Model Making Workshop - Structure of Tall Buildings and Towers CONTENTS Lesson 1 Model Making Workshop - Structure of Tall Buildings and Towers Introduction to Tall Buildings Loads and Forces on Buildings Vertical Forces Horizontal Forces Internal Forces Typical Structural Systems in Tall Buildings Project Brief on Tower-Making Workshop Class activity Role Play | Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Model Making Workshop

Model Making Workshop – Structure of Tall Buildings Lesson 1 Model Making Workshop – Structure of Tall Buildings and Towers | Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Introduction to Tall Buildings

Introduction to Tall Buildings Do you know these tall buildings? How tall are they? What are the structures? | Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Introduction to Tall Buildings

How tall are they? The Leaning Tower of Pisa (55.86 m) was built in 1372, using marble stone in a Romanesque style. Its current leaning appearance is due to sub-soil settlement. The Eiffel Tower is a 320-m-high steel structure that was completed in 1889 as the entrance arch for that year’s World’s Fair. | Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Introduction to Tall Buildings

In the early 20th century, cities became bigger and denser In the early 20th century, cities became bigger and denser. Urban populations were growing but land supply was limited. High-rise buildings became an essential solution to the problem. New technologies and building materials, such as industrial reinforced concrete, steel and elevators, made high-rise structures feasible and drove innovation. The 90-m-high Royal Liver Building in Liverpool was one of the first concrete buildings in the world. It was completed in 1911 after a Neoclassical design by Walter A. Thomas. © Chowells － Wikipedia User | Model Making Workshop – Structure of Tall Building and Tower | 6 Lesson 1 – Introduction to Tall Buildings 6

The 36-storey Equitable Building in New York was completed in 1915 The 36-storey Equitable Building in New York was completed in 1915. Its architect, Ernest R. Graham, used a Neoclassical style despite the building’s modernity: it was the first building equipped with elevators. It triggered the implementation of height limits and setbacks for tall buildings to allow sunlight to reach street level. The modernist Wainwright Building in St. Louis was completed in 1891 by architects Dankmar Adler & Louis Sullivan. Its 10-storey are supported by an early steel framing system. | Model Making Workshop – Structure of Tall Building and Tower | 7 Lesson 1 – Introduction to Tall Buildings 7

Loads and Forces on Buildings The statics of a building deal with its structural stability. According to Newton’s First Law, when an object is in equilibrium, the sum of all forces equals zero. What are the sources of forces that act on the building structure? | Model Making Workshop – Structure of Tall Building and Tower | 8 Lesson 1 – Loads and Forces on Buildings 8

There are three types of loads generally: Dead Load Dead loads are the loads of the structure and fixed components. It is a permanent force that is relatively constant for a extended period of time. The force is gravitational. Live Load Live load is a changing force generated by mobile objects inside the building, such as people within the building or stock in a warehouse. Environmental Load Environmental loads are forces acting on the building from its environment and may include wind, rain, earthquakes and temperature changes. The forces created can be either horizontal or vertical, positive or negative. | Model Making Workshop – Structure of Tall Building and Tower | 9 Lesson 1 – Loads and Forces on Buildings 9

Vertical Forces Dead loads and live loads contribute to the vertical forces on the structure of buildings. Vertical loads are transferred from the floors to the columns and walls, and eventually to the soil or bedrock. At times, environmental loads also act vertically. Dead loads e.g. Weight of the building Environmental loads e.g. Wind | Model Making Workshop – Structure of Tall Building and Tower | 10 Lesson 1 – Loads and Forces on Buildings 10

Horizontal Forces Environmental loads contribute most of the horizontal forces acting on the structure of a building, with loads from wind being the most common. Architects refer to these horizontal forces as shear force. Adding cross bracing or shear walls can improve structural resistance to shear forces. Environmental loads e.g. Wind | Model Making Workshop – Structure of Tall Building and Tower | 11 Lesson 1 – Loads and Forces on Buildings 11

Internal Forces The internal strength of the entire structure must be = or > the total forces applied on the building The ability to withstand all forces depends on the structural component’s dimensions and the solidity and elasticity of the material. Internal forces : Compressive and Tensile Forces According to Newton’s Third Law, forces act in pairs. In structural terms, tensile force pulls a structural element apart while compressive force compresses it. Torque If opposing forces are applied at different points, a structural element may become twisted. Compressive Force Tensile Force Torque Internal forces in a structural element | Model Making Workshop – Structure of Tall Building and Tower | 12 Lesson 1 – Loads and Forces on Buildings 12

Typical Structural Systems in Tall Buildings Installation of outriggers at the International Commerce Centre © Raymond Wong | Model Making Workshop – Structure of Tall Building and Tower | 13 Lesson 1 – Typical Structural Systems in Tall Buildings 13

Core and Outrigger structure The International Commerce Centre is built using a ‘Core and Outrigger’ concept. The core at the centre of the building bears most of the vertical load, while columns at the perimeter carry less weight and are thus smaller in dimension. Loads are transferred to the core through steel outriggers that balance the lateral forces on the whole building. Outrigger connecting the core and the columns Plan of International Commerce Centre | Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Typical Structural Systems in Tall Buildings

Steel It is a common construction material for tall buildings good performance in withstanding compressive and tensile forces, as opposed to concrete’s low tensile strength in compression. Steel bars can be used to reinforce concrete to add extra structural performance. Relatively weak in fire-resistance. The Bank of China Tower is a steel trussed-tube structure. The whole building acts as a single tubular truss, with the diagonals wrapping the building to transfer loads. Bank of China Tower | Model Making Workshop – Structure of Tall Building and Tower | 15 Lesson 1 – Typical Structural Systems in Tall Buildings 15

Truss Common structural element in architecture. Steel members are joined together into triangular shapes, which are able to resist external forces. When joined together, these triangles can form large truss systems that can span long distances. | Model Making Workshop – Structure of Tall Building and Tower | 16 Lesson 1 – Typical Structural Systems in Tall Buildings 16

Truss Common types of truss © Structural Building Components Association | Model Making Workshop – Structure of Tall Building and Tower | 17 Lesson 1 – Typical Structural Systems in Tall Buildings 17

Summary Although humans have long attempted to build tall structures, skyscrapers began to appear in our cities in the late 19th century as a result of technological breakthroughs in building materials and methods, including reinforced concrete, steel, and elevators. | Model Making Workshop – Structure of Tall Building and Tower |

Summary Buildings bear three types of loads: dead loads, live loads and environmental loads All loads are resolved into vertical and horizontal forces on the structure. Typical structural systems used in tall buildings include core and outrigger structures, steel frames and trusses. | Model Making Workshop – Structure of Tall Building and Tower | 19 19

Class Activity: Model Making Workshop- Tower | Model Making Workshop – Structure of Tall Building and Tower | 20 Class Activity 20

Class Activity - Model Making Workshop - Tower Step 1- Divide the class into groups of four to five. Step 2- Each group is required to build a tower that should be: • Structurally stable and aesthetically pleasing • Height • Weight-height ratio • Resistant to wind • Load supporting | Model Making Workshop – Structure of Tall Building and Tower | 21 Class Activity 21

Class Activity - Model Making Workshop - Tower Tools needed • Sketching papers and pencil • Scissors, cutters, tape, glue • Different weights (10 g/ 50 g/ 100 g/ 500 g/ 1 kg) • Weight scale • Measuring tape • Electric fans Suggested materials • Cardboard • Bamboo sticks • Recycled cans • Recycled plastic bottles • Fishing line | Model Making Workshop – Structure of Tall Building and Tower | 22 Class Activity 22