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Interview for TSR Building
1. As an introduction, it would be important for us to know something about the following steps:
- Project history
- Logistics and organization of the building yard
- Current stage of development
-The clients are a family (a father and a son) who are psychiatrists and have been running a mental health clinic in Minato ward in central Tokyo for fifty years. Although the clinic has a long history housed in its current old wooden building, it became necessary for it to relocate due to a road schedule based on an urban plan formulated immediately after the Japanese defeat in World War II. In accordance with the relocation, the family decided to purchase an old building a five-minute walk from the clinic and build a new building on the site in order to reopen the clinic there. The beginning of this project was to the dismantling of the old building.
-Design and Supervision
-We constructed the building by utilizing an existing aged building with land which we had purchased.
-Programing & Schetatic Design Stage: February 2008-December 2008
Design Development Stage: January 2009-March 2009
Construction Development Stage:May 2009-August 2009
Construction face Stage October 2009-December 2010
Completion: December 2010
-Current stage of the development
Title of Project:T.S.R.Building
Client:Rinnosuke Ryu, Yonosuke Ryu
Building Site:Minatu-Ku Tokyo JAPAN
Kind of the Project:New construction
Use: Mental Clinic,Office,Residence
Number of Stories: B1+ 8 stories
-Architect : Junâ€™ichi Ito(Design Principal), Naoko Ito / Junâ€™ichi Ito Architect & Associates
-Collaborate Architect: Kaoru Yuzawa/Kaoru Yuzawa & Associates
-Structure Design: Jo Ko, Yoichi Chiba/JSD
-Equipment Design : Kazuhiro Endo, Shou Takahashi/EOS plus, Naohisa yamashita/Comodo Design
-Building :Tanaka Co.Ltd.
-Equipment: Yamato Co Ltd.
-Total Floor Area:1805.56sqm
-building coverage 82.14%<100& -rate of building volume to lot 649.78<700% Each floor area -B1 : 201.88sqm -1F : 218.63sqm -2F : 196.07sqm -3F-7F : 213.88sqm -8F : 119.58sqm Max. Height : 28.85m Structure System -B1 : RC -1F-8F : Precast Pre-stressed Concrete 2. Was it necessary to face particular problems of accessibility, transport and on-site storage of the material during the construction phase?
Construction of buildings in central Tokyo is always difficult because of the density of built-up areas. This project was no exception. The lot on which the project was carried out had an old eight-story building on the west side, and the other three sides had roads around them; the width of each road was 4 m to the north, 6 m to the east and 15 m to the south. There was another old building, this one four stories, on the east. The lot was not shaped like a regular tetragon.
As mentioned, there were roads on three sides; however, the roads to the north and east were too narrow for the planned building and for the cranes. Only the road on the south, which was 15 m wide, was accessible to us, but even there we had to face the difficulties. The building was designed to have an entrance 10 m wide, 20 m long, and 30 m tall. It was necessary to use a large rough-terrain crane of more than 100 tons. In addition, we had asked the metropolitan authority to stop the road completely during construction. It is really difficult to stop a road completely in any part of Tokyo, and our request was turned down by the local government.
Since the south road was our only approach, we finally reached the idea of splitting the construction process. In normal PCaPC construction, work proceeds floor by floor. Our method, in contrast, was to go side by side, starting with the north side. In this way, we reached the eighth floor. This method required only a small crane, and closing the road was not necessary. However, we had to plan in detail, with every minute point considered. I would say that the construction was one of the most difficult in Japan.
Tokyo, a densely built site, requires of architects not only technical skill but unique and creative ideas.
3. How was the collaboration between the architects, the structural engineers and the contractor?
-The relationships between the three parties were really good. We owe a lot to our client, who showed a thorough understanding of the characteristics of the land and also understood PCaPC construction well.
As we all know, a major earthquake and tsunami occurred in the Fukushima area on March 11, 2011, which has totally changed the image of construction for Japanese people. Our project had already started before the earthquake, but we Japanese know that a big earthquake can occur any time. PCaPC construction is earthquake resistant, long lived, and sustainable. In fact, the TSR building was not damaged at all in the earthquake of March 11.
The construction designer of our project was a leading designer of PCaPC buildings in Japan. He has experience working with the architect who built Nihonbashi Mitsui Tower, a skyscraper in Chuo ward, Tokyo. The architect selected a construction company with high-level skills in PCaPC construction. The three parties kept good relations and trust even after the project was over.
4. Were there any problems related to preexistences that required different constructive choices and/or a different organization of the building yard?
-When the client purchased the land, there was an old office building there, eight stories high with a basement. Our original plan was to fill up the preexisting basement and construct the new building on it. Then we came up with an idea of how to reuse the basement space. Our idea was to keep the basic frames of the basement and build new frames inside the preexisting frames. With this so-called double-skins construction, we were able to reduce cost and noise and give strength to the structure. However, we had many problems. One was the softness of the ground. Most buildings on the site had sunk pillars into the ground. We hoped to reuse those pillars, but we were not able to find a record that showed the details of their constructive strength. We had to put in new pillars, avoiding the old pillars, and construct the building on those new pillars. It required deliberate planning and was really challenging.
5. Were there any particular problems related to the geologic nature of the building area? If so, which measures were taken as regards safety in the site preparation?
The bearing ground was a hard fine sand of GL-22 depth, so we used the base pillars. We did not have any liquid forms; it is good ground.
6. Extension and depth of the excavations
As mentioned earlier, since we utilized the preexisting basement space, we did not excavate. We kept the old frames of the basement pit and built a new basement inside them.
7. Detailed description of the structures:
- Beams and pillars
- Particularly important overhangs or spans
-Foundation: Pile foundation – reinforced-concrete piles with enlarged tips
ďĽŤPillars and beams:
Pillars and beams were produced with precast-Prestresses concrete. The cross-section sizes are the same; 150â€“200 width with tapers. The beam depth is 400 mm. We had made the frame pitch small at 500 m, trying to lessen the strain of the weight. We tried to keep the size of the cross-sections as small as possible.
Floors were produced with precast-Prestresses concrete united with beams with 180 mm thickness. Walls are also with 180 mm thickness and are united with columns in order to configure a ring of a same cross-section with wall panels and floor panels.
Standard span is 9.65 m and pillars and beams pitch is 500 mm.
8. Were the structures built entirely on site or were there any prefabricated elements? If any prefabricated elements of huge size were used, which problems of transport and/or storage did they cause?
-Every beam of PC panel used on the ground floor was produced in a PC factory; 320 PC panels were used, including 199 pieces of floor panels, 201 pieces of wall panels. Every PC panel was produced with two kinds of floor panel and two kinds of wall panelâ€”in other words, four kinds of formwork. We ensured a concrete factory and storage area for the TSR building. To maintain the conditions needed for production, we also prepared a place for controlling temperature and humidity. The longest PC panel was 9.65 m, and we needed conditions sufficient for maintenance and transportation of this panel. The stresses of PC panels change during suspension, curing, transportation, and completion.
Based on various considerations, we transported PC prestressing bars wiring to the ribs of the floor first applying tension and conducted a skeleton work in order to ensure safe curing, transportation, and skeleton work of PC panels.
Furthermore, we added 50% temporary tension in the vertical direction, because the tension of the reverse beam is conducted to the inside of the building after the completion of the skeleton work due to the construction method of constructing the building from one side to another. In addition, we added the tense of the PC prestressing bar in the inside direction after the completion of the work and added 100% tension to the vertical direction.
9. Are there some outstanding constructive details or innovative technical solutions you would like to go thoroughly into (with the help of construction images, drawings, technical reports…)?
-Characteristics of the construction detail
The curtain wall on the exterior has a design with waves. The contrast of the inside and outside is organic: a mathematical, rational inside area with PCaPC ribs and a waving, random faĂ§ade. The glass is made of four modules, and the urban scenery reflected in the waving glass is fragmented. The atmosphere of the TSR building is natural, and gives us a gentle, strong feeling amidst inorganic urban scenery.
-The curtain wall has a stainless frame, and the draining area of the side frame is twisted three-dimensionally. We devised a way to avoid getting the building dirty by creating pipe spaces among the creases of the steel plate of the side.
-The production of beam members
The members of PCaPC structures are used for walls and floors. Structural materials are used for interiors and therefore a high level of construction technique is required for joint areas and landscape in addition to concrete finishing with an integrated design. Before production, we applied seals to the joint areas of rib and mold formwork to avoid leakage from the concrete and repeatedly placed de-molding concrete in these areas.
-Adoption of the floating method of the precast and prestressed concrete structure
We used precast members with united columns and walls and also united beams and floors. First, we produced wall panels, then floor panels; this method shortened the construction period without any support frames. At the fastest, one layer is built a day. Environmental noise is limited. The piled members are united, giving tension to the PC-steel materials, and deformation and damage are less after earthquakes. Furthermore, fabrication of the members is controlled in a factory, and they are of high quality. The life span of the building frame is more than 200 years.
10. Which measures were taken for fire protection?
-The TSR building is in a fire-prevention area. Fire regulations in Japan, especially in Tokyo, are stringent. They require that people inside be able to evacuate safely, that fire from inside buildings should not spread to adjacent buildings, and that exterior fires should not spread to buildings. Fire regulations mandate provisions for the roof, exterior walls, floors, partitions, columns, beams, stairs, doors, interior, and lots.
-Designated areas for evacuation from stairwells, wide spaces, and smoke-prevention measures facilitate evacuation. It is also important to install smoke-exhausting windows and emergency exits for rescue and firefighting efforts.
These facilities are part of the TSR building: emergency exits on the south and north sides, emergency stairs on the west side, and emergency balconies on the east side. The PCaPC of the main structure, including exterior walls, columns, beams, and floors, has two-hour fireproof performance; the exterior iron plates are also effective. The protective area of each glass pane, including glass with steel and fireproofed glass, is as follows: 3 m on the first floor and 5 m above that.
11. Energetic concept of the building: which solutions were adopted to improve energetic efficiency and sustainability? Mostly as regards
-The TSR building is a sustainable building and is good for the environment. There are several basic concepts incorporated in this regard.
Reuse: We reduced the CO2 emissions the dismantling by using the underground frames of the old buildings. Drawing of old pillars and dismantling of underground frames reduce the emissions significantly.
Control of heat environment: We included argon gas internally by using low-emissivity or â€śLow-eâ€ť glass. Furthermore, ceramic printing was performed on the glass. The ceramic print reduced the solar heat load indoors and enhanced energy conservation.
Under floor air-conditioning system: We adopted an air conditioning system for residential areas so that it could be regulated from each fan outlet. The air conditioning is minimized by the energy-conservation effect and low running cost.
-Free air-conditioning arrangement: The under-floor air-conditioning system works with a floor-fan unit. The layout of the unit is easily changed because it is movable. Further, the space under the floor can be used for PC trace owing to the free access of ductless and requires no finishing work. Therefore, we were able to reduce the expense of construction.
-Adoption of PCaPC structure: PCaPC structure is a construction method for assembling materials at the site that were previously produced in factories. The method minimizes the clearance needed between adjacent buildings and utilizes the site to best advantage. Further, it method enhances structural strength and reduces environmental impact due to the shorter construction period it enables.
-Long life: A PCaPC structure has a strong building frame; regular replacement and maintenance can prolong the strength of the frame almost permanently. Therefore, this type of construction is sustainable for prolonging the lives of buildings.
12. How were the works organized in the different seasons and how climate and weather influenced the choices?
-The color and surface finish of PC beams depends on temperature and humidity; hence, we considered producing a uniform product in accordance with temperature and humidity requirements using steam from a boiler during production.
Dismantling of the basement at the site was conducted in the rainy season, and the groundwater level would rise around the site. Therefore, we lowered the water level regularly by using a submersible pump, improved the ground to avoid collapse, and conducted underground work.
13. Did the construction of this building require any specific traning courses for workers?
Working with precast concrete requires good accuracy due to the need to work in high places. Therefore, we organized a professional team to deal with PC construction. Furthermore, the method is highly risky, especially when dealing with heavy loads. Before beginning the work, we discussed these issues elaborately and formulated procedures for safe and speedy construction. At the site, we ensured the safety of the neighborhood and traffic vehicles, because we used 100 t tow trucks, employed large trailers, and placed five security guards.
PC prestressing bar tension requires advanced expertise and certainty, and we held a training session at the site with leading instructors to enhance our knowledge and understanding. In addition, we conducted an exhaustive check with a site manager to ensure whether the tension certainly had reached the regulation point. Furthermore, we took a double-check approach to tension management. Grout injection also requires certainty, and so we had a visual inspection and ensured that more than adequate grout was injected.