Building Construction 2 Project 2 Report

LONDON OLYMPIC STADIUM 2012

BUILDING CONSTRUCTION 2 [ARC 2513]Project 2: Understanding Forces in Solid Structure and Surface Structure

Tutor: Mr Bruce Lee Xia Sheng

GROUP MEMBERS: TAN WEI HOW (0310707) YONG CHANG THENG (0310925) LEE YUAN JUNE (0311128) WONG PEAKKY (1101A13474)CHUAH WEI HONG (0310900) CHEONG SIEW LEONG (0310845)

SCHOOL OF ARCHITECTURE, BUILDING & DESIGN Bachelor of Science (Honours) in Architecture

CONTENT

1 INTRODUCTION2 DRAWINGS3 CONSTRUCTION4 STRUCTURAL SYSTEM5 MODELLING PROCESS6 CONCLUSION

INTRODUCTION

In this project, we are to do research and choose a building with at least 2 different types of structural system and study the various structural systems that are used in that building. In a group of 6 persons, we need to build a structural model with suitable scale and materials to understand the construction of the building.

Our chosen building is the Olympic Stadium, which is located on a 40-hectare, diamond-shaped island in the Queen Elizabeth Olympic Park, Stratford, London. It was constructed to serve as the host stadium for the 2012 Summer Olympics and Paralympics. It was designed by Populous, specialists in the design of sports venues. It is the lightest Olympic Stadium ever built and it stands as a testament to steel’s speed of construction and its flexibility.

DRAWINGS

PLANSECTION

ELEVATION

CONSTRUCTION OF DIFFERENT PARTS

Populous’s architects, the designers of the stadium, created a Lego-like modular structure wherein the roof, outer bowl, inner bowl and auxiliary support pieces are all independent of each other. Steelwork has played an important role during the construction programme and 112 steel rakers were installed to support the two tiers of seating. Circling the stadium at high level, a steel roof compression truss, made from 28 individual steel sections, each one 15m high by 30 m long and weighing 85 tonnes, supports a cable net roof and 14 lighting towers. During the Olympic games, the stadium was able to hold 80,000 spectators. That is why the structure of the foundation is very important to support the whole building. There are 5,000 piles reaching up to 20 metres deep in the foundation of the base level which are cast in situ piles, continuous flight auger piles, and vibro concrete columns.

STRUCTURAL SYSTEMSkeletal structure systemThe stadium is designed using steel skeletal structure system, which transfers all load gravity, uplift, and lateral loads to the foundation. Besides that, there are precast concrete, which are heavy, solid, can hold weight on the upper tier seats and lower tier seats.

Rigid concrete frame with reinforcementConcrete is weak in tension but strong in compression. Therefore, reinforcement is needed is needed to resist the tensile stresses resulting from the loads. The rigid structures made of linear elements, beams and columns that are connected that do not allow rotations. Structures are built at the site, which may or may not be poured monolithically. When concrete column and beams are cast in one piece.

Prefabrication of concreteThe concrete elements of the building are manufactured in factory and then transported to the site. All the process involved in concrete construction are done at the factory. This speeds up construction and thus, saves cost. The concrete prefabricated parts will be erected and jointed on site.

External Bracing

It is not only for structural use but it also offers aesthetics to the building. The advantage of steel is to stabilize the frame against strong winds. Lateral forces are resisted by axial actions of bracing and columns. It is more efficient than rigid frame.

The arrows on the image show the external bracing Structural detail of bolted jointsmade of steels

JOINTS

The London Olympic Stadium’s temporary structure will be dismantled after the event. To allow for best flexibility, the roof structure is isolated from the terrace structure. The most efficient way to do so while also saving cost is to employ precast technology and bolted joints for the construction of concrete and steel structure. The V-shaped steel supports act as bracing for the steel truss structure that forms a compression ring. Specially designed cable construction holds the lightweight PVC roof membranes together. For the terrace structure, the precast concrete terrace module is bolted onto the raking lattice girders spanning the whole stadium. As for the permanent structure, precast concrete joints are used.

Photo shown is the concrete terrace module bolted onto the large raking lattice girder

Photo shown is the typical precast concrete joint

LOAD DISTRIBUTION

ROOF LOAD

UPPER TIER LOAD

LOWER TIER LOAD

Load Transfer Pathway

Roof load: Light tower > Roof & Steel cable > Roof truss > V shaped column

Upper Tier load: Precast seating module > Raking lattice girder > Column

Lower Tier load: Floor slab > Beam > Column

STRUCTURAL DETAILS

The Wrap BannersFabric wrap made from polyester and polyethylene

Upper tier seatsPrecast concrete upper bowl has a capacity of 55,000 seats.

Lower tier seatsSunken elliptical bowl that is made up of 40% less embodied carbon precast concrete. It has a capacity of 25,000 seats.

The roof structureMade from recycled materials like meltdown scrap and others from an abandoned gas pipeline project. It is light- weighted and completely eco-friendly.

STRUCTURE AND MATERIALS

112 steel sectionsProvide support to the upper bowl. 126,000 bolts were used to fix the temporary black section in place.

14 light towers Located over the inner ring. Each weighs 34 tonnes and has a power of 70,000 watts. 532 floodlights are used in the 14 towers.

Temporary Permanent structure

CONCLUSION

By completing this project, we get to understand more about different structures and its relevant structural components. We can learn about construction and building structures by doing research and demonstrate our understanding through modelling. As designers, it is very important to understand when and where each of the different type of structural system is used. Furthermore, teamwork is also very important in order to complete a project. This project has brought 6 of us closer together to work as a team. Finally, we want to thank our lecturer, Mr Bruce Lee for guiding us during tutorial classes in order to choose a suitable building and complete this project.

REFERENCES

1. London 2012 - Olympic Stadium, 2012, Detail architecture-topics.[online] Available at:http://www.detail-online.com/architecture/topics/london-2012-olympic-stadium-019389.html

2. Olympic Stadium, London, 2012, Structural Steel Design Awards, Steel Construction.[online] Available at:http://www.steelconstruction.info/Olympic_Stadium,_London

3. How to Construct the Lightest, Most Open Olympic Stadium Ever built, 2012, Popular Science.[online] Available at: http://www.popsci.com/technology/article/2012-07/how-construct-lightest-most-open-olympic-stadium-ever-built

4. London 2012 Olympic Stadium, 2014, Designing Buildings Wiki.[online] Available at:http://www.designingbuildings.co.uk/wiki/London_2012_Olympic_Stadium#Engineering_for_the_Seating_Bowl