3003 W CASINO RD BLDG 45-06 2025-07-17

SITTS & HILL ENGINEERS, INC. TACOMA, WASHINGTON (253)474-9449 JOB: 17659 DESIGNED: EMF DATE: 01/13/2019 3° PROJECT: SITE PUMPED INDUSTRIAL WASTE CHECKED: BKL DATE: 01/13/2019 Trench Base Slab: , The trench base slab shall be 12" thick, and the overcut replacement slab on grade on either side of the trench shall match the thickness of the existing slab on grade. The longitudinal reinforcing in the proposed trench is checked for its ability to achieve the same flexural capacity as the removed portion of the existing reinforced slab on grade adjacent to the basement wall. The 12'-0" wide section of the existing slab adjacent to the basement wall is reinforced with #9 reinforcing bars at 4" O.C. at the bottom of the slab and #5 reinforcing bars at 12" O.C. at the top of the slab, and a 7'-0" section of this slab will be removed to construct the new trench. Per the attached Enercalc analysis, the flexural capacity of the total section is 998 kip-ft. The equivalent flexural capacity of the trench, calculated by idealizing the trench walls and slabs as a T-beam, has a flexural capacity of 1080 kip-ft per the attached Enercalc analysis. This indicates that the new trench will exceed the flexural stiffness of the section of the existing slab that will be removed. The trench base slab, wall, and replacement slab on grade reinforcement will be doweled into the existing basement wall with alternating top and bottom bars to provide shear and flexural stiffness at the interface. The replacement slab on grade reinforcement will be doweled into the existing slab on grade with alternating top and bottom bars to provide shear transfer and some measure of flexural stiffness at the interface. The replacement-existing slab on grade joint will be underlain with CDF or concrete to provide additional stiffness at the interface. The trench base slab was also checked as a retaining wall using the software program RetainPro. Soil and loading properties were assigned to the model per the values provided in the reference Geotechnical report for the site attached in Appendix A. The wheel load was applied as a linear live load to the top of the 2'-0" tall retaining wall, and the load is calculated below assuming a 1:1 load distribution through the wall to the base of the slab. A surcharge load of 1000psf was applied in to account for the second set of wheels at the main strut. This surcharge load was calculated by multiplying the 250psf surcharge load per AASHTO LRFD Bridge Design Specifications Table 3.11.6.4-2 by the ratio of two wheels of main strut load and an HS-20 truck axle load. The retaining wall toe width is checked as 2/3 the width of the trench. WLL:= = 109(l8 pl f 6 ft Slab and walls of 12" thickness reinforced with #5 bars at 6" O.C. top and bottom and each face are found to be adequate for the design loads per the attached RetainPro analysis. The maximum soil bearing pressure was found to be 3886psf, which is deemed to be adequate given the short term nature of the wheel loading. This assumption is also justified by the maximum allowable mat slab design soil bearing value of 4000psf given in the reference Geotechnical report. I I 1 I I