SCR Pile Cap Foundation Design Using STAAD v8i Excel

摘要

To expedite the design of foundations for the SCR support structure (40 m wide x 170 m long x 85 m high) at a Southeastern U.S. coal fired power plant, a number of STAAD Pro v8i (Bentley Systems, Inc., 2008) models were developed and Excel (Microsoft 2003) spreadsheets utilized. The forces were summarized in Excel to assist in the reinforcing design. There were a large number of primary load cases which resulted in thousands of service and strength load cases that needed to be analyzed. The large amount of data generated required post processing using Excel to consolidate and summarize the information. Typically, information is copied from STAAD Pro v8i and pasted into the appropriate location in the spreadsheet, however, one spreadsheet was utilized which uses Open STAAD (A library of exposed functions) to extract the pertinent information and combine the plate forces (Mx, My & Mxy). This spreadsheet was enhanced by graphics of the foundation plates that were then color coded to represent the extent of the required reinforcing. This provided a convenient visual representation of the extents of the required reinforcing. Due to poor soil capacity and large loads, micro piles to rock were required to support the pile caps. The micro piles were modeled in STAAD Pro v8i and the forces extracted to an Excel spreadsheet which compared the values to allowable capacities. Foundation thickness was confined due to existing obstructions (feed water pipes, electrical duct banks, etc) which limited the foundation shear capacity. In a number of locations micro piles were located within d of the columns requiring a deep beam shear check of the foundation. Another spreadsheet was developed to provide this check by extracting the plate moments and shear for each load case and applying it with the appropriate deep beam shear formula. A comparison between the allowable deep beam shear and the actual was then made.