Laserfiche WebLink
AMENDMENT <br />Coddle Creek Reservoir <br />October 22, 1993 <br />Page 2 <br /> <br />1.5.9.2 <br /> <br />1.5.9.3 <br /> <br />1.5.9.4 <br /> <br />Spillway Slab Evaluation - During the construction of the principal <br />spillway, it was discovered that the Contractor had an error in <br />construction that resulted in the upper left and lower left coruers of two <br />adjacent spillway slabs being constructed five (5) inches too high. The <br />situation required additional analysis of the impacts of the construction <br />error and review of proposed solutions. Construction of the remaining <br />two slabs was delayed several months during the analysis and resulting <br />repairs. <br /> <br />HDR incurred additional contract administration costs in the amount of <br />$12,070 during the evaluations of the spillway slab construction error and <br />negotiations that resulted in the successful resolution of the construction <br />error. <br /> <br />Piezometer Evaluation - During the latter stages of the dam construction, <br />it was discovered that several of the piezometers (instrumentation installed <br />in the dam core to measure the level of groundwater in the dam) installed <br />had unusually high water levels and one piezometer was flowing artesian. <br />The possible causes of these high levels had several implications, some of <br />which were potentially very serious (i.e. stability of the dam). <br /> <br />Extensive additional efforts were undertaken including data collection over <br />several months, installation of additional piezometers by Law Engineering, <br />and detailed analysis of the data to detemdne to extent of the problem, if <br />any. <br /> <br />It was determined that the high water levels were due to excessive pore <br />pressures developed within the dam during construction, and that the <br />problem was not serious and should dissipate with time. We have <br />continued to monitor the information from the piezometers and have <br />observed that the water levels have in fact steadily lowered as predicted. <br />Monitoring will continue as necessary. <br /> <br />HDR incurred additional contract administration costs in the amount of <br />$16,975 during the evaluations of the elevated piezometer levels. <br /> <br />Additional Clearing Contract Administration Fee - HDR's agreement with <br />Cabarrus County for Engineering Services during construction covers the <br />period of the dam construction contract and was developed on the <br />assumption the clearing contract would run concurrently with the final <br /> <br /> <br />