6 7 CRYSTAL HALL Municipal hall, Tuscon, Arizona, Bachelor Project, spring 2018 Competition entry, pending Integration of acoustical design A translusent City Hall, for a transparant demo- cratic system. A design collaboration with Clara Havström and acoustc students Anand Kelkar and Tom Houterman that has worked very well. Starting the project with Clara and a clear set of goals we made it almost all the way. A lot of time collecting materials and clarifying a precise vision and a core set of values, looking into different materials and ways to get there, researching the plans of old city halls as well as contemporary architecture became the key in the starting process, and then the ability to decide and go for and select one of three concepts. Early phase was a lot of experimenting, even though I myself could have been more active in the start, we did good in analyzing the work we had done, which made it possible to iterate and develop to get three concept ‘s out, similar in vision, but architectonically different. the openness when including the acousticians and aiming for fast calulations and try out made a very good collaboration happen. Mid phase shoud in retro- spective been more intese and we should have been better to stick to our deadlines to be able to actually iterate our presentation work once more, especially when it comes to model photo (and everything else) Model Photograph of the back in the Community Hall, the variable crystal wall 1:20 8 9 The construction is decoupled from the ground, standing on springs to avoid vibrations from the tram and outside traffic. IIC 75 criteria is fulfilled with no structure borne sounds entering the building. Corridor to Court A long ceremonial corridor leading to the courtroom. The walls are translucent, respecting yet showing the accused. Roof window Frosted glass panels in the ceiling let in diffused light from above. The light is taken in behind the prismas, dispersing the light to the community hall. Corridors and overhang Long corridors are located around the building, creating one extra layer to prevent the outside noise from entering the courtroom and city hall. The overhang of the roof and the trees shields the intense sunlight of Arizona Speech privacy STC 60+ Conference rooms are surroun- ded by stacked glass of 300 mm so that no discussions can be overheard. Acacia Longifolia Light yellow blossom in springtime. Works well in hot dry climate. Grows up to 7-10 meters. Long leathery leaves that only take in sunlight from the sides. Originally from South Australia. Circular glass pillar The Garden The micro-climate in the courtyards create good conditions for a green space with blossoming flowers. The garden creates a calm and shaded indoor and outdoor environment. The Cafeteria The garden court is an open public space for the citizens, a place for people to meet and bring them closer to the politicians. Lobby Double wall STC 70+ 200 mm soda lime glass 100 mm air 650 mm soda lime glass with Helm- holtz resonators The community hall is surrounded by a double wall, with a windbreak and double doors, avoiding the sound from the courtyard and lobby. Vibration Springs IIC 75 Detail 1:20 150 mm inox profile with airtight window tape 10 mm damping material 150 mm white terrazzo Spring system 100 mm air-gap 340 mm concrete Impact sound isolation IIC 60 80 mm concrete 10 mm vibration damping material Double Wall STC 65+ 100 mm soda lime glass 100 mm air 300 mm soda lime glass Different thicknesses of the glass panels for different eigenfrequ- encies and critical frequencies. The double wall reduce sound from traffic and sirens from the police and fire station. The Garden Court Sound Absorbtion in Soil The greenery and soil helps reduce the noise from the street in the courtyard. The exact absorption value depends on the porosity and dryness. Impact sound Impact sound isolation 10 11 HVAC System Behind the community hall is a plenum silencer, on the first floor. It allows a slow airflow of fresh air that sippers up underneath the seats and is collected through air-curtains along the sides of the ceiling. Community Hall Seating 238 people Volume 1750 m3 1.05 sqm/person Double Glass Window STC 65+ 20 mm insulation glass 66 mm helium 16 mm insulation glass A highly reflective wall behind the stage helps the sound to reach the audience. Elevators and technical rooms Elevators are acoustically decoupled from the load-bearing system with an air-gap between the doc and the floor. Technical rooms have thick double walls and vibration springs so that no noise is transmitted through the structure. Sun Chimneys 5 mm black steel 300 mm air-chimney 20 mm glass Blue Jacaranda Tree Purple blossom for more than 8 weeks in spring. Prefers bright sunny conditions, enriched sand and moisture but tolerates drought. Grows up to 20-30 meter. Originally from Central America. The Crystal Hall Rear Entrance 2.5 m A corridor large enough to transfer a grand piano and other large objects. City Offices Wedding Aisle A large centered aisle for special occasions and weddings. Working Environment Large windows towards the atrium creates an open and pleasant working environment in the office. Natural airborne cooling system. Dark panels directed towards south heat up the air in the chimneys and creates a natural airflow in the building. The chimenes goes down into the ground cooling the air. All channels are decoupled acoustically from the structural system. 12 13 Garden courtyards The views out are all directed to the four garden atri- ums for a relaxed and calming atmosphere. The garden court provides an oasis to the city. Public city plaza The traditional city hall plaza is inverted and placed in the main atrium to invite people in. The public square acts as an extension of the lobby connected to a cafe and restaurant. Room for democracy The community hall is easily reached from the lobby and Garden Court which creates a floating, open space, con- necting politicians to civilians. With ceremonial respect of the walk to a trial, a stair and glass corridor slows one down and prepares before entering the Court room. Glowing with focus inside Stacked panels of soda lime glass creates a translucent, but not transparent building, The building light up in the night thus keeping focus inside the Court and Jury room. lobby Anter Office Wing StorageElectrical Community Hall café information jury wc A A Office Wing cell Bailiff technical waitingCourt Room cellcell Judge Conferance Conferance storage cell wc A A Plan 1:500 Plan 1 Plan 2 14 15 Fine demands in spoken word requires a fine instrument The Crystal Hall is a multipurpose city hall located in Tucson, Arizona. A new venue for political meetings, small events, trials, weddings and home for many city offices. The garden plaza provides a green living room for the citizens of Tucson connecting to intimate spaces. The rooms are small and the sound precise to create good conditions for speech and music. Studio environment In a building hosting the democratic institution of justice and politics, it is important that people speak the truth. To hear all nuances of speech, the integrated Helmholtz resonators can absorb even the lowest of frequencies from 20 Hz, resulting in a studio environment. Small volumes Both the community hall and the court room have approximately one square meter per person to create a sense of intimacy both spatially and acoustically. Small volumes have naturally a low reverberation time, so only a little absorption is needed. The low reverberation time helps achieve a good STI. Stacked Glass as Diffusers Glass panels on all walls are stacked together such that they are at different depth when looked from inside creating an uneven surface. This ensures diffusion and also helps get rid of flutter echo. The Court Room Seating 48 in audience Seating 66 in total Volume 380 m3 1.3 sqm/person Reflecting and Absorbing Walls Behind the judge and witness is a highly reflective wall increasing the sound strength and helps it reach the audience. Helmholtz resonance absor- bers are placed in the back and along the sides of the courtroom near the audience, to prevent the annoying whispers from the audience reaching the judge and jury. Courtroom 1. Section B-B Courtroom 1:100 2. Modelphotograph of Courtroom and corridor 16 17 Micro Perforation Detail 1:2 15x15 mm neck opening Micro perforation for viscous friction Helmholtz Resonant Absorber 20 Hz Detail 1:10 2 mm micro-perforated glass 100 mm neck 450 mm diameter 650 mm glass panels Laminated glass panels Transparent sound absorbers Integrated Helmholtz resonators The transparent integrated Helmholtz resonantors in the walls allows absorption and can be tuned to desired frequency. Micro-perforation at the end of the neck ensures absorption because of viscous friction. The Helmholtz resonant absorbers gives total control over even the lowest frequencies as low as 20 Hz. In the community hall the Helmholtz resonators are integrated in the back walls that are exposed when the crystals are open. Helmholtz resonance absorbers are placed in the back of the court room near the audience, to prevent the annoying whispers from the audience reaching the judge and jury. Fabrication The walls are made of laminated glass panels of the commercial and easily recycled soda lime glass. The glass walls act in compression and bending is prevented by lamination. Thanks to the thin panels, the spherical absorbing volume integrated in the walls are created by circles cut in each glass panel. In the mid panel, also acting as the neck of the Helmholtz, a thin channel is cut almost to the edge, saving a small bit for micro-perfora- tion of holes drilled from the side. The viscous friction achieved by micro-perforation makes it possible for no other absorption material. Put together the panels create a three dimensional effect of spheres, diffusing light through the walls. The Helmholtz are visible in the lobby, in the corridor to the community hall and on the walls of the court room, having an appearance of frozen bubbles. 18 19 Rotating Crystal Panels Detail 1:10 200 mm diagonal axis Rotating around different axis. The surface is frosted and the cut clear creating an dispersing light effect. High Frequencies Absorption Detail 1:20 100 mm concrete high frequency absorber Absorbing material placed at the back of the crystal wall ensures the absorption of mid to high frequ- encies. Dispersing light and sound The crystal wall allows variable acoustics and natural lighting in the community hall. Fully opened they expose the hall to high and low frequency absorbers behind, and when closed they reflect the incident sound resulting in higher reverberation time. The crystals also scatter and diffuse the sound in different directions depending on their orientation and help to get rid of flutter echo between parallel walls. Opening up to low and high frequency absorbers, a flat rever- beration time for music and speech is achieved. The crystal walls are located in the back and along the sides of the room letting light through while the focus of the audience is directed towards the stage. The big Jacaranda tree in the atrium behind create a calm and centered view. Music Most of the crystals are closed to reflect sound and elongate the reverberation time and to get the required clarity for music between -2 and +2 dB. Speech Most crystals are open to the absorbing corridor that creates a flat reverberation and good STI value. The rise in reverberation time due to slight increase of volume is dealt with by having sufficient absorption so that the net reduction in reverberation time meets the requirements for speech. Variable acoustic Crystal wall Model photographs 1. Corridor into the Community hall walking between the Helmholtz resonant absorbers and crystal wall 1:20. 2. Pattern of Helmholtz resonators appearing as frozen bubbles dispersing the light. 3. Cut section of Helmholtz. 1:10 20 21 Model photographs, early phase. Experimenting with an inverted plaza and a glowing inside. 22 23 Sketches of early study models, tape and graphite.