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Home My WebLink AboutBLD2017-00534 Structural Evaluation Report - BLD Engineering / Geo-tech Reports - 4/14/2017 STRUCTURAL EVALUATION REPORT PROPOSED GARAGE STEVEN HAWKINS 12780 NE NORTH SHORE ROAD PARCEL 32234-50-00038 BELFAIR, WASHINGTON Prepared for: Morgan-Built Homes 10233 Yates Lane NW Bremerton, Washington 98312 Prepared by: Envirotech Engineering PO Box 984 Belfair, WA 98528 360-275-9374 CLYI) AIs Sy�� 4304 NAL Project Number: 1747 April 14, 2017 Introduction Envirotech Engineering (Envirotech) completed this structural engineering assessment for a planned 2-story garage located at 12780 NE North Shore Road (Parcel 32234-50- 00038) in Belfair, Washington. The proposed structure will be 2-stories, and an approximate building envelope of 26 feet by 24 feet. Engineering Analysis The following analysis provides methods and calculations for this project, and mostly references the 2000 Residential Structural Design Guide by the US Department of Housing and Urban Development, utilizing working stress design. This design guide was used for analysis only. The structural design of this project meets or exceeds the 2015 IBC. Design Loads - The vertical loads of the structure provided below accounts for the factored dead loads and factored live loads. Snow=25 psf live Roof= 15 psf dead Floors=40 psf live Floors = 12 psf dead Decks = 10 psf dead Decks = 60 plf live Walls= 10 psf dead Wind= 85 mph Seismic = Category D2 Lower Story Lateral Analysis Wind Loads - Design winds speed is 85 miles per hour(mph), which correlates to the peak g p p gust (V). Since the project is a two story structure, a velocity pressure exposure coefficient (Kz) of 0.67 is used, along with a default value of 0.85 for the wind directionality factor(Kd). The basic wind velocity pressure (K) is determined as follows: K=0.00256KdKzV^2 = 0.00256(0.85)(0.67)(85 mph)^2 = 10.53 psf Adjustments to the basic wind velocity pressures are as follows. A factor of 0.9 is used because the structure is within a non-hurricane environment, and a factor of 1.4 is used because of the potential open terrain and/or near a body of water. K= 0.9(l.4)(10.53 psf) = 13.27 psf The wind velocity pressure is divided into two categories for the structures` vertical projections; wall (Kw), and roof(Kr). For vertical walls and roofs with a 5:12 pitch, the Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair, Washington 98528 Pagel 360-275-9374 lateral pressure coefficient is 1.2 and 0.33, respectively. Kw= 1.2(13.27 psf) = 15.92 psf Kr=0.43(13.27 psf) = 5.17 psf Both directions are considered below. Vertical Projected Area — The vertical projected area is estimated per the construction plans. Direction A wall VPA= wall len th(1/2 lower story height ht + upper story height) = 26ft(1/2 * 10ft+ 8ft) = 338 sf Direction A roof VPA= 1/z(building width)(roof pitch)(building length) _ %(24ft)(5/12)(26ft) = 130 sf Direction B wall VPA= wall length(1/2 lower story height + upper story height) + area of gabled end= 24ft(1/2 * 5ft+ 8ft) + 60 sf= 372 sf Wind Shear Load-- The estimated wind shear load for one entire building face is estimated by the product of the roof/wall VPA and their respective velocity pressures. Direction A: Kw(Wall VPA) + Kr(Roof VPA)= 15.92 psf(338 sf)+ 5.17 psf(372 sf) = 7304 lb Direction B: Kw(Wall VPA)= 15.92 psf(372 sf) = 5924 lb Earthquake Loads - Design earthquake loads can be assessed by using the following equation for the design seismic category: Ve = 1.2(Sds)(W)/R, where Ve is the lateral force exerted by an earthquake in pounds. Sds=design spectral response acceleration=2(Ss)(Fa)/3 Ss= 1.Og for a D2 seismic design category Fa= 1.1 (based on value of Ss) Sds=2(1.0g)(1.1)/3 =0.73 g W= un-factored dead load of structure in pounds. Foundation= (1281f x 0.87 sf)(150 psf) = 17066 lb Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair,Washington 98528 Page 2 360-275-9374 Floors = 624 sf(12 psf) = 7488 lb Roof= 840 sf(15 psf)= 12600 lb Walls = (230 if x 0.5 ft)(10 psf) = 1150 lb = 17066 lb+ 7488 lb+ 12600 lb+ 1150 lb= 38304 R=response modification factor =6.0 Ve= 1.2(0.73 g)(383041b)/6.0= 5596 lb Shear Capacities - Based on the exterior sheathing type, thickness, fasteners and fastener spacing, the factored shear capacity can be determined from Table 2306.2.1(1) of the IBC. 255 plf (7/16" sheathing, 8d nails @ 6" spacing at edges) 340 plf (7/16" sheathing, 8d nails @ 4" spacing at edges) 575 plf (7/16" sheathing, 8d nails @ 2" spacing at edges) Shear Conclusions - Shear capacity exceeds the designed shear load. Direction A: Fcapacity=255 plf x 16 ft=4080 lb Fdesign= 7304 lb/2 = 3652 lb Fcapacity> Fdesign o.k. Direction B: Fcapacity=255 plf x 6 ft+4870 = 6400 lb Fdesign= 5924 lb/2 = 2962 lb Fcapacity > Fdesign o.k. Upper Story Lateral Analysis Wind Loads - Design wind speed is 85 miles per hour(mph), which correlates to the peak gust (V). For one story, velocity pressure exposure coefficient (Kz) of 0.6 is used, along with a default value of 0.85 for the wind directionality factor (Kd). The basic wind velocity pressure (K) is determined as follows: K= 0.00256KdKzV^2 = 0.00256(0.85)(0.6)(85 mph)^2 = 9.43 psf Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair, Washington 98528 Page 3 360-275-9374 Adjustments to the basic wind velocity pressures are as follows. A factor of 0.9 is used because the structure is within a non-hurricane environment, and a factor of 1.4 is used because of the potential open terrain and/or near a body of water. K= 0.9(1.4)(9.43 psf) = 11.88 psf The wind velocity pressure is divided into two categories for the structures` vertical projections; wall (Kw), and roof(Kr). For vertical walls and roofs with a 3:12 pitch, the lateral pressure coefficient is 1.2 and 0.3, respectively. Kw= 1.2(11.88 psf) = 14.26 psf Kr= 0.43(11.88 psf) = 5.11 psf Both directions are considered below. Vertical Projected Area — The vertical projected area is estimated per the construction plans. Direction A wall VPA= wall length(upper story height)=26ft(8ft) = 208 sf Direction A roof VPA= %Z(building width)(roof pitch)(building length) _ '/z(24ft)(5/12)(26ft) = 130sf Direction B wall VPA= wall length(upper story height) + area of gabled end = 24ft 8ft + 60 sf=252sf Wind Shear Load - The estimated shear load for one wall is estimated by the product of the roof/wall VPA and their respective velocity pressures. Direction A: Kw(Wall VPA) + Kr(Roof VPA) = 14.26 psf(208 sf) + 5.11 psf(130 sf) = 3630 lb Direction B: Kw(Wall VPA) = 14.26 psf(252 sf) = 3594 lb Earthquake Loads - Design earthquake loads can be assessed by using the following equation for a seismic design category of D2: Ve = 1.2(Sds)(W)/R, where Ve is the lateral force exerted by an earthquake in pounds. Sds=design spectral response acceleration= 2(Ss)(Fa)/3 Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair,Washington 98528 Page 4 360-275-9374 I Ss= 1.Og for a D2 seismic design category Fa= 1.1 (based on value of Ss) Sds=2(1.0g)(1.1)/3 = 0.73 g W=un-factored dead load of structure in pounds. = 840 sf(15 psf) + 624 sf(12 psf) + 150 sf(10 psf) =20588 lb R=response modification factor = 6.0 Ve = 1.2(0.73 g)(20588 lb)/6.0 = 3006 lb Shear Capacities - Based on the exterior sheathing type, thickness, fasteners and fastener spacing, the factored shear capacity can be determined from Table 2306.2.1(1) of the IBC. 255 plf (7/16" sheathing, 8d nails @ 6" spacing at edges) 340 plf (7/16" sheathing, 8d nails @ 4" spacing at edges) 575 plf (7/16" sheathing, 8d nails @ 2" spacing at edges) Shear Conclusions-- Shear capacity exceeds the designed shear load. Direction A: Fcapacity=255 plf x 8 ft=2550 lb Fdesign= 3630 lb/2 = 1815 lb Fcapacity> Fdesign o.k. Direction B: Fcapacity=255 plf x 10 ft= 25501b Fdesign= 3594 lb/2 = 1797 lb Fcapacity > Fdesign o.k. Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair,Washington 98528 Page 5 360-275-9374 STEEL FLOOR BEAM ANALYSIS Load Parameters DL 12 psf LL 40 psf SL 0 psf RL 0 psf Maximum Bending Moment(ft- Beam Parameters Ib Length (1) 13.000 ft Span, L 24.00 ft PL/4(point load) 0 ft-lb Moment of Elasticity, E 29,000,000 psi wL^2/8 (dist. Load) 73,382 ft-lb Moment of Inertia, 1 341.0 inA4 El 9889000000 psi Mmax Total 73,382 ft-lb Bending Moment Capacity(ft- Support ff lb (ff=fixed on ends, c=cantilever ffc=fixed on ends and center) Bending Design Value, Fb 0 psi Repetative Member factor, Cr 1.15 M=fb*S 280,000 ft-lb Size factor, CF 1.0 (PER AISC TABLE 3-2) M > Load Duration factor, CD 0.9 Mmax Beam Stability factor, CL 1.0 Cv 1.0 280,000 > 73,382 o.k. breadth, b 0.000 in depth, d 0.000 in Deflection Applied Loads(lb, lb/ft) PL^3/48E1 0 in Point Load, P 0 5wL^4/384E1 0.76937 in P Location (c,x) c c=center of beam Total Deflection 0.76937 in x=load dist from furthest support 12.0 Allowable Deflection 0.8 in Distributed Load,w 1,019.2 plf Deflection<Allow ok Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair,Washington 98528 Page 6 360-275-9374 UPPER WINDOW HEADER GABLE ANALYSIS Load Parameters DL 0 psf LL 0 psf SL 25 psf RL 15 psf Maximum Bending Moment(ft- Beam Parameters lb) Length (1) 4.000 ft Span, L 8.00 ft PL/4(point load) 0 ft-lb Moment of Elasticity, E 1,700,000 psi wL^2/8 (dist. Load) 1,280 ft-lb Moment of Inertia, 1 105.5 inA4 El 1.79E+08 psi Mmax Total 1,280 ft-lb Bending Moment Capacity(ft- Support ff lb) (ff=fixed on ends, c=cantilever ffc=fixed on ends and center) fb=Fb*Cr*...*Cv 932 psi S=bd^2/6 0.0163 cf Bending Design Value, Fb 900 psi Repetative Member factor,Cr 1.15 M=fb*S 2,183 ft-lb Size factor, CF 1.0 M > Load Duration factor,CD 0.9 Mmax Beam Stability factor,CL 1.0 Cv 1.0 2,183 > 1,280. o.k. breadth, b 3.000 in depth, d 7.500 in Deflection Applied Loads(Ib, lb/ft) PL^3/48EI 0 in Point Load, P 0 5wL^4/384E1 0.08224 in P Location (c,x) c c=center of beam Total Deflection 0.08224 in x=load dist from furthest support 12.0 Allowable Deflection 0.26667 in Distributed Load, w 160.0 plf Deflection<Allow ok Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair, Washington 98528 Page 7 360-275-9374 GARAGE HEADER ANALYSIS Load Parameters DL 12 psf LL 40 psf SL 25 psf RL 15 psf Maximum Bending Moment Beam Parameters fftAtl Length (1) F 2.000 Span, L, F 16.000 Length (1) R 15.000 ft Pab/L 25344 ft-lb Span, L R 16.00 ft wL^2/8 (dist. Load) F 3,328 ft-lb Moment of Elasticity, E 1,800,000 psi wL^2/8 (dist. Load) R 19,200 ft-lb Moment of Inertia, 1 2,490.8 in^4 El 4.48E+09 psi Mmax Total 47,872 ft-lb Bending Moment Capacity(ft- Support ff lb) (ff=fixed on ends, c=cantilever ffc=fixed on ends and center) fb=Fb*Cr*...*Cv 2,484 psi S=bdA2/6 0.1602 cf Bending Design Value, Fb 2,400 psi Repetative Member factor,Cr 1.15 M=fb*S 57,287 ft-lb Size factor,CF 1.0 M > Load Duration factor, CD 0.9 Mmax Beam Stability factor,CL 1.0 Cv 1.0 57,287 > 47,872 o.k. breadth, b 5.125 in depth, d 18.000 in Deflection Applied Loads(Ib, lb/ft) PL^3/48E1 0.145 in Point Load, P 8,448 5wL^4/384E1 0.23154 in P Location c x c c=center of beam Total Deflection 0.37654 in x=load dist from furthest support 12.0 Allowable Deflection 0.53333 in Distributed Load,w, FLOOR 104.0 plf Deflection<Allow ok Distributed load,w, Roof 600.000 PLF a 12.000 ft b 4.000 ft Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair, Washington 98528 Page 8 360-275-9374 BEAM ANALYSIS Load Parameters DL 0 psf LL 0 psf SL 25 psf RL 15 psf Maximum Bending Moment(ft- Beam Parameters lb). Length (1) 15.000 ft Span, L 8.00 ft PL/4(point load) 0 ft-lb Moment of Elasticity, E 1,700,000 psi wL^2/8(dist. Load) 4,800 ft-lb Moment of Inertia, 1 443.6 in^4 El 7.54E+08 psi Mmax Total 4,800 ft-lb Bendiniz Moment Capacity(ft- Support ff lb) (ff=fixed on ends, c=cantilever ffc=fixed on ends and center) fb=Fb*Cr*...*Cv 932 psi S=bdA2/6 0.0446 cf Bending Design Value, Fb 900 psi Repetative Member factor,Cr 1.15 M=fb*S 5,988 ft-lb Size factor, CF 1.0 M > Load Duration factor,CD 0.9 Mmax Beam Stability factor,CL 1.0 Cv 1.0 5,988 > 4,800 o.k. breadth, b 3.500 in depth, d 11.500 in Deflection Applied Loads (Ib, lb/ft) PLA3/48E1 0 in Point Load, P 0 5wL^4/384E1 0.07333 in P Location (c,x) c c=center of beam Total Deflection 0.07333 in x=load dist from furthest support 12.0 Allowable Deflection 0.26667 in Distributed Load, w 600.0 plf Deflection<Allow ok Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair,Washington 98528 Page 9 360-275-9374 LOWER EXTERIOR DOOR HEADER ANALYSIS Load Parameters DL 12 psf LL 40 psf SL 25 psf RL 15 psf Maximum Bending Moment(ft- Beam Parameters lb) Length I F 2.000 Span, L, F 3.000 Length (1) R 15.000 ft Span, L R 3.00 ft wLA2/8 (dist. Load) F 117 ft-lb Moment of Elasticity, E 1,700,000 psi wL^2/8 (dist. Load) R 675 ft-lb Moment of Inertia, 1 149.3 in^4 El 2.54E+08 psi Mmax Total 792 ft-lb Bending Moment Capacity(ft- Support ff lb) (ff=fixed on ends, c=cantilever ffc=fixed on ends and center) fb=Fb*Cr*...*Cv 932 psi S=bd^2/6 0.0216 cf Bending Design Value, Fb 900 psi Repetative Member factor, Cr 1.15 M=fb*S 2,898 ft-lb Size factor, CF 1.0 M > Load Duration factor, CD 0.9 Mmax Beam Stability factor, CL 1.0 Cv 1.0 2,898 > 792 o.k. breadth, b 3.500 in depth, d 8.000 in Deflection Applied Loads(lb, lb/ft) PL^3/48E1 0 in Point Load, P 0 5wL^4/384E1 0.00075 in P Location (c,x) c c=center of beam Total Deflection 0.00075 in x=load dist from furthest support 12.0 Allowable Deflection 0.1 in Distributed Load,w, FLOOR 104.0 plf Deflection<Allow ok Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair,Washington 98528 Page 10 360-275-9374 ISOLATED FOOTING ANALYSIS COLUMNINPUTS Pu (lb) 13764 design column load m (in) 5.5 column width (parallel to B) n (in) 5.5 column length (parallel to L) FOUNDATION GEOMETRY B(in) 36 footing width (short side) L(in) 36 footing length (long side) h (in) 16 footing depth CONCRETE AND STEEL fc(psi) 2500 28-day compressive strength of concrete cp 0.85 capacity reduction factor for shear cp 0.9 capacity reduction factor for steel reinforcement effective depth; distance from top of footing to average depth of two d (in) 11.5 perpendicular steel layers fy(psi) 40000 yield strength of steel f 0.002 steel yield stress ratio x-x bars 0.5 rebar diameter in inches, db y-y bars 0.5 " x-x area 0.2 rebar area in inches y-y area 0.2 " cover(in) 11 distance between bottom of bars and bottom of footing cover2 (in) 13 depth above bottom of reinforcement R 1 epoxy coating factor y 0.8 size factor BEARING PRESSURE Af(in2) 1296 design footing area; B*L qu (psi) 10.62 ultimate pressure under footing; Pu/Af qu (psf) 1529 o.k. ALLOWABLE CONCRETE SHEAR STRESS b1 (in) 17 m + d b2 (in) 17 n + d Ap (in2) 782 critical area in punching shear; 2(b1+b2)d R (lb) 3069 resultant of soil pressure distribution; [Pu(b1)(b2)]/Af Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair,Washington 98528 Page 11 360-275-9374 vu (psi) 13.68 punching hear stress; -R /A p g s ess; (pu ) p vc(psi) 54 allowable concrete shear stress; (2+y) SQRT(fc) where y is min{2, 4/(n/m), 40d/(Ap/d)) = 2 vu <cpvc o.k. FOOTING DEPTH FOR ONE-WAY SHEAR STRESS hl (in) 10 minimum footing thickness; 6 + dia. of x-x bars+ dia. of y-y bars+ 3 h > h1 o.k. STEEL REINFORCEMENT A 1.15 initial lamda; 0.1 d 11 (in) 15.25 critical section for steel parallel to x-x; (L-n)/2 12 (in) 15.25 critical section for steel parallel to y-y; (B-m)/2 Mu (lb-in) 44458 factored moment in column at juncture in x-x; quBl^/2 Mu (lb-in) 44458 factored moment in column at juncture in y-y; quLl^/2 As (in2) 0.1193 initial area of steel in x-x direction; Mu/(gfy(d-A)) As (in2) 0.1193 initial area of steel in y-y direction; Mu/((pfy(d-A)) Ac(in2) 2.25 area of concrete in x-x direction; fyAs/0.85fc Ac(in2) 2.25 area of concrete in y-y direction; fyAs/0.85fc A 0.03 iterative lamda; Ac/26 x-x A 0.03 iterative lamda; Ac/21- y-y As(in2) 0.1077 revised steel area in x-x direction; Mu/((pfy(d-A)) As (in2) 0.1077 revised steel area in y-y direction; Mu/(gfy(d-A)) Amin (in2) 1.152 minimum steel area for x-x bars; L*h*f Amin (in2) 1.152 minimum steel area for y-y bars; B*h*f use Amin for x-x bars 5.76 MIN BARS use Amin for y-y bars 6.76 MIN BARS Id (in) 19.2 bar length Id min (in) 12 minimum bar length Minimum rebar length = 19.2 in 3h (in) 48 18 Maximum rebar spacing = 18 in Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County,Washington Belfair,Washington 98528 Page 12 360-275-9374 Retaining Wall Soil Parameters Structural Parameters y = 134 psf Wall Support: Fixed-fixed cP = 34 ° 0.75 in wall flexural rebars vertical, diameter ca = 20 psf 0.441786 in2 wall flexural rebars vertical, area #4 wall temperature rebars horizontal, Pore Pressure: No 0.75 in diameter Earth Pressure: At-rest 0.441786 in2 #4 wall temperature rebars horizontal, (3 = 0 ° 0.75 in #4 footing rebars, diameter yw= 62.4 psf 0.441786 in2 #4 footing rebars, area 0.9 strength reduction factor, flexural 0.85 strength reduction factor, shear fy = 60 ksi yield stress in steel reinfort Load Inputs 0.0018 yield stress ratio q 0 psf fc = 2500 psi concrete compressive stre DL 750 Ib/ft 3 in reinforcement steel cover LL 40 Ib/ft yc = 150 pcf concrete unit weight w 10000 lb Soil Conclusions K 0.44 Wall Geometry Ke 0.25 B = 48 in b 22.67 h = 8 in W 0.00 b = 12 in Rs1 2953.41 H = 10 ft RsH 1 2725.29 t= 8 in RsV1 1138.15 D = 0 in Rw 0.00 n = 2.83 in Rq 0.00 Key: No RqH &00 RqV 0.00 Re 1277.83 Rs2 0.00 RsH2 O.00 RsV2 0.00 Sliding Fr= (FWi + RsV1 + RgV)tan5 + cA + RsH2 + RsV2 3601 Ib/ft Fs = RsH1 + RqH + Re + Rw 2725 Ib/ft F.S.static = Fr/ Fs 1.5 OK F.S.dynamic = Fr/ (Fs + Re) 1.1 OK Overturning Mr= IWixi + RsH2y2 + RsV2xsV2 + RsV1 + RgVxsV1 11852 lb Mo = RsH1yl + Rwyl + RgHyq 9084 lb F.S.static = Mr/ Mo 1.6 OK F.S.dynamic = Mr/ (Mo + Reye) 1.1 OK Flexural Steel in Wall (vertical) Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair, Washington 98528 Page 13 360-275-9374 L Wall load from resultant earth pressure = 1.4*(Rsl + Rw+ Rq +Re) = 5923.7 Ib/ft Mu = (Rsl + Rw+ Rq)*(H-h)^2/20 = 12863.7 ft-lb As = Mu*12/(strength reduction factor, shear*fy*1000*(t - 3 - 0.1*(t-3))) = 0.64 in2 Ac= fy*1 000*As/0.85/f c = 17.9 in2 Mn = As*fy*l000*(t-3 - 0.1*(t- 3)) = 171516.4 in-lb cpMn = strength reduction factor, flexural*Mn/12 = 12863.7 ft-lb As2 = As*Mu/cpMn = 0.64 in2 Number of rebars per foot 1.44 rebar spacing 13.20 in Temperature Steel in Wall (horizontal) As = yield stress ratio*b*dc = 0.9324 in2 Number of rebars per foot= Asi#4 footing rebars, area = 2.11 rebar spacing = 12/number rebars per foot = 52.65 in Wall Footing Pu = 1.4*DU12+ 1.7*LU12 + RsV1/12+ RsV2/12+ (yH(B/12 -t/12- n/12))/12 +q/12 = 533.90 lb/in qu = Pu/B = 11.12 psi Vc = 2*fcl/2 = 100.00 psi d = h - reinforcement steel cover- 1.5*#4 footing rebars, diameter= 3.88 in Vu = qu/d*((B-t)/2-d) = 46.29 psi oVc= Vc*strength reduction factor, shear= 85.00 psi ovc > Vu o.k. Flexural Steel in Wall Footing Mu = qu*(B-t)2/8 2224.58 in-lb As = Mu/(strength reduction factor, flexural*fy*900*d) = 0.0118 in2 Ac = As*fy*1000/0.85/fc= 0.3335 in2 A =Ac/2/b = 0.0139 in As2 = Mu/(strength reduction factor, flexural*fy*1000(d-A)) = 0.0107 in2 As = yield stress ratio*b*hc = 0.0999 in2 Number of rebars per foot=As2/#4 footing rebars, area = 0.2261 P 9 rebar spacing = 12/number of rebars per foot= 53.07 in Temperature Steel in Wall Footing As = ycBh = 0.69 in2 Number of rebars per foot= As/#4 footing rebars, area =. 1.56 Spacing = 1/number of rebars per foot*12 = 7.67 in As2 = yield stress ratio*B*h = 0.69 in2 Number of rebars per foot= As2/#4 footing rebars, area = 1.56 Minimum spacing = 1/number of rebars per foot*12 = 7.67 in Maximum spacing = 5*h = 18 in Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair, Washington 98528 Page 14 360-275-9374 rebar spacing Choose in Glossary y = soil unit weight q = surcharges (P = angle of internal friction DL = dead loads on wall ca = adhesion LL = live loads on wall extra sliding/overturning Pore Pressure: pressures due to water w= resistance Earth Pressure: active, passive, or at rest R = angle of backfill yw = water unit weight fy = yield stress in steel reinfor fc= concrete compressive stre B = fuutiny width yc= concrete unit weight h = footing thickness b = footing length Fr= resistance against sliding H = height of wall Fs = sliding forces t = wall thickness F.S.static = Factor of Safety (static) D = foodting depth F.S.dynamic= Factor of Safety (dynamic; n = footing length beyond wall face Key: "notched" footing for sliding resistence Mr= resistance against overtun Mo = overturning forces F.S.static = Factor of Safety (static) F.S.dynamic= Factor of Safety (dynamic; K= earth pressure coefficient Mu = Maximum moment Ke = earthquake pressure coefficient As = Area of steel b = Ac = Area of concrete at stress 4' = Mn = Nominal moment capacity Rs1 = soil partical resultant force cpMn = Design moment capacity RsH1 = horizontal resultant force As2 = New area of steel RsV1 = vertical resultant force Rw = pore water resultant force Pu = Factored dead and live loz Rq = surcharge resultant force qu = Load per unit length of wa Shear strength capacity of RqH = horizontal surcharge component Vc = concrete vertical surcharge RqV = component d = Effective footing depth Re = earthquake resultand force Vu = Shear stress at critical sec Rs2 = opposite soil partical relultant force ovc = Reduced shear strength c, RsH2 = horizontal component RsV2 = vertical component Hawkins Structure Envirotech Engineering 12780 NE North Shore Road PO Box 984 Mason County, Washington Belfair, Washington 98528 Page 15 360-275-9374