CITY MARKET FLOOR N ground floor (scale 1/32’’ = 1) 0 10 20 50ft Concept Design... · 2016. 2. 1. · way reinforcing slab, but the slab above the tunnel and at corridor area

0 10 20 50ft

CITY MARKET FLOOR

ground floor (scale 1/32’’ = 1)

Mecanoo Martinez+Johnson 41Mecanoo Martinez+Johnson 40

N

0 10 20 50ft

Mecanoo Martinez+Johnson 43Mecanoo Martinez+Johnson 42 Mecanoo Martinez+Johnson 42

THE EDUCATIONAL FLOOR

2nd floor (scale 1/32’’ = 1’) N


THE READING FLOOR

3rd floor (scale 1/32’’ = 1’) 0 10 20 50ftN


THE HISTORY AND FUTURE FLOOR

4th floor (scale 1/32’’ = 1’) 0 10 20 50ftN


THE ROOF GARDEN FLOOR

5th floor (scale 1/32’’ = 1’) 0 10 20 50ftN

6-7-8th floor (scale 1/32’’ = 1’)

32,897 GSF/FLOOR 0 10 20 50ft


N

roof floor (scale 1/32’’ = 1’) 0 10 20 50ft


N

parking floor (level B) (scale 1/32’’ = 1’)

122 parking places 0 10 20 50ft


N

mechanical floor (level C) (scale 1/32’’ = 1’) 0 10 20 50ft

N


longitudinal section (scale 1/32’’ = 1’) 0 10 20 50ft


0 10 20 50ftcross section (scale 1/32’’ = 1’)


G Street Elevation (scale 1/32’’ = 1’) Mecanoo Martinez+Johnson 53Mecanoo Martinez+Johnson 52

G Place Elevation (scale 1/32’’ = 1’) Mecanoo Martinez+Johnson 53Mecanoo Martinez+Johnson 52

9th Street Elevation (scale 1/32’’ = 1’) Mecanoo Martinez+Johnson 54

Alley Elevation (scale 1/32’’ = 1’)

Artist impression of loggia and main entrance


4. artist impressions

Artist impression of outdoor cafe


images

Artist impression of extended east wing program


Artist impression of the great hall


Artist impression arriving at the corner of 9th Street and G Street


Artist impression arriving from 10th Street



appendix 1structural and mechanical engineer


Martin Luther King Jr. Memorial LibraryWashington, D.C.

ABT structural engineerConcept DesignDelft, June 13, 2014


Content1. Concept narrative 2. Existing structure 3. Public cores and outdoor patios 4. Non-public cores 5. Ramps 6. Ventilation voids & sky lights 7. Bicycle kiosk 8. Mixed-use volume 9. Auditorium 10. Structural system 11. Conclusion


1. Concept narrativeThe Martin Luther King Jr. Memorial Library in Washington D.C. is extended by means of a mixed-use volume that appears to float on top of the existing building block. The additional volume consists of three floor levels and has the shape of a large skewed rectangular box. As the new volume is slightly raised and positioned diagonally on top of the rectangular-shaped library building, a playful open intermediate space is created, hence introducing a curious interaction between the two volumes. Additionally, the diagonal placement of the addition emphasizes the delicate rhythm of the existing façade as well as the horizontality of the whole.

This report explores the structural aspects relating to the existing libarary building as well as the proposed additional mixed-use volume.

Sincerely,

W. KlaverveldF. Huijben

Impression of the additional volume that is positioned diagonally on top of the existing library building. The diagonal placement of the extension invokes a curious interaction of the two volumes while emphasizes the horizontality of both parts.


2. Existing structureThe current state of the existing building has been described in the report “Pre-Design Building Evaluation, 1st Draft Submission, 09/20/2013, Volume One, Executive Summary Facilities Overview (1)”.

Structurally speaking there are 3 main components to distinguish:1 conditions structure;2 geotechnical;3 structural.

2.1 Conditions structureThe existing frame shows some defects. The main defect is concrete damage. The report states that this damage can be restored, so the existing frame is suitable for renovation.

2.2 GeotechnicalAbout the geoscience the following is stated:An engineering study of the MLK library building was performed using available data. The study indicates that two types of foundations were used for building support: mat foundation and piles. A 6ft thick concrete mat foundation was used for the Mechanical Level while piles with 120 kip capacity were used for Level B. A soil bearing capacity of 5000 psf was estimated for the mat. According to available information the initial building design included a 150psf allowance for an additional library floor. The study shows that additional floors may be added without any modification of foundations as long as the final loading does not exceed the design load. If the future load exceeds the maximum design column loads, however, new piles may be required to support the additional loads. Micropiles are considered feasible for this purpose

For a future expansion the following is stated: a. Level BFor Level B, if the new loads from the additional floors exceed the maximum design column loads, any excessive loads should be carried by new piles. Considering the current conditions, micro piles are generally believed to be most feasible foundation method. Micro piles may be installed at new locations or installed in the current pile caps to increase the capacity. A 6-inch micro piles installed to EL -21.0 or deeper may be designed for a capacity of 60 to 80 kips.b. MatThe current mat foundation is expected to support some additional loads. For preliminary design purposes, a load increase of 20 percent of the current loads may still be adequate for the existing mat. However, structural analysis should be performed by the structural engineer.

2.3 StructuralIn (1) the following is stated regarding the existing structure: An existing condition assessment of the Martin Luther King Jr. Memorial Library was conducted by the structural team. The structural system was examined and evaluated per the information obtained from the original structural design drawings and the visual survey of the building. The evaluation was intended to determine the building’s general physical conditions and its ability to support future additional stories above the existing structure. The building is generally structurally sound and in good condition but numerous defects were found during the inspection. A complete report of findings and recommendations of remedial work to avoid further damage are provided below. The existing structure has

1. Structural System Per the original structural drawings, the building’s primary structural framing system is described as follows. The findings of deficiencies are also mentioned below.a. Foundationi. Concrete mat foundationA concrete mat foundation was provided under the Mechanical Level. It was constructed of two ways 6 feet thick flat plate concrete mat with top and bottom reinforcing at each way. Type II low heat cement with cool materials of concrete mix was used for the concrete mat to prevent shrinkage problems. The concrete compressive fc is 8000 psi at 28 days.

ii. Drilled steel piles foundationPile foundations were used above partial “B” level area without mat foundation below. The existing piles are drilling piles made of steel shell, steel pipe or steel wide flange. The concrete fill compressive strength inside the piles is 4000 psi at 28 days. There is 1’-8” thick concrete pile cap on top of piles.

b. Foundation walli. Concrete wall: All exterior building walls are reinforced concrete walls below finished grade. At mat foundation area, the wall thickness is from 1’-5 ½” to 3’-0”. At pile foundation area, the wall thickness is from 1’-0” to 1’-4”. ii. Masonry wall: Some masonry walls were used at non-structural partitions such room divider, fire separation wall and non- bearing exposed exterior wall. The main structural masonry walls of the building are located around the perimeter of the ramp openings above the finished grade. This 16” thick masonry wall was constructed of 4” brick veneer on each side of 8” CMU block wall.

c. Structural framingi. Mechanical level: The entire mechanical level floor is on the top of the described 6’-0” mat foundation with 3” concrete topping slab.ii. “B” Level: Concrete floor framing at pile caps area is constructed of 1’-8” flat plate two way reinforcing slab, but the slab above the tunnel and at corridor area is 10” one slab framed between concrete bearing wall and beams.iii. “A“ Level & First floor level: Concrete framing in those areas consists of 10” concrete flat plate slab framed between concrete columns with at least 8” drop panel above columns.

For a future expansion the following is stated: Per the design live load information stated in the original structural drawing S-33 dated Nov. 4, 1966, the live load at roof is 150 psf. At IBC 2009, the live load for multifamily dwellings is 40 psf. It can be assumed that the original design has already considered the future roof design load with its column load calculation. Therefore altering the existing roof to floor use, will leave 110 psf for future additional floors. We recommend to use lighter structural framing such as framing with 2 ½” light weight concrete on metal deck resting on steel joist @24”O.C.supported by steel beams, using light Ga. metal stud walls and using light metal framing in fill between steel columns with EIFS or brick veneer for outside finish. Furthermore, it is also possible to further reduce the live load from 100 psf to 40 psf per IBC 2009. The leftover 60 psf can be used for another additional floor. An extra saving would also involve changing the use at the existing fourth floor to strictly office use wich could alsosave and additional 100 psf for more floors addition above. In principle an extension of two residential floors appears to be workable. If the extension includes more than two floors a more detailed stability study will need to be performed.

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MLK LIBRARY

STRUCTURALPRE-DESIGN BUILDING EVALUATION

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MLK LIBRARY

STRUCTURALPRE-DESIGN BUILDING EVALUATION

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3. Public cores and outdoor patiosAnalysisThe existing staircases are combined with the elevators. The architect’s wish is to open up these spaces to make it a light and transparent space. To achieve this the masonry between the columns will be removed. On the location of the first floor a patio on the front side will be created.

Proposed solutionThe main structural beams in the floor will be maintained. The construction between these main beams will be removed. It will be replaced with a new infill. The weight on the foundation in total will be reduced.To create the patio at the front side an extra floor slab will be removed.

ConclusionStructurally it will be relative easy to remove the infill in between the main construction.

4. Non-public coresAnalysisCurrently, the stability of the library building is obtained by means of fixed connections between the beams and columns.

Proposed solutionsIn order for the additional wind loads on the added mixed-use volume to be transferred to the foundations through the existing columns, diagonal steel members can be placed inside the existing cores to provide stability.

ConclusionThe existing columns need to be strengthened to withstand the additional loads. In the following stages of the design, the exact additional loads need to be calculated, which will determine the amount of strengthening.

5. RampsAnalysisThe goods supply is currently on the ground floor. The wish is to relocate this under the building. For this the existing concrete ramps need to be altered.

Proposed solutionsThe existing ramps are completely made out of cast concrete. The ramp on the backside of the building will be maintained, the one on the right side will be changed. This will probably mean that the existing ramp will be demolished and a new one will be constructed. This does not need to add extra weight on the foundation. The sizes of the new ramp will be approximately the same as those of the old one.

ConclusionThis interference is structurally speaking a relative easy one. However, executing this will be more difficult. In the preparation phase this needs to be calculated and designed in detail.


7. Bicycle kioskAnalysisThe new bicycle kiosk will need to be placed on a new foundation.

Proposed solutionDepending on the structure of the soil the foundation will be on piles or on steel.

ConclusionStructurally it will be relative easy to make the bicycle kiosk. The structural design will be made together with the architect.

6. Ventilation voids & sky lightsAnalysisBecause of the required fresh air for ventilation and the addition of daylight in the lower floor a few openings in the ground floor are needed.

Proposed solutionsThe new openings are too large to make without reinforcing the existing concrete floor. The floor can be reinforced by using carbon fiber polymer reinforcement or steel beams. This will be further elaborated in the next phase of the design.

ConclusionIt is possible to make the openings in the floor with relative easy structural interventions.


8. Mixed-use volume AnalysisThe additional weight of the mixed-use volume, as well as the additional live loads and wind loads, need to be taken up by the existing load-bearing structure, which consists of steel composite beams and columns on a rectangular grid of 30 by 30 feet.

Proposed solutionsIdeally, the new structure needs to be as light as possible. The proposed load-bearing structure is therefore composed of steel members and composite metal floor decking.While respecting the existing structure, a number of columns that are positioned within the freely-curved boundary of the intermediate floor level can be used to transfer the additional weight of the added volume to the foundation. To prevent potential unequal settlements of the foundation, the additional loads need to be more or less equally distributed amongst these columns.

ConclusionThe basic grid of 30 feet in longitudinal direction can be beneficially reintroduced as a structural line for the additional volume. The columns that are available to carry the weight of the additional volume need to be extended up to the 6th floor level. In aiming to span the 60 feet spans at the center part of the structure and for carrying the weight of the additional volume, a series of steel trusses can be introduced within the height of the 5th floor (the intermediate floor level). This requires the additional floor levels to provide their own stability system, as the intermediate level merely acts as a ‘table’ supporting structure.

The columns that are positioned within the freely-curved boundary of the intermediate floor level can be used to transfer the additional weight of the added volume to the foundation.

Impression of the columns that are to be extended to carry the additional mixed-use volume.


9. AuditoriumAnalysisAt the 5th floor level at the North-East part of the building underneath one of the ends of the added volume an auditorium is introduced. The auditorium is gently merged with the existing top floor of the library building by locally creating an opening in the existing roof structure.

Proposed solutionsFor the additional volume to freely span the auditorium space, it needs to be cantilevering, since no existing columns can be extended at this part of the building. For the cantilevering part of the additional volume, a steel (mega-)truss can be introduced over the total height of the new volume.

ConclusionWith this in mind, it appears to be a logical step to create a series of mega-trusses to transfer the load of the additional volume to the extended columns. The mega-trusses are spaced 30 feet apart, which relates to the original grid size of the main load-bearing structure of the existing library building.

Impression of a series of steel trusses that span the areas where no columns of the existing structure are available. Impression of the steel mega-trusses.

Impression of the cantilvering volume to span the auditorium space.


10. Structural systemAnalysisThe space of the potential partition walls located at the structural grid lines can be effectively used to transfer to loads from the mega-trusses to the available columns by means of structural V-frames.

Proposed solutionsThese V-frames slightly vary in shape, due to the fact that the steel mega-trusses are not aligned with the existing grid of columns as a result of the diagonal placement of the additional volume. Together with the composite metal floor decking of the additional floor levels in fact two large tubular truss structures are created, which are able to take up torsional loads due to the asymmetric positioning of the supports.

ConclusionThe structural concept of the two tubular trusses eliminates the use of diagonals at the intermediate floor level, hence introducing an open space. Apart from that, the internal area of the additional floor levels can be opened up to create large openings or atria.

Impression of the various shapes of the V-frames that are positioned on the structureal grid lines.

Impression of the tubular load-bearing structure.

Impression of the potential separation walls and atrium space of the added mixed-use volume.

Impression of the two tubular steel trusses, which form the main load-bearing system of the additional volume.


11. ConclusionThe existing structure of the Martin Luther King Jr. Memorial Library in Washington D.C. has the capacity to be retrofitted to the new requirements. Furthermore, an additional mixed-use volume can be placed on top of the existing building while retaining its specific character. The existing columns will need to be strengthened to withstand the additional loads. For providing stability of the extension, diagonals can be added at the non-public cores.In the following design stages, sophisticated numerical analysis models of (parts of) the structure can provide additional information regarding the remaining capacity of the existing structure.By means of a 3-dimensional structural analysis model of the additional volume, the exact additional loads can be determined, based on which the existing structure can be structurally enhanced. By applying structural optimisations, it will be possible to minimise the structural weight of the extension. Furthermore, a structural parametric model can be used to provide additional insights with respect to the consequences of various design choices in relation to predefined boundary conditions and aspirations.

Impression of the internal space of the additional mixed-use volume with partition walls.Impression of the internal space of the additional mixed-use volume.

Impression of the overall structure.Impression of the open space of the intermediate floor level (5th floor).


Martin Luther King Jr. Memorial LibraryWashington, D.C.

ABT mechanical engineerConcept DesignDelft, June 13, 2014


Content

1. Concept narrative

2. Heating, ventilation and cooling (HVAC) 2.1 Existing HVAC analysis 2.2 Heating and cooling improvement 2.3 Ventilation improvement

3. Facade renovation

4. Daylight 4.1 Exterior light studies 4.2 Interior light studies

5. Acoustics

6. The roof

7. LEED certification

8. Conclusions and recommendations

CITY MARKET FLOOR N ground floor (scale 1/32’’ = 1) 0 10 20 50ft Concept Design... · 2016. 2. 1. · way reinforcing slab, but the slab above the tunnel and at corridor area

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