Use minimum cross-section dimensions as specified in Article 5.12.5.3.11

For maintenance, the clear height of interior box section should not be less than 6 feet.

Analyze segmental spans in accordance with Article 4.6.2.9 Analysis must consider timedependent construction methods; short- and long-term post-tensioning, creep, and shrinkage effects; and secondary force effects due to post-tensioning.

Estimate shrinkage and creep using the provisions of the

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Model Code for Concrete Structures (

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2010), or the CEB-FIP Model Code 1990 (CEB 1990), include the effects of specific materials (when known), structural dimensions, site conditions, construction sequence, and concrete age at various stages of erection.

Base live load reactions per lane on the combined effect of the truck loading added to the lane loading.

Round prestress losses to 1 ksi.

Satisfy all stress limits for prestressing tendons and concrete as required in Articles 5.9.2.2 and 5.9.2.3. Use limits for severe corrosive conditions in areas of the state where de-icing agents are frequently used or in marine environments.

For all considerations other than preliminary design, determine prestress losses as specified in Article 5.9.3, including consideration of the time-dependent construction method and schedule shown in the contract documents.

Check principal stress in webs as required in Article 5.9.2.3.3.

Check shear and torsion as required in Article 5.12.5.3.8.

Determine tie back reinforcement behind anchorages as required in Article 5.9.5.6.7b. Minimize the amount of tie back reinforcing steel penetrating through segment bulkheads by adjusting the location of anchorages or using hooks for development.

Overhang strength for extreme events, described in Article 9.5.5, is satisfied through TxDOT’s rail crash testing.

Calculate prestress losses for creep, shrinkage, elastic shortening and relaxation as prescribed in Chapter 3, Section 4 - Pretensioned Concrete I-Girders, or by analysis software that has concrete time-dependent capabilities to capture the effect of creep and shrinkage.

Provide 2 in. clear cover to reinforcing steel for entire cross section. Add 1 in. grinding allowance to top slab. Also, increase top slab clear cover to 2.5 in. for areas of the state where de-icing agents are frequently used.

Include shear keys in webs of precast and cast-in-place segmental spans. Space shear keys 1 ft. 6 in. along centerline of web.

Provide a minimum 5 ft. tangent length of tendon from the anchorage head before introducing any curvature. Determine minimum radius of curvature for individual duct sizes based on published values from suppliers.

Include extra longitudinal reinforcement above a horizontal construction joint to mitigate cracking from restraint shrinkage.

Include extra longitudinal reinforcement above a doorway opening or other significant cross-section change, to mitigate cracking from differential shrinkage.

Include provisional post-tensioning ducts as required in Article 5.12.5.3.9. Provisional anchorage hardware is not required, but allowance for future placement of hardware must be considered.

Provide a ¾” deep continuous drip-bead adjacent to deck coping as shown the Miscellaneous Slab Details for Prestressed Concrete I-Girders (IGMS) standard drawing.

Provide access openings at maximum 600 feet spacing and the distance from any location of box girder to the nearest opening should not be more than 300 feet. Provide at least two openings per box girder line. The size of access opening should be 32 in. x 42 in. or 36 in. diameter at minimum.