EFTA00619838.pdf

PaulFerreras, PE StructuralEngineer March 19, 2013 Director Smith Department of Planning and Natural Resources CEK Airport St. Thomas. USVI 00802 Subject: American Yacht Harbor Emergency Repairs to Columns Red Hook, St. Thomas. USVI Director Smith: I had been notified of a structural problem at the subject premises yesterday. I did make a site visit and observed two columns that had been structurally distressed. I was informed that on Sunday (the previous day) that occupants had been on the upper level and felt a drop in the structure. The upper level was at that point cleared of the occupants and it has not been occupied since that time. I observed at the main level (above the parking garage) that on the rear of the building that 4 inch diameter steel columns support the upper level. Two of these columns have a problem at the base. It appears that water has caused a corrosion issue at the base of the column and reduced the column section to a point that the base has failed and collapsed about 2 inches in height (see attached photo). I have conducted a load analysis on the two columns in question and determined that each of the columns have about 331 square feet of tributary support area from the floor above. The column has about 9 feet of un-braced height. My evaluation is that these columns each support about 29,800 pounds of dead load and 33,100 pounds of live load. My evaluation is based on assumed concrete thickness, floor finishes, approximate steel framing and a live load of 100 pounds per square foot. This evaluation uses assumptions that have not been verified but are to be expected for construction of this pe • The repair procedure (without considering finishes) is as follows and shown on the attached detail: 1) Support the column on each side. 2) Jack the structure back to level (about 2 inches) 3) Cut out the damaged column section from a few inches below the top girder to the base plate on the lower support. 4) Bevel cut the existing column section to remain and weld a new top plate to the existing section. 5)Inspect the lower base plate and either replace or reuse the base plate. 6) Install the new 4 inch diameter, X-Strong steel pipe column by bevel welding the pipe to the top plate and base plate. EFTA00619838 Page March 19, 2013 We are requesting that DPNR provide an emergency repair permit for this work. I have asked that the welder start by obtaining all the necessary materials and fully supporting the column in place. I will ask that the owner come to DPNR to pay whatever permit is necessary for this emergency repair permit. If you have any questions with this submission please contact me. Sincerely, Paul Ferreras, PE Attachments: Disclaimer: It should be noted that the above report is based on a visual observation and that there is no claim, either stated or implied, that all conditions were observed. The opinions and comments in this report are based on visual observation only. Architectural, mechanical. electrical or plumbing conditions are not included and no warranty expressed or implied as to the condition of the structure is intended. The engineer shall not be responsible for the means, methods, procedures, techniques or sequences of construction, nor the safety on the job site, nor shall the engineer be responsible for the Contractors failure to carry out the work in accordance with the contract documents. EFTA00619839 Page 3 March 19, 2013 Photo of Column Base - note corrosion at base and crushed base section. EFTA00619840  PAJA.a.41 esid- slit t5 aW31.- -f 51-.•-4 rtonroC , rtErgAr t • .,`"1. 17 i06 Clonal N gt -v£.- CA'r Elovr pot It - 1 " x ef *1— 1-46“) -44' tkhiC. Csicabe. V LemAit.( e-tni_Aet_ As SiCcitspsi t r14/,a,-) 4 x- Sts-c6 <ss1 77s) fipe_. A 55 ki Cfcat 104,44..poe_ ORM-I Ft ottµ e,yerr cmg- ReoLtcf_ - eiAlse 5rE£L Tit In-'sce-c- C").“9 m'Aui FERRERAS. PE Si EFTA00619841 Paul Ferreras. PE Structural En neer RIB • g:1EnOnect1VIRGIN-1)Proixis\AYKREDHOO-ICOLUMN-LEC6 Steel Column ENERCALC. INCA 913-2013. Build:6.13227. VerS.132.27 Description : Column Replacement Code References Calculations per AISC 360-05, IBC 2006, CBC 2007, ASCE 7-05 Load Combinations Used : ASCE 7-05 General Information Steel Section Name : PIpe4 x-Strong Overall Column Height 9.0 ft Analysis Method : Allowable Strength Top & Bottom Fixity Top & Bottom Pinned Steel Stress Grade Brace condition for deflection (buckling) along columns : Fy : Steel Yield 35.0 ksi X-X (width) axis : E : Elastic Bending Modulus 29,000.0 ksi Unbraced Length for X•X Axis budding = 911, K = 1.0 Load Combination : ASCE 7-05 Y-Y (depth) axis: Unbraced Length for NW Axis budding = 9 II, K = 1.0 Applied Loads Service loads entered. Load Factors will be appaed for calculations. Column self weight included : 126.684 lbs ' Dead Load Factor AXIAL LOADS ... Axial Load at 9.0 ft, D=29.80, L=33.10 k DESIGN SUMMARY Bending & Shear Check Results PASS Max Axial+Bencing Stress Ratio = 0.9540 : 1 Maximum SERVICE Load Reactions .. Load Combination +D+L+H Top along X-X 0.0k Location of msui.above base 0.0 It Bottom along X-X 0.0k Al maximum location values are ... Top along Y-Y 0.0 k Pa : Axial 63.027 k Bottom along Y-Y 0.0 k Pn / Omega : Allowable 66.067 k Ma•x : Applied Maximum SERVICE Load Deflections ... 0.0 k-ft Mn•x (Omega :Allowable Along Y-Y 0.0 in at 0.Oft above base 9.658 k-ft for load combination : : Applied 0.0 k-ft Mn•y (Omega :Alowatie 9.658 k-ft Along X-X 0.0 in at 0.0ft above base lot load combination : PASS Maximum Shear Stress Ratio = 0.0 :1 Load Combination Location of nuurabove base 0.0 ft Ai maximum location values are ... Va : NOS 0.0 k Vn / Omega : Allowable 0.0 k Load Combination Results Maximum Axial • Bending Stress Ratios Maximum Shear Ratios Load Combination Stress Ratio Status Location Stress Raba Status Location D Only 0.453 PASS 0.00 ft 0.000 PASS 0.00 ft +D+L+H 0.954 PASS 0.00 ft 0.000 PASS 0.00 ft +D+Lr+H 0.453 PASS 0.00 ft 0.000 PASS 0.00 ft +D+S+H 0.453 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.750Lr+0.750L+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.7501+0.750S+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +D+W+H 0.453 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.70E+H 0.453 PASS 0.00 ft 0.000 PASS 0.00 ft +8+0.750Is+0.750L+0.750W+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.750L+0.7505+0.750W+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.750Lr+0.750L+O.5250E+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +D+0.750L+0.7505+0.5250E+H 0.829 PASS 0.00 ft 0.000 PASS 0.00 ft +0.60D+W+H 0.272 PASS 0.00 ft 0.000 PASS +0.600+0.70E+H 0.272 PASS 0.00 ft 0.000 PASS EFTA00619842 Paul Ferreras. PE Structural En neer .g:IEnpneeiVIRGIN-I)ProOctskAYlfREDHOO-ICOLIJMN-1.EC6 Steel Column INERCALC. INC. I983-2013. Build:6.13227. VerS.132.27 Lic. # : KW-06009109 Licensee : Paul Ferreras, PE Description : Column Replacement Maximum Reactions - Unfactored Note: Only non-zero reactions are listed. X•X AS Reaction Y•Y Axis Reaction Axial Reaction Load Combination @ Base @ Top @ Base @ Top @ Base D Only k k 29.927 k L Only k k 33.100k Dit k k 63.027 k Maximum Deflections for Load Combinations • Unfactored Loads Load Combination Max. X•X Deflection Distance Max. Y•Y Deflection Distance 5 5' 5' 5' 5' 5' D Only 0.0000 0.000 ft 0.000 in 0.000 ft L Orly 0.0000 0.000 ft 0.000 in 0.000 ft D+L 0.0000 0.000 ft 0.000 in 0.000 ft D Only 0.0000 0.000 ft 0.000 in 0.000 ft L Orly 0.0000 0.000 ft 0.000 in 0.000 ft D+L 0.0000 0.000 ft 0.000 in 0.000 ft Steel Section Properties : Pipe4 xStrong Depth = 4.500 I In = 9.12 nA4 J 18200 W4 Sn = 4.05 W3 Diameter = 4.500 I Rn = 1.480 in Wal Thick = 0.338 I Zx = 5.530 ins13 Area = 4.140 W2 I yy = L120 W4 Weiahl = 14.076 pit S )7 = 4.050 W3 Rw = 1.480 I Ycg 0.000 I Loads are total entered value. Mows do not felled absolute <I tenon. EFTA00619843