/91. All ladders must be secured top and bottom.

9. Steel Stairs

Steel stairs on church projects are typically pre-fabricated in the shop as flight assemblies (two stringers with treads/risers welded in) and set by crane. They’re heavier than they look — a 3.5 m floor-to-floor stair flight can weigh 800–1,200 kg.

Setting Sequence

1. Verify landing elevations with the Leica total station. Stairs are unforgiving — the OBC requires uniform riser height within ±5 mm for the full flight. If the landings are wrong, the stairs don’t fit.
2. Set the bottom flight first, shimming the stringer bearing points to achieve correct elevation. Use steel shims, not wood.
3. Bolt the base connections: Typically 4× ¾″ A325 bolts at each stringer bearing.
4. Set the intermediate landing (if applicable), then the upper flight.
5. Grout under stringer bearing plates with non-shrink grout after final alignment is confirmed.
6. Install temporary guardrails immediately. Stairs become circulation routes for all trades as soon as they’re in. O. Reg. 213/91 requires guards on open sides of stairs during construction.

10. HSS Connections

Hollow Structural Sections (HSS) — round, square, and rectangular tubes — are increasingly common on church projects for exposed architectural elements, canopies, and bracing. They look great but they’re a different animal to connect than open sections like W-shapes.

Welded HSS Connections

The challenge with welding to HSS is that you can’t get inside the tube to place backing bars, and the curved or flat face of the tube means your weld angle is constantly changing. CWB W47.1 qualified welders are mandatory. Key considerations:

• Wall thickness matters: Thin-wall HSS (less than 6 mm) is prone to burn-through. Match your heat input to the wall thickness.
• Slot connections: A common detail for brace-to-gusset connections. The HSS is slotted at the end and slipped over a gusset plate, then fillet-welded around the perimeter. The slot must be clean-cut and the gusset must fit without forcing — if you’re hammering a gusset into an HSS slot, something is wrong with the fabrication.
• Unequal stiffness: The face of a rectangular HSS perpendicular to the applied load can flex inward (called “face deformation”). The engineer accounts for this, but field welds must develop the full connection capacity to prevent premature failure.

Bolted HSS Connections

Bolting to HSS typically requires a shop-welded tab, end plate, or through-plate because you can’t access the inside for a nut. Alternatives include blind bolts (e.g., Huck BOM, Lindapter Hollo-Bolt) that expand inside the tube. These are specialty fasteners — follow the manufacturer’s installation procedure exactly and verify torque with the calibrated wrench specified.

11. Steel Plumbing & Alignment

Getting steel plumb and aligned isn’t a one-time event — it’s a continuous process from the first column to the last roof beam. Every piece affects the next, and errors accumulate. CSA S16-19 Clause 28.6 defines the tolerance world you live in:

Verification with Total Station

The Leica total station (covered in depth in the Survey Layout & Control article) is the primary verification tool. After each erection sequence (typically each bay or each grid line), the survey crew checks:

• Column centres at base and top (both axes)
• Beam flange elevations at mid-span and ends
• Overall building dimensions at each floor level

Readings are recorded on form SE-005 and compared against the design coordinates. Any deviation beyond the project targets triggers a hold for review with the engineer before proceeding. Deviations beyond CSA S16 limits trigger a non-conformance report (NCR).

12. Rigging for Steel Erection

Every piece of steel that leaves the ground does so at the end of a rigging configuration. Bad rigging kills people. There’s no softer way to put it. This section covers the rigging fundamentals every crew member must know.

Common Hitch Types

Rigging Hardware

Tag Lines, Hand Signals & Communication

Every steel pick uses tag lines to control the load. Minimum one tag line per end of a beam; two tag lines for columns (to prevent spinning). Tag lines must be non-conductive (polypropylene, not wire rope) when working near electrical. Never wrap a tag line around your hand or body.

A common approach is to use standard CSA hand signals for crane operations. The designated signaller wears a high-visibility vest and is the only person communicating with the crane operator during the lift (except for emergency stop, which anyone can give).

13. Temporary Bracing & Stability

Temporary bracing keeps partially-erected steel frames from becoming very expensive dominoes. Until the permanent lateral load resisting system is complete (moment frames fully bolted, braced bays complete, metal deck acting as a diaphragm), the building depends entirely on temporary bracing to resist wind, construction loads, and the not-insignificant force of a crane swinging a 3-tonne beam into the side of the frame.

• Cable bracing: Wire rope guys from column tops to dead-man anchors or adjacent bays. Minimum 16 mm wire rope with turnbuckles for adjustment. Two cables per plane, forming an X pattern.
• Angle bracing: L-angles or WT sections bolted diagonally in bays designated on the erection plan. These must be engineered — don’t just throw an angle in a bay and call it braced.
• Removal sequence: Temporary bracing is removed only after the permanent system in that zone is fully installed, inspected, and approved by the engineer. Removing bracing too early is how collapses happen.

14. Bolt Inspection & Documentation

Steel erection quality lives and dies by documentation. The best bolt installation in the world is worthless if you can’t prove it happened. Maintain a complete bolt installation and inspection record for every project.

Inspection Checklist

• Bolt lot verification: Every lot of bolts delivered to site has a mill certificate. Confirm the lot number on the certificate matches the markings on the bolts.
• Skidmore calibration: Verified at start of each shift and with each new bolt lot. Results recorded on form SE-007.
• Visual inspection: After installation, inspect every pretensioned bolt for rotation marks (turn-of-nut) or spline breakage (TC). Snug-tight bolts are inspected by confirming all bolts are in place and nuts are tight against the connected material.
• Arbitration testing: If there’s a dispute about bolt tension, the inspector can remove bolts and test them in the Skidmore. Bolts must be within ±5% of the specified minimum pretension.
• Surface condition: For slip-critical connections, verify the faying surfaces meet the specified Class (A, B, or C). Class A is clean mill scale; Class B is blast-cleaned. No paint, no oil, no dirt between the plates.

15. Putting It All Together — Typical HCMI Church Steel Sequence

Here’s what a typical steel erection looks like on a sanctuary project, from mobilization to punch list:

1. Day 1–2: Crane setup, rigging inspection, shakeout of first steel delivery. Survey crew verifies all anchor bolt positions. Erection plan briefing with all crew.
2. Day 3–5: Set columns in the first bay. Plumb, brace, and bolt. Survey verification.
3. Day 5–10: Set beams and girders, bay by bay, working from back to front. Install temporary bracing as each bay is completed. Erection bolts in, snug-tight.
4. Day 10–12: Steel joists and joist girders for the roof. Bridging installed as each joist is set.
5. Day 12–15: Pretensioning of all bolts requiring it. Skidmore verification. Bolt inspection and documentation.
6. Day 15–18: Metal deck installation. Puddle welds, side laps, pour stops, closures.
7. Day 18–20: Shear stud welding. Bend tests. Quality documentation.
8. Day 20–22: Steel stairs, miscellaneous metals, touch-up paint.
9. Day 22–24: Final survey verification of all steel. Engineer’s field review. Punch list.
10. Day 25: Demobilize crane. Celebrate. Iron workers’ tradition: last beam signed by the crew.

Key Standards & References