School Of Architecture, Building &

Science

Building Construction 2 (ARC 2513)

Project 1: Understanding Forces in Skeletal Structure

Prepared by:

D a n i e l Ya p C h u n g K i a t 0 3 0 9 1 0 0

L o o G i a p S h e n g 0 3 1 0 3 9 0

C h r i s t i o d y 0 3 0 4 1 9 1

T e o K e a n H u i 0 3 1 0 1 6 5

G a n C h i n B o n g 0 3 1 3 7 3 2

Content Page Page

Introduction 1

Design Process 2-3

Design Solution 4-5

Force Analysis 6-7

Model Constructed and Detail 8

Model Testing & Failure 9

Efficiency 9

Design Improvement 10-11

Conclusion 12

Introduction

Architecture, not only consisting design concept, form and

spatial quality but also the structure as it helps in constructing the

architecture. As a successful architecture, structural strength of the

architecture should be concerned during the design process. There are

various types of supporting structure but skeletal structure construction

are nowadays widely used in most of the architecture in the world as

building support. Therefore, it is important for us as an architectural

student to study how these skeletal structure works and influences the

stability of an architecture.

In this project, we are required to understand the skeletal

structure and the components and how they work. In order to show our

understanding, we were required to create a convincing structural model

to show our understanding of how a structure works under a load.

Design process

Design 1

Triangular core to distributes load could be a very strong structure. The triangular core was pre-

stressed to oppose the load force (mechanism of spring). The triangular core was joined with a

square base to maximize the base area of the structure. The tip of the triangular core are faced

up and down respectively at each level to distribute the load force evenly. The weakness of the

structure is the absence of vertical structure.

Design 2

The theory of pre-stress was still applied in this model. The square base provides larger base

area and better stability. The square base also provides maximum number of pre-stressed

column. Zigzag bracing were used to support beams meanwhile cross bracing used to maintain

the form and prevent the structure to be twisted. This design has its potential and with proper

bracing, it can be a very strong structure.

Design 3

Squared base with 8 columns at each level produce a very strong structure.

The columns are bended inwards a little to make sure it breaks inward.

Therefore, there are square bracing inside to prevent the bended column from

breaking. A-bracing is use for vertical bracing to support the beams and to

prevent the square bracing inside from breaking. Each popsicles stick are

supporting each other. This design distributes the load force to different

direction so force becomes weaker and weaker.

Design solution

Learn how is a building’s fundamental work. Besides, we also learn about pre-stretch method. Explore

how to tie to thing two string together to get maximum outcome. Learn how much loads that one popsicle

stick can handle.

Double square diagonal base

The square diagonal base give good impact and give maximum strength to the base as supporter. The

double layer of popsicle on the base support and giving stability to the vertical structure where are going

to place it on the base. The mechanism is the double layer of the popsicle stick will clip the vertical

structure so it giving more balance and stability.

The 4 pre-stretch column

The 4 pre-stretch column is giving a lot of benefit in a way to handle the load. The 4 column also became

the connector between the ground level to the next level.The mechanism is using 8 popsicle stick as the

vertical structures which tied together as two per column with leaving gap in between the structure to give

a space for the popsicle stick to stretch and support each other when the load force down from the top.

The balance slot in triangle bracing

The triangle bracing is the usual bracing that the being used by construction as structure supporter

nowadays. The slot in triangle bracing being bring into the skeletal structure. The slot in triangle bracing

giving a lot of benefit and advantages. The center part is to help the triangle bracing keep stable. The

mechanism is slot in the bracing that create a triangle shape that make the popsicle stick force each other

and force it to the 4 pre-stretch column. the bracing we put it on 4 sided of the structures and it helps a lot

on handle the load that force down to the structure.

Consistency of tying the string

Consistency is the most important thing on tying thing. For example this skeletal structure use string as

connector if the consistency and the way of tying the string is not right so the structure and connection

will decrease the strength and the stability of the structure. So for this skeletal structure the string tying

has been set like the number of tying. The mechanism of tying system is the string come from all the

sided and way with the same number of repetition with same loose-ness that given to every repetition.

Force Analysis

The characteristics of a Popsicle stick is experiment and tested. We

realized that it actually can be bent, so it has a tensile property and we have decided to

make use of it. In order to create a strong tower, we need to make use of all the

possibilities of Popsicle stick. The idea is to create a model with tensile strength and

using it to withstand the heavy load force and transfer it to other direction rather than

just acting downwards.

Pre-bent – To lead the force to the direction where it bends when force is exerted.

This is to predict the direction where the Popsicle stick breaks and from there, reinforce

it. A straight vertical column is unpredictable where the direction it breaks. Therefore it

is difficult to control the direction of force. A horizontal beam is placed at both ends to

hold them firmly and preventing them from shaking.( Shown in diagram beside)

Load

Force

Another shorter pre-bent Popsicle stick is placed in between two pre-bent

columns to carry the force transferred from the columns. By doing so, the originally

weakest point of the column now separate the entire column into two, making it harder

to bend. Just by adding a beam in the middle between two pre-bent columns

significantly enhances the strength.

The way it works is that the load force coming from top will compress the pre-

bend columns. After a pre-bend beam is added in between the middle of two pre-bend

columns, the heavy force transferred is reduced due to the tensile property countering

the force. The reason of using a pre-bend beam is to make is easily bendable in its

already bent position. This way it reduces the overall load force, like a spring.

To further enhance it, an inverted ‘V’ shape bracing is used in all sides of the

structure. Not only it shares the load by making use of the horizontal beam to transfer

the load, it also prevents the whole structure to tilt to 1 side. Besides, it holds the shorter

pre-bent beam from bending too much and break.

The idea is to be able to reduce the load force and to direct the force

experienced to all directions instead of just acting downwards.

Load

Load

Force

Force

Model Constructed and Detailed

After finish testing mock up model which only giving

unsatisfied result which became challenging thing to find out the problem

and solve it with the 4 method. After found out the problem, the 4 method

that became our specialty and best method to construct the skeletal structure.

84 popsicle stick is the number to construct the skeletal structure. after

counting the popsicle stick start to weighing the structure which the weight

reach exactly 100 grams and the height of the tower also reach the

requirement height or the minimum height that has been stated which is 30

cm.

First Experimental Model

Model Testing & Failure

The first testing is going smoothly. The structure handle 104 kilogram

without cracking any of the popsicle stick or structure. Stop at 104 kilogram

because out of loads at that time. After that, the lecturer require a test for

submission. Unlucky the lecture only bring 40 kilogram load to the studio.

After testing on studio the structure still can handle without cracking

anything. So all of the group member doing the final test at gym which

supply more loads. Then for the final test, the structure end up with satisfied

result which can handle load more than 100 kilogram which exactly 108.75

kilogram. About the structure it’s not breaking the popsicle stick it’s only fall

down because of the structure tilting at the moment and make the bracing all

pop out from the place where it should be.

Efficiency

Efficiency = Height X Load_______________

Mass

=_______________30.0 X 108.75

100= 32.625

Design improvement

Our initial design was to use pre-stressed column to execute opposite force from the load. We

used 8 columns for every level and stressed the sticks (to create the mechanism of spring). Then

we have zigzag bracing as our vertical bracing and cross bracing for horizontal bracing. The

methods of both bracing are slotted-in. It gives us unsatisfied result. We used 66 sticks and it

breaks at 30KG.

We replay the mock up video to observe and analysis how and why the model were crushed. We

then knew that our structure was not crushed directly vertical because the upper structure actually

slide off aside causing the middle structure to gets imbalanced and it crushed downwards. We

checked on the crushed structure and noticed that there weren't any broken stick. The major

problems are not the structure is weak itself, it was the positioning and equilibrium that twisted

the structure. The structure did not maximize its load endurance. The factor behind the structure

failure were the inappropriate bracing applied and inconsistency of workmanship caused the

structure to be tilted aside.

We got aware of the importance of workmanship therefore, we made up several systems

and methods in model making to ensure every one using the same way. We then

realised that the pre-stressed column are not as strong as pure vertical column so we

changed our plan. We decided to stressed the stick a little inwards to force the stick to

break inwards rather than using it as pre-stressed. This method ensured that if the

column breaks, it would definitely break inwards.

We then strengthen the inner side by adding bracing into the weakest point of the

bended column which is the middle of the stick. Moreover, we improved our zigzag

bracing to A-bracing. The A-bracing functioned as two; supporting the bracing of the

bended column and to maintain the beam in its position. This method distributes the

force from the load to many and different directions, minimizing the force each time it

changes direction. We have improved from the theory of opposing its force to

distributing load force to different directions.

Conclusion

In the conclusion, a lots of experiences and

understandings have been gain through this structural model making.

Throughout this project, we have learnt how a skeletal structure works under

loading. In order to maximize the load handled by a structure, several

experiments have been carried out. We have tried different ways of bracing,

different way of tithing method and also different types of structure.

After been through these experiments, we have learnt that

bracings are needed to strengthen the structure as they play an important role

in maintain the original shape of the structure.

Besides that, our creativity have also been aroused to create

different kinds of structure and test them to their limit. This project have

indirectly help us to realize that how an organic structure can possibly

construct in different skeletal structure.