13.1 Formwork, Falsework, Scaffolding, Shoring/Reshoring, Bracing, and Anchorage

Temporary works carry real structural load while the permanent system is incomplete. Their short service life does not excuse an incomplete load path or unstable stage. For July 2026, use the April 2024 PE Civil: Structural specification, ACI 318-14, the AISC Steel Construction Manual 15th edition, PCI Design Handbook 7th edition, and only the NCEES-supplied July 2020 Title 29 CFR excerpts. Do not substitute April 2027 editions or current-web OSHA language for the exam excerpts.

Name Each Temporary System Correctly

Formwork gives fresh concrete its shape and supports it until the concrete can carry the intended load. Sheathing, joists, studs, walers, ties, shores, and their connections transfer fluid pressure, wet-concrete weight, placement loads, and form self-weight. Wall-form pressure is lateral and depends on the stated placement conditions; it is not automatically equal to a floor slab's vertical weight model.

Falsework is temporary structural support for an incomplete permanent element, such as a girder, arch, precast unit, or cast-in-place span. It includes towers, caps, beams, foundations, connections, and bracing. Differential settlement or an eccentric bearing can destabilize the system even if axial capacity appears adequate.

Scaffolding provides a working platform and access. It carries workers, tools, stored material, and environmental loads under the supplied OSHA provisions. A scaffold is not a shore or falsework tower unless it has been specifically engineered for that structural function. Platform support, base conditions, ties, braces, access, and fall or falling-object protection remain part of its safety system.

Shoring temporarily supports new work or an existing structure. Reshoring is installed as shores are removed so construction loads continue through slabs or framing below. Reshores do not erase load; they change its distribution among levels with different ages, strengths, and stiffnesses.

Bracing restrains translation, rotation, sidesway, or out-of-plane movement during erection. Steel frames, wall panels, precast members, form towers, and falsework may be unstable before permanent diaphragms and connections exist.

Anchorage transfers temporary tension, shear, uplift, and overturning forces into concrete, masonry, steel, soil, or another support. Capacity depends on the anchor, spacing and edges, installation, embedment, substrate condition and strength, and the receiving element's load path. An anchor bolt without a verified foundation is not a completed restraint.

One Workflow for Every Stage

1. Define the stage and transition. List what is installed, cured, connected, braced, and about to change.
2. Inventory simultaneous loads. Include wet materials, forms, workers, equipment, stockpiles, delivery or impact effects, and applicable wind or other environmental action.
3. Draw the path to ground. Follow sheathing to joists, shores or towers, lower floors, mudsills or foundations, and soil. Include every connection.
4. Use stage properties. Do not assume final concrete strength, composite action, diaphragm restraint, or completed welds and bolts.
5. Check strength, stiffness, and stability. Evaluate bearing, buckling, overturning, sliding, uplift, settlement, deflection, and local connection modes.
6. Inspect and control changes. Define hold points, tolerances, monitoring, and who can authorize placement or release.
7. Analyze removal. Shore stripping, reshoring, brace release, or anchor removal is a new load case.

Worked Form-and-Shore Calculation

An 8 in concrete slab is placed on forms supported by interior shores spaced 5 ft by 6 ft. Use fresh-concrete unit weight 150 pcf, formwork self-weight 10 psf, and a problem-specified construction live load of 50 psf. Find the service axial load delivered to one interior shore, before shore self-weight or any eccentricity.

Fresh concrete:

q_c = (8/12 ft)(150 pcf) = 100 psf

Total stated placement load:

q = 100 + 10 + 50 = 160 psf

Interior shore tributary area:

A_t = (5 ft)(6 ft) = 30 ft^2

Shore load:

P = qA_t = (160 psf)(30 ft^2) = 4,800 lb = 4.80 kips

If the problem supplies a compatible allowable shore load of 6.00 kips, the axial utilization is 4.80/6.00 = 0.80. That comparison does not complete the design. Check the shore's unbraced length and plumbness, head and base bearing, horizontal bracing, connection eccentricity, mudsill or floor capacity, concentrated equipment loads, and load combinations required by the controlling documents. An end or corner shore also has different tributary geometry.

Sequence Scenarios

During multistory concrete construction, a newly placed slab may send load through shores into a young floor, then through reshores to additional levels. Removing all shores from one level before installing or confirming reshores can create an unintended load transfer. Concrete cylinder or field-cured test information, engineering criteria, and the approved sequence—not elapsed calendar time alone—govern readiness.

During steel or precast erection, a member may have adequate final strength but little lateral stability before deck attachment, weld completion, diaphragm connection, or brace installation. Temporary braces require anchors and foundations capable of both brace force directions. Release only after the permanent stabilizing path is complete and verified.

Falsework near traffic or water also needs impact, scour, settlement, clearance, and protection considered as the problem directs. Scaffolds altered for access must be reevaluated rather than treated as unchanged. Field substitutions, relocated shores, drilled anchors, damaged components, or an altered placement rate require communication and review by the responsible party.

Final Stage Audit

For every exam scenario, circle the next construction action and ask what force moves when it occurs. Confirm all six categories: formwork, falsework, scaffolding, shoring/reshoring, bracing, and anchorage. Then verify a continuous path, adequate stage properties, lateral stability, foundation support, inspection, and a controlled release sequence.