| Proposed BDDM Changes for April, 2008 |
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Letter from State Bridge Engineer, Bruce V. Johnson
1.1.2.7 End Panels- correct "offend" to "of end" (posted in 1.1.2.9)
1.1.2.9 Other Things to Keep in Mind- (8) Railroad Considerations: new UPRR requirements for crash walls, drainage and protective fencing during structure repairs/rehab.
1.1.5.5 Drilled Shalfs- revise Fig. 1.1.5.5A: add 2'-0" max. casing shoring height; (6) rock sockets; (14) cover requirements; (19) shaft diameter for seismic analysis
1.1.7.1 Dead Loads- add: If a loading change is planned, confirm structure load capacity. Includes deck truss bridges and analysis of gusset plates.
1.1.8.4 End Bents- Integral Abutments: clarify terminology (bents vs. abutments); various text revisions, revise Fig. 1.1.8.4A, add new Fig. 1.1.8.4C
1.1.10 Seismic Design- Major rewrite of section to incorporate new AASHTO LRFD seismic provisions.
1.1.14.1 Design of Precast Prestressed Elements- change "Interstate" to "National Highway System", review 1000 ADTT
1.1.20.2 Deck Expansion Joint Seals- Deck Joint Skew and snowplows- clarified. (3) Expansion Joint Settings, General- equation guidance for steel vs. concrete superstructure, revise Fig. 1.1.20.2D.
1.1.21.1 Rail Selection- add BR290 to table, explain Texas barriers
1.2.1 Steel Girders- Change deck concrete to 4000 psi; Certified Erector not required for typical steel bridges.
1.4.2 Soundwalls, Figure 1.4.2A- Wing velocity corrected on 80 mph contour, "AASHTO" spelling correction.
1.4.7 Utilities on Structures- a) For historic structures, have proposed utility installations reviewed by Region Cultural Resource Specialist. b) For proposed utilities with added dead load: should be routed to Load Rating group for review.
1.4.9.2 Temporary Detour Bridges- Seismic design reference to 1.1.10
1.4.9.4 Falsework- Bridge Deck Falsework: add steel interior girder limitations
A1.1.8.7 End Bent Details for Slabs and Boxes_ Figure A1.1.8.7B: correct "polystyrene" spelling, resolve conflecting width dimensions.
2.1.2 Directory setup- Standard drawings can be found in both dgn and pdf formats.
2.4.2 Title Block Information- How to fill in title block One structure number= one set of structure plans
2.6.1
Plan- Adding railroad mile point and USDOT number
A2.7.3
Plan and Elevation- General Notes: Major rewrite of Seismic Design section to incorporate new Interims of AASHTO LRFD Bridge Design Specifications and new AASHTO Guide Specifications for LRFD Seismic Bridge Design.
BDDM Update Summary April 2008
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