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SITTS & HILL ENGINEERS, INC. <br /> TACOMA, WASHINGTON (253)474-9449 JOB: 17659 <br /> DESIGNED: EMF DATE: 03/17/2020 6 <br /> PROJECT: SITE PUMPED INDUSTRIAL WASTE CHECKED: BKL DATE: 03/17/2020 <br /> 45-01 Exterior Trench <br /> Construction of a new trench is proposed to convey PIW piping from where it exits the 45-01 <br /> building to the existing steam line utilidor. The proposed trench will be 3'-0" wide x 2'-0" deep <br /> and will be designed to withstand HS-20 loading. The lid, walls, and base slab are checked <br /> per the following calculations. <br /> HS-20 Loading <br /> P:=32 kip HS-20 axle loading <br /> f;:=1.3 Impact factorf <br /> l <br /> P <br /> P:= =20.8 kip Half axle/wheel group load <br /> 2 <br /> w,:=20 in Tire contact width per AASHTO LRFD Bridge Design <br /> Specifications Section 3.6.1.2.5 <br /> 4:=10 in Tire contact length per AASHTO LRFD Bridge Design <br /> Specifications Section 3.6.1.2.5 <br /> P :=1.6 P=33.28 kip Factored half axle/wheel group load <br /> Trench Lid Design: <br /> The proposed trench lids will be constructed of precast concrete panels. To keep the weight <br /> and size of the panels at a manageable lifting load for a light forklift, the panels will span the <br /> trench width, typically be 5'-0" (4'-5 1/2" minimum) wide, and be 6" thick. This keeps the <br /> weight of the panels at the larger trench under 1500Ibs. Because of the width and the span of <br /> the precast panels, a single panel will only be subjected to half an axle load at any given time. <br /> The concrete panels will be reinforced and cast into a C6x13 welded channel assembly, and <br /> shear studs will be provided around the perimeter. The following limit states were checked to <br /> determine the adequacy of the precast panels: 1 <br /> Punching Shear: <br /> Punching shear is conservatively checked applying half the axle load over one tire contact area. <br /> c/):=0.75 Strength reduction factor for shear per ACI <br /> 318-14 Table 21.2.1 <br /> f',.:=4000 psi Compressive strength of concrete <br /> A:=1.0 Factor for normal-weight concrete <br /> h:=6 in Thickness of precast panel <br /> db:=0.625 in Diameter of reinforcement I <br /> ce:=1.5 in Clear cover to reinforcement <br /> d:=h—c(.-0.5 db=4.19 in Depth to reinforcement <br /> f3:=—wt =2.00 Ratio of long to short side of load area <br /> 1, <br /> I <br />