# Brooklyn Bridge

A dusk\-lit model of the Brooklyn Bridge: its stone towers, steel cables, the path the weight takes, and the caissons dug beneath the East River

By Daniel Doorley

Topic: History

[Open the interactive Jig](https://ask.jig.com/j/x6ZnIKlsFnpa)

## Transcript

### 1. The Brooklyn Bridge

In 1883 this bridge joined Manhattan and Brooklyn across New York's East River\. For a while it was the longest suspension bridge in the world\. Drag any empty space to turn the model\.

Its main span stretches 1,595 feet \(486 m\) from tower to tower\.

### 2. Two stone towers

Each tower is built from blocks of granite and limestone and rises about 276 feet \(84 m\) above the water\. Two tall pointed arches let the roadways pass straight through the stone\.

Pointed arches like these are a Gothic style, the kind seen in old cathedrals\.

### 3. Four great cables

Four main cables drape over the towers and run down to each shore\. Every cable is about 16 inches \(40 cm\) thick and is made of 5,282 steel wires bundled together\.

It was the first suspension bridge with cables of galvanized steel wire, coated in zinc to resist rust\.

### 4. Follow the weight

Thin vertical ropes called suspenders hold up the deck\. They pull on the cables, the cables pull on the towers, and the towers press down into the riverbed\. Amber glows where the bridge pulls \(tension\); blue where stone pushes \(compression\)\.

### 5. Anchored to the shore

At each end the cables plunge into an anchorage, a huge block of stone weighing about 60,000 tons\. Its sheer weight holds the cable ends, so the bridge cannot pull itself into the river\.

Each anchorage covers a base of about 129 by 119 feet \(39 by 36 m\)\.

### 6. A web against the wind

Designer John A\. Roebling added diagonal stays that fan out from the towers, plus deep steel trusses along the deck\. Together they stiffen the bridge so the wind cannot set it swaying\.

That makes it part suspension bridge and part cable\-stayed bridge\.

### 7. Digging under the river

Under each tower sits a caisson: a giant wooden box, open at the bottom, sunk into the riverbed\. Workers dug out the mud inside it, breathing compressed air that kept the water out, while the growing tower pushed it deeper\.

The Manhattan caisson came to rest 78½ feet \(24 m\) below high water\.

### 8. A family's bridge

John Roebling died before building began, so his son Washington took charge\. When illness from working in the caissons kept Washington at home, his wife Emily Warren Roebling carried his plans to the site and managed the work\.

The bridge opened on May 24, 1883, and people still stroll its wooden promenade today\.