Minnaert Building

Minnaert Building, Utrecht | Technoledge Facade | Group 12 | Mats Horck 4369238 | Prateek Wahi 4934695 | Tessa

Rouwenhorst 4275292 | Yarai Zenteno 4922204

Cover Page : Elevational Drawing , Ector Hoogstad Architecten Pan view : The Minnaert Building , Utrecht. Source : Author

Contents 01

About Introduction Photo Reportage Context Architecture

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Literature Research Literature Study Municipality Archives

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03

Facade Composition Facade Structure Chosen Fragment Building Sequence Materialisation Details Tolerances and Movements

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04

Facade Analysis Building Physics Fire Safety Maintenance

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05

Summary Conclusion and Reflection References

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Date Course Subject Students

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14/03/2019 Technoledge Facade Design (AR0115) Future Envelopes (AR0821)

Facade Analysis of Minaaret Building, Utrecht Mats Horck 4369238 Prateek Wahi 4934695 Tessa Rouwenhorst 4275292 Yarai Zenteno 4922204

About

1. Introduction 2. Photo Reportage 3. Context 4. Architecture

01

Introduction The Minnaert building is the central building of the Science Faculties in the Uithof area of Utrecht University. The building which is a homage to Professor Minnaert, takes a creative expression of his name as the structural columns near the entrance of the building. The building facade was inspired as a direct reflection of ripples on sand. This was inspired from the faculty of geology right behind the building.

Location

Utrecht, Leuvenlaan 4

Client Year of Design Year of Completion Architect Contractor

University of Utrecht 1994 1998 Neutelings Riedjik Architects ABT: Rob Nijsse

Renovation Architect Contractor

2016 - 2018 Ector Hoogstad Pieters Bouwtechniek

Installation Adviser Contractor

Ingenieursburo Linseen bv J.P. van Eesteren

Installation Adviser Contractor

Valstar simonis Wijnen Bouw

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Photo Reportage

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1. View from entrance ; South Facade

2. North Facade with the new building attached to the facade.

3. North facade with structural niches and lily pool.

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1

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Key Plan with photograph markers. Source : Authors

4. The artificial ripples made on the facade to give an expression of ripples in sand.

5. The ripples on the facade acting as a sun shade to the windows.

6. The facade texture is achieved through the process of shortcrete.

7. Dilations joints between tow layers of shortcrete.

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03

Context

Geographical context The building is located on the Utrecht Science Park, the campus of the university of Utrecht.

Building heights The building has an average height of 13.8 m with east and west parts slightly higher at 15.7 m and 21.8 m respectively. (Esri Nederland, 2017) Solar Orientation The building is oriented with its long side and entrance to the south. It only has sun shading on east, south and west facade. Since there are no other buildings close to it on the east, south and west it has an unobstructed sun-path (SunCalc, n.d.).

Layer 4: Surrounding Acoustics

Wind Analysis The Netherlands has a Cfb classification according to the Kรถppen climate classification: Sea climate with precipitation in all seasons and a temperate summer. The main wind direction is south to west. The facade of the building is resistant to this rain with a 10 mm water penetration (Meteoblue, n.d.), (Nijsse, 2003, p. 152).

Surrounding Acoustics Analysis Layer 4 indicates Traffic sound map (BGT, 2019). Even though the campus is situated next to the highway ring road Utrecht the traffic sound load on the building is only 61 dB (53 dB at night) (BGT, 2019).

Layer 3: Wind Analysis

Layer 2: Solar Orientation

Layer 1: Building Height

Figure : 1 Surrounding buildings and context . Source : Google Earth

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Figure : 2 Contextual layers analysis

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Architecture

Concept

Materialization

As part of the University of Utrecht the building serves as faculty of Physics and Astronomy providing the general facilities for the faculties of Mathematics and Earth Sciences (Nijsse, 2003, p. 148). These faculties are all linked by aerial walkways with the Minnaert building on the first floor as designed in the concept of the Uithof by Rem Koolhaas’s Office for Metropolitan Architecture (OMA) (Neutelings, 1998, p.8).

“For Neutelings and Riedijk, textures are a narrative tool, used to reinforce the character of a building” (Sanguigni, 2011, p. 158). Since the building had to be compact the building got its monolithic shape. To strengthen its shape the building is wrapped by an envelope that is as rational and linear as possible (Sanguigni, 2011, p. 162).

The standard configuration for a school building is turned on it’s side, instead of a corridor with classrooms on each side, the classrooms are on different levels all connected to one large hall (Neutelings, 1998, p.12) of 20 x 50 m and a height of 8 m (Nijsse, 2003, p. 148). This large hall also functions as housing for all the tare space (Neutelings, 1998, p.12) and as it was intended to be a transition area it is not climate-controlled (Thompson, 2018, p. 214) and only had to be kept frost-proof (Nijsse, 2003, p. 19).

Inspired by the faculty of geology and earth sciences, images of different surfaces of earth such as boulders served as references for the facade (Nijsse, 2003, p. 152). The material that is used, shotcrete, is a rough material which helps create a texture in which shadows and depth play an essential role (Sanguigni, 2011, p. 158). This texture helps emphasizing the zoomorphic character of the building (Sanguigni, 2011, p. 160). The flexibility of shotcrete is such that you can make fanciful forms and sculptural figures with it. They integrated relief elements in the facade plane, ridges whose shadow effect emphasizes the thickset quality and roughness of the skin.

(Neutelings, Riedijk, 2005, p. 283). These ridges are added by fastening flexible PVC pipes to the hard-press insulation and covering them with a layer of moulded welded wire mesh. Shotcrete was sprayed on to cover everything (Sanguigni, 2011, p. 165). This process was because of the intensity of the fitting activities, a very expensive element and were used sparsely (Nijsse, 2003, p. 152). This gives the building a look like patterns that were made by wind in the sand emphasising the monolithic shape even more and give the building an almost sculptural character. The windows look as if they were carved out with a razor-sharp knife (Thompson, 2018, p.

214).

Figure : 3 Programe of the building (Neutelings, 1998)

“Utrecht University seeks to fulfil the role of exemplar in its sensitive dealings with the environment and its use of

materials. Hence the brief states that the new-build must be realized within ecological planning constraints - to

be specific, a compact built form, ecologically sound materials, natural ventilation, heat recovery, high-frequency lighting, water-saving systems and an environment-friendly restaurant. The building and its services must be so designed that the result on site is energy-saving, sustainable and low maintenance.” (Neutelings, 1998, p.7).

Typographic expression : Building standing on it’s own name The building expresses typological take over the name of the building. The part of the building which was built first was its name (Nijsse, 2003, p. 150). The text M-I-N-N-A-E-R-T is 4 m in height and 25 m in length (Sanguigni, 2011, p. 151). Instead of using regular columns the building is supported by columns hidden inside the letters. The load bearing part of the letters are steel hollow sections with a diameter of 400 mm filled with concrete to make them fireproof (Nijsse, 2003, p. 150). “Instead of the building carrying its name the name carries the building” (Neutelings, 1998, p.34). Behind these letters used to be parking space for bikes but since the renovation houses the extension of the restaurant and terrace.

Figure : 4 Erecting the name .

Source: At Work (2005,p.289)

Figure : 5 Loadbearing steel columns.

Source: At Work (2005,p.289)

Figure : 6 Terracotta colored Shotcrete on the facade along with the load bearing letters made in steel column towards the entrance of the building.

Tare space As already described in the concept the building has a large central hall containing all the tare space. Since the insulation rules are so strict the architects found that the heat generated by people, lights and computers will cause cooling even in winter (Neutelings, 1998, p.14). Therefore they decided that they would use the rainwater for cooling, flushing toilets and cleaning (Nijsse, 2003, p. 148). About 3000 cubic meters of rainwater falls on the roof yearly. They catch the rainwater on an impluvium in the roof and let it fall in a large pool in the central hall (Sanguigni, 2011, p. 164, 165). The pool is fifty meters long and up to six meter wide, depending on the amount of rainfall and can hold about 180.00 liters of water. If there is to much rain, the water will stream out of the building (Neutelings, 1998, p.32). Through ducts in the ceilings the water will absorb the heat from the laboratories and will be pumped up to the roof at night to release the heat to the cold sky (Neutelings, 1998, p.14). The sound and smell of the rain falling through the ceiling adding to sensory experiences (Ibelings, 1999, p. 79). Unfortunately after a couple of years the open pond began leaking and the thermal buffer was found to be too small to cool the entire building. The technical failure was so large that the cyclifying element was abandoned (Lettow Studios, n.d.). During the renovation they placed grates in the floor. The rainwater will fall down the grates and be collected outside in a collection basin next to the building. It will then be used for the sprinkler reservoir (Ector Hoogstad architecten, 2017).

Figure : 7 Water collected in the tare space Source: Universiteit Utrecht

Figure : 8 Schematic diagram of the concept Source: insideflows.org

Facade composition The facade does not have a uniform composition. The main grid (1) is based on the load bearing columns on the ground floor every 600 mm. The sub grids that the windows on the west part of the building are based on two times the main grid (so 1200 mm). The difference between subgrid 2 and 3 is that they differ 600 mm. The sub grid (4) that the middle part of the building is based on three times the main grid (so 1800 mm). This is the same size as mixed grid (6). Sub grid 5 is based on a 300 mm shifted grid of the main grid.

Figure : 9 South Facade with structural grids

Figure : 10 North Facade with structural grids

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Literature Research

1. Literature Study 2. Municipality Archives

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Literature Study Publications by the Architect The building was designed in 1994 and completed in 1996. This make the information about the building accessible in terms of publications done by the architect. There are a lot of publications about the building but all of them are in reference to the architectural design part and very little information could be gathered about the facade in general. The publications which we referred to are included to facilitate future references about the building.

Publication by the Construction Consultant Rob Nijsse, the construction consultant of the building, mentions in detail about behind the scene conversation with the architect. In his book, Glass in Structures , he has discussed the building under the examples of structural design beyond glass. He explains about different stages of discussion for the realization of the building and the facade.

Existing Researches.

There were few researches already done with respect to the prefab structure and its construction. These researches were referred to understand the overall view of facade compositions and construction of the facade on the prefab. building envelope.

1. At Work, 2005, Neutlings Riedijk Architects, explains about the building in construction phase.

2. Minnaert Buidling, Neutlings Riedijk Architects, explains about the concept behind designing of the building. It also explains about the functional aspect of the building.

3. Glass in Structures,Rob Nijsse, 2003 , This publication explians the building from the point of view of construction consultant.

Fig 11. Detail of the fixing between the shortcrete, the system of PVC pipes and welded wire mesh, Minnaert Utrecht, 1994-1998. Source: Neutlings Riedijk Architects, Giampiero sanguigni, 2011

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4. Neutlings Riedijk Architects, Giampiero sanguigni, 2011, This publication includes facade details from the project. The book is however, complied on occasion of the inauguration of the MAS Museum, Antwerp

1. Sketch of Facade detail, Neutlings Riedijk Architects. The sketch gives a basic idea about the facade fixation onto the prefab wall and slab. The sketch also represents the layers in between the shortcrete and the building envelope. This sketch was provided to us by the architect’s office .

2. Components of building structure, Glass in Structures,Rob Nijsse, 2003. The figure explains about the thought behind the structure of the building. The structure was made in a portal system, where the diagonal element behave as an extra support to t he overall structure.

3. Prefabrication study of Minnaert Building , Farid Mahmmod , 2018. The diagram suggest the building sequence of the entire prefab structure. This helped us to understand the sequence of the building and when does the facade construction must have accomplished during this sequence.

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02

Municipality Archive The drawings we received from Municipality of Utrecht were only for the part of the building which was renovated. However, apart from all the drawings received we referred to only few of them to understand the facade. The drawings which were used to understand are mentioned hence forth.

Fig 12. Transverse section of the building. The drawings represents the scale, vertical circulation and connection between the floor slabs and outer envelope.

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Fig 13. Vertical detail of the ground floor window opening.

Fig 14. Vertical detail of the load bearing window openings.

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Fig 15. Horizontal Window Detail

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Fig 16. Vertical detail of the window openign on first floor.

Facade Composition 1. Facade Structure 2. Chosen Fragment 3. Building Sequence 4. Materialisation 5. Details 6. Tolerances and Movements

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01

Facade Structure

Load bearing structure

Regulations

In order to achieve the large atrium of 20 m wide and 8 m high with no visible support construction all the columns are positioned in the facade plane (Nijsse, 2003, p. 151). On one side by sixteen upturned buttress elements (Neutelings, 1998, p.32). On the ground floor the building looks as if it is floating on glass (Neutelings, 1998, p.30). For this the concept of the spread columns was used. The columns are integrated in the window frame structure. 100 x 100 mm cylinders filled with concrete and covered with fireproof paint were placed every 600 mm. (Nijsse, 2003, p. 151). These beams are clamped on the top and the bottom to reduce the bucking length to about 70% of the normal length of the column. The insulated glass panels were fixed straight to the steel hollow sections of the columns with an internal clamp construction (Nijsse, 2003, p. 151).

Since the building was built between 1994 and 1998 the building had to comply with the Dutch Building Decree 1992. Since it’s renovation in 2016-2018 it has to comply with the dutch building degree 2012 (the most recent version of october 2016). The Dutch Building Decree refers to Eurocodes and NEN-EN norms.

The roof was found in the catalogue of the prefab concrete industry: standard bridge I-girders in the shape of fully prestressed concrete. 400 mm wide with a height of 1250 mm in the middle (Nijsse, 2003, p. 149). Instead of resting the roof slabs on top of the beams, large concrete trays were mounted underneath them anchored in place with 16 stainless steel threaded ends protruding from the beams (Neutelings, Riedijk, 2005, p. 277).

Fixing system No information can be found on how the shotcrete is connected to the prefab concrete panels. Assumed is that some anchors are placed directly in the prefab panels and support the shotcrete through the insulation. This might be the cause of some cold bridges.

Loading system of the facade - wind load In NEN-EN 1991 - Eurocode 1: Actions on structures - part 1-4: General actions - Wind actions, the fundamental value of basic wind velocity for Utrecht (wind region III) is found to be vb,0 = 24.5 m/s. The peak wind velocity is based on wind climate, terrain roughness and orography and the reference height. The peak wind velocity is found to be for 18.7 m qp(h) = 0 .807 kN/m2.

Loading system of the facade - dead load NEN-EN 1991-1-1+C1: Eurocode 1: Actions on structures - Part 1-1:General actions - Densities, self-weight, imposed loads for buildings. The dead load of the facade is estimated in table 1. This is a representation of the facade parts where shotcrete is used so other parts like the windows, window frames and anchorages are left out to simplify the calculations. As you can see in the table the shotcrete is a very heavy cladding system.

Dead load Shotcrete Wire mesh EPS insulation Prefab conctete Total Figure 17. roof construction (Neutelings, 1998).

Density

Thickness

[kg/m3]

[m]

2200 7800 1040 2500

0.05 5 0.08 0.2

Weight per Weight of Weight of square meter whole facade whole facade [kg/m2] [kg] [N] 110 33000 3237300 39 11700 1147770 83 249600 2448576 500 1500000 14715000 732 2196600 21548646

Table 1. Estimation of dead load

Figure 18. Structure south facade, ground floor is made of beams.

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Chosen Fragment As mentioned in fig 9. the facade is governed with different structural grid. On the ground floor where the facade has a grid of 600 mm apart load bearing columns, the first floor has the grid slightly different. Since the entire facade is an innovative take over the use of shotcrete layer. It became imperative to understand these different components right from structure to material in such kind of unique facade type.

The south façade was chosen to understand how these ridges behave as sun shading to the window, also to understand any potential thermal bridge. The fragment was chosen in such a way to incorporate the load bearing bottom and different sub grid on the first floor and a ridge on it. Since, the ridge was also an important part of the architect’s idea , it was important to include it in the process of facade analysis.

Since the building is 150 m long. It was decided to understand the fragment that could be showcase necessary dilations on the façade due to thermal expansion of concrete within itself.

Fig 19. South Facade marked with the chosen fragment

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Building Sequences

01a. Foundation

Firstly the foundation is made. The ground is excavated and the concrete is poured inside (a). A hard insulation material (EPS) is placed inside the excavation to wear stand the large forces of the layers which will be placed on top. To finalize, another concrete layer is poured in situ on top of the EPS to create the base layer of the ground floor.

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01b. Insulation ground floor

01c. Ground floor

02a. Prefab load bearing structure bottom

02b. Steel columns poured with concrete

02c. Prefab load bearing structure top

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03. Wooden window frame first floor Adding a shotcrete outer layer at the outer plane could cause lots of dirt and damage to the already installed components. Because shotcrete is very alkaline, the upper floors are assembled first. Wooden frames are placed in the openings of the load bearing structure to which the window frames will be placed later.

04. L- and Z-profiles

Certain profiles need to be attached to the load bearing structure before the insulation is placed. These profiles will carry the shotcrete layer (Z-profile) and a sun shading system (L-profile). Firstly the L-profile will be added (a), followed by the Z-profiles (b). The first profile has a Z shape which enable the sun shading system to fit perfectly between the load bearing structure and shotcrete layer.

03. Wooden window frame

04a. L-profile 22

Because a continues profile is placed on top of a discontinuous profile, spaces in between will appear and will lower the attachment of the Z-profile to the load bearing structure. Therefore plastic components are placed in between to fill up the gaps. These elements have the same thickness of the L-profile, which is around 4 mm.

04b. Z-profile

05. Insulation of the upper part

Hard insulation material (EPS) is placed on top of the concrete structure to satisfy the thermal energy requirements of the building. Although, because of the shaped profiles which are installed before, thermal bridges will appear between the inside and outside environment. Also the large area at which the sun shading system is installed will create a huge thermal bridge.

The hard insulation material is glued directly to the load bearing structure behind. Because this layer need to carry a part of the load of the shotcrete, it is necessary to divide the forces, which are acting on the EPS, evenly.

05. Insulation of the upper part

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06. Creating the shotcrete layer Because the shotcrete skin had to be applied to the hard insulation material, the suggestion was to use a steel mesh (c) fillet with another insulation material (b) to create the riffs. In between PVC pipes (a) will be placed which enables the shotcrete (d) to have a round edge at the location of the riffs.

In accordance with the faculty of geology, the building need to have an earthen character which results in a terra-cotta color. Moreover, all edges, corners, window frames and gutters had to be made in shotcrete as well.

The contractor was allowed to apply the shotcrete directly onto the hard insulation material because the load bearing structure would be dampproof, hence the seams were taped properly. This implies there is no cavity presence in the structure. Also the maximal amount of water penetration would be 10 mm. Because the total thickness of the shotcrete is 50 mm, no water was able to penetrate trough this layer.

06a. PVC 24

06b. Filling material

06c. Steel mesh

06d. Shotcrete

07. First stage window frame ground After the shotcrete has dried, the contractor is able to start finish the facade structure at the ground floor. The same principle is used as at the upper floor, firstly a wooden frame (a) is placed on which the whole window frame will be assembled. In front of the prefabricated load bearing structure, insulation material (b) is placed followed by a prefabricated concrete element (c). Later an aluminum profile (d) is attached to the wooden frame to close off the gap between the insulation and concrete layer. This creates the first line of defense.

08. Window frame upper floors

07a. Wooden frame

08a. Aluminum profiles

08b. Prefab windowframe

07b. Insulation material (EPS)

07c. Prefab concrete element

The window frames are prefabricated and are therefore different from the custom made windows which are applied at the ground floor. Aluminum profiles are attached to the wooden frame (a). A prefabricated window frame is attached to the wooden frame (b) and will close off the plane between the insulation and concrete layer. This will create the first line of defence.

07d. Aluminium profile 25

09. Glass Plastic blocks (red) are placed 100 mm from the edges in the windowframe before the glass is placed. This allows for tolerances of the glass. Between the glass and the facade structure, placeholders (blue) are added which prevent the glass from damaging. The gap that is created is later filled with silicon to create a water protective sealant. To keep this sealant in place, filling material (white) is added between the placeholders.

09a. windowframe without glass 26

09b. windowframe with glass

09c. windowframe without glass

09d. windowframe with glass

10. Profiles + sealant To fix the glass in its frame, profiles are attached to the structure behind.

At the ground floor the profile is made of steel and attached to the wooden frame (a). An aluminum profile is used at the upper floor and attached to the prefabricated window frame (d). The water- and air tightness of the facade is solved by adding a sealant between the profiles and the glass.

10a. profile ground floor

10b. sealant ground floor

10c. sealant ground floor

10d. sealant upper floor 27

11. Sunshading system Finally the sun shading system can be placed to finish the facade. First the sun shading box (a) is attached to the L-profiles (stage 6) which transfer the weight to the load bearing structure. This box will shelter the actual sun shading which is made of fabric (b). Eventually the whole system is closed (c) to provide a smooth surface. In the end the shading system is able to lower (d) by itself due to sensors and prevent glare or unwanted solar heat from coming in.

11a. Sunshading system box

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11b.sunshading

11c. Closure of the box

11d. Shading down

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Materialisation

1

2

3

4

5

6

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Layer

Material

Denisty [kg/m3]

Heat transfer coeficient [W/mK]

Floor finishing

Tiles

2000

1.2

Thickness [m] 0.05

Load bearing wall 1C Hollow core slab

Concrete 2500 prefab

1.9

0.20

Concrete 2500 prefab

1.9

0.25

1D Load bearing column 1E Load bearing wall 1F Ground floor 1G Insulation 1H Foundation

Steel 2200 Concrete

1.9

0.1 x 0.1

Concrete 2500 prebaf

1.9

0.20

Concrete 2200 in situ EPS 1040

1.9 0.04

0.08

Concrete 2200 in situ

1.9

0.20

1A 1A

1B 1B

1C

1D 1E 1F 1G 1H

Material Denisty [kg/m3]

Heat transfer coeficient [W/mK]

Insulation primary

EPS

1040

0.04

Thickness [m] 0.08

Filling material 2C Tupe

EPS

1040

0.04

-

PVC

1300

0.19

-

2D Insulation primary

EPS

1040

0.04

0.08

2A 2B 2C

2D

30

2B

- Self bearing elements that spans till 14 meter - Transferring the load through the load bearing structural walls to the foundation.

- Load bearing structure to realize the window openings - Steel outer skin because of the finishing - Concrete inner filling to satisfy the fire safety requirements - Prefabricated element - Assembled as differnt puzzle pieces - Concrete elements which is poured in situ

Layer 2A

- Tiles are used to continue the monolithic atmosphere to in the inside of the building - Easy to clean - Prefabricated element - Assembled as differnt puzzle pieces

- Hard insulation material to withstand the dead load of the concrete ground floor and variable forces - Concrete elements which is poured in situ

- Primary layer of insulation material - Glued against the load bearing structure - Anchors between the insulation material to carry a part of the dead load of the steel mesh and the shotcrete finishing layer, thermal bridges are created as a result - Functions as a mall to create the riffs at the shotcrete outer skin - To create the round edges of the riffs at the shotcrete outer skin - Carried by steel anchors which transfer the load the load bearing structure, thermal bridges are created as a result - Primary layer of insulation material

Denisty [kg/m3] 700

Heat transfer coeficient [W/mK] 160

Alluminum

2700

237

3C Water protection vertical 3D L-profile

Alluminum

2700

237

Steel

7800

45

3E

Steel

7800

45

Wood

700

160

Steel

7800

45

Layer

Material

Prefab window frame Sealant

Aluminum

Denisty [kg/m3] 2700

Heat transfer coeficient [W/mK] 237

Rubber

-

-

4C Double glass 4D Profile

Glass

2580

1.05

Aluminum

2700

237

4E 4F

Sealant Double glass 4G Profile 4H Spacer

Silicon Glass

2580

1.05

Steel Plastic

7800 975

45 0.25

4I

EPS

1040

0.04

Pastic

975

0.25

3A

3A 3B

3B

3C

3D 3E

Material

Primary frame structure Water protection vertical

Wood

Z-profile

3F

Primary frame structure 3G Water protection horizontal

3F

3G

4A

4A 4B 4C 4D 4H

Layer

4I

4J

4E 4F 4G

4B

4J

Filling material Glass block

- Primary layer as a basis to fix the window frames - Attached with screws to the load bearing structure - Screwed against the primary wooden frame structure, placed behind the window frame to make it water tight - The width of the horizontal protection is greater than the distance between the vertical elements - Screwed to the primary wooden frame structure, placed behind the window frame to make it water tight - Steel profiles which transfer the dead load of the sun shading system to the load bearing structure - Steel profiles which transfer the dead load of the shotcrete outer layer to the load bearing structure - Primary layer as a basis to fix the window frames - Attached with screws to the load bearing structure - Screwed to the primary wooden frame structure, placed behind the window frame to make it water tight - The width of the horizontal protection is greater than the distance between the vertical elements

- Prefabricated aluminum window frame which is fixed at the primary wooden frame - Frame to fix the glass - Ensures water protection at the edges between the window frame and the glass - Provides insulation, water protection and air tightness of the vertical plane - After the glass is placed in the window frame, an aluminum profile is placed in front the fix the glass at its place See 4B See 4C - Steel profile that fix the glass at its place - Plastic piece between the glass and the structure to protect the glass from damaging - Creates a space between the glass and the structure which can be filled with silicon - Material between the spacer to provide a smooth straight surface which allows to add the silicon - Placed below the glass panel to allow for tolerances 31

5A 5B 5C 5D 5E 5F 5G 5H 5I 5J

Layer 5A

Shading box (top) 5B Shading box (side) 5C Shading box (profile)

Aluminum Aluminum Aluminum

5D Shading box (bottom) 5E Shading 5F Cable 5G Profile

Aluminum Fabric Steel Aluminum Plastic Plastic Steel

5H Clamp 5I Placer 5J L-Profile

Layer

6A 6B

6C

32

Material

Material

Denisty [kg/m3] 2700

Heat transfer coeficient [W/mK] 237

2700

237

2700

237

2700

237

7800 2700

45 237

975 975 7800

0.25 0.25 45

- Top part of the sun shading box that protects the fabric - Fixed to 5C, assembled at the same time - Side part of the sun shading box that protects the fabric - Fixed to 5C, assembled at the same time - Load bearing part of the whole system - fixed to the L-profiles which transfer the load to the concrete inner skin - Bottom part of the sun shading box that protects the fabric - Fixed to 5C, assembled after the shading is placed - To fix the fabric along a vertical line in front of the window - Produces weight to keep the surface straight and in the vertical plane - Holding the aluminum profiles together - Fixate the whole bottom element between the steel cables - To attach the steel cables

Denisty [kg/m3]

Heat transfer coeficient [W/mK]

7800

45

Thickness [m] 0.005

6A

Wireframe Steel

6B

Finishing top

Shotcrete 1800

1.9

0.05

6C Finishing bottom

Concrete 2200 prefab

1.9

-

- Creating a rough surface which is able to keep in the shotcrete in place - Through steel anchors attached to the concrete inner skin - Finishing layer which is sprayed against the insulation layer - Is added from to top part to the bottom part of the building to prevent damage are dirt - Prefabricated concrete finishing element which is placed in front of the insulation - Massive element which is able to withstand the external factors of the outside ground

Details

8 m.

Insulation EPS 80 mm thk.

2013.5

Prefabricated concrete walls Prefabricated concrete slabs

EPS

1572.5

2109

Roller Blind Sunshading system

det B

PVC for ridges dia. 120 mm

2109

Shotcrete Faรงade

Shotcrete Ridges PVC

det A

Steel Mesh

Steel Mesh Anchors Roller Blind Sunshading system

Spacer L-Profile

2239

Z-Profile Sun shading box Double Glass Panes

det C

122

det A Custom Made Window Steel frame

Primary Wooden Frame

837.5

05

Wall section through the chosen fragment

Detail A

33

2013.5

Load Bearing Concrete Prefab Steel Mesh Double Glass Panes

Steel Mesh Anchors

Silicon Sealant

Shotcrete

122

Primary Insulation EPS

Filler

Primary Wooden Frame

Steel Frame

Horizontal Water Protection (steel)

L-Profile

Z-Profile Sun shading box

837.5

Spacer

Primary Insulation EPS

Double Glass Panes

Concrete Prefab, Finishing Bottom

1572.5

Aluminium Window Profile

Load Bearing Wall Concrete Prefab

Detail B

34

Detail C

06

Tolerances and Movements

Tolerances regards to the allowable deviation from the standard limit of any component. These deviations must be taken into account while designing different facade elements, since it can affect the overall appearance or performance of the facade. For the analysis of the facade, we identified the scope of tolerances on three levels.

1. Material or manufacturing tolerances.

These tolerances relates to the deviation it may be caused while the production of the building materials used. For instances according to NEN 14992 the prefabricated wall elements ranging between .5m to 3m can have a dimensional tolerance of ∓ 5mm. While the NEN 1168 specifies the tolerances of the hollow core slab in terms of length is ∓ 25mm, while the width should have ∓ 5mm.

The pressured concrete layer of the hollow core slab can have a maximum deviation of - 10mm.

2. Assembly Tolerances.

These tolerances are taken into account while fixing facade components like window frame and supporting elements from facade to the main structure.

3. Thermal Movements The design should also consider tolerances take into account the thermal movement due to different thermal expansion of materials and structural movement due to different load conditions.

D

C

Fig 20. Detail C

B

Fig 21. Detail D

Material / Manufacture Tolerances Assembly Tolerances Thermal Movements

Fig 22. Detail A

Fig 23. Detail B

A

Fig 24. Wall Section through the chosen facade fragment

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Since, the entire facade structure is 150 m long and has to have the monolith geological expression as per the original idea of the architect. Since the facade is dark Terracotta color, it is susceptible of large heat gains from the south sun. The facade is expected to undergo a diurnal temperature gradient of 80 °C , where the highest temperatures can go about 60 °C in summer while lowest can go to -20 °C . These temperature differences can lead up to 150 mm of expansion throughout the year (Nijsse, 2003, p. 152, 153). This could lead up to cracks in the facade. However, the architect wanted to let nature play its role and have the cracks stay on the facade, but this might have caused the concrete to fall down from the facade.

These problems were then resolved by first dividing the entire facade into a grid of 10 x 10 m as mentioned fig. 28. These grids were then used to provide artificial dilations line which were made to follow along the curve lines of ridges. Some space for the thermal expansion of concrete was also left below and above the windows (fig 25). The second problem was taken care of as the wire mesh used for the form-work did not allow the concrete to fall from the facade (fig 27).

The building facade details were not available directly. This lead us to read the fragments of the details available and to make assumption about the materials and connections used on various levels.

Fig 25. Space for dilation

Fig 26. Space for dilation along the ride lines

Fig 28. 10 X 10 m grid division on the facade

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Fig 27. Wire Mesh along the ridge lines

Facade Analysis 1. Building Physics 2. Fire Safety 3. Maintenance

01

Building Physics

Building Degree The Dutch Building Law (Bouwbesluit) describes multiple requirements that a building must fulfill in order to be build. Below are the minimal insulation values (R-value) described of the building skin (Isobouw, w.d.): - For façade the R-value should be minimal 4,5 m2K/W - For roof the R-value should be minimal 6,5 m2K/W - For floor the R-value should be minimal 3,5 m2K/W Since 2015 a law about the insulation values of renovation projects have been described in the Building Law, the following insulation values are required: - For façade the R-value should be minimal 1,3 m2K/W - For roof the R-value should be minimal 2,0 m2K/W - For floor the R-value should be minimal 2,5 m2K/W However, if 25% of the total insulation layer will be replaced, the renovation must fulfill the requirements of a new building (Isobouw, w.d.).

Thermal and water barriers The wind- and water tightness of the façade is mainly solved by using a concrete load bearing structure.

This structure is assembled as multiple prefabricated pieces. The space between these elements are fillet with a silicon and glue to make the whole air- and watertight. Located at the window openings, sealants are also used between the glass and the window frame to prevent water or air from coming in. At the prefabricated window frames rubbers are used. Located at the custom made window frame a silicon is used, which needs to be maintained and replaced every 5 to 10 years. The picture below describes the first and second layer of defense.

Thermal calculations The U-value for a double glazed panel, filled with argon has approximated a U-value of 1,80 W/m2K, for this exercise we assume for the aluminum window frame at the first floor a U-value of 1,70 W/m2K (Isolatie.net, w.d.). The U-values of the opaque part and the window frame at the ground floor can be calculated using the following formula R = d / λ, where λ is the heat transfer coefficient [W/mK] and d the thickness of the construction layer [m]. To calculate the U-value, we use the formula U = 1 / R. Opaque part d λ Inside layer Concrete 0,2 1,9 Insulation 0,08 0,04 Shotcrete 0,05 1,8 Outside layer Total The U-value of the opaque part of the façade is equal to 0,43 W/m2K

R 0,13 0,11 2,0 0,04 0,04 2,31

Window frame – d λ ground floor Inside layer Wooden frame 0,05 0,14 Outside layer Total The U-value of the window frame at the ground floor is equal to 2,32 W/m2K

R

Window frame – ground floor Glass Total

U [W/m2K] 2,32 1,80

A [m2] 1,08 0,28

Total U-value window ground floor = (U1 * A1 + U2 * A2) / (A1 + A2)

Water resistant layer

Water resistant layer

Thermal line

Thermal line

Vapour barrier

Vapour barrier

Fig 29. Detail B

Fig 30. Detail D

Water resistant layer Thermal line Vapour barrier

Fig 33.

Detail along the ground floor window in plan.

Window frame – first floor Glass Total

U [W/m2K] 1,70 1,80

A [m2] 0,50 0,55

Total U-value window first floor = (U1 * A1 + U2 * A2) / (A1 + A2)

0,13 0,35 0,04 0,52 U*A 2,51 0,50 3,01 2,22 U*A 0,85 1,00 1,85 1,76

Water resistant layer Thermal line Vapour barrier

Water resistant layer Thermal line Vapour barrier

Fig 31. Detail A

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Fig 32. Detail C

Based on the calculated U-values, we can conclude that the whole façade (both closed as transparent parts) doesn’t satisfy the current requirements for thermal insulation. This building is designed in 1994 and finished in 1997. The standards in that time weren’t high whitch could explain the bad insulation performance of the building.

Solar load The total amount of solar heat during warm sunny days could reach 900 W/m2 (BKWiki, 2010). The total amount of glass area determines the total energy which will be transmitted through the faรงade. Our chosen fragment consist out of 34% of transparent elements, which is equal to 20,9 m2. The other 66% (40 m2) is made of opaque parts. Therefore the total amount of solar heat which is transmitted through the faรงade openings is equal to 18,81 kW. Sun shading systems are installed to withstand this unwanted heat. These systems are regulated by sensors which will lower the shading in case the total amount of sun lights becomes too high. Furthermore, pistons which are attached to window frames allows to open the window automatically to stimulate the natural ventilation in order to cool the building.

D

C

Sustainable solutions For the transition to sustainable-energy use, the Mineart building is heated and cooled by District Aquifer Thermal Energy Storage (DATES, in Dutch: warmte- en koude opslag, WKO). DATES connects all the wells and all the buildings in its area (North-West Cluster) with each other using a groundwater filled distribution network. This enables energy exchange between buildings and simultaneously delivery of cooling as well as heating at the same time. With this sustainable energy source, Utrecht University saves fossil energy and reduces the CO2 emission. This is in line with the ambition of Utrecht University to be fully CO2 neutral in 2030.

B

A

Acoustics To insulate a building against internal and external sound, lots of mass has to be integrated in the building design. The Mineart building is due to this manner very simple and easily insulated against unwanted sound, since the whole load bearing structure consists out of prefabricated concrete elements. The opaque part of the buildings can be seen as one layer made of heavy material. The voids between these elements are filled with silicon to make the whole layer air tight, which is beneficial for the total internal and external sound insulation.

On the other hand, the transparent part on the ground level of the building faรงade blocks less sound.

Because this part is custom made and no preparations are made, this window frame can be seen as the weak spot of the faรงade again external sound.

Fig 34. Wall Section through the chosen facade fragment

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02

Fire Safety

Overview on regulations and general concept The regulations taken into account for this building were: NEN-EN 1991-1-2+C1: Eurocode 1 - Actions on structures - Part 1-2: General actions - Actions on structures exposed to fire NEN-EN 1992-1-2 Eurocode 2: Design of concrete structures - Part 1-2: General rules - Structural fire design NEN-EN 1994-1-2+C1 Eurocode 4: Design of composite steel and concrete structures - Part 1-2: General rules - Structural fire design

STEEL TUBE

CONCRETE

The regulations used date from 1994, since this building was first conceptualized in 1994 and built in 1996. It can be inferred that this does not meet with the actual regulations, although when adding the new cafeteria on the first floor and the major renovations done throughout the building in 2016 they revised the fire safety regulations.

A new fire concept was devised as shown in the next figure.

100 mm

The fire escape system was perfected by adding the required automatic fire alarms which are shown by the red dots. This are mainly located in the halls, as well as the exits and emergency stairs. Additionally, three manual fire alarms were placed in the main hall.

An important feature to mention about the renovation is that the emergency exits, which include emergency stairs, were built in a way that allowed for a 60 minute long fire resistance. The rest of the building has a duration of around 30 minutes, mainly the partition walls and other components. As for the main structure, according to the building information acquired from the Gemeente Utrecht “ Fire-resistance for the main load-bearing construction was done according to specifications (fire-resistant lining)�.

In the fragment analyzed, what appears to be the window mullions are actually rows of small columns. They are steel hollow sections, and since they are part of the main support construction, they were filled with concrete to make them fireproof. This columns are also covered with a fireproof painting. (Bob Rijse, pp.150) This is represented in the figure to the rifht.

Figure 36. Fire Safety concept

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Figure 35. Small Column material composition

Most of the elements of the fragment chosen are made of concrete (the columns, prefabricated concrete walls, and floor slabs).

The 200 mm prefabricated concrete wall has a single layer of reinforced steel, so if the walls fail or collapse due to fire, it is most likely due to the failure of this internal steel layer. The melting point of steel may vary, though in average is a 1370°C. The documented temperature of common fire is around 590 °C and could go up to 750 °C , which although it still lower than the melting point of steel, it does not mean it would not fail, since the increase on temperature could affect the strength of the reinforced steel. Thus, this becomes an area of opportunity to further research and discuss since steel has a maximum range of service temperature of 150°C to 180 °C, although concrete has a maximum service temperature range from 540 °C to 640 °C. (CES Edupack Database, 2018).

Other material present in the façade that needs attention is the expanded polystyrene (EPS) used for the insulation. EPS is a lightweight cellular plastic material consisting of small hollow spherical balls. EPS starts to soften at a temperature of 100 °C, and self-ignite at a temperature of about 450 °C. Since the EPS in this fragment of the façade is covered mainly by concrete and/or steel, the those are the elements that have the most important role in contributing to fire safety, since they are the immediate contact point with the interior and the users.

Even though, some general fire prevention measures need to be taken into account for this material:

Always use a covering material: which passes in our case

Quality of the details : how different materials meet and are connected is essential for fire safety. So as evidenced by the next photo taken on site, the building façade is not properly maintained and the details are not perfectly done. This could become a problem in the future and could compromise the fire safety of the whole shotcrete façade and the building in general.

Using a fire retardant EPS: with the information found, it is not known if a normal EPS was used or a fire retardant one. The question arises of whether this could be upgraded or not since it would mean to work around the shotcrete (a task somewhat impossible only taking the whole thing down).

Figure 37. Façade Details

Figure 38. Material Selection Concept (redrawn by group) .

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03

Maintenance

According to the construction consultant “The facade is four years old now and looks perfect and almost new, despite all the fears of its getting dirty. The water penetration requirement of 10 mm was a major condition in this respect. All in all, it is fair to say that this large-scale implementation of shotcrete, used as a facade skin, or a (rain)coat, for a building, turned out to be a perfect new option for facades that need a touch of the threedimensional” (Nijsse, 2003, p. 153). Although this was the case some years ago, now, 20 years later, the façade shows some deterioration. The red color is somewhat muted, and some parts are whiter than others, showing its decay through time. The façade facing south shows the most decoloration.

Another important element to mention is the presence of moss on shotcrete façade. The moss is more apparent on the north façade, which tends to be colder and wetter, though all façades have moss on them. As it can be

seen in the image 2 of photo reportage, the amount of moss gives the idea that maintenance on the shotcrete is not performed, and only windows are clean regularly. A maintenance unit is located on the highest part of the roof as shown on figure x, but only on the west part of the building, which is where most windows are located.

(Include photos with moss and calc on the steel).

As previously stated, the window frames are of steel, and from the inspections done on site a white layer is found.

This could be calc or the concrete of the façade bleeding and tainting the window frames below. One reason for maintenance not to be applied regularly on the frames could be because then the galvanized properties could also come off if they clean the windows with a special chemical.

Figure 39. Building maintenance unit located on highest part of the roof. (Sanguigni, 2011) (Google, 2019) (Neutelings, 1998)

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Summary 1. Conclusion and Reflection 2. References

1

Reflections

Even Though we found a lot of books and received a lot of drawings from the architects there were little details to work with. The only details we found were made early in the design and where not that detailed. Therefore a lot of research was done to limit the amount of assumptions we had to make. The modeling of the 3D and making it ready for the VR took a lot of time. We split up the work to make sure everyone did about the same amount of work.

Relevant problem statement For assignment B we will continue with the redesign of the facade fragment. The research topic will be Adapative Facades: Smart Textile Skin. A relevant problem statement we found during the analysis is: “how can we make this heavy facade demountable, but keeping the same looks and feel and increasing its functionality.

Conclusion By making a detailed analyses of the facade of the Minnaert Building, new insights shows us that this building is really unique. A fully custom made window frame and the way the shotcrete layer is attached to the rest of the wall. However, doing things differently could shorten the overall performance of the façade. Frames which are custom made will never be that good as prefabricated frames, because the connection between elements will be less perfect. This could influence the total maintenance and repairs during its service life period. Also, using multiple or different materials to assemble a custom made façade results in reducing the recyclability of the whole element. Further, both the load bearing structure as the finishing consist out of concrete. Therefore combined together, this building isn’t easy to recycle after it will be demolished. The positive aspect of using a high amount of concrete is the acoustical performance.

Also due to the low amount of insulation material and using a self-assembled window frame, the thermal performance of the building are minimal. The building standards weren’t that high during the time it was designed, which could explain these low insulation values.

2

References

BGT. (2019, January). Geluidsbelastingkaarten gemeente Utrecht. Retrieved January 24, 2019, from http:// www.utrechtmilieu.nl/geluidskaarten/ De Wit, Annelies. Behavior and structural sign of concrete structures exposed to fire. KTH Architecture and the Built Environment. 2011. Retrieved from http://www.diva-portal.org/smash/get/diva2:441311/FULLTEXT01.pdf.

Accessed March 8, 2019.

Dlubai. (n.d.). Selection of location on map of the Netherlands and determination of wind load according to NEN EN 1991-1-4. Retrieved March 5, 2019, from https://www.dlubal.com/en/load-zones-for-snow-wind-earthquake/ wind-nen-en-1991-1-4.html?

Ector Hoogstad architecten. (2017, December). Minnaertgebouw heropend! Retrieved March 3, 2019, from https://www.ectorhoogstad.com/nl/blog/minnaertgebouw-heropend Esri Nederland. (2017, February 23). Waterschap hwh-bm - homepage. Retrieved March 3, 2019, from http:// www.ahn.nl/index.html Fire safety briefing- EPS insulation. Retrieved from http://www.eps.co.uk/pdfs/fire_booklet.pdf (Accessed Mar 8, 2019) Google. (2019). Minnaertgebouw. Retrieved from https://www.google.nl/maps/@52.0868707,5.1659922,109m/ data=!3m1!1e3 Ibelings, H. (1999). Architectuur in Nederland: jaarboek 1998-1999 = Architecture in the Netherlands: yearbook 1998-1999. Rotterdam: Nederlands Architectuur Instituut (NAI).

Lettow Studios. (n.d.). Minnaert building. Retrieved March 3, 2019, from https://www.insideflows.org/project/ minnaert-building/ Meteoblue. (n.d.). Wind rose Utrecht. Retrieved February 24, 2019, from https://www.meteoblue.com/en/ weather/forecast/modelclimate/utrecht_netherlands_2745912 Nassiv, A. FINITE ELEMENT THERMAL ANALYSIS OF CONCRETE FILLED HOLLOW STEEL SECTIONS DURING FIRES. 2004. Retrieved from https://www.researchgate.net/publication/237334130_FINITE_ ELEMENT_THERMAL_ANALYSIS_OF_CONCRETE_FILLED_HOLLOW_STEEL_SECTIONS_DURING_ FIRES [accessed Mar 11 2019].

Neutelings, W. J. (1998). Minnaertgebouw Universiteit Utrecht = Minnaert Building Utrecht University. Rotterdam: 010 Publishers.

Neutelings, W. J. & Riedijk, M. (2005). At work : Neutelings Riedijk Architects. Rotterdam: 010 Publishers.

Nijsse, R. (2003). Glass in structures: elements, concepts, designs. Basel: Birkhauser-Publishers for Architecture.

Sanguigni, G. (2011). Neutelings Riedijk architects. Roma: Edilstampa.

SunCalc. (2009). SunCalc sun position and sunlight phases calculator. Retrieved February 24, 2019, from http:// suncalc.net/#/52.0868,5.1665,12/2019.06.19/22:18 Thompson, W. (2018). Ornament and identity : Neutelings Riedijk Architects. Berlin: Hatje Cantz.

Isobouw, (w.d.). WETTEN EN REGELGEVING M.B.T. ISOLATIE. Source: https://www.isobouw.nl/nl/kennisbank/ wetten-en-regelgeving-mbt-isolatie/, Retrieved March 10, 2019 BKWiki, (2010). Zon bouwfysica. Source: https://wiki.bk.tudelft.nl/bk-wiki/Zon_bouwfysica/, Retrieved March 10, 2019 Isolatie.net, (w.d.). Kozijnen van Aluminium isolatiewaarde. Source: https://www.isolatie.net/aluminium-kozijnenisolatiewaarde/

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