Development Sketches and models.
-Form and structure - Page 1
A sketch model of two of the main structural components, looking at how they might connect together.
Construction sketch model: I decided to use a pin joint to connect the 2 main members together, in order to allow easier assembly of the structure. But also to reduce the shear/ turning force that would otherwise be felt at this if it was a rigid joint. Also now makes the tension cables more of an important feature instead of just an aesthetic pleasantry.
Model of the span between the five main structural components. This picture is of the underside, showing how ribs will be used to bring the load from the roof cladding into the main components.
After drawing various types of roof structure, I decided on a cantilever design and began further development.
Decided on a design that feature 2 overlapping triangles connected by cables. To form a repeated structural element.
Primary span (main Secondary span component) (ribs
Tertiary span (Roof cladding)
-Form and structure - Page 2
Alexander Baldwin-Cole Grade316 Stainless steel cabling, 20mm
1:200 South West Elevation
Corten Steel cladding and struts. H55 square steel beam.
1:50 Detailing of connection cap over main compression member. Showing the connection of the 4 tension members, by using cables with loops on the end and slotting pins through them. 1:20 detailing of connection point of tension cable member to compression member, through pin joint. Plus section showing shear diaphragm member and roof cladding.
1:200 South East Elevation
1:50 Detail of connection point with foundations
Corning house ruins
The roof structure covers an area of 400m^2 and has the dimensions of 40mx10m. The main structure is made of 5 cantilevering structures with a shear diaphragm bridging the gap between the structures. The maximum span between the structural members is 10m thus making the minimum depth of these members 500mm. It is 8.04m at its highest point from the foundations of the structure. The entire structure has a foot print of approximately 806m^2
Gravity Load Diagrams
-Form and structure - Page 3
I decided to show the internal forces within the connection structure mounted on the main compression member, as well as the forces felt within the main horizontal component between the tension cable connections.
No roof structure cladding, so less force is felt through the member. So still is, especially as the diagram has been modelled for the gravity load also acting on the primary cantilever beam. Tension from Low-High Pin joint allows movement, doesnâ€™t act a fixed joint, to reduce turning force from cantilever. Also makes construction easier.
Compression from Low-High Gravity Load
This member in different points acts in both compression and tensional forces. Depending on how great the force felt of the roof plane is..
Resultant forces at foundation Load Path
Diagram drawn with gravity load influencing on both the roof plane and the top of the main compression member.
These tension cables have very small influence in managing the gravity load, however come drastically into play in the lateral wind diagram.
Shear diaphragm ribs also act as trusses for the roof planes to be mounted onto. They form the secondary span of the roof load system. The smaller arrows show how the first route of the forces., through the roof cladding and onto the horizontal beams.
Lateral Wind Diagrams
-Form and structure - Page 4
Tension from Low-High Compression from Low-High
Reaction forces at foundations. Wind direction Load Path
Diagram modelled from wind acting on both the horizontal and vertical components.
These tension members do nothing with the direction of wind modelled in this diagram, but will when its modelled from the opposite direction.
Shear diaphragm handles the turning force felt through the roof. By keeping the entire structure rigid. The roof cladding also helps to stop the struts from deflecting.
Final presentation Model
-Form and structure - Page 5
Final model was made at 1:100, in order to more easily show all the structural members. I included a small site section in order to show where it sits over the corning house. The final roof cladding has been left off the model in order for the primary and secondary spanning members to be more easily visible. The final span (tertiary) is formed from the roof cladding itself which is strips layered vertically across the 6l struts (Seen easiest in the picture to the left.)
Stage 1: A Cement arm poorer is used to lay the foundation points. Then metal caps are added to produce foot in cast iron shoes.
Stage 2: The main vertical component is craned i9nto position and is fixed to the base, while also resting on temporary structures, to keep it in position.
-Form and structure - Page 6
Stage 3: The backward bracing member is craned in and will be connected to the structure with a pin joint and to the foundation through another foot in cast iron shoe. For now it rests on the temporary structure waiting to be connected to the pin join later. It is connected to the foundations at this point.
Stage 4: The connection cap is craned into position and rest just on top of the vertical compression member. A mild weld joint is made to secure it. The temporary structure acts as scaffolding in order to get the workers up thee structure.
Stage 5: The main horizontal component is craned into place and is connected to the structure at the pin joint. A Pin is slotted though the joint, securing this member and the bracing member. After the joint is made it is rested on more temporary structure.
Stage 7: Now the lateral cables are connected, tying all the five components together. The Main structure of the roof is now present all that is required is the roof system.
Stage 6: The 4 main tension cables are connected, securing the canter levering member and the main vertical compression member. All temporary structures can now be removed. Now the five individual structure components are
Stage 8: The Horizontal struts are craned into place and are immediately welded to the main structural elements, forming the secondary spanning members, as well as a shear diaphragm.
Stage 9: The final roofing finish is lowered into place in the form of strips of Corten Steel. These are then welded into place and the joins are sealed from underneath. These strips act as the tertiary spanning member. The structure is now complete.