Presentation on theme: "A BYU Civil and Environmental Engineering Capstone Project by: Charles Connors, Andrew Luna, and Jonathon Archer Parallel Engineering Seattle Temple: Bearing."— Presentation transcript:
A BYU Civil and Environmental Engineering Capstone Project by: Charles Connors, Andrew Luna, and Jonathon Archer Parallel Engineering Seattle Temple: Bearing Column Replacement
Where is the column we are replacing?
Existing Condition The column is currently located in a less than ideal spot.
The Problem The chapel in the baptistry of the LDS Seattle Temple has large column in the center of the view to the font. View from the chapel Existing Condition
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. View from the chapel Fourth Points
Proposed Solution #2: Long Span The column might also be supported by a much heavier beam that would span from wall to wall. View from the chapel Full Span
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.
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.
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; Total earthquake effects are: Using Load combinations #5&6 our total column forces are:
Beam Analysis Using software, we designed possible beams to carry the loads that would be exerted at the location where the column comes down from above. The beam was modelled as simply supported with point loads at the middle.
Beam Options PROPOSED SOLUTION #1: SHORT SPAN Beam Length:13 ft. Beam Depth:26.5 in. Beam Weight:5.4 kips. Service Load Deflection:0.04 in. Deflection ratio:L/3900 PROPOSED SOLUTION #2: LONG SPAN Beam Length:29 ft. Beam Depth:26.5 in. Beam Weight:23 kips. Service Load Deflection:0.281 in. Deflection ratio:L/1200
Existing Column to Beam Connection Our calculations showed that the existing column was limited in its tensile strength. Using the tensile capacity of the existing rebar we established a conservative value for the maximum uplift that could be transferred to the beam. Assuming the rebar could possibly sustain a stress of 1.25fy (ACI 318). Uplift capacity of existing column Uplift capacity of new column
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 Column Size: 24 in. X 24 in. X 12 ft. Footing Size: 7.0 ft. X 7.0 ft. X 2 ft. 3 in.
Foundation Column Cross Section: 24 in. X 24 in. Use (8) No. 11 bars Ties: No. 22 in. O.C.
Footing Area: 7 ft. X 7 ft. Thickness: 2 ft. 3 in. No. 6 8 in. O.C. Plan ViewSection View
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 engineers 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.