Assignment 1 | Design & Modelling | Report Student ID Number: 311027008, 430071236 Tutor name: John Mai Tutorial Group: 12:00 Group A
Project Outline Details, Perspective,Material
Details
The project aims to provide a roof shelter for a market hall covering about 400 sqm. It mainly consists of concrete base, hinged timber arch structure and tensile cable structure. The timber structure is formed by five hinged-arches as primary structures with the in-between twenty four timber members as secondary structures. Each timber arch is prefabricated off-site with three piece of LVL glued together. The whole arch structure is based on concrete foundation while the central hinged member is pulled by the two cable strands side by side. There are also concrete sitings around two concrete bases which are casted with the concrete base and form a sense of landscape while echoing with the idea of market hall that gathers people together. Many member parts could be prefabricated and delivered to site to assemble such as the three-piece LVL arches and the masts. The mast can be divided at where bending moment is zero along its height. The cables aim to prevent the hinged arches from falling and keep the structure stable under lateral loads. Generally, the materials used are steel, concrete, and laminated veneer lumber.
1
2
Pinned connection between mast and base plate
Welded connection between steel plate, 1200 WB, and side plates
3
Welded connection between two 150 x 150 SHS and steel clip
4
5
Pinned connection between end cap and tensile cables
Pinned connection between base plate and tie-back cable with swaged socket and turnbuckle
4
3
Material
Steel Plate/SHS (square hollow section)/ CHS (circular hollow section)/ WB (welded beam) Concrete Base/Concrete Siting LVL (Laminated Veneer Lumber) Cable
The mast is made out of three circular hollow sections positioned in an triangular orientation to best resist wind loads. The mast is slender towards end and strong in the middle, which is determined by the bending moment distribution. 2
PTFE (polytetrafluoroethylene coated opaque fiberglass membrane)
1
5
The shape of the timber arches are profiled according to the bending moment distribution, therefore the arch is deeper close to the pillar base and thinner towards the hinge.
Perspective
Structure Plan and Elevation Structure Plan and Elevation
2500 9200 3800
8500 9200
12000
12000
9200
9200
Plan 1:200
Short Elevation 1:200
2500 1300 2500
8500
7150
Long Elevation 1:200
4850
1200 2000 1200
3000
3000
3000
3000
3000
3000
3000
3000
1200 2000 1200
4850
7150
Torus Theory: All the timber arches are in the same length and have same curvature, which could reduce the cost of structure and increase manufacturing efficiency.
Structure Hierarchy
Plan 1:200
Long Section 1:200
Short Section 1:200
Gravity Load Gravity Load
( Actions, Reactions and Internal Forces )
( Load-path and Deflected Shape )
( Actions, Reactions and Internal Forces )
Action/ Load- path
Tension
Reaction
Compression
Deflected ( Load- path and Deflected Shape )
Lateral Load
( Actions, Reactions and Internal Forces )
( Load-path and Deflected Shape )
( Actions, Reactions and Internal Forces )
Action/ Load-path
Tension
Reaction
Compression
Deflected ( Load- path and Deflected Shape )
Construction
Sequence
concrete bases are cast in-situ through formworks together with the concrete sitting work.
6. Prefabricate three pieces of timber arches glued together with three secondary timber noggings, while leaving a groove in the middle timber piece to fit into the improved section.
11. Prepare four segments of steel SHS (square hollow section) to weld into one continuous piece on site. Each segment is made up of two 150 x 150 welded along side each other. Prepare five clips, which are welded on top of where the segments join.
2. The steel plate is bolted to the concrete base. It anchors down in case of pulling by upper structures.
7. Lift the prefabricated timber arch and fit it into the improved section. Use falsework to support the cantilevered end .
12. Bolt the clip with the timber structure
3. Repeat step 2 on the other side of the concrete base.
4. Prepare five 1200 welded beam ( Improved Section), in order to hold the timber arches in place and stop them from moving sideways.
5. Weld five 1200 welded beams onto the steel plate on site and repeat step 4 and 5 on the other side.
8. Bolting two sides of the improved section with two steel side plates to prevent the improved section from buckling in weak axis.
9. Repeat step 6 to 8 and finish one side (5 timber member) of the structure while supported by falsework
10. Complete the other side of the structure (overall 10 primary timber structure) while supported by falsework
13. Prefabricate cable masts off-site and deliver them to site to assemble, and bolt the base plate into the ground.
14. Pull the cables and assemble PTFE coated polyester roof. Finally remove falsework and add the handrail around the mast.
Model Photos