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Microsoft Word - 578 Park Ave - Micropile Wall - 9-30-21.doc700 South Fulton Street, Salt Lake City, Utah 84104 (801) 908-7664 (801) 908-7681 fax Engineering Report – Micro pile Retaining Wall, Braudis Residence, 578 Park Ave, Park City, Utah. 9/30/2021 Page 1 of 4 September 30, 2021 To: Kevin Garside Advanced Shoring & Underpinning Inc. Re: Engineering Submittal Micro Pile Retaining Wall Braudis Residence 578 Park Ave Park City, Utah Mr. Garside, This report details the design of a new proposed micro pile retaining wall located on the south side of the subject project building lot. General The project consists of constructing a new micro pile retaining wall along a portion of the south property line of the subject lot. The wall will be built and incorporated into an existing micro pile shoring wall that was installed during the previous excavation phase of the project. This existing wall is now fully backfilled and buried with only the top ends of the micro pile tendons exposed. The new wall will tie into the existing micro pile tendons using couplers. The new retaining wall will extend 5.5 feet above the bottom of wall (BOW) which is at a finish grade (slab) elevation of 7031.5 making the top of wall (TOW) elevation 7037. The wall will be backfilled with clean free draining gravel with a finish uphill slope of a maximum of 2:1 (H:V) up to the existing house foundation wall or existing rock retaining wall (on the east end of the wall). The micro pile retaining wall will consist of two vertical rows of extended micro piles from the existing micro pile shoring wall embedded in cut and formed reinforced shotcrete. The wall length is approximately 45 feet. Engineering Report – Micro pile Retaining Wall, Braudis Residence, 578 Park Ave, Park City, Utah. 9/30/2021 Page 2 of 4 700 South Fulton Street, Salt Lake City, Utah 84104 (801) 908-7664 (801) 908-7681 fax Loads The wall will be subject to seismic load as per USGS seismic mapping and IBC design codes which have been presented on the attached SEA seismic load determination. These values have been used in our design calculations. We do not expect any external loading from the existing adjacent house footing, the bottom of which is at the same elevation as the bottom of the proposed micro pile retaining wall. Design Details We have used the most critical cross section in our design calculations which is where the existing adjacent rock foundation wall is located (east end of wall). This wall is located approximately 3 feet horizontally from the back of the proposed micro pile wall and extends approximately 3 feet above the top of the proposed micro pile wall. The micro pile retaining wall design is incorporating and vertically extending the existing micro pile/shotcrete shoring wall that was used for excavation support during the construction of the new house foundation. This wall is a 24 inch wide retaining wall consisting 3 vertical column rows of micro piles that together with the reinforced shotcrete provide lateral support for the supported soils. This existing wall is fully backfilled and the micro piles extend approximately 45 feet down from the finish grade (slab) which is 7031.5. Only the outside column rows of the existing micro piles will be used for the new micro pile retaining wall of which one column row will be in tension only and one in compression. The existing micro piles consist of T40N hollow self drilling bars grouted in 6 inch minimum diameter holes and encased in shotcrete for the top 15 feet. Most of the micro piles have the bottom end embedded in bedrock. The maximum allowable design capacity of these micro piles are 68.3 kips in compression and 72.6 kips in tension following IBC design requirements and our geotechnical capacity calculations. Wall bending moments and shear loads have been calculated using Shoring Suite software. These loads have then been used to calculate the allowable compression and tension loads exerted on the micro pile tendons. We have verified that the proposed micro piles will meet the structural capacity requirements (axial loads and shear loads) as well as the geotechnical bonded lengths. Soil Conditions There are two soil conditions that affect the proposed new micro pile wall. At the critical cross section located on the east end where the existing rock retaining wall is located, there will be clean free draining gravel directly behind the new wall up to the existing rock retaining Engineering Report – Micro pile Retaining Wall, Braudis Residence, 578 Park Ave, Park City, Utah. 9/30/2021 Page 3 of 4 700 South Fulton Street, Salt Lake City, Utah 84104 (801) 908-7664 (801) 908-7681 fax wall where the backfill will consist of local back fill like clayey gravel like mentioned in the soil investigation by AGEC dated June 8, 2020. The wall portion that runs along the existing adjacent house foundation will only consist of free draining clean gravel up to the existing house foundation. We have used the following soil parameters in our design soil model: Clayey Gravel Soil Density: 125 pcf Friction Angle: 32 degrees Cohesion: 200 psf Backfill - Gravel Soil Density: 130 pcf Friction Angle: 28 degrees Cohesion: 0 psf Design Configuration The final design consists of two vertical rows of Titan T40N tendons that are coupled to the top ends of the existing micro piles embedded in a 2 foot thick layer of cut reinforced shotcrete. Shotcrete shall be a 4,000 psi min 28-day strength mix reinforced with two vertical mats of #4 rebar placed at 12 inches on center each way with the mats spaced at 14 inches. Design calculations and results from the slope stability and facing analyses as well as design sketches have been included as an attachment to this report. We represent that these services were performed in a manner consistent with the level of care and skill normally exercised by other professional consultants under similar circumstances. No other representation, expressed or implied, and no warranty of guarantee is included or intended. We do not assume responsibility for the accuracy of information provided by others. 700 South Fulton Street, Salt Lake City, Utah 84104 (801) 908-7664 (801) 908-7681 fax Engineering Report – Micro pile Retaining Wall, Braudis Residence, 578 Park Ave, Park City, Utah. 9/30/2021 Page 4 of 4 We appreciate the opportunity to provide design services for this project. Please contact us if you have any questions or need further clarifications. Respectfully submitted, PDA Engineering Inc. Per-Ole Danfors, P.E Attachments: Shop Drawings Design Calculations – Shoring Suite Design Calculations – Hand Calculations Design Calculations – Micro pile calculation spreadsheet USGS Seismic summary sheet DESIGNED: SHEET NUMBER: CHECKED: DRAWN: APPROVED: DATE:NO.DATE:DRAWN:REVISION:DESIGN:CONTRACTOR:801-908-7664801-908-7664POD MH POD Drawing IndexDrawing TitleSheet # Sheet 3 Sheet 2 Sheet 1 Site Plan General Notes Drawing Index Drawing Index Sheet 4 SHORING+UNDERPINNINGof1 Micropile Retaining Wall Braudis Residence 578 Park Avenue Park City, Utah POD578 Park Avenue, Park City, UtahMicropile Retaining Wall 4 9/30/2021 Cross Section Detail DESIGNED: SHEET NUMBER: CHECKED: DRAWN: APPROVED: DATE:DESIGN:CONTRACTOR:801-908-7664801-908-7664POD MH POD SHORING+UNDERPINNINGGeneral Notes: of2 NO.DATE:DRAWN:REVISION:General NotesPOD 1. GENERAL 1.1 The scope of work is outlined by these general notes and specifications as defined below and includes the installation of a permanent micropile retaining wall. 1.2 All wall lengths and dimensions will be in accordance with drawing details. 1.3 All materials, workmanship and construction will be in accordance with this sheet. 1.4 The General Contractor is responsible for field locating all utilities. 1.5 These drawings are the property of PDA Engineering, Inc for the proprietatry and sole installation by Advanced Shoring & Underpinning inc. and drawings or parts of drawings cannot be duplicated without written permission. 2. MICROPILE AND HARDWARE 2.1 Existing micropile tendons shall be extended by using threaded couplers matching the existing bars. 2.2 All micropile tendons shall consist of Titan 40N and shall be straight and undamaged. 2.3 Hex nuts and couplers shall conform to tendon manufacture's specifications and be capable of transferring the full tensile capacity of the tendon. 3. DRAINAGE 3.1 Retaining wall shall be backfilled with clean freedraining gravel. 3.2 Weep drains shall be placed evenly along the wall starting 5 feet in from each end and not spaced more than 7 feet horizontally. Weep drains shall have filter fabric around the end inside the backfill. 3.3 Weep drains shall exit the wall at elevation 7032 or 6 inches above the new sidewalk slab. 4. SHOTCRETE REINFORCING 4.1 Shotcrete reinforcement shall consist of #4 deformed Grade 60 reinforcing bars. Place bars at 12 inch spacing horizontally and vertically starting 6 inches down from top of wall and 6 inches back from each end of the wall. Ensure at least 2 inch shotcrete cover to exposed wall areas and 3 inches to covered wall areas. Welded wire mesh can be used for facilitating shotcrete placement but is not a structural requirement. 4.2 Ensure that shotcrete fully encapsulates the bars. 5. SHOTCRETE 5.1 Shotcrete will be Portland 1 & 2 cement, 7-8 bag mix with a minimum 28-day strength of 4000 psi. Apply the shotcrete wet with shotcrete application equipment. 5.2 Use supported backform for shotcrete and cut exposed shotcrete using shotcrete knife. 5.3 Shotcrete shall not be placed at temperatures 90 degrees or rising or 40 degrees and decreasing. Use cold weather protection if tempreatures will be under 40 degrees after placement until concrete strength has reached 4,000 psi. 5.4 Place cure sealing compound on wall after shotcrete has set. Follow manufacturers recommedations for application. 4 9/30/2021578 Park Avenue, Park City, UtahMicropile Retaining Wall New Residence 578 Park Ave Existing HousePark AvenueProperty Line (Approximate) Existing rock wall. Verify in field. New micropile shotcrete wall Property line A 5 DESIGNED: SHEET NUMBER: CHECKED: DRAWN: APPROVED: DATE:NO.DATE:DRAWN:REVISION:DESIGN:CONTRACTOR:801-908-7664801-908-7664POD MH POD SHORING+UNDERPINNINGof3Site Plan Site PlanPOD 4 9/30/2021578 Park Avenue, Park City, UtahMicropile Retaining Wall Cross SectionA 5 2" min. 7"7" 2' T40N Tendon, typ 2" Property line Existing house foundation Reinforcing Bar #4 spaced at 12" vertically and horizontally. Shotcrete 3" min. Free draining gravel backfill Weep drain. 2" Nom Sch40 pvc pipe with end covered with filter fabric. Slope at 2 % down angle. 6" Backfill with clean draning gravel. Existing cut slope. Existing new house. Proposed finish slab. TOS elevation 7031.5. New micropile retaining wall. TOW Elevation 7037. Existing micropile earth shoring wall. 35 ft deep. Coupler. Typ. Typical. Finish Grade. max 2:1 slope (H:V) DESIGNED: SHEET NUMBER: CHECKED: DRAWN: APPROVED: DATE:NO.DATE:DRAWN:REVISION:DESIGN:CONTRACTOR:801-908-7664801-908-7664POD MH PODCross Section DetailsSHORING+UNDERPINNINGof4Cross Section Detail POD 4 9/30/2021578 Park Avenue, Park City, UtahMicropile Retaining Wall ©PDA Engineering 1 of 1 Micropile Design V1.0 Design References: ACI 318-14; 2015 IBC; AISC Steel Construction Manual 14th ED. Project: Description: Date: Designed By:POD Checked By:MJH Objectives:1. Determine required bonded micropile length, Lbond 2. Determine required bearing plate area, AB 3. Determine required bearing plate thickness, treq Loads Axial Design Comp. Load, Pc (kips)27.0 Axial Design Tension Load, Pt (kips)27.0 Material Properties & Geometry f'c (ksi)4 Bar Size T40N fy-bp (ksi)36 Bit Diameter, D (in)4.5 fy (ksi)84.07 Nut Diameter, Dn (in)2.56 Assumed Grout Diameter, D' (in)6 As (in2)0.96 (reduced by corrosion) Allowable Structural Strength OD (in)1.57 Allowable Comp. Steel, Pc(s) = 0.4*fy*A's (kips)32.3 Allowable Comp. Grout, Pc(g) = 0.33*f'c*Ac (kips)36.1 Check Allowable > Load Allowable Comp. Strength, Pc = Pc(s)+Pc(g) (kips)68.3 »COMPRESSION IS OK Allowable Tension Steel, Pt(s) = 0.9*fy*A's (kips)72.6 »TENSION IS OK Maximum Steel Loss Rate* (mil/yr)0.472 Assumed Ultimate Bond Strength, BS (k/ft) Structure Design Life (yrs)75 "Soil Material"20.0 psi Sacrificial Steel (in)0.035 4.52 k/ft*Value from FHWA-NHI-00-044. Equivalent to 12 µm/yr 1. Req'd Embedment Depth Bond Strength Factor of Safety, FOS 2 Req'd bonded length, Lbond (ft)11.9 Lbond = max(Pc,Pt)*FOS/BS 2. Req'd Plate Bearing Area ACI 318-08 10.14.1 Req'd Bearing Area, Abc (in2)0.00 Req'd Bearing Area, Abt (in2)8.57 Abc = ((Pc-Pc(g))*W/(0.85*f'c))/(A2/A1)1/2 Abt = ((Pt)*W/(0.85*f'c))/(A2/A1)1/2+p*OD2/4 (A2/A1)1/2 = 2 (A2/A1)1/2 = 2 Use: ABc (in2)NA Use: ABt (in2)16 3. Req'd Bearing Plate Thickness Mmax = wl2/2 (k-in)NA Mmax = wl2/2 (k-in)0.73 w = Wb*(Pc-Pc(g))/AB (k/in)NA w = Wb*Pt/AB (k/in)2.82 l = (ABc1/2 - Dn)/2 (in)NA l = (ABt1/2 - Dn)/2 (in)0.72 Sxc-req = Mmax/(Fy-bp*.67) (in3)NA Sxt-req = Mmax/(Fy-bp*.67) (in3)0.03 tc, req = (6S x-req)1/2 (in)NA tt, req = (6Sx-req)1/2 (in)0.43 Plate Required:NA Plate Required:4''x4''x0.5'' Micropile Design Calculator 27 kip micropile 9/30/21 Bearing PlateMicropile TendonGrout 578 Park Ave - Compression/Tension Member at 15 ft down from TOW Bearing Plate Area for TensionBearing Plate Area for Compression Plate Thickness for TensionPlate Thickness for Compression Soil/Rock ProfileCorrosion Rate/Sacrificial Steel 578 Park Ave. 578 Park Ave, Park City, UT 84060, USA Latitude, Longitude: 40.645255, -111.497273 Date 9/30/2021, 4:07:41 PM Design Code Reference Document IBC-2015 Risk Category III Site Class D - Stiff Soil Type Value Description SS 0.64 MCE R ground motion. (for 0.2 second period) S1 0.214 MCE R ground motion. (for 1.0s period) SMS 0.824 Site-modified spectral acceleration value SM1 0.422 Site-modified spectral acceleration value SDS 0.55 Numeric seismic design value at 0.2 second SA SD1 0.282 Numeric seismic design value at 1.0 second SA Type Value Description SDC D Seismic design category Fa 1.288 Site amplification factor at 0.2 second Fv 1.972 Site amplification factor at 1.0 second PGA 0.253 MCE G peak ground acceleration FPGA 1.294 Site amplification factor at PGA PGAM 0.327 Site modified peak ground acceleration TL 8 Long-period transition period in seconds SsRT 0.64 Probabilistic risk-targeted ground motion. (0.2 second) SsUH 0.677 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration SsD 1.5 Factored deterministic acceleration value. (0.2 second) S1RT 0.214 Probabilistic risk-targeted ground motion. (1.0 second) S1UH 0.226 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration. S1D 0.6 Factored deterministic acceleration value. (1.0 second) PGAd 0.6 Factored deterministic acceleration value. (Peak Ground Acceleration) U.S. Seismic Design Maps https://seismicmaps.org/ 1 of 3 9/30/2021, 4:08 PM Type Value Description CRS 0.945 Mapped value of the risk coefficient at short periods CR1 0.947 Mapped value of the risk coefficient at a period of 1 s U.S. Seismic Design Maps https://seismicmaps.org/ 2 of 3 9/30/2021, 4:08 PM DISCLAIMER While the information presented on this website is believed to be correct, SEAOC /OSHPD and its sponsors and contributors assume no responsibility or liability for its accuracy. 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