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| Q | 1.1.4 What functioning experiences has this system had in previous earthquakes? |
| A | Vancouver, Canada ranges amongst the most dangerous seismic areas in the World and experiences sporadic earthquakes and so far the IHI buildings built since 1999 have not experienced any problems resulting from these earth movements. IHI manufactured other mobile structures including a mobile school, mobile offices, mobile presentation center and mobile technical rooms. In addition, many modules in these buildings were manufactured and assembled at the IHI factory and moved to site and none of them have experienced any negative effects as a result of earth movements. IHI buildings are resistant to heavy earthquakes and this can be verified in structural tests conducted for every building designed with the IHI system and verified by the Client's structural engineers before entering the manufacturing process.
As for the difference in the size or type of seismic movement from one area to another, please note that the IHI panels have been designed to meet any international standards through Structural Equivalences. Of course, in certain cases some laboratory or field tests may be required by local authorities. It is worth noting that the Canadian tests are acceptable in most countries world-wide. IHI panels are designed to withstand not only compression but also various skin stresses and tensions whether horizontal or vertical or a combination of both. The panels -which are biased inwards towards the interior portion of the panel, absorb and distribute seismic forces to the entire three-dimensional structure and the biased frame members act to absorb residual seismic forces reaching the individual panels. Thus it is not just the configuration of each individual panel but also the behavior of all the panels together in the totality of the structure which render the building earthquake resistant.
When a building is designed, the structural engineer designs the structure to resist earthquakes. IHI provides independent Structural Engineers with the necessary structural data and calculations for them to check the resistance of every IHI building to the forces of nature including seismic movements. IHI does not have a standard product, thus, every project is studied individually. IHI has obtained building permits for their factory, office building and Vancouver show home in British Columbia that has the strictest seismic code in the world. These buildings have been exposed to continuous earth movements since 1999 and have not experienced any differential settlement or cracks.
The IHI buildings are manufactured only after obtaining the required building permits which means that the government authorities have approved the structural characteristics of the building and its resistance to seismic forces. |
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| Q | 1.1.5 How much is the value of response modification coefficient (R) based on standard 2800 or other regulations applied in this structure? |
| A | Not only is the Richter scale 8 IHI's minimum standard but also all connections are ductile to filter out any built-up stresses due to earthquakes, tornados, fire, etc.
IHI structure is a ductile moment resistance space frame. Based on this definition and according to CAN/CSA-S16.1.M the R value is 4.0 |
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| Q | 1.1.6 What kind is the common lateral load bearing system used in this structure? What other methods are applicable to be used to bear the lateral loads? |
| A | Each panel is designed to work on its own to resist axial (tension and compression), torsion, bending and shear mainly because the perimeter that acts as a built-in formwork and that is welded together with multi-layers of reinforcement on each side, all confined together with 2 high strength (12,000 psi) concrete layers, each acting as a diaphragm to increase the stiffness of each surface and in order to eliminate any torsion both transversal and longitudinal, reinforced high-strength cylinders are specially designed not only to connect the high strength structural plate together but also to confine them structural boundary of each panel that also act as a built-in formwork, the only way to understand it is to create a 3-dimensional finite analysis using different structural materials and study the behavior of various loadings from all directions. |
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| Q | 1.1.7 What elements stand the gravity loads? |
| A | We have conducted gravity loads tests based on a self-weight of a 3 meter by 12 meter panel spanning on its weak axis connected to a 90 degree panel acting as a shear column, the combination of the assembly had a 55 lb. / square foot (that covers its dead weight); that was equivalent to a 150 mile/hr. wind and the deflection was absolutely minimum. Moreover, we applied uniform load on 10 ft. x 10 ft. panel (which we submitted the results) and the loading equipment failed at 562 lb./sq.ft., the panel deflection was at a minimal. Currently if you want to apply the same test based on the advanced panel version we expect the result to be by far higher. |
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| Q | 1.1.8 How are the connections design and execution in presented system? |
| A | All connections (steel connections and using high strength galvanized bolts) are ductile to filter out any built-up stresses due to earthquakes, tornados, fire, etc. After the building is bolted together properly, all (recessed) connections are welded. |
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| Q | 1.1.9 Describe the type of ceiling, material and the thickness that is used to make the ceiling. |
| A | (if there are a variety of methods, describe all of them). All building documents including calculation booklet, architectural, structural, mechanical and electrical plans (HVAC, utilities, sewage and ...) of the following sample with all constructional details should be presented. (If there is any).
The IHI panels are designed to be used as Foundations, External and Internal Walls as well as Slabs (ceilings) and Roofs. When these panels are interconnected, they form a 3 dimensional steel structure resulting in a building that can theoretically be carried as one piece and shaken without experiencing any structural effect or deformation. Although the plant produces panels only, the system allows for pre-servicing panels with electrical, plumbing and mechanical systems, which are connected during the assembly process. IHI integrates the necessary openings for HVAC systems provided by the Client's engineers during the preparation of coordinated shop drawings as well as conduits for the electrical network throughout the building.
Our panels have no redundancy, and each of them is designed to have by far a much higher strength to weight ratio. In normal reinforced concrete (for example) we agree with you that each slab deflects based on its own dead weight mainly because 35% of on average of the effective reinforced concrete is carrying the 100% portion that includes the 65% redundancy. The whole gests and principles of IHI system is to eliminate redundancy, save of the cost of that huge redundant volume and at the same time make the panel by far stronger, so the 35% in other words, is 35% effective concrete that be mainly acting under compression will simply not defect under its own weight (again because the strength to weight ratio is extremely high). Naturally at heavy loading, we designed the panel to have no deflection greater than 1/500 of its span in a very elastic manner.
We have done cyclical loading and every time the deflection re-bounces back to zero under very heavy loading conditions and without leaving any residual deformation, and the reason it is elastic is because each panel is continuous from every aspect and covers the whole perimeter that is fully welded to the interior steel structure of the reinforced steel imbedded into each structural plate (confined within the structural steel perimeter separated by elastic rigid insulation and connected as per above with high strength reinforced cylinders). |
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| Q | 1.2 Supplementary Questions |
| A | 1.2.1 Technical specifications of system
Panel System
The key to the IHI process is a unique panel system, which is both structurally superior and less costly than traditional site-based or pre-manufactured system. The panel system is based on a composite steel reinforced high strength concrete and rigid foam insulation structure. Steel tubes provide frame strength, built-in formwork, and mechanical connections and can serve as well as electrical and utility conduits. Steel cables within the panels are connected to the steel frame and tensioned to provide diagonal stiffness. A combination of special flanges and steel pins connect the panels at corner points in a very ductile manner.
The overall structure is analyzed as a three dimensional space frame and has excellent characteristics of flexibility and lateral stability (i.e. wide earthquake loads make it essentially earthquake proof). Even without the pins, the structure is statically stable and the pins are only present for dynamic stability.
Each IHI panel is sealed by an advanced IHI chemical mix to boost a previously sealing process within the production process to create a very crystallized thin layer of hard surface that will allow fast painting application without having any vapor to seep through the surface and ruin the paint.
This process will minimize micro-cracking and at the same time will allow each panel to continue sub-curing in specially designed automated shelving system under full humidity and temperature control. This process of sub-curing should take approx. 3 hrs for the concrete to achieve 30% of its high strength designed criteria (28 days), i.e. 30% of 12,000 p.s.i.(84 mpa approx.). This is equivalent to 3600 p.s.i. (approx. 25.2 mpa
The steel used by IHI is equivalent to ASTM A500 GRADE C |
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| Q | 1.2.2 How much is the approximate dead load of this structure in commonly used buildings per square meter? (Separately present the amount of the dead load for structure, rendering and paving with all presumed details) |
| A | Approx. it should be in the area of 500 kg/m2 of buildable area. Approx 200kg/m2 for the panels and with a ratio of 2.5 approx. (panel area to buildable area) for economically designed buildings, the total buildable weight per m2 is 500 kg./m2. |
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| Q | 1.2.3 Please specify the connection regulations and limitations of non-structural members (like in-filled frames) of the main structure. If these elements have effect on seismic force resistance, how will be the manner of connections will? |
| A | and how, If they have no contribution in stiffness of structure?
The IHI structural panels are interconnected with the slabs, thus at the end the building becomes one piece and there are certain walls including all exterior walls that are needed for the structural integrity of the building and can not be replaced by hybrid systems. There is a minimum of 20% of IHI internal walls needed for structural integrity. The type of connections will be decided during the overall structural analysis.
The connection regulations for non structural members varies with each code, in our case, any non-structural member or element can be easily welded or bolted or screwed into our panels without any problem as long as 20% of the interior structure is made out of IHI panels connected to the slabs that in turn are connected to the exterior walls. |
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| Q | 1.2.4 Specify the opening limitations on exterior walls or floors. |
| A | There are no limitations in the opening sizes for external walls used as windows or cutouts, in fact, the cut-outs used for windows and doors are surrounded by structural steel tubes to which the windows and doors are connected together making them resistant to hurricane wind forces/earthquakes, etc. Again IHI panels work under positive or negative pressure. The floors can have any opening necessary for stairs or shafts as specified in a particular design since all panels are custom-made.
There are no structural limitations for the openings -- the structure is designed to accommodate the architectural design of the buildings. Hollow structural steel tubes provide a sub-frame for windows and doors -- in case of a very large opening, the panel above the window becomes a beam plate. In our show homes as you can see in our website we have openings more than 6 m x 3m high. At the same time we have double height living area which can be considered like a 100% opening between walls. We believe above is clear enough. |
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