---
title: "Sound Transit East Link Extension I-90 Crossing – Seattle, Washington"
url: "https://www.systra.com/ibt/project/sound-transit-east-link-extension-i-90-crossing-seattle-washington/"
type: projects
date_published: 2022-01-01
date_modified: 2026-08-03
schema:
  @type: WebPage
language: en-US
word_count: 306
reading_time: 2 min
canonical: "https://www.systra.com/ibt/project/sound-transit-east-link-extension-i-90-crossing-seattle-washington/"
featured_image: "https://www.systra.com/ibt/wp-content/uploads/sites/21/2023/01/i-90-bridge_2022-scaled.jpg"
project-market:
  - Transit Bridges
  - Segmental Bridges
project-location:
  - USA
---

# Sound Transit East Link Extension I-90 Crossing – Seattle, Washington

![Sound Transit East Link Extension I-90 Crossing – Seattle, Washington](https://www.systra.com/ibt/wp-content/uploads/sites/21/2023/01/i-90-bridge_2022-scaled.jpg)

## DESIGN-BUILD

**Main Span: ** 360 ft (109.8 m) main span, 245 ft (74.7 m) and 250 ft (76.2 m)
side spans.

**The Sound Transit East Link Extension I-90 Crossing expands the existing Seattle light rail system from Seattle across Lake Washington to Bellevue. **

The 14 mi (22.5 km) alignment is primarily situated at grade with isolated
elevated and tunnel sections. The I-90 crossing at the eastern terminus of the
I-90 floating bridge is one of two long-span structures along the alignment.
This cast-in-place segmental balanced cantilever bridge includes a 360 ft (109.8
m) main span with 245 ft (74.7 m) and 250 ft (76.2 m) side spans.

The double-track alignment traverses a compound curve with a minimum centerline
radius of 526 ft (160.4 m). The segmental super-structure consists of 175 ft 8
in (53.6 m) cantilevers off of each of the two main piers and 60 ft 6 in (18.4
m) and 65 ft 6 in (20.0 m) falsework sections at each end pier. Typical segments
are 15 ft 4 in (4.67 m) long.

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