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Milton S. Hershey Medical Center Biomedical Research Building Joshua Zolko, Structural Option.

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Presentation on theme: "Milton S. Hershey Medical Center Biomedical Research Building Joshua Zolko, Structural Option."— Presentation transcript:

1 Milton S. Hershey Medical Center Biomedical Research Building Joshua Zolko, Structural Option

2 Introduction The Biomedical Research Building (BMR) is located in Hershey, Pennsylvania. 245000 sq. ft, in 7 stories above grade Built between 1991-1993 Cost $49 million Used a Bid-Build project delivery method Used for Education and Laboratory space Table of Contents Introduction Architecture Existing Structure Process Cost Comparison Conclusion

3 Introduction Site soil is considered poor, and as such, columns were designed as pinned at the bottom. Goal of this proposal is to determine if a steel structure is more cost effective than a concrete structure. Table of Contents Introduction Architecture Existing Structure Process Cost Comparison Conclusion

4 Architecture Façade of the BMR consists of long horizontal concrete and limestone slabs, and black glazing Façade designed to relate to buildings already existing on campus Cylinder and Planar wall on corners add to the otherwise flat building Table of Contents Introduction Architecture Existing Structure Process Cost Comparison Conclusion

5 Existing Structure The BMR is a monolithic concrete structure, using a two-way flat plate system with the average column size about 22” by 22” Building sits on a deep foundation system of caissons 3 to 7 feet in diameter Table of Contents Introduction Architecture Existing Structure Process Cost Comparison Conclusion

6 Process Assumed gravity loads were to be: 45 PSF dead 40 PSF snow 20 PSF superimposed 125 PSF live core, 100 PSF live offices Typical Floor Plan Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

7 Process Dead Load is from 3.5” slab (t = 3”) using 1.0CSV Conform decking from Vulcraft assuming 5’ joist spacing. Gives 45 psf, plus 20 psf superimposed for 65 psf dead. Preliminary Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

8 Process Using 1.2D + 1.6L, loading is 278 PSF core. Loading for joist is 1.4 KLF with 5’ tributary width. Requires a W14x22 joist size. Deflection under this loading is.63”, satisfying L/360. Preliminary Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

9 Process Beam loading with a tributary width of 21’ is 5.8klf. Braced at every 5’, under this load, requires a w12x120. Beams deflects.47”, satisfying L/360. Preliminary Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

10 Process Gravity columns have a tributary area of 21’ by 33’. Total of 693 sq ft. Due to the large live load, live load reduction does not apply to members supporting only one floor, and those that do, maximum of 20% reduction. Preliminary Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

11 Process Axial load per floor is 192.7 Kips. After LLR, load is 165 kips. With alternate loading of bays, and axial loads, gravity column sizes range from W14x90 to W14x159. Gravity Column Shapes Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

12 Process Analysis was repeated for the office spaces, and no changes were made. Column sizes were the same aside from the third story where a reduction to a W14x132 could have been made, but it was decide to keep it uniform with the core. Preliminary Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Cost Comparison Conclusion

13 Process Goal of Lateral Design was to keep the drift of the building under 2.6”, or H/400, with H = 88’ Hall/office spaces to have minimal drift as they attach to an adjacent building. Initial Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

14 Process Initial Lateral design consisted of only Moment Frames. Frames were assumed to be equally stiff, and checked via RAM. Equal stiffness allowed for individual frame design. Initial Layout Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

15 Process Using ASCE 7-10, Wind loads were derived. Loads were then divided amongst the moment frames. Portal method was used to estimate loads. Wind Loads Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

16 Process Loads from both lateral and gravity forces were combined using interaction equations, including biaxial forces from overlapping lateral frames. Drifts from the initial design were too high, and frames were rearranged, and braced frames were added. Final Frame Design Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

17 Process Loads from both lateral and gravity forces were combined using interaction equations, including biaxial forces from overlapping lateral frames. Drifts from the initial design were too high, and frames were rearranged, and braced frames were added. Biaxial Lateral Columns Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

18 Process Braced Frames were designed in order to decrease the drift caused by torsion. A specific rigidity was found in order to move the center of rigidity to the center of mass, and braces were sized in order to acquire this rigidity in order to decrease torsional effects. Braced Frame Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

19 Process Problem with this braced frame being placed at the north side, is that the braced frame will be placed directly in front of the glazing. Braced Frame Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

20 Process Loads from both lateral and gravity forces were combined using interaction equations, including biaxial forces from overlapping lateral frames. Drifts from the initial design were too high, and frames were rearranged, and braced frames were added. Braced Frame Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

21 Process Braced Frames were placed in order to not block entrances into maintenance shafts Halls go through center bay Braced Frame Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

22 Process Overturning was checked, and was not an issue in either direction under controlling loads of either wind or seismic. Overturning Tables Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

23 Process Braced Frames were placed in order to not block entrances into maintenance shafts Halls go through center bay Final Frame Design Table of Contents Introduction Architecture Existing Structure Process Gravity Lateral Cost Comparison Conclusion

24 Cost Comparison Original Plan costs $49 million Proposal costs $.... million Calculations Table of Contents Introduction Architecture Structure Process Cost Comparison Conclusion


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