Laserfiche WebLink
Hazeltine Mine Spilway,Adams County <br /> ELE 6'ATIO,V CHANGE <br /> The original designed spillway had a capacity of 7.I00 cubic feet per second (cfs) with one foot of <br /> free board The new design calls for the spillway crest to be raised 1 foot (from 5,039.8 to 5,040.8 <br /> feet on the riverside), but will have the same cross sectional area Thus the capacity remains the <br /> same but there is no Freeboard <br /> CONCRETE APRON <br /> The concrete apron on the spillway crest will be t foot in thickness and reinforced with No. 4 rebar <br /> I8-inches on center. The reinforcement will be structurally tied into the vertical, concrete cutoff wait <br /> and ribbed center bulb PVC water stop will span cold joint between the cutoff wall and the apron <br /> The concrete apron was designed to resist uplift from flows over the spillway crest. The analysis was <br /> conducted using information published in the USBR publications Uplift and C rack Flow Resulting <br /> froin High Velocity Discharges Over Open Offset Joints (DSO-07-07) and Design Stcindarcl 14 <br /> .=lppiu-tenaiit Sttztctztt,e.s for Dates (,Spillways anct Outlet Works). An uplift force may occur on a <br /> concrete slab when there is an offset joint. This force is counteracted by the weight of concrete and <br /> weight of Neater at the joint. Using the methodology in the publication, the uplift force and resisting <br /> forces were calculated for the concrete slab. The maximum flow velocity was estimated to be <br /> approximately 20 feet per second at a flow depth of 2 feet. The calculations show that a 12 inch <br /> thick slab has a factor of safety of 1.1 for resistance to uplift forces. <br /> Uplift calculations are provided in Attaclunent 2 of this memo. <br /> Attachment 1 Design Memo January 21, 2008 and Riprap Sizing Letter April 7, 2008 <br /> Attachment 2 Additional Calculations <br /> P 'iJ!1 i _ -.�-0_ll� S;'ii�• :•,iS�xlurte Si i!M.� IIr,�L•:,.,?doc <br /> 2 <br />