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OCR for page 82
82 Attachment DS1: Revised Article 2.1 Definitions Revision of current article to include definitions of emu- lative and hybrid systems Attachment DS2: Revised Article 4.3.3 Displacement Magnification for Short Period Structures Revised Article to account for hybrid systems Attachment DS3: Revised Article 4.7.2 Vertical Ground Motion, Design Requirements for SDC D Expanded Article to include explicit requirements for consideration of vertical excitation with integral precast bent caps discontinuous at bent Attachment DS4: Revised Article 4.11.6 Analytical Plastic Hinge Length Revised Article to account for integral concrete super- Figure 3.7. View of column bar buckling at interface structures between the bent cap and columnCPFD (after Attachment DS5: Proposed Article 5.6.6 Ieff for Hybrid removal of concrete post-test). Systems New Article for hybrid systems Attachment DS6: Revised Article 8.4.2 Reinforcing Steel GD and CPFD specimen tests confirmed the importance of Modeling accurate placement of the column top hoop and the unsup- Revised Article for hybrid systems ported column bar length (22, 23). Figure 3.7 shows column Attachment DS7: Proposed Article 8.8.14 Lateral Re- bar buckling at the interface between the cap and column for inforcement Requirement for Columns Connecting to a the CPFD specimen (post-test). The unsupported column Precast Bent Cap bar length was considerably larger than the regular column New Article to ensure spacing between the hoop at top hoop spacing. Although this did not affect the maximum of column and the bedding layer hoop does not com- force induced in the joint and the specimen achieved over 4% promise system ductility drift, system ductility was limited by buckling of column lon- Attachment DS8: Revised Article 8.5 Plastic Moment gitudinal reinforcement. Capacity for SDC B, C, and D The proposed specification addresses this issue as follows: Revised Article for hybrid systems Attachment DS9: Revised Article 8.8.1 Maximum Longi- The spacing between the first hoop at the top of the tudinal Reinforcement column and the bedding layer hoop shall not exceed Revised Article for hybrid systems the spacing used for hoops in the plastic hinge region. Attachment DS10: Revised Article 8.8.2 Minimum Longi- The concrete cover above the first hoop at the top of the column shall be permitted to be less than that specified tudinal Reinforcement in Article 5.12.3 of the AASHTO LRFD Bridge Design Revised Article for hybrid systems Specifications. Transverse reinforcement used for piles Attachment DS11: Proposed Article 8.8.14 Minimum shall be similarly detailed. Debonded Length of Longitudinal Reinforcement for Hybrid Columns New Article for hybrid systems 3.3 Proposed Changes to AASHTO Attachment DS12: Revised Article 8.10 Superstructure Guide Specifications for LRFD Capacity Design for Longitudinal Direction for SDC C and D Seismic Bridge Design and Revised Article for integral precast systems AASHTO LRFD Bridge Design Attachment DS13: Proposed Article 8.13 Joint Design for Specifications SDC A Based on the test results and development of design speci- New Article for SDC A precast bent cap connection design fications, proposed design specifications have been prepared Attachment DS14: Proposed Article 8.14--Joint Design and are provided as attachments to this report (available online for SDC B at www.trb.org/Main/Blurbs/164089.aspx). Proposed addi- New Article for SDC B precast bent cap connection design tions or revisions to the AASHTO Guide Specifications for LRFD Attachment DS15: Revised Article 8.15--Joint Design for Seismic Bridge Design, 1st Edition (1), are as follows: SDCs C and D