| Popis: |
This paper discusses crane-wharf interaction analysis methodology, modeling, analysis results, and conclusions for Pier E at the Port of Long Beach (POLB). The port is constructing a modern wharf at the south end of Berth E24, which includes new landfill and extension of the berth length to approximately 2,900 ft. The new wharf is designed for a pierhead and channel depth of 55 ft, will accommodate tandem lift container cranes, and meets the port's Wharf Design Criteria (WDC). According to the POLB WDC, if the crane translational period is less than twice the wharf period, a crane-wharf interaction analysis is required. Based on the wharf and crane period calculations, this analysis was required for the Pier E wharf. Therefore, a crane-wharf nonlinear time-history analysis was conducted to determine the effects of the crane on the wharf seismic displacement demand and the shear key forces between wharf segments. The wharf was initially designed with width of 175 feet to accommodate a crane with a 138-foot gage. During the final wharf design stage, the crane gage was reduced to 120 feet. The wharf design was revised for a 133-foot width. The crane-wharf interaction analysis was performed for two sets of soil conditions [upper bound (UB) and lower bound (LB)] and for three earthquake performance levels at Operating Level Earthquake (OLE), Contingency Level Earthquake (CLE), and Code-level Design Earthquake (DE). Seven design spectrum-compatible time-history motions were used for each seismic level, consisting of two horizontal (Fault Normal and Fault Parallel) components. The maximum displacements were reduced when the cranes were considered in the seismic analysis. The displacement demand of the piles is predicted to be 1.8 inches for the OLE, 5.9 inches for the CLE, and 7.5 inches for the DE. The demands are less than those found in the linked wharf analysis for all three seismic performance levels. The force demand for the shear key between wharf segments is determined to be 2,900 kips for the OLE, 5,156 kips for the CLE and 5,157 kips for the DE. These values are greater than the values found by the linked wharf analysis for all three seismic performance levels. The cranes appear to act as auxiliary mass dampers. |
