Mar 3, 2013

structural and thermal calculations gehry bank berlin



How does the form of the building affect its structural system?
The inner conference and atrium space has a very different feel to the rest of the building. It is many stories tall, with a glass roof interlaced with structural steel beams. These are important in strengthening the building because the curved glass acts like the hull of a boat and is subject to many complex forces and behavior. The free-form, conch shell shaped structure that forms the conference auditorium is 29 meters long, 12 meters wide and 10 meters high. It is made from concrete in two halves. The floor of the atrium is also made from glass with interlaced steel at 80 cm centers and the interior enclosed space incorporates a lot of wood paneling.

How does the form and location of the building affect its HVAC system?
As with the structural system, the HVAC system for most of the building would have been fairly straightforward to design. The heating and cooling system for the large interior space will have been an issue though purely because of its size. It is approximately 13,000 sq ft, meaning it makes up nearly a third of the building footprint. It is reasonable to assume that the heating system has been placed under the floor. On a hot day, the glass roof would 

Drawings/Diagrams

Ground Floor

1.     Office Space
2.     Central Atrium
3.     Conference Auditorium
4.     Residential Block
Transverse Section

Longitudinal Section

North Elevation

South Elevation

Aerial View




Analysis

What are the relative magnitudes of the total Dead, Live and Horizontal loads and what implications do these have for the structure of the building?

    The relative dead load is 216,862,008.5 lbs and the relative live is 11,858,380 lbs making the vertical load to be 228,720,388.5 lbs, while the horizontal load is 372,120 lbs. As you can see the vertical load on the building eclipses the horizontal load, the implications of the structure of the building would be focused on the support of each floor and the foundations. Since the DZ bank has a unique design from most buildings the loads would effect differently on each part of the building. On the front side there are 5 stories which can be considered as a regular commercial building, there is also a very intricate atrium which covers most of the building that has a auditorium and a lobby. Finally towards the back of the building there are 9 stories of 39 residential apartments including a sweet penthouse overlooking the Berlin skyline. These parts of the building would required different supports that lead up to the foundation of the building.   

Looking at the foundation load what do you think it means for the type of foundation to be used, and what additional information would you need?
         
    Since the information of this building was hard to find, trying to figure out what type of foundation the building rest on would be a challenge. But judging from my calculations the building would be using many reinforced concrete slabs as its foundation. Since the total foundation load of the building is 4,950 PSF which is rather large, the foundations would need to be strong to support the weight. While looking at the different types of foundations: Piles, Caissons, Spread Footing, and finally Concrete Slabs, the most reasonable choice would be the slabs. But i could be wrong, it can be any of the other foundation types that i just mentioned. Considering i don’t have enough information about the building, i would need to know more about the structure of the building, how it was built, and the site its was built on to have a more accurate assumption.

Would this be an easy or a difficult building for which to develop the structural calculations (assuming you’d already completed the senior year structural sequence?) Why?

    Trying to develop structural calculates for this building would be a challenge. Even though it might look easy at first because of its simple rectangular exterior look. But taking a quick glance on the inside, you can tell that the calculations wouldn't be so juvenile. The calculations on the residential, commercial, and office areas would be fairly simple. Since most of it can be considered like a regular a apartment or office building. But when looking at the atrium of the building the calculations wouldn't be so simple. First off there is a large amount of glass used and a huge glass canopy covering the entire atrium. Not only that but the all the glass used has a curved shape, so making the calculations would be difficult. Most of it would be figuring out how the steel frameworks can support the weight of the glass and outdoor climate conditions. Next is an odd looking auditorium in the middle of the atrium. The strange shape of the auditorium would be the most difficult part of all the calculations. The stainless steel that forms the shape has many bends and curves, so the structural calculations would be troublesome.

Calculations

Dead Load

Partition: 215,000 ft^2 x 5 PSF = 1,075,000 lbs

Equipment: 215,000 ft^2 x 5 PSF = 1,075,000 lbs

Ceiling: 215,000 ft^2 x 2 PSF = 430,000 lbs

Glass:
  • Front Entrance: 28 windows (3.21m x 4m x .04m) = 14.38m^3
  • Back Entrance: 117 windows (1m x 1.2m x .04m) = 5.616m^3
  • Glass Canopy: 1,220m^2 x .05m = 61m^3
  • Glass Atrium: 14.3m x 25m x .04m = 14.3m^3

14.38m^3 + 5.616m^3 + 61m^3 + 14.3m^3 = 95.296 m^3 = 3365.35 ft^3

3365.35ft^3 x 185 PCF = 622,589.75 lbs

Concrete:
  • Volume of concrete of 9 floors (residential): 31,215 ft^2 x 1 ft = 31,215 ft^3
  • Volume of concrete of 5 floors (office): 132,396 ft^2 x 1 ft = 132,396 ft^3
  • Reinforced concrete slabs: 35 ft x 30 ft x 75 ft = 73,500 ft^3

31,215 ft^3 +  132,396 ft^3 + 73,500 ft^3 = 237,111 ft^3

237,111 ft^3 x 145 PCF = 34,381,095 lbs

Steel:
  • Conference Auditorium (stainless steel): 29m x 10m x 0.2m = 58 m^3
  • Canopy Framework: .04m x 20m x 60m = 47.55 m^3
  • Steel Framing (assumed): 10,000 m^3

58 m^3 + 47.55 m^3 + 10,000 m^3 = 10,105.55 m^3 = 356,874.13 ft^3

356,874.13 ft^3 x 490 PCF = 179,278,323.7 lbs


Total Dead Load: 1,075,000 lbs + 1,075,000 lbs + 430,000 lbs + 622,589.75 lbs + 34,381,095 lbs + 179,278,323.7 lbs = 216,862,008.5 lbs

Live Load  
  • Residential: 31,215 ft^2 x 40 PSF = 1,248,600 lbs
  • Office: 132,396 ft^2 x 80 PSF = 10,591,680 lbs
  • Auditorium Max Capacity: 100 occupants x 181 (weight of an avg. male) = 18,100 lbs

Total Live Load: 1,248,600 lbs + 10,591,680 lbs + 18,100 lbs = 11,858,380 lbs

Foundation Load
  • Total Vertical Load: 216,862,008.5 lbs (dead load) + 11,858,380 lbs (live load) = 228,720,388.5 lbs
  • Load on Foundation: 228,720,388.5 lbs  46,200 ft^2 = 4,950 PSF


Wind load
  • Wind Pressure: 21 PSF (90mph)
  • Wind Load: 17,720 ft^2 x 21 PSF = 372,120 lbs
  • Drawings/Diagrams


    The red arrows shows how horizontal or wind loads distribute throughout the building. Traveling from the exterior walls to each floor to the vertical structure members and finally to the foundations.



    The blue arrows similar to the red ones show how the vertical loads are distributed throughout the building. Spreading the weight evenly from the top of the canopy and the roof to each level and finally reaching the foundations of the building.



    The yellow arrows show the weight distribution of the “shell” of the conference auditorium. The unique pattern required the steel to deform into many different shapes and lengths, the steel framing eventually comes together and lies the weight on top of many vertical support columns which aren't shown on the picture. 

    Analysis


    What are the relative magnitudes of the total hourly heating and cooling loads?

            The total hourly heating load is 18,423,425 Btu/hr. This was calculated using many of the assumptions given on the course website. The average minimum temperature during the coldest months (Nov. - Mar.) of the year is 35 F. Cooling load was not calculated for this building because the maximum daytime temperature does not go above 73 F during the hottest months (July & August) of the year.

    What are the relative costs of heating and cooling the building?

            Because no cooling load was calculated, there is no annual cooling cost for this building. The annual heating cost for this building was found to be about $663,000, or roughly $4.05/SF.


    Would this be an easy or a difficult building for which to develop the HVAC calculations (assuming you'd already completed the senior year HVAC courses)? Why?

            This is a relatively difficult building to calculate heating and cooling loads. The main reason for this is the central atrium and its massive skylight. Not only is there a lot of fenestration through the ceiling, the skylight itself is oddly shaped, which makes calculations that much more difficult. 
     In addition, there are two separate sections of the building with very different purposes. The office section on the south side of the building has daily heating requirements to keep employees comfortable, but nighttime loads are much less important. On the north side of the building, the 9-story residential tower has much different heating requirements. Not only is comfort important 24 hours a day, but each resident would ideally have control over his/her own apartment. This would have an effect on heat loads depending on the preferences of the residents.

    Calculations

    Heating load out of the building on cold winter night (no people/no lighting) [BTU/hr]

    • Location - avg temp at night in winter
      • 35 F
    • Length of cooling season at avg temp
      • 5 mo. (Nov-Mar)
    • Neglect HVAC airflow and leakage
    • Rwall = 10 [ft2F-h/Btu]
      • North Wall Area = 10500 SF
        • Minus Window Area = 4200 SF (assuming 7 windows * 5 floors * 120SF/window)
        • Actual Wall Area = 6300 SF
      • South Wall Area = 17720 SF
        • Minus Window Area = 5850 SF (assuming 13 windows * 9 floors * 50SF/window)
        • Actual Wall Area = 11870
      • E&W walls not included b/c they are directly adjacent to other buildings
      • Qwall = U*A*dt = 1/10*(6300+11870)*(70-35) = 63,595 Btu/hr
    • Rroof = 30 [ft2F-h/Btu]
      • Total Roof Area = 46200 SF
      • Minus Skylight Area = 22500 SF
      • Actual Roof Area = 23700 SF
      • Qroof = 1.15*U*A*dt = 1.15*1/30*23700*(70-40) = 27255 Btu/hr
    • Rglass = 2 [ft2F-h/Btu]
      • Ext Window Area = 10050 SF
      • Skylight Area = 22500 SF
      • Total Glass Area = 32550 SF
      • Qglass = U*A*dt = ½*32550*(70-40) = 488250 Btu/hr
    • Convert to gal/hr of heating oil (120,000 Btu/gal)
      • Qwall = 63595 [Btu/hr]*1/120000 [gal/Btu] = 0.53 gal/hr
      • Qroof = 27255 [Btu/hr]*1/120000 [gal/Btu] = 0.23 gal/hr
      • Qglass = 488250 [Btu/hr]*1/120000 [gal/Btu] = 4.07 gal/hr
      • Total Heating Oil = 4.42 gal/hr
    • Calculate cost of oil/year ($2/gal)
      • Total Cost/Year = 4.42 [gal/hr] * 720 [hr/mo] * 5 [mo] * 2 [$/gal] = $31,824/Year (only calculating for cooling period from Nov. through Mar.)

    Total heating load of the HVAC system

    • Hourly heat load - [Btu/hr] [Tons of HVAC] [W]
      • Total Hourly Heat Load = 18,423,425 Btu/hr = 5,400,000 W = 1535 Tons of HVAC
    • Daily heat load (24 X Hourly Load)
      • Total Daily Heat Load = 442,162,200 Btu/hr = 129,600,000 W = 36,840 Tons of HVAC
    • Seasonal heat load -> annual heat load (5 months = 150 days)
      • Total Annual Heat Load = 6.63(1010) Btu/hr = 1.94(1010) W = 5.53(106) Tons of HVAC
    • Convert to cost/SF
      • Using $0.10/KWH * 6.63(1010)Btu/(10[Btu/W-h]*1000[W/kW] = $663,000/163611[SF] = $4.05/SF
    • Assumptions:
      • 300 [BTU/hr] by people
        • Qpeople = qs*n*CLF = 250*((39*4)+(132,400/200))*0.72 = 147,240 Btu/hr
      • 200 [SF/Person]
      • 1.5 [W/SF] for lighting
        • Qlighting = 163611 [SF] * 1.5 [W/SF] = 245,416 W = 837,394 Btu/hr
      • 3 [W/SF] for equipment
        • Qequip = 163611 [SF] * 3 [W/SF] = 490,833 W = 1,674,791 Btu/hr
      • 100 [W/SF] incident solar on horizontal surface
        • Qhoriz = 46200 [SF] * 100 [W/SF] = 4,620,000 W = 15,764,000 Btu/hr
      • 60 [W/SF] incident solar on West or east facing surface at peak time
        • Equals 0, E&W walls concealed by adjacent buildings
      • Ton of AC = 12,000 [BTU/Hr per ton]
      • Seasonal Energy Efficiency Ratio (SEER) is 10 (explain what this means)
        • SEER is the ratio of seasonal cooling energy [Btu] to seasonal power consumption [W-hr]
        • The higher the SEER value is, the more energy efficient the unit is
      • Electrical Energy costs $0.10/KWH
      • Drawings/Diagrams

        Section - We assumed that this building would use 2 HVAC systems because of the separate needs of the commercial and residential sections. The red lines show heat flow to the building, blue arrows show points of intake and exhaust

        .
        Elevations - Fenestration, such as windows and the open skylight, is highlighted with red trim to show where heat can most easily escape the building. 

        6. Evaluating Accomplishments

        A. Expectations vs. Results
        I. Architectural System (Sean Davis)
                I expected this task to be fairly hard for us due to the fact that we picked a building to analyze that isn’t that well known. I was surprised by the amount of information that we managed to find on the internet. The one area that didn’t turn up much information was the actual dimensions of the building which I expected to find quite easily, so I made educated guesses about the area of the facades and the footprint based on a few measurements I took in Google Earth. If we had been set this assignment professionally, without use of the internet, I believe now that it would have been quite hard to find out information from an architectural point of view without actually physically visiting the building and carrying out some analysis.
                I learned that it is quite easy to make a rough guess at a lot of the calculations and elements used in buildings, but had I been told to go into more detail, I would have found it a lot harder.
                All systems within a building depend on one another, and the same is true for the DZ Bank, especially in the large atrium and conference center space. For example, the shape of the unusual glass roof meant a structural system had to be designed to support it, and the conference area is in a very strange structure, and the HVAC system will have to be changed accordingly.
                One problem that I found with this assignment is that I had difficulty converting between metric and imperial units.
        II. Structural System (Junwah Ng)
                While looking at other submissions from previous years I can tell that this assignment wasn't going to be so easy, and choosing a building that isn't well known doesn't help much either. As what Sean said before it was fairly difficult to find information about this building, but the information we did find we tried to use it to the best of our abilities. My part of this assignment was to do the structural system, which includes the calculations of loads and different types of material that form the building and what holds it together. When I started to do these calculations at first it didn't seem so hard, like trying to find the surface areas of glass and the size of the auditorium in the atrium. But when I had to figure out the loads of the steel and concrete, there was little to no information about it. So I used similar buildings to make a reasonable assumption on how much each one weighed. After this assignment I realized that there are many things that go into the structure to make it stand and I hope that my estimates are close enough to the actual values of the building. 

                I learned that the foundation of the building is a key part to the stability of the structure. Since all the lateral and horizontal forces travel through the building and eventually reach to the foundation, it's necessary to have a suitable footing to withstand the weight it's under. 


        III. HVAC System (Thomas Bosc)
                Before starting my section of this assignment, I knew that it would be challenging.  I recently took the Intro to HVAC course, but that by no means makes me an HVAC design expert.  I didn't know what to expect in terms of assumptions that needed to be made.  Much of the basic information for this building, such as the architect, contractor, and owner, was easy to find, but details were not as easy to come by.  I could not find any information on the exact HVAC system used, so I had to assume many variables in my calculations.  At the beginning of the assignment, I expected the building to be relatively expensive to heat due to the amount of fenestration. I did not realize how cold Berlin was throughout the year. I used to think that it got hot and muggy there during the summer, but the highest average monthly temperature was 73 F in July and August. On average, it is below 50 F from November through March.

                After completing the assignment, I understand better why it is expensive to heat a building with an almost completely glass ceiling in addition to large windows on two of the four exterior walls. In the calculations for night time heat load, the glass was responsible for over 90% of the total heat loss.
        B. System Interaction
                The interaction between the systems is at an apex of innovation when it comes to the atrium structure in the center of the building. The other sections of the building see the interaction occur between all systems as in a more conventional way where the Structural system supports the visual goals of the Architectural system, then the HVAC system comfortably controls the climate within the given space. The atrium area provides a very unique challenge that is particular to this building. This complex form was an unprecedented feat of Architectural design in the planning and design phase. The Structural aspect of implementing this vision into an actual structure certainly presented enormous challenge. Then once this structure was in place the HVAC system would have to work according to the challenges presented, primarily related to the glass enclosure that was responsible for a lot of heat loss during the mainly colder months of the year. So clearly there was a requirement for a lot of creativity with the interaction between all systems for this innovative building.

        C. Group Process
                At the start of the assignment as a group we unanimously chose the DZ Bank as our building. From there we assigned each team member to do one of the systems. Sean chose the architectural system, Junwah the structural system, Thomas the HVAC system, and lastly Daniel was to create the website. Once each person knew their objective we all went on to search for the information pertaining to their systems. But finding said information was difficult, due to the fact that the building we've chose wasn't well known. Therefore we assembled as much information as we can gather from the internet. We also formed team meetings to evaluate how far each member was doing and assisting them when help was needed. After the weeks of research and work we were finally able to combine all the information on to the website. Each member has done a sufficient amount of work and has showed teamwork throughout the course of the assignment.
            

1 comment:

  1. Structural Calculations

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