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Seattle Temple: Bearing Column Replacement A BYU Civil and Environmental Engineering Capstone Project by: Charles Connors, Andrew Luna, and Jonathon Archer Parallel Engineering Where is the column we are replacing? Existing Condition The column is currently located in a less than ideal spot. Existing Condition View from the chapel The Problem The chapel in the baptistry of the LDS Seattle Temple has large column in the center of the view to the font. Fourth Points View from the chapel Proposed Solution #1: Short Span Our proposed solution is to move the column load out to two smaller columns six feet in from the outside walls. Full Span View from the chapel Proposed Solution #2: Long Span The column might also be supported by a much heavier beam that would span from wall to wall. Short Span 3D View Column Loads The un-factored loads on the structure are: Dead: 135.7 kips Live: 81.5 kips Snow: 2.3 kips Rain: 12 kips Earthquake (-Y): 1557 kips Earthquake (+Y): 1387 kips A shear wall above the column is imposing very large earthquake loads. These loads obviously govern our design. Calculations of these loads are shown on the following slides. Seismic Loading Based on the pertinent seismic design criteria, we calculated and distributed a base shear force. The base shear force approximates the effects of a seismic event on the building. Wx hx Wx*hx^k Fx Story (kip) (feet) (for k=1.03) (kip) Roof 2725 84 258522 1199 Mechanical 2281 72 184701 857 Level 4 3495 60 234658 1088 Level 3 3655 45 182602 847 Level 2 5629 30 185405 860 Ground Floor 6028 15 97402 452 Sum 23813 Sum 1143291 Vx (kip) 1199 2055 3144 3990 4850 5302 Diaphragm Distribution Based on the stiffness of the individual wall segments, the earthquake forces were distributed to each of the walls. The diaphragm was assumed to be rigid and torsional moments were included in the analysis. The shear wall in question had a maximum shear force of 475 kips. Xstart (ft) 0 A.T.? Y Global Structure Dist Load 1 Dist Load 2 Xend (ft) w (K/ft) Xstart (ft) Xend (ft) w (K/ft) 164 29.57317073 0 194 27.32989691 Point Load (k) Length X(ft) 194 Load Direction Center of Mass (x,y) Length Y(ft) Y 89.83392435 89.8339243 142 P (K) 10152 A.T. Offset 9.7 Individual Walls Wall # 1 2 3 4 "COF" Center of Frame Wall Stiffness Orientation COF X COF Y Dist. From Datum to (K/in) of wall Coordinate Coordinate Center of Wall (ft) 4780 Y 163 48 163 4780 Y 163 116 163 10920 Y 194 18 194 10920 Y 194 124 194 Xr (ft) Fi (kip) 86.1 Yr (ft) 71.1 475 475 1114 1114 Moment @ C.R. (K-ft) 136798.4 Direction Clockwise (-) Shear Wall Overturning Moment The compression/tension reactions required to prevent the shear wall from overturning are calculated to be 1557 kips. By summing moments about bottom right corner; π × 15′ π = = 491 πππ 14.5′ Total earthquake effects are: πΈβ = 491πππ πΈπ = 0.2ππ·π ∗ π· = 24πππ πΈ = πΈβ + πΈπ = 515πππ Using Load combinations #5&6 our total column forces are: ππ = 1.2 + 0.2ππ·π π· + ΩπΈ + πΏ = 1557 πππ πππππππ‘ = 0.9 − 0.2ππ·π π· + ΩπΈ = 1387 πππ Beam Options PROPOSED SOLUTION #1: SHORT SPAN PROPOSED SOLUTION #2: LONG SPAN Beam Length: Beam Depth: Beam Weight: Service Load Deflection: Deflection ratio: Beam Length: Beam Depth: Beam Weight: Service Load Deflection: Deflection ratio: 13 ft. 26.5 in. 5.4 kips. 0.04 in. L/3900 29 ft. 26.5 in. 23 kips. 0.281 in. L/1200 Existing Column to Beam Connection A connection with adequate tension capacity was designed to connect the new beam to the existing column from above. Foundation Column & Footing ο§Column Size: 24 in. X 24 in. X 12 ft. ο§Footing Size: 7.0 ft. X 7.0 ft. X 2 ft. 3 in. Removing Existing Wall Foundation Constructability – Long Span (29ft.) The long beam option cannot be maneuvered into place without significant changes to the laundry room. Removing walls adjoining the engineer’s offices is not an option because they contain concrete shear walls. Baptistry Constructability – Short Span (13ft.) The shorter beam option can be maneuvered into place simply by moving the large tables in the laundry room. It is also 16 kips lighter. Cost Estimate - Short Span Category Cost Man Hours Demolition & Protection $51,200 320 Concrete $53,165 424 Metals $77,503 340 Openings & Finishes $51,900 328 Fire Suppression, Plumbing, HVAC, & Electrical $34,200 456 Earthwork $166,800 664 Total $434,768 2532 Questions?