Published by department of transportation

48-2.02 MATERIALS

48-2.02A General

48-2.02B Design Criteria

48-2.02B(1) General

Anticipated falsework settlement must not exceed 1 inch.

Design footings to carry the imposed loads without exceeding estimated soil bearing values or anticipated settlements.

Falsework spans for T-beam girders must not exceed 14 feet plus 8.5 times the T-beam girder depth.

Design falsework supporting deck slabs and overhangs on girder bridges such that there is no differential settlement between the girders and the deck forms during deck concrete placement.

For individual steel towers with maximum leg loads exceeding 30 kips, design foundations to provide uniform settlement under all legs of each tower.

Design support systems for form panels supporting concrete deck slabs and overhangs on girder bridges as falsework.

Temporary bracing must be designed to withstand all imposed loads during erection, construction, and removal of any falsework. Wind loads must be included in the design of the bracing.

Falsework removal systems employing methods of holding falsework from above, and members of the independent support system, must support the sum of the actual vertical and horizontal loads due to falsework materials, equipment, construction sequence or other causes, and wind loading. Identifiable mechanical devices used in the falsework removal plan must comply with applicable industry standards and manufacturer instructions for safe load carrying capacity. Unidentifiable winches must be capable of carrying twice the design load.

The load used for the analysis of overturning moment and sliding of the winch system must be 150 percent of the design load.

48-2.02B(2) Loads

Dead loads must include the weight of concrete, reinforcing steel, forms, and falsework. Loads due to concrete, reinforcing steel, and forms must be assumed to be at least:

1. 160 pcf for normal concrete

2. 130 pcf for lightweight concrete

1. Actual weight of any equipment to be supported by the falsework applied as concentrated loads at the points of contact

2. Uniform load of at least 20 psf applied over the area supported by the falsework

3. Load of 75 lb/ft applied at the outside edge of deck overhangs

If the concrete is to be prestressed, design the falsework to support any increased or readjusted loads caused by the prestressing forces.

Design the falsework with sufficient rigidity to resist the assumed horizontal load without considering the concrete load.

For heavy-duty steel shoring or steel pipe column falsework with a vertical load capacity greater than 30 kips per leg or column, the minimum horizontal wind loading must be the sum of the products of the wind impact area, shape factor, and wind pressure value for each height zone. The wind impact area is the total projected area of all elements in the tower face or falsework bent normal to the direction of the applied wind. Use a shape factor of 2.2 for heavy-duty steel shoring and 1.0 for pipe column falsework. Use the wind pressure values shown in the following table:

1. Girder stems and connected bottom slabs are placed more than 5 days before the top slab

2. Distance between falsework posts is at most 4 times the depth of the portion of the girder stem placed in the 1st pour
Falsework for box girder structures with internal falsework bracing systems that use flexible members capable of withstanding only tensile forces must be designed to include (1) the vertical effects caused by elongation of the flexible member and (2) the design horizontal load combined with the dead and live loads imposed by concrete placement for girder stems and connected bottom slabs. This requirement does not apply to falsework composed of individual steel towers that use flexible members capable of withstanding only tensile forces to resist overturning.

48-2.02B(3) Stresses, Loadings, and Deflections

48-2.02B(3)(a) General

48-2.02B(3)(b) Timber

The maximum allowable stresses, loadings, and deflections for timber are as shown in the following table:

48-2.02B(3)(c) Steel

Except for flexural compressive stresses, the design stresses for unidentified steel must not exceed those specified for steel complying with ASTM A36/A36M in the AISC Steel Manual or as shown in the following table:

48-2.02B(3)(d) Manufactured Assemblies

Do not exceed the manufacturer's instructions for loadings and deflections on jacks, brackets, columns, joists, and other manufactured devices except the dead load deflection of joists at locations other than under deck slabs between girders must not exceed 1/240 of their spans.

48-2.02B(4) Special Locations

Design and construct falsework over or adjacent to roadways or railroads that are open to traffic such that the falsework is stable if subjected to impact by vehicles.

Falsework posts at the following locations are considered adjacent to roadways or railroads:

1. Posts supporting members that cross over a roadway or railroad

2. Posts located in the row of falsework posts nearest to the roadway or railroad and where the horizontal distance from the traffic side of the falsework to the edge of pavement or to a point 10 feet from the centerline of track is less than the total height of the falsework and forms

The falsework design at the above locations must comply with section 48-2.02B and the following requirements:

1. The vertical load used for the design of falsework posts and towers that support the portion of the falsework over openings must be the greater of:

1.1 150 percent of the design load calculated under section 48-2.02B(2), not including any increased or readjusted loads caused by prestressing forces

1.2 Increased or readjusted loads caused by prestressing forces

2. Falsework posts must be steel with a minimum section modulus about each axis of 9.5 cubic inches or sound timbers with a minimum section modulus about each axis of 250 cubic inches.

3. Each falsework post must be mechanically connected to the support footing at its base or laterally restrained to withstand a force of at least 2,000 lb applied at the base of the post in any direction except toward the roadway or railroad track. Posts must be mechanically connected to the falsework cap or stringer. The mechanical connection must resist a load in any horizontal direction of at least 1,000 lb.

4. Mechanically connect (1) exterior falsework stringers, (2) stringers adjacent to the ends of discontinuous caps, (3) stringers over points of minimum vertical clearance, and (4) every 5th remaining stringer to the falsework cap or framing. For falsework over railroads, mechanically connect all stringers to caps. Mechanical connections must resist at least a 500 lb load in any direction, including uplift on the stringer. Install connections before traffic passes under the span.

5. Connect timber bracing to falsework using at least 5/8-inch-diameter bolts or coil rod with a root diameter equal to that of the shank of a 5/8-inch-diameter bolt.

6. Falsework member clearances must be at least those shown in the following table:

Falsework member	Clearance
	To railing members, barriers, and anchored temporary railings	To unanchored temporary railings
Footings	0'-3"	2'-0"
Piles	1'-0"	2'-9"
Other members	2'-0"	2'-9"

7. Falsework bents within 20 feet of the centerline of a railroad track must be sheathed solid from 3 to 17 feet above the track on the side facing the track. Sheathing must be plywood at least 5/8 inch thick or lumber at least 3/4 inch thick. Brace these bents to resist the required assumed horizontal load or 5,000 lb, whichever is larger.

8. Provide clear openings through falsework as described.

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