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Home My WebLink About914 Marine Dr - Technical TECHJICAL Permit 12 -23i Address °I i Ma k() nf b� Project description Ih5fcoinairt 04. blot() ca t�5kru (A-CA t n 1(197 low ►nod ha l&l Date the permit was finaled N Number ofitechnical pages a Owen Structural Engineering Inc. 220 E First Street Phone: (360) 452 -8574 Port Angeles WA 98362 Fax: (360) 457 -8020 March 14, 2012 Tom Brunoau 914 Marine Drive Port Angeles, WA 98363 Dear Tom: RE: Review of 40' x 80' X 35' -Tall Pre engineered Steel Framed Building The review of your building is general in nature without structural analysis of major components. Since the structural building plans were not available, obtaining details for analysis can be very time- consuming and determining the grades of steel would require destructive testing of samples taken from the structure. Determining the geometry of the foundation would require excavation and potential removal of a portion of the slab (reported to be 10" thick). Ground penetrating radar may be an option but that would not indicate reinforcement in the footings or potential ties from the short concrete columns into the slab. Reinforcement in the portion of the columns open on opposite sides could be determined with x -ray but that is very expensive. Magnetic rebar detection can provide some clues but is not usually definitive. Chipping concrete away to expose rebar located by such means can be done and adequate repairs can be accomplished if further investigation is desired. Although the tapered rigid frames could be measured, it is time consuming, as well as incorporating the effects of member tapering into a structural frame analysis. I did measure and perform analysis on girts, purlins, and the east endwall columns that were accessible for measurement in the upper level. Although it is common structural engineering practice to use 30 ksi yield stress on steel that is not documented, I am not aware of any pre engineered building constructed after the mid eighties with cold- formed steel members having a yield stress less than 50 ksi. Although some steel plates welded to make beams and columns are 42 ksi in pre engineered buildings, the vast majority are 50 ksi, so I will use that in this review analysis. During my overall review of your steel building I have noted items of interest that may reflect on the quality of the building and potential areas of concern based on my previous experience with "pre- engineered" steel buildings. This experience includes structural design, specification of design criteria with review of building submittals, structural analysis of existing structures often for relocation at other sites, forensic investigation of structural failures of existing buildings and consultation regarding contract disputes with metal building manufacturers. 12561 rpt s Report to Tom Brunoau March 14, 2012 Page 2 of 6 1) This is a relatively tall rigid frame building (about 31' above the base plate). This creates a lower horizontal thrust at the base with gravity loads including snow (generally this horizontal force controls) but a higher horizontal reaction with wind loads. This also means that wind load controls the haunch (where the roof beam meets the column) and its connections as compared to snow load. a. Range bracing as angles extending diagonally from the wall girts and roof purlins to the interior flange of the column and roof beam resist lateral torsional buckling under loads that produce compression in the interior flange. Flange braces near the top of the column are at each girt and from the first interior purlin on the roof beam but skipping braces at the second purlin. This would be expected with wind load controlling the negative moment at the haunch. b. The flange braces are typically on both sides of the rigid frames from the girts and purlins. Many pre engineered metal buildings just have flange braces from one side. There is just one brace on the rigid frame adjacent to the overhead door. This may still be adequate in this situation but it does take a rigorous analysis to verify the adequacy of a single -sided brace. I have investigated failures in pre engineered steel buildings due to the removal of column flange braces on both sides of a column due to overhead doors placed on both sides of the column. So, these little angles are very important in maintaining the structural integrity of your building. Columns can be designed or modified to be adequate without flange bracing by having larger flanges or a channel added to the flange(s). 2) The typical pre engineered metal building has a rigid frame spacing of 20' to 30' where the frame spacing on this building is just 16'. This, of course, reduces the stress and allows smaller rigid frame haunches and smaller girt and purlin sizes between the frames. 3) Some important details imply that the engineering design was thorough which is not always the case with pre engineered buildings. a. The end bays of the sidewalls between the last rigid frame and the endwalls have L1 x 1 bracing at the center of the girts and two fines of such lower flange bracing at the roof purlins. The bracing effect of these angles would be much greater if they were "grounded" by connecting them to a Z member placed between the Z purlins and girts with the angle 1 x 4 attached to it without such "groundings" the moment resistance of the angle and its attachment to each Z. These continuous girts and purlins have the highest positive moment in the span of the end bays. Positive moment from outward wind pressure creates compression in the inner flanges of the girts and purlins for which buckling resistance is aided by bracing. Again 12561 rpt Report to Tom Brunoau March 14, 2012 Page 3 of 6 this is the logical location for such braces as it is the location of highest stress. b. Additional roof purlins were added adjacent to another one to be in alignment with the east interior endwall columns so the horizontal reaction to wind load can be transferred into the cable bracing system of the building. This additional purlin also reduces the stress from the combination of flexure from wind uplift and compression in purlins resisting the horizontal reaction of an endwall column. This combination of effects from wind loading on roof purlins was determined to be the cause of many structural failures of pre engineered steel buildings in Darwin, Australia during a windstorm in the 1970s. 4) Without knowing the specific date of building permit application, it is not known specifically which code(s) were applicable particularly with regard to wind design loads. Not only was the Uniform Building code applicable, but different versions of different codes were acceptable alternatives at different times based on ICBO (International Conference of Building Officials) reports. The other codes that may have been in effect are ASCE 7 (American Society of Civil Engineers) and MBNA Code (Metal Building Manufacturers Association). Originally there was limited data regarding wind speeds for the coastal areas of Washington so some conservative assumptions were made until better data was available. This better wind data was used in ASCE 7 in the late 1970s and incorporated into the 1981 MBNA code and then the 1982 UBC. Unfortunately there were those who thought the old criteria based on guesswork was more appropriate so the 1985 UBC had increased wind speeds as compared to the 1982 UBC and ASCE 7 was modified to show the coast to be a special wind region to be determined by local data (e.g., the local building departments). The local data indicates the fastest mile wind speed ever recorded at Ediz Hook was 66 mph during the Columbus Day Storm on October 12 of 1962. The Coast Guard Station at Ediz Hook is an exposure "D" site, so the equivalent velocity to a typical exposure "C: site would be about 62 mph. The fastest mile design speed in the 1988 UBC is 85 mph. The fastest mile design wind speed is 75 mph in ASCE 7 and the MBNA code. Considering that the wind pressure is based on the velocity squared, the UBC results in nearly 30% more design pressure. Since the typically lower coefficients to adjust the design pressure in the MBNA code were based on tests on low rise buildings, some ICBO acceptance of the MBNA code was modified to not accept taller buildings such as yours. ANCI /ASCE7 -88 approved 11/27/90, has wind design criteria for all shapes of buildings but shows the special wind region on the north coast referring to the local jurisdiction and then instructing how the speed would be obtained. The methodology would result in a lower design wind speed rather than higher. ASCE 7 -88 has a reduction of pressure based on the area of wall (or roof) 12561 rpt Report to Tom Brunoau March 14, 2012 Page 4 of 6 contributing to the member under review (more area, less pounds per square foot) as compared to the 1988 (and 1999) UBC. However, ASCE 7 has a more severe exposure "D: for buildings within 1500 feet of large bodies of water which is more severe than the 1988 UBC where exposure "C" is the most severe. a. Computer analysis of the sidewall girts and the roof purlins, made continuous by a 2' overlap with a bolted connection, was performed. The Z 6 x 2 1 /2 x 16 ga. sidewall girts and roof purlins made continuous by overlapping at the frame are adequate based on the 1988 and 1991 UBC except for one condition. The overlap is relatively short, creating high shear stresses in the overlapped portion of the members. The combination of this shear and flexural stress from negative moment shared by both girts and by both purlins causes overstress per the cold- formed steel design specification. However, according to MBNA members' companies (those that design and produce pre- engineered buildings) this is not a problem as verified by testing and in use. Nearly every girt and purlin made continuous by overlapping in pre engineered metal buildings has this condition. b. The west simple span Z 9 x 3 x 14 ga. endwall girts are also adequate to resist wind loads based on the 1988 UBC. c. The west endwall interior columns are also adequate with 1988 UBC wind loads. ASCE 7 -88 wind criteria includes exposure "D" but allowing a coefficient reduction due to the large area of wall from which wind load would be applied creating lower design Toad on the columns. This method applies the 85 mph fastest mile wind speed (rather than the 70 mph or 75 mph for which could be argued as appropriate). However, the highest design wind pressure is outward which puts the inner flange in compression. Normally we would apply flange braces from the girts to this inner flange to stabilize it. There is some stabilization provided by the connection (if tightly bolted) of the Z9 girts to the web of these columns. In my designs I have provided similar bracing to the web of continuous monorail crane beams at suspension points from above that cause compression in the lower flange but connection directly to the lower flange would interfere with the crane trolley. However, in that case we are usually dealing with a much thicker web on a rolled "1" beam providing more stiffness to resist lateral torsional buckling and the analysis is quite involved. 5) Cable braces with eye bolts for attachment (for overall building stability rather than the above mentioned braces for member stability) at the roof sidewalls and west endwalls are at logical locations and sizes appear to be larger at locations where higher forces from lateral loads are expected. No analysis was performed to verify capacity. 12561 rpt Report to Tom Brunoau March 14, 2012 Page 5 of 6 Current wind design criteria is different than when the building was designed as the wind speeds are specified in 3- second gusts rather than fastest mile. But the most significant change was the elimination of an allowable stress increase of 1.33 to account for the low probability of occurrence. Although the current design wind gust is 85 mph by ASCE 7 -05 (referred to by the 2009 IBC as the appropriate code for wind design) it indicates that all of Clallam County is in a special wind zone. The City of Port Angeles and eastern Clallam County is specified by local jurisdictions as 100 mph wind gust_ This puts the stress level of members between 1.4 and 1.8 times the 1988 UBC resisting wind and about 1.35 times the previous ASCE 7 -88 criteria. This is very close to the difference in pressure between the 85 mph gust and 100 mph gust so the application of what could be argued as the appropriate wind speed. Western Jefferson County is rated at 85 mph gust speed but Hood Canal has the highest recorded wind speeds in the state at slightly over 100 mph and Whidbey Island has the highest land based recorded wind speed at over 90 mph and meteorologist Wolf Reed has analyzed the topography to determine why this occurs. However, western Jefferson County, eastern Kitsap and Island counties are not specified in special wind regions and have a design wind speed of just 85 mph. The roof snow load in Port Angeles is specified at 25 psf and after the 1995 -6 snow storm that was the minimum recommended snow load in the state. By Snow Load Analysis for Washington the ground snow for Port Angeles is 20 psf. Roof snow load is usually not higher than the ground snow. Snow load in this area increases fast with increasing elevation. My measurement of snow load was 23 psf at about 200 feet elevation in Port Angeles after the 1995 -6 snow storm. Your building was probably load tested to about 20 psf during that event. We certainly don't expect failure near the design load, in fact, that should not occur until we reach about 170% of the design snow load, which was probably 25 psf based on the capacity of the purfins. The purlins were checked with the full 25 psf snow applied uniformly and 20 psf (ground snow typically used for unbalanced and accumulation calculations). A timber structure that may have adequately carried a previous snow load cannot be counted on to do the same in the future due to the potential of accumulation of fiber damage. This is discussed in Chapter 14, which 1 authored in The Forensic Structural Engineering Handbook. A steel structure like your building should not be detrimentally affected by supporting such a load in the past. It should be capable of resisting that load many times, or at least until it resists that load repetitively thousands of times when metal fatigue may have an effect. So all the members I analyzed are appropriately designed for the code at the time with the possible exception of the west interior endwall columns that may benefit from added interior flange braces. The rigid frames, and concrete piers at 16' on center were not analyzed nor the foundation supporting them. The steel roof deck and steel siding also were not analyzed, but if constructed of 26 ga. steel decking typical of pre engineered buildings, the approximate 5' on center girt and purlin 12561 rpt Report to Tom Brunoau March 14, 2012 Page 6 of 6 spacing would be sufficient. The large sliding door at the east elevation, its supports, connections and building frame members to which it attaches were not analyzed. The connections of the door support beams to the building structure would not be easily inspected. It is obvious that this large door should not be opened in a major wind storm. None of the wood framing was inspected or analyzed and some of the wood framing covered and prevented observation of steel wall framing. The observations were general and no inspection was made to verify if all bolts were installed at connections, etc. However, the general review and the analysis that was performed indicate that this steel building compares favorably with the typical pre engineered steel buildings constructed at the time. Please contact me if you have questions or comments, or if you wish to have closer review or analysis of other building components. `G Respectfully submitted, 0 r` Cr R. Owen, P.E., S.E. r r gas CRO /cs Encl. 12561 rpt E 12.5( L C. M B Ai A A 1 cCt._/%t.,...7 K) i NJ. c.,4/k i`e-/) .S Yvk F k sef e.JJ Aitk t s I n 1 7 1, 04 /9 &2 L.f3, R �w O �Z ..<z.3%,0? G ,c 0 +o tcv /1 3 X30 q i t o y 4 4 ii lig Z t 4 r f 1 175 Z ,''''=.10N A 0 1 c u WA L EP1�' P 7.- L cii t -e Z tk d vv 6 4 .11? )7 €....1.~,e7 4 5 eA e V e I'' 9 e 4..f sr cmA-4,- I d e-od St Prf pr 49V )Zy S ;of Dith a c,) vvie."1" fo f e NO 0 (k1 c( OAAr5e.) 0 2 0 )3. 781 3 i 6 1 XLI 4g.,tA, y 6 ,I .-,7J)(61)(2t 5 Z) Q e G„w 4 t---1 r\ j_ Nt o LO t &AU €68.e„6' l -9 3) 0,,2) 2 1 2,C c .ENE 8, s t h i e Z t Ca.,p t -4 t ax.,) 4 f> (2,,C)(1,2.4(1 ,0 d 3 +,3 it4C i A l' Q,v, 3,7��1 V.42.eir,,,.c-r 2 0003 iii OWEN STRUCTURAL ENGINEERING INC. Steel Building Review Tom Brunoau 220 E. 1 St, Port Angeles, WA 98362 914 Marine Drive (360) 452 -8574 FAX (360) 457 -8020 Port Angeles, WA 1" 2 g Co G �t-P ,Fw.sy EN&c,J(J.-t c_tol".0,-..„v,s. F. a, z Is tof 4'4 q „..,1 717 a4L E? k /0 Pd,4i. )-7/1t 3 b ►3.g 2. Z 6, o G l X$E1 e- t 1 43 (c)0,, 4- uoi.44-)(22_ 6,_. a 17.71 7 5 aw 23 •T_ -3i." i I 2) t_5) Pia S ()/24k j 2 9 i ev SP- a iiC 2 M ce 4 3 ,I Z= 37 f (1920 j F 4-6, sir Y1- 8 /t c E 7- 86 g)( 0 6 1 P,ozs J 20,2. D Z vs 2 4., 20 o1 tZc- 5cE "7 -05 (0� 160 E G --e W(i•tb, cAt vaQit :(..8-1--,1?)(25,00,1-2..) .30,6 0 p)-- 0 Steel Building Review OWEN STRUCTURAL ENGINEERING INC. Tom Brunoau 220 E. 1s St., Port Angeles, WA 98362 914 Marine Drive (360) 452 -8574 FAX (360) 457 -8020 Port Angeles, WA 3 e CP t t (r ■kr$ i ty, CA AN k...)kki i chs icps ttr H 7; c7 oo. ....6 cm I 01 1 6— e' LbAo i l -6 t r 0 e N a kri 4 t•..• 7 0 dit f ‘v 2 '1 l'i 6- o e \I) '41F .-,:j 1 E, w 0 "7" ...1 1 •'t ii 1 --f i: 6. II k.r.„ 4.,...,...„ 4, Sri l iN) e';:::..... 1/\ 't CO G 0 1%4 t iler 1 t_-> f----., c 0 ,4 ,..4,., _5 f c ti 1 (...0) c P f-t- A.._ I c_A3 VI y ..1,:› NI .5 70 GO ri I N r --P- sr) --sz u cd., al 0 7 tr V\.1 .....b. 1 t p n 4 )21 sae .1 -(D LA -C3 l 0 1 -1' Cg r•,. 0 ,6 ,..,1 cc) '1- ,-I... I r-I 0 er t j\,) 4 D e A e Ur' 4 6 Jr 0 riep OWEN STRUCTURAL ENGINEERING INC. Steel Building Review 220 E. 1 St., Port Angeles, WA 98362 Tom Brunoau (360) 452-8574 FAX (360) 457-8020 914 Marine Drive Port Angeles, WA 1 tiR SP i 2 5 AI_ 1 y if WR S S CSS CA MI r-i SU Dm E 3 ZS 6 0 2$1.s. p 0 .28 4a/ f I 2 of 4 i Steel Building Review OWEN STRUCTURAL ENGINEERING INC. Tom Brunoau 220 E. 1 St., Port Angeles, WA 98362 914 Marine Drive (360) 452-8574 FAX (360) 457-8020 Port Angeles, WA f '5 ,-..',1" )r\ 1-'- 16 2 r DD y i i 1 DU r DONE 1 33 0 1 7 hzqL) 0 G R. 4 't'l lt• f OWEN STRUCTURAL ENGINEERING INC. Steel Building Review 220 E. l' St., Port Angeles, WA 98362 Tom Brunoau (360) 452-8574 FAX (360) 457-8020 914 Marine Drive Port Angeles, WA G 12,s(61 -1-:-:: 1,0e \I t 7 DE: CP Tp sll LA DONE OA 4 C L*■ Cl' 2--. 7,- 2-4 p) -Iv -.1 If 4 iip -4 i A k :4, 727,1 3 ,6. 1 te i OWEN STRUCTURAL Steel Building Review ENGINEERING INC. Tom Brunoau 220 E. 1't St., Port Angeles, WA 98362 914 Marine Drive (360) 452-8574 FAX (360) 457-8020 Port Angeles, WA ro5/ 7 7 1:6: .:7 D'D 5: A CP y 1 r:f• S SC- CADA C.:: RH Ty ,5,C70 7 R. 3 41-' •Si' '4ft 1* Alb i 4, I I i le Steel Building Review OWEN STRUCTURAL ENGINEERING INC. Tom Brunoau 220 E. 1 St, Port Angeles, WA 98362 914 Marine Drive (360) 452-8574 FAX (360) 457-8020 Port Angeles, WA Owen Structural Engineering Inc. 220 E. First Street Phone: (360) 452 -8574 Port Angeles, WA 98362 Fax: (360) 457 -8020 March 15, 2012 Tom Brunoau 914 M D Port Angeles, WA 983683 STATEMENT File #12561: Steel Building Review: General structural inspections of bolding and measurements of exposed steel framing members with uniform section. Computer analysis of girts and pulins made continuous by lap splicing at rigid frames Calculations on endwall girts and columns including section property determination, Preparation of report describing the results of structural calculations and other observations. Inspection, measurements, discussions, analysis, and report preparation. DESCRIPTION DATES HOURS AMOUNT Principal March 9,10,12 -14 8.5 1020.00 Engineering Clerical March 12 -14 3.5 140.00 Total Amount Due 1160.00 Thank You