Please Someone Save Betsey (P.S.S.B) AD 272: Architectural Technology 2 Group 6: Folded structure
TABLE OF CONTENTS INTRODUCTION 01 TEAM MEMBERS 02 TIMETABLE 03 DESIGN PROCESS
Precedent Research Cardborigami 04
St-Loup Cathedral 05 Westborough Primary School 06
Model Iterations 07
PROTOTYPE DEVELOPMENT & RESEARCH
Scale Model 13 Flexibility & Forces 14 String Model 15 Hinges 16
FINAL DESIGN 19 MATERIALS
Plywood Cuts 20 String Tests 21 Steel Supports 22
PHOTO DIARY 23 1:1 CONSTRUCTION 26 Timetable 27 Revised 28 CAD Drawings 29 Materials & Strategy 30 Day 1- Cutting 31 Day 2- Filing & Quality Control 32 Day 3- Hinge Work & Test 33 Day 4- Stitching 34 Day 5- Reinforcement 35 Test Day Conclusion 36 Test Day & Structure 37
INTRODUCTION
The aim of team Six is to design a folded structure that acts as a shelter and that is strong enough to hold our lightest team member. Ultimately the main goal is to ensure that all building requirements are met while still creating a structure that is aesthetically pleasing. Team members were allocated specific tasks as a means to spread out the workload in the most effective way, with one team coordinator overseeing the entire project. Individual strengths were used to determine the roles and responsibilities of each member. This was to ensure that the work produced was of the highest quality achievable. Although we had individual roles, it was still necessary at all points in the project to bring our ideas together through team meetings. Research into build precedents was the initial phase that kick started the design process. Model making and initial design sketches propelled us forward in attempts to come up with one design prototype that would later be constructed at 1:1. A crucial aspect of a folded structure is the way in which the respective pieces are attached to one another; therefore, research into these methods was a crucial part of the design process as well. There were a number of restrictions, detailed within the document, that were set out in the brief as a means to keep the project manageable and cost effective. These limitations played a big part in our decision of the final model. All research and design process had to meet specific deadlines in order to keep the project on schedule. The 1:1 construction of the decided upon prototype will be made out of plywood supplied by the university which is to be recycled at the end of the project. The entire project, including the completed 1:1 build was to be wrapped up and ready for testing by December 14, 2012.
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TEAM MEMBERS Roles & Responsibilities
Amy O’Shaughnessy
Project Coordinator
ensures all members meet their responsibilities on time towards fullfilling the tasks set out.
Laura Olivier
Time Table Manager
Produce the time-table spread sheet showing all deadlines
Je-Shae’ Pace
Document Production
Responsible for lay-out, text, image and drawing inclusion within the one-to-one document
Risha Patel
Documentation
Responsible for photography recording design iterations, and team working practice
Document Text Production
To produce and edit all significant text for the document. Erasmia Papallou
Eliana Pereira
Structure Design Team/ Calculations Evidential calculations during design development.
Athina Rigopoulou
Drawing Office
Anahita Malekyazi
Produce drawings and sketches for one-to-one construction
Oliver Riviere
Ping Wong
Construction Team
Responsible for overseeing the 1:1 construction of the folded structure
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DESIGN PROCESS
Precedent Research
To get an idea of what can possibly be acheived through folded strcutures, the research team found a number of precedents that had similar qualities to those set out in our build packs.
Precedent 1 “Cardborigami: Thinking inside the This system of building is, according Box” to the source “sturdy enough to hold Tina Hovsepian invented cardboriga- someone”. Additionally, the monomi, which is a combination of origami coque system also enables the strucand cardboard that folds together to tures to be folded up and reduced greatly in size, which can make the make a shelter. object portable. The design of the cardboard shelter is based on an accordion design, h t t p : / / s i m p l e s h o e s . t y p e p a d . c o m / s i m ple/2010/12/cardborigami-thinking-insidewhich was inspired by the “monocoque the-box.html system (using an object’s exterior rather than interior for support)”.
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DESIGN PROCESS
Precedent Research
Precedent 2 The Temporary Chapel for the Deaconesses of St-Loup, Architect. Localarchitecture and Danilo Mondada. Built in Hopital de St-Loup, Switzerland. (2008) The folded structure was designed as a temporary structure for worship whilst a new place of worship was being constructed. Constructed in timber panels which with the use of a computer software where designed specifically to calculate the widths, lengths and load bearing weights. The predesigned elements of the structure were made in a factory and assembled onsite. The structure used steel plates and screws for joints
and the structural timber elements were coated with a bitumen layer. Images: http://plusmood.com/2008/11/chapelfor-the-deaconesses-of-st-loup-localarchitecture-danilo-mondada/
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DESIGN PROCESS
Precedent Research
Precedent 3 Westborough Primary School One of the most innovative projects has been the construction of a multipurpose small building using only cardboard components. The initial small building project was the result of intensive research into the properties of cardboard as a viable construction material that was supported by the then Department of Trade and Industry (DTI) in 2001. The challenge was to use 90% recycled materials, in constructing
the cardboard building providing an after school club, a kitchenette, a storeroom and a toilet block and for the building to be 90% recyclable at the end of its life. http://www.burohappold.com/projects/project/westborough-primary-school-cardboardbuilding-73/ Images: http://www.gb0063551.pwp.blueyonder.co.uk/cardboard/
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DESIGN PROCESS
Model Iteration
Type: Irregular Combination
The model was constructed at a scale of 1:20 to span 3 meters, a criteria our structure must meet as set out on the brief. It is irregular in shape with each piece having an individual dimension no less than 900x650 mm. Because there is no set pattern, it has a lot of flexibility in regards to the form it can take on. The irregularity also means that its strength varies at different points.
An advantage of this type of design is that its practical to build and deliver in a short period of time. A disadvantage is that because of its irregularity, the junctions would need to be carefully considered and a base may be required as both will play a major part in the structure’ stabilty and movement.
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DESIGN PROCESS
Model Iteration
Type: Triangluar Pattern
This fold pattern is created by repetition of triangles at the same dimension. It is extremely flexible allowing for many iteration from this one pattern. The smaller the triangles, the greater the opportunities. However, to produce a structure out of this fold pattern, the junctions
and supports have to be carefully considered in order to prevent it from expanding or taking on unitended forms.
in efforts to recycle the materials, we intend to keep the plywood sheets in tact as much as possible.
Although the triangular pattern provides us with many different options,it will be time consuming to cut and join all pieces when constructing at a scale of 1:1. Also,
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DESIGN PROCESS
Model Iteration
Loading the Triangular Patterns
Unlike the other groups, our structure is not concerned so much with calculations but rather how the structure will react once it is loaded. With this particular fold pattern, once it is loaded it has the tendency to expand uncontrollably at all angles. This factor is due in large part to the flexibility.
Too much flexibility can be a liability in our 1:1 construction. If we were to build from this pattern the control of expansion would be a major challange.
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DESIGN PROCESS
Model Iteration
Type: Regular Two-Fold
This type of folded structure is based on a regular pattern of folds. (ref. Precedents 2 & 3) The vertical and diagonal folds give the model its strength and rigidity, more so than the alternative triangular pattern. This model can still be manipulated to curve as shown when pinched at one end. This increases the density at one end of the structure, which directly correlates with its strength.
Due to the technicalities of our build project, such as, cost and time constraints, this type of folding will be a more manageable project compared to the triangular more origami based structures.
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DESIGN PROCESS
Model Iteration
Additional Iterations
These are simple diagrams and digital models of different model experiments using the previously mentioned folding patterns. Specifically the regular two-fold and triangular patterns.
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Prototype Development & Research
SCALE MODEL 1:10
The golden section
been used and found within Architecture, Art and Nature.
The golden section is a ratio defined by the number Phi and will divide a line proportionally where ‘ A is to B as B is to C ‘.
Our preferred model in our design process was designed as a regular pattern (ref. pg 07) onto an A3 sized piece of card with no wastage. Paper sizes are based on the golden rectangle, which uses the golden ratio and so by creating a regular pattern within the golden rectangle the model is well balanced with good proportionality and so is most aesthetically pleasing.
in relation to our best model.
The ratio was used historically in the design and build of structures as early as the Parthenon (432BC) and proportionally gives the most aesthetically pleasing design. Because of its proportionality, the ratio has
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FLEXIBILITY & FORCES 1:10 Model
Our structure shares similar properties to a cruck fram system when it comes to load distributions. Frames are tied by their junction to the ground which prevents them from sliding outwards. In turn, we will have to figure out a way to achor our structure like a cruck frame. Which will insure its stability.
In regards to its flexibilty, our prototype shows abilities like that of an acordion. The model is constructed from cordboard, a lightweight, flexible material. The challenge comes when we need to replicate this ability with the 3mm ply wood. The success will depend majorly on how we fix the junctions of our structure.
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STRING MODEL 1:20 Model
This is a 1:20 model representing the repetitive pattern of our folding structure. It is an experiment to see how the joints of the triangle behave when the structure folds and unfolds. Rather than having the planes meet at a point, we decidede to round the edges in order to provide a neater junction. We chamfered the ends of the cor-
ners in a circular shape. The model is made of MDF and stitched together with string.
We were not satisfied with the end result because as the stitching proceeded the assembling became more and more difficult. In the end the circular shape of the joints was ruined and became two circles instead of one. However we had the chance to test how the stitch joints behave when the pieces are put together and test how the structure works when is loaded.
When loaded, it flattened out and to stop it we may have to make the joints more rigid or make base points that prevent the structure from unfolding. The model might have worked better if the scale of the string used in the model correlated with the wood planes.
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HINGES Scale 1:1
A series of hinges and joints were modeled in efforts to test the flexibility and durability of each type. Shown and documented are the results of each.
Piano hinges
Riveting
Angled timber insert
This is by far the most elegant method of joining we tested. The joints are very neat and rigid but also flexible. This method is very time consuming as the hinges and bolts need to be cut and filed neatly down to size. Furthermore the cost of the hinges is very high. With this method chamfering is not necessary as the hinges already hold the edges in a set position.
Although this type of joining does not apply to the edges of the structure, we think that it will be suitable to join two flat panels together. With two rows of rivets this join is very strong and could be made stronger still with the inclusion of glue or a greater overlap. The rivets are a neat way of joining the two panels this method is also pretty quick and cheap.
An angled piece of softwood timber is inserted on the inside of the fold, this supports the fold and holds it in a set position. This method requires a high degree of accuracy when cutting the inserts to the correct angle. In this particular example the inserts are large to ensure they do not split when the panels are screwed to them. However it would be possible for the supports to be slimmer if a different fixture is used. These inserts allow us to add to the rigidity of the structure, therefore increasing the allowed load. Although we would not want to use them excessively, they may well be appropriate in certain positions. The cost and time involved in making is very low.
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HINGES Scale 1:1
Wood glue
Fabric
Stitching
Conclusion
One of the ways to join the 3mm plywood triangles was wood glue. We also chamfered the edges of the triangles so that there would be a smoother finish at the edges. Chamfering the edges might be appropriate in the final design as it would give the structure a set position to fold out and into. The result is aesthetically very satisfying but it is not particularly strong and we would like to avoid using glue as our final joint. Furthermore we found that it is a very rigid way of joining the pieces together and as we want flexibility in our joints we do not think that glue as joining material will be appropriate. This method would be low cost and quick but simply isn’t appropriate.
In this method we glued pieces of fabric at the edges of the panels. This joint is fairly strong and allows some flexibility however we feel that other methods, such as stitching the panels together would be superior. Chamfering the edges would again help to improve the appearance of the structure and to fix the position of the panels. The result in neither elegant or neat, however this method is quick and low cost.
To do this kind of joining we drew a 1cm frame in each triangle and then we drilled holes every one 1.5cm. After we used strong twine to sew the pieces together. The result a very strong and flexible joint and if done neatly is pleasing aesthetically. If it is used in the final design the holes should be made with precision, there should also be an offsetting between the holes on adjoining panels so the string doesn’t pull the panels out of position when it is tightened. Chamfering the edges would also help hold the panels into position. This method would be low cost although the process of sewing the panels together is fairly time consuming.
For the final design we decided to use a combination of both the piano hinges and stitching. Its necessary in order for the structure to flex and fold as needed, while still mantaining stability.
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HINGES
String & Piano
The piano hinges, which are stronger than the string hinges, are placed on the joints that carry more load than the joints that are fixed with the string/ stitched method. Combining both mechanisms will not only guarantee durable and strong joints, but will also reduce the costs of materials. Additionally to the strength of the hinges, both types are aesthetically pleasing, which is a large factor of our design. Also, both types
of hinges allow us to work well within the time limitations and the material constraints. ** This particular model uses MDF rather than the 3mm plywood we will be working with during actual construction.
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FINAL DESIGN
Prototype Resolved Scale 1:10
Necessary Improvements The meeting on Friday the 26th of October revealed quite a few faults with our initial model- the long caterpillar-like structure (site page). There were several issues that make the design impossible to make within the limitations that were given to our group, i.e. material and cost constraints, as well as time issues. Building Constraints: • 1500x1500 sheets of 3mm plywood *to be recycled* • Sheets can be cut down to leaving at least (2) 900x400 rectangular
panels Any further plywood that will be used for the folded structure will have to be cut so that the pieces are appropriate for the laser cutter once recycled. This constraint forced us to rethink our design proposal and come up with a more cost-effective design.
of supporting up to 50kg. It is shorter in length, and more stable than the initial design proposal because of an improved base that provides added support by anchoring it to the ground. Since the new design idea will be made solely made out of triangular shapes, this will allow the structure to be folded quite easily.
The new prototype is an effective shelter for Betsy, will be able to handle the time, material and cost limitations and fully meet the goal
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MATERIALS 3mm Ply Cuts
Optimising Material. Primary materials – 1500 x 1500 sheets 3mm plywood, to be recycled after use. Due to limitations on our materials we had to adapt our design to be cut leaving little wastage from our material. To be used after our construction the plywood needs to be in sheets of 900 x 400 to be used easily on the laser cutter. The cost of 3mm sheets of plywood is high and so it is not feasible to just cut how we would have preferred to make our folded structure into the most beautiful we could. With the limitations we chose to construct just a section of our original design to reduce the amount of plywood needed. Our main problem however was that our structure is con-
structed from triangular panels which meant we would have to cut big enough to allow for the 900 x 400 panels to be laser cut. We also have to allow for space where holes can be cut/ drilled in order to hinge the panels together. By adjusting the angles by which the repeated triangular panels are cut by we can make the structure out of 4 (1500 x 1500) sheets. 3 of those panels will be cut to leave 2 (900 x 400) on each and so leaving 6 (900 x 400) panels to be laser cut. A 4th panel will be needed to cut down into smaller triangles for the base triangles and so will not leave 900 x 400 areas, however this plus other wastage form the other panels can be used for other model making.
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MATERIALS
String- Load Testing
The reasoning behind the incorporation, as mentioned previously, is to provide the structure with both stability and flexibility while remaining aesthetically pleasing. The string conveys a sort of elegance sharing similarities with the mechanisms of a corset. One key feature of the structure is that it must be able to withstand a load equal to the weight of our lightest team member without collapsing.
METHOD • Sisal Twine Single and Plaited were both used in our tests. • Both types of string were measured to be 500mm in length. • The string was tied to a steel rail with a bucket attached at the other end. • Our loads would increase by 4kg each time.
RESULTS • Sisal Twine Single string held up to 20kg of sand • Plaited string held up to over 52 kg of sand, together with the addition of 1kg, 2kg and 10kg of weights.
CONCLUSION The material used would be stable enough to hold it together. The string will be wound through a series of holes along the edge of the timber panels, which will also provide it with durability.
A test was carried out to guarantee that the material of the string used to bind each timber panel together was robust enough to hold our load.
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MATERIALS Support
At specific joints of the folded structure, a triangular sheet of (metal) will be bound to the edge of the plywood panels. This will ensure that the load is not straining one particular area, it will however, be spread equally in that triangular area. The string will then be sewn through these holes as shown in the image. Although, due to the sharp edges of the metal holes these may cut the rope, after the rope has been fed through. The solution to this problem in this case is to file down the (metal) holes preventing from this to happen.
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PHOTO DIARY
model making...
NOVEMBER 2 First attempt at the model for our prototype. Was reconsidered to portray construction and material cuts more seriously. 12:00 prep work- cutting
13:00 join pieces together according to pattern
13:45 final form is complete. unfortunately it is not a match to what we will be building.
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PHOTO DIARY
working up to the build... NOVEMBER 9 14:00 Discussing loads and calculations with Kirsty.
14:30 Construction team hard at work building a model to show the steel supports at the base of our folded structure.
15:00 Load testing- WIll the piano hinges fail under pressure?
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PHOTO DIARY
last minute resolutions...
NOVEMBER 11 15:15 How are we going to control the expansion? Group members altogether trying to figure out a solution for the base.
NOVEMBER 16 Interim crit
13:30 feedback on the document emphasis ‘quality control’
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1:1 CONSTRUCTION 2 weeks until DECEMBER 14 test date
TIMETABLE 03/12-14/12
Ideal timetable created NOVEMBER 30 *subject to change*
Each person was given a specific time to to be in to complete tasks geared towards meeting the daily goals.
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TIMETABLE Revised
Our intended work schedule depended majorly on the materials being delievered on time. The wood supplied from the school did not arrive until Tuesday, delaying our time by one full day.
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MATERIALS & STRATEGY Materials list
Construction Strategy
4 of 1500x1500mm 3mm beech ply 10mm M4 Bolts M4 Nuts M4 Washers 10 of 100mm Piano hinges Sisal twine Fast Grab wood glue Double sided tape 100x100mm 1mm steel sheet Small Bulldog clips where also used but proved not to be necessary
• Cut panels out of sheets of 3mm ply. Left over wood can then be cut into 20mm wide strips, which will latter be used to reinforce central sewn joint. This is a fairly straightforward job, which could be undertaken by any member of the team after a short introduction to the band saw. • The edge of each panel needs to be sanded using a block and a fairly fine grade sand paper to remove any splinters of wood and to produce a high quality finish to the cut. Any member of the team again could do this. • The 20mm strips of ply then need to be glued and clamped along the central joint. Clamping ensures a strong bond between the two pieces of ply. Again this an unskilled job, although care is required to reach the required high standard, as excessive glue will quickly make the joint look messy. • Once the glue is fully set holes for the string can be drilled along the reinforced edge, to achieve the best finish the pillar drill can be used and it would be best if one of the more skilled members of the team carried this out. It is important the holes are offset on opposite edges to ensure the panels are not pulled out of position when they are latter sewn together. • The piano hinges then need to be cut to length. There is a certain technique to ensuring a clean cut so would be best done by an experienced member of the team. The ends also need to be filed down to provide a clean finish and to remove any sharp edges, someone less skilled to do this. • Once the piano hinges have been cut to length, they then need to be lined up against the panels so the bolt holes can be drilled, a high level of care is required here to ensure the piano hinges are in the right place and are straight. The holes will then be drilled with a hand drill, which can be done by any member of the team. • The hinges are then bolted into place, using 8mm M4 bolts, washers and nut. This is a time consuming process simply as there are so many bolts. It is however, very unskilled and could be done by the whole team together to speed things up. • The edges of the central hinge now need to be chamfered, this id done using a sanding block and a rough grade sand paper. This needs to be done very carefully to prevent any gaps appearing along the joint. It is important an experienced member of the build team carefully regulates this stage of the build. • The central joint can now be sew together, this is more time consuming than it looks as it is very fiddly and each loops needs to be pulled tight to ensure a strong joint. Any member of the team can quickly be shown how to do this. • The sheet steel can be cut and filed into the appropriate shapes for where the string will join the ply. Although a high level of care is required here any member of the team can quickly learn how to use the metal guillotine. • The holes then need to be carefully measured out and drilled into the steel plates using the pillar drill and the drill holes need to be filed down to remove any sharp edges that might tear through the string. • Holes also need to be lined up off the steel plates onto the wood and drilled through using a hand drill. This would be best done by a skilled member of the team as these holes need to line up exactly, before the steel reinforcement plates are then attached using double sided tape, which can then be clamped, which will increase the effectiveness of the tape. • Lastly the string reinforcement need to be plated through the ply and attached in the appropriate place, this stage could be carried out by any members of the team.
Tools Skil Saw Sandpaper Hand drill Quick Clamps Spring Clamps Hacksaw File Fine file Screwdriver Adjustable Spanner
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Construction Day 1-Cutting
Tuesday DECEMBER 4 Plywood panels were cut from 1500 x 1500 panels into two equal triangles per panel as per the cutting pattern. The edges were then reinforced using a thin strip of ply along the edge of the triangular panels.
ters or uneven edges, this was done to prevent any damage to the paracord, which will be used in place of the string for the stitched hinge.
Holes were then drilled in a straight line through this edge at an even distance apart. Sandpaper was then used to ensure that there were no splin-
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Construction
Day 2- Filing & Quality Control
Wednesday DECEMBER 5 There are six panels of triangular plywood with reinforced edges. The reinforced edges needed to now be filed and then sanded down creating 45 degrees. angle. This would allow the edges to be joined together seamlessly by the sisal twine stitch. Each drilled hole was filed to in efforts to reduce damage to the twine during final testing. Along the length of each reinforced edge we measured in 6mm and a straight line was drawn. The angle between
this line and the outside edge of the panel would be 45 degrees. The angle was created by vigorous filing efforts of the team. There were two team members per triangular panel in order to speed up the process. Clamps were used to hold the panels in place during the process. By securing the panels, we hoped to ensure the angles came out as accurate as possible. We kept the motion of the sanding and filing in a one straight vertical movement along
the height of the triangular panel, working with the grain of the ply. The angles on the plywood panels were put together as we worked to make sure that they were joining up properly. Each drilled hole was filed to prevent any damage to the Sisal Twine string, which would be thread into them after the bolting process. To ensure quality control, other team members checked the work periodically.
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Construction
Day 3- Hinge Work & Tests
Thursday DECEMBER 7 As mentioned previously in the document, the piano hinge would allow the folded structure to fold in one direction to an extent. The hinges were measured and cut to fit the ply panels along the sides opposite the stitch. Each hole was drilled using a hand drill according to the spacing of the existing holes on the hinge. Clamps were used again during this process to keep the materials secure. We used steel bolts to fix the hinges in place. Each bolt was fastened with a plain washer on each side of
the panel and then secured by tightening the nut on the outside plane. This step was repeated for each hole. We got as many as the team members to help with the bolting process to speed up what was a very tedious task. The construction leaders inspected each joint was done correctly and the standard of each construction task, up to this point, was to it’s highest before moving onto another.
Quick tests were carried out in the evening on each half of the structure separately and as a whole to see whether everything was going as planned. We could then reflect on its strengths, limitations and where we could implement necessary improvements.
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Construction Day 4-Stitching
Friday DECEMBER 7 We had a quick group meeting at the beginning of the day that had been scheduled to discuss our process for the day with one of our tech tutors. Together we would thread the spine of the folded structure together. As mentioned, we would be using singly ply sisal twine. Before we started to stitch the bolts were double checked to make sure every bolt was tight, ensuring tensile strength. As a team, and with the help of our tutor, we lifted the two halves of the structure into its final position.
Two to Four members of our team sat underneath the structure while the remaining members held the edges of the structure into place. The Sisal Twine string would be threaded through the reinforced side of the plywood panels. We utilized a simple stitch pattern for all of the respective joints. Before we started stitching we used the thread at interval to tact the structure together, holding it together (similar to the clamps in previous processes). Ten holes would be counted along both
panels and a 100mm length of string or less would be used to tack it into place using a double or triple knot. Each base and fold along both sides was also tacked in the same manner. This process took us into the afternoon. By the end of the day our structure had been completely fixed together and was standing on its own for the most part.
As it stood we noticed that the outside panels from the apex to the floor drooped inwards, not to any fault on our behalf, but because of the lightness of the material. It was decided that for aesthetic purposed we would need to figure out a way to also reinforce these edges. To do that we would have to dismantle and restitch the whole thing.
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Construction
Day 5-Reinforcement
Thursday DECEMBER 13 The structure was taken apart so that we can attach the necessary fixture to improve the previously mentioned edges. Before we started this process, we ensured that all the nuts and bolts were tightened. Three holes were drilled on the two highest points in the middle of the structure. A square steel plate was then fixed onto the plywood panels as reinforcements. These two points would later be joined together by a tightly plaited sisal twine rope as
a means of increasing the tension between the two and therefore holding them up. The new position of the points would decrease the amount of sagging along the edges that run from the points to the base of the structure. Bulldog clips and piano hinges were also used as further reinforcements along the drooping edges. Once the reinforcements were in place we then re-stitched the structure together.
Pre-test The same day, we loaded the structure with 25kg of sand to get an idea of how it would be distributed and whether our folded structure could bear more than half the load. It successfully held.
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FINAL TEST DAY Friday December 14
On the final day we had to first overcome the transportation of the built form by its folding capabilities working as they should. The flexibility in the piano hinges allowed us to fold and move the structure into the testing room. Then we tested the structure using 2.5 kg bags of sand. We started cautiously placing the weights one by one along the middles panels where the structure was stitched and trying to keep the weight evenly distributed to ensure the whole structure would react equally and to not load all the weight to one point. Our aim was to load the structure with 50 kg of weight. Our main worry was that the weight and forces acting on the structure would lead to either the plywood panels to split and warp due to their size and weakness or for our piano hinges to break. The structure however performed well to begin with and the central panels when out folded proved to be very strong and rigid. As the weight increased past 30 kg we started to notice the forces acting on the weakest points of the structure. For example the top corners of the central plywood panels began to warp at the ends where the piano hinges were being used as hinges. This was due to both the plywood being weak in its form and also the bolting to the piano hinges were not strong enough to hold where the forces were greatest. Due to our rule of saving the plywood panels for use in the laser cutter we didn’t want to load the structure past the point of breaking, however the structure did hold over 50kg which fulfilled our expectations. As our form was built as a prototype of a bigger structure it performed better than we expected. Imagining the section built as part of a bigger structure would mean the strength would only increase, showing that our design was right and although was heavily influenced by aesthetic qualities it did not lack in its practical qualities. As we had limitations on the use of the plywood, because of its cost, our design was at its limit in terms of being at the most efficient use of material. Throughout the design process also we had always been redesigning the form to make the forces act down to the floor to reduce the amount exerted onto the panels and so the final form worked at its limit on the test day. One area which would need to be improved its that we used bulldog clips and locked piano hinges along the plywood panel lengths as a way of representing how when as a connected section the lengths would be hinged and so the forces would act differently, and the loads would be distributed differently. This was partly due to the time and material constraints and also are limitations on cutting the plywood. If we has more time and access to more materials we would have liked to construct several more sections which we could have connected with our piano hinge and stitching methods to build up a whole length of section that could hold more weight and perform better. The craftsmanship of the structure definitely contributed to the success of the structure as it meant the areas which were loaded distributed the forces down the hinges to the floor correctly, allowing more weight to be added. As all the panels were accurately measured, cut and hinged its meant the whole form was equal and did not result in additional weak points which could have reduced the strength of the whole structure. Also a major part of our design was the beauty of the form which meant it necessary for good craftsmanship at all stages of construction. The attention to detail considered when fixing both the piano hinges and the stitching meant the whole form looked simple and built to a high standard. Also resulting in a beautiful form which displayed the plywood panels well and we were especially proud of the corset-like stitching down the centre.
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FINAL TEST DAY
Photo Record & Final Structure
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