203 - Loads and Load Factors
203.4 - LOAD FACTORS AND COMBINATIONS
203.4.1 - Load Factors and Load Combinations
| SPECIFICATIONS | COMMENTARY |
| The following shall supplement the Strength II description in A3.4.1:
Permit loads to be considered are illustrated in Section 108 – Bridge Load Rating. Refer to Figure 108‑4. Permit Load Vehicle Axle Loadings and Spacings. The following shall modify Table A3.4.1-1: In evaluation of the Service III Load Combination, the Live Load (LL) Load Factor shall be taken as 1.0. Delete Table A3.4.1-4. |
203.4.3 - Load Factors for Jacking and Post-Tensioning Forces
203.4.3.1 - Jacking Forces
| SPECIFICATIONS | COMMENTARY |
| The following shall replace the first paragraph of A3.4.3.1:
Hydraulic jacks shall be sized by applying a factor of 1.65 to the unfactored permanent loads. All jacking elements, excluding the hydraulic jacks, shall be designed using the provisions of AASHTO LRFD with the following exceptions:
|
C203.4.3.1D
The 1.65 factor used for sizing hydraulic jacks is the product of a load factor equal to 1.5 and a factor to account for the “sticky force” of the bearings equal to 1.1. |
203.6 - LIVE LOADS
203.6.1 - Gravity Loads: LL and PL
203.6.1.1 - Vehicular Live Load
203.6.1.1.2—Multiple Presence of Live Load
| SPECIFICATIONS | COMMENTARY |
| Delete the third paragraph of A3.6.1.1.2. | C203.6.1.1.2
Delete the third through fifth paragraphs of AC3.6.1.1.2. |
203.6.1.3 - Application of Design Vehicular Live Loads
203.6.1.3.2 - Loading for Optional Live Load Deflection Evaluation
| SPECIFICATIONS | COMMENTARY |
| The following shall replace the first paragraph of A3.6.1.3.2:
The deflection control provisions of A2.5.2.6.2 shall apply to all bridge designs as modified by 202.5.2.6.2 herein. |
C203.6.1.3.2
Both paragraphs in AC203.6.1.3.2 shall be deleted. |
203.6.1.6 - Pedestrian Loads
| SPECIFICATIONS | COMMENTARY |
| The following shall replace A3.6.1.6:
A pedestrian load of 0.075 ksf shall be applied to all sidewalks wider than 2.0 feet and considered simultaneously with the vehicle design live load. The pedestrian load is distributed using the lever rule. When the pedestrian load is required, two loading conditions shall be considered. The first loading condition assumes that the sidewalk is not present (i.e., an extended roadway surface and barrier would replace the sidewalk area) and that the bridge is used for vehicular live load only. For the second loading condition, the pedestrian load is present and the vehicular live load is factored at a reduced level. Load factors for Strength I shall be 1.45 for live load and 1.75 for pedestrian load. |
C203.6.1.6
The following shall replace AC3.6.1.6: The simultaneous occupancy by a dense loading of people combined with a 75-year design live load is remote. |
203.7 - WATER LOADS: WA
203.7.1 - Static Pressure
| SPECIFICATIONS | COMMENTARY |
| The following shall replace the second paragraph of A3.7.1:
For structures that do not span or that are not adjacent to a waterway, the design water level shall be assumed to be coincident with the invert elevation of the structure’s weep holes. For structures that do span or that are adjacent to a waterway, the design water level shall be assumed to be coincident with the water elevation of the applicable design storm. |
203.10 - EARTHQUAKE EFFECTS: EQ
203.10.5 - Operational Classification
| SPECIFICATIONS | COMMENTARY |
| The following shall supplement A3.10.5:
For the purpose of evaluating seismic design parameters, all bridges within the State of Delaware shall be considered “Essential” bridges. |
203.10.6 - Seismic Performance Zones
| SPECIFICATIONS | COMMENTARY |
| The following shall replace A3.10.6:
All bridges within the State of Delaware are considered to be within Seismic Zone 1 with a corresponding Acceleration Coefficient, ≤ 0.15. |
≤ 0.15.
203.12 - FORCE EFFECTS DUE TO SUPERIMPOSED DEFORMATIONS: TU, TG, SH, CR, SE, PS
203.12.2 - Uniform Temperature
| SPECIFICATIONS | COMMENTARY |
| The following shall replace A3.12.2:
The design thermal movement associated with a uniform temperature change shall be calculated using Procedure A. |
203.14 - VESSEL COLLISION: CV
203.14.2 - Owner’s Responsibility
| SPECIFICATIONS | COMMENTARY |
| The following shall supplement A3.14.2:
During the TS&L/Preliminary Design Phase of the bridge design, the designer shall engage the Bridge Design Engineer in discussions related to the site-specific vessel, degree of damage, and protective systems warranted for a particular project. |
203.14.16 - Security Considerations
| SPECIFICATIONS | COMMENTARY |
| The following shall supplement A3.14.16:
During the TS&L/Preliminary Design Phase of the bridge design, the designer shall engage the Bridge Design Engineer in discussions related to the establishment of the size and velocity of the vessel to be used in the bridge security analysis for a specific site. |