Page 245 - Bridge and Highway Structure Rehabilitation and Repair
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220            SECTION 2                                        STRENGTHENING AND REPAIR WORK



         5.6.5  Substructure Design—Service Loads
         Table 5.6b  LRFD service load combinations for substructures.
         DL of super 4 DL of substr. 4 live load   1.0  1.0  1.0  0.30  1.0  1.0  1.0 1.00/1.20    TG    SE
         4 reduced wind on super 4 substr. 4
         wind on live
         (Service I)
         DL of super 4 DL of substr. 4 with  1.0  1.30  1.0  —    1.0    —    1.0 1.00/1.20  —     —
         max. live load
         (Service II)
         DL of super 4 DL of substr. 4 with min.  1.0  0.80  1.0  —  1.0  —   1.0 1.00/1.20    TG    SE
         live load
         (Service III)
         DL of super 4 DL of substr. 4 with  1.0  —  1.0   0.70   1.0    —    1.0 1.00/1.20  —    1.00
         reduced wind on superstr. 4 substr.
         (Service IV)

         5.6.6  Limit State Design for Superstructure Components
         A.  Deck slab, haunch, girders, parapet, median barrier, sidewalk, railing, sign panel supports
         Four extreme events may be described as follows:
            •   Three load combinations for flood conditions and scour

                –  Water impact on pier and superstructure
                –  Settlement of pier or abutment from soil erosion under footings
                –  Increased axial stress in piles due to reduced embedment length from soil erosion.
            •   Two seismic load combinations in transverse and longitudinal directions
            •   Two vehicle collision impacts on superstructure and on pier
            •   Vessel collision impact on piers located in navigational channel.

         Table 5.7  LRFD primary and secondary load combinations for superstructures.

                                Primary Loads                                  Secondary Loads
                              Dead Loads
                            (Components     Live Loads    Wind on   Erection  Concrete  Temperature  Support
         Load Combinations  Wearing Surface)  and Friction Superstr.   LL  Load  Properties  Gradient  Settlement
                           (DC1 4 DC2) 4 DW (LL+ IM 4 PL)  (WS) 4 (WL)  (EL)  (TU) 4 (CR   (TG)  (SE)
                                           4 (CE) 4 ( LS)                   4 SH)
                                              4 (FR)
         (DL 4 LL) 4                p          1.75         —         —    0.5/1.20      TG        SE
         secondary loads
         (Strength I)
         (DL 4 permit load)         p          1.35         —         —    0.5/1.20      TG        SE
         4 secondary loads
         (Strength II)
         (DL 4 wind) +              p           —          1.40       —    0.5/1.20      TG        SE
         secondary loads
         (Strength III)
         (DL) 4 secondary loads     p           —           —         —    0.5/1.20    —         —
         (Strength IV)
         DL 4 LL 4 wind 4 EL        p          1.35        0.40      1.0   0.5/1.20      TG        SE
         (Strength V)
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