Basic Structure of the Original World Trade

The North and South Towers [3]

The picture on the left shows a cross section of the buildings. The towers were 208 ft by 208 ft with a structural core in the middle. This core is where the elevators are housed as well as other service areas such as bathrooms. This center column was believed to be the downfall of the towers in the 9/11 attacks because it acted like a chimney and quickly burned. Although the structure held strong after the impact, the prolonged fire damage was irreversible.

The picture on the right highlights the revolutionary elevator system and also shows the height of the building. The building is a massive 110 stories and 1368 feet tall. Since the building is too tall for an elevator to reach the top, a system of express and local elevators was put in place to get occupants to the higher stories faster.[1]

This is the basic structure of the floors. The joists were resting on angle clips that were attached to the inner core and the outer shell. These clips are also speculated to be one of the main causes of the building collapse. The floors were only designed to hold the 1,300 tons of weight. They would have failed when the weight from rubble, other floors, and airplane fuselage were resting on them. The buildings collapsed within themselves by the floors falling onto the floors below them. This caused a domino effect of collapsed floors and it brought down the entire building[1].

[2]


This is an original blueprint of the twenty fourth floor. This picture shows the lightweight steel core structure that the rest of the building was constructed around. This was considered to be a new way of making skyscrapers when the twin towers were constructed and is still in common practice today. The core was 138 ft by 88ft  in size.

[1] Eager, Thomas, and Christopher Musso. "Why Did the World Trade Center Collapse? Science, Engineering, and Speculation." Why Did the World Trade Center Collapse? Science, Engineering, and Speculation. N.p., n.d. Web. 07 May 2015.
[2] 9-11research.com. N.p., n.d. Web. 7 May 2015. <http://www.tms.org/pubs/journals/jom/0112/eagar/eagar-0112.html>.
[3] "The Towers' Design." 9-11 Research:. N.p., n.d. Web. 07 May 2015. <http://911research.wtc7.net/wtc/arch/plan.html>.

Design Proposal

Purpose

Our group will be covering the famous structure the freedom tower that was recently constructed. We will first research and compare the freedom tower to its predecessors the twin towers  showing how they were improved so the previous problems would not happen again. From there we will see how it is possible to try and improve on the current design. We will then demonstrate our findings by building a model to represent our new structure.

ENGR 103 - Spring 2014

Freshman Engineering Design Lab

“Freedom Tower”

Project Design Proposal

Date Submitted: April xx, 2014

Group Members           {Kyle Breiman, Kjb336@drexel.edu}

                                     {Liam Walsh, lsw43@drexel.edu }

                                     {Stephen Maciejewski, sam446@drexel.edu }

                                     {Chen Sitong, sc3348@drexel.edu }

                                     {Tilvinder Singh, ts862@drexel.edu }

Technical Advisor        { Aspasia Zerva, zervaa@drexel.edu}

Abstract:

Our project was started to create a better structural design for the Freedom Tower. It will be influenced in the changes made since the fall of the Twin Towers. There is expected difficulties in finding how to improve the design of the building because it was constructed so recently. By the end we will be submitting a physical design and a CAD model as well as our research on the Freedom Tower.

1           Introduction

With this project we will grasp a better understanding of the construction of skyscrapers and how they can be built with a stronger resistance to heat. This starts with the comparison between the twin towers and the freedom tower. The building itself is fairly new so structural issues will be difficult to find. The goal is to make any possible corrections to the building in order to make the building structurally safer.

2           Deliverables

By the end of our lab we should have constructed a physical model of our newly designed structure. We will have a CAD model of the freedom tower and multiple different sources of research on the building, as well as ways to show how we will improve the current Freedom Tower.                                                                    

3           Technical Activities

We will be creating our model using data that we have gathered analyzing how the structure will be affected by things like wind, fire, height, deterioration and other natural causes. There will be a physical model as well as a virtual CAD model created.

4           Project Timeline

	Week
Task	1	2	3	4	5	6	7	8	9	10
Literature study	x	x	x
System analysis		x	x	x	x	x
CAD model			x	x	x	x
Mechanical design					x	x	x
Testing							x	x	x
Final report preparation								x	x	x

5           Facilities and Resources

-3D printer

6           Expertise

- Finite elements

- Loading analysis

-Creo Parametrics

-Solid works

-AutoCAD