Erection Plans in Ontario: OHSA Reg 213/91, P.Eng Requirements & MTO Standards

OHSA Construction Regulation 213/91 Requirements

Ontario's Occupational Health and Safety Act (OHSA) and its Construction Projects Regulation (O.Reg 213/91) govern health and safety on construction sites. Part XIV of O.Reg 213/91 (Steel Erection) and Part XV (Prefabricated Structural Components) contain the key erection plan requirements:

• Section 135 (Steel erection): Requires that structural steel erection be carried out in accordance with an erection plan prepared by a professional engineer. The plan must ensure the structure maintains stability at each stage of erection, including provisions for temporary bracing and connection sequencing.
• Section 157 (Precast erection): Requires an erection plan prepared or reviewed by a P.Eng. for precast elements weighing more than 2,300 kg or where erection involves conditions (site constraints, unusual support geometry, stacking) that require engineering judgment on temporary stability.
• Constructor obligations: The constructor (general contractor) must ensure the erection plan exists and is available on site before erection begins. Workers must follow the plan. If field conditions deviate from the plan, erection must stop until the plan is revised by the P.Eng. and the revision is reviewed and approved.

What an Erection Plan Must Include

A compliant Ontario erection plan is an engineering document, not a scheduling document. It covers:

• Erection sequence: The order in which structural elements are erected — which columns are set first, which bays are completed before proceeding, what constitutes a stable "bay" or "tower" that can stand alone before the adjacent structure is complete
• Temporary bracing plan: Location, size, and attachment of all temporary bracing elements (cable braces, kicker struts, knee braces, compression struts) that provide lateral stability before permanent connections and diaphragm action are in place; design calculations confirming bracing adequacy for construction loads, wind, and any construction equipment loads
• Connection completion requirements: Minimum bolt quantities, weld lengths, or other connection completions that must be achieved before the next lift proceeds — partial connections do not provide the same rigidity as fully completed connections and the plan must account for this
• Crane positions and picks: Crane location(s) relative to the structure, pick weights, boom radii, and confirmation that the crane capacity is adequate for all planned picks including rigging weight. Multiple crane configurations for sequential erection phases
• Rigging and sling requirements: Sling angles, dunnage requirements, and any special lifting hardware (spreader beams, balance beams) needed for asymmetric or heavy precast elements
• Temporary supports and connections: Any supplemental temporary columns, shores, or stools required to support long-span elements before the permanent supports are in place
• Safety requirements: OHSA fall protection provisions specific to the erection activities; working at heights plan for steel connection workers

Temporary Stability During Erection

The governing engineering challenge in erection plan design is ensuring the partially-erected structure maintains stability under construction loads at every stage. A complete structural frame achieves stability through its designed combination of connections, diaphragms, and lateral load-resisting systems. During erection, those systems are only partially in place.

Key temporary stability considerations:

• Column base stability: Columns must be plumb and stable before the bolt pattern is fully grouted. Base plate temporary bolt arrangements must resist erection wind loads on the bare column.
• Beam-to-column connection stability: Simple shear connections (single plate, seated angle) provide no moment resistance until the floor diaphragm is complete. Temporary cable bracing must carry lateral loads in the bay until diaphragm continuity is established.
• Diaphragm action lag: Composite metal deck diaphragm action is not available until the deck is welded to the steel frame and the concrete topping is poured and cured. The erection plan must provide for lateral bracing during this entire period.
• Long-span element deflection: Long-span beams or girders may deflect significantly under their own weight when placed before the rest of the frame provides restraint. The erection plan must verify that mid-span deflection during erection does not create geometric incompatibility with adjacent elements.

Structural Steel Erection Plans

For building structural steel, the erection plan is typically prepared by the fabricator's engineer (the P.Eng. providing process engineering for the steel contractor) in coordination with the project's structural engineer of record. The SER's input is essential because the SER holds the original design calculations and knows the connection geometry, camber values, and load-path assumptions that must be respected during erection.

CSA S16 (Design of Steel Structures) section on erection requires that stability be maintained throughout construction. The standard specifically addresses: lateral stability of beams prior to composite action; column plumb tolerances; and the structural engineer's role in providing erection information on the structural drawings (camber, connection completion sequence, temporary support requirements).

Precast Concrete Erection Plans

Precast concrete erection presents distinct challenges compared to steel: elements are heavier, connections take time to achieve full strength (especially grouted connections), and the temporary stability situation between setting and connection completion requires careful planning.

Under O.Reg 213/91 Section 157, erection plans for precast elements over 2,300 kg must address:

• Pick points and lifting insert capacity — inserts must be designed for the actual pick angle and load, not just the vertical element weight
• Temporary bearing and bracing during setting and before grouted connections achieve design strength
• Erection tolerance requirements and how mis-set elements will be corrected without damaging bearing pads or connection hardware
• Stacking and storage of precast elements on site — ground conditions must support the stored precast loads without settlement

Bridge Erection and MTO Requirements

Bridge construction in Ontario introduces additional oversight layers beyond building construction. For provincial highway bridges, the Ministry of Transportation Ontario (MTO) is the approval authority and its requirements govern alongside OHSA.

MTO's Structural Manual and supplements to CSA S6 (CHBDC) establish requirements for:

• Falsework design: All falsework supporting bridge girders or form travellers during concrete deck construction must be P.Eng. designed and inspected. MTO requires falsework drawings to be submitted for review before construction begins.
• Steel erection sequence for bridges: The erection sequence for bridge steel girders must account for staged composite action — the dead load of the wet concrete deck is carried on the non-composite steel section, while subsequent live loads are shared with the hardened concrete. The erection plan must confirm that non-composite member stresses under construction loading are within allowable limits.
• Launching and incremental bridge construction: Launched bridges or incrementally constructed bridges require especially detailed erection plans addressing launching nose design, pier temporary loading, and monitoring requirements during launching.

Professional Responsibility & Liability

The P.Eng. who stamps an erection plan takes full professional responsibility for the engineering content of that plan. If an erection failure occurs and it can be traced to a deficiency in the erection plan, the stamping engineer faces professional liability to injured parties and professional discipline by PEO.

Important professional responsibility boundaries:

• The erection plan P.Eng. is responsible for the engineering in the plan — not for field implementation. The constructor is responsible for following the plan on site.
• If field conditions deviate from the plan (e.g., different ground conditions affect crane positioning, or connection hardware is substituted), the constructor must not proceed without revised P.Eng. approval of the deviation.
• The structural engineer of record of the permanent building is responsible for the permanent structure. Where erection loads or sequences could affect the permanent structure (e.g., concentrated construction loads on slabs, temporary point loads not part of the original design), the SER must be consulted.