Commercial Architecture March 2018 - 20

building design

FEATURE

first of their kind, validated design criteria and ensured

work on 150 North Riverside, which was designed and

the curtainwall attained a sound-transmission-class rat-

constructed for LEED Gold Core and Shell certification

ing of 43.

and exceeds all local code requirements for energy and

One component that was not challenging was incor-

efficiency. Specifically, eco-friendly features include a

porating sustainability. The growth and development of

100% green roof, high-efficiency plumbing and mechan-

our communities has a large impact on our natural envi-

ical systems, a high-performance floor-to-ceiling curtain-

ronment. To that end, sustainability is a tenet that guided

wall system, open floor plates, lobbies with significant

Innovative Engineering And Construction
Solutions Solve Site Challenges
F

rom the start, everyone involved with 150 North Riverside

FOUNDATION AND CORE

knew the construction challenges of building on this

Because this project has a smaller footprint than normal, the

tiny parcel of land were going to be significant. The project

core resisting the lateral loads and the foundation carrying

required innovative problem solving and collaboration. The

the gravity loads were both increased. To do this, the core

correct point in time so that the tower didn't block the barge

team of engineers, led by Magnusson Klemencic Associates

was elongated and the walls thickened to 4 ft. The walls were

crane, the team used two independent schedule paths to get

(MKA, Chicago), and craft workers, headed by Clark

constructed of 12-ksi reinforced concrete, with specifications

both aspects to coalesce simultaneously.

Construction Group, Chicago, provided significant knowledge

defined for strength and stiffness. This massive, concentrated

Loading symmetry is of particular issue with core-

and experience in building on challenging sites.

load was carried on a reinforced-concrete mat, 150-ft. long x

supported buildings. In this instance, imparting equal and

40-ft. wide x 10-ft. thick.

opposite reactions to efficiently transfer dead loads from

Extensive planning occurred in the very early stage
of the project's life cycle. In the design and construction

The concrete mat caps the 16 caissons, each a 10-ft.-

perimeter to core, it was necessary to have tension members

phases, numerous operational tasks were performed with

dia. steel tube filled with concrete extending 110 ft. deep and

located at level eight and compression members at level

a variety of precedence. For example, experience from a

socketed 5 ft. into bedrock. These are the largest caissons in

four. Site constraints required that only the west elevation

nearby job taught the team that digging belled caissons

Chicago, carrying gravity loads of 28 million lb. The caissons

incorporate the cantilevering beams to transfer loads to the

can produce a lot of messy spoils that must be removed.

also resist lateral loads by vertically cantilevering above the

core. Perimeter columns on the east elevation could have

They also require a big rig that takes time to demobilize.

Chicago River.

extended to grade level, but achieving the balance required

Since pile driving at 150 North Riverside could only be done

There was no space for an on-site crane to build the tower. The
solution was a floating platform system that allowed use of a massive barge-mounted Manitowoc 888 Ringer crane.

to maintain an upright structure would have needed heroic

from 1:00 a.m. to 5:00 a.m. to avoid clashing with nearby

USING THE RIVER

train service, belled caissons were ruled out as a structural

While the architectural design used the Chicago River

option. Clark personnel, working with engineering firm MKA

for inspiration, the waterway also provided construction

TANKS MANAGE DRIFTS

and geotechnical consultant GEI Consultants Inc., Madison,

solutions. Once the foundation was completed, the focus

Like so many other aspects of this project, the drift and

WI (geiconsultants.com), redesigned the foundations to a

turned to erecting steel and placing concrete, including

acceleration standards were also a challenge. MKA

9 1/2-in.-dia. "micropile" system. This made it possible to use

enclosing the active rail lines to create a public plaza. The

introduced tuned mass dampers at the top of the building.

a smaller rig that produced no spoils and could be quickly

team used 30-ft.-tall, cast-in-place concrete walls and

The dampers house some 200,000 gal. of water in 12 concrete

maneuvered in and out of the rail yard.

precast concrete bulb tees to cover the tracks. Due to limited

tanks stacked in two layers of six. The inertia of the water in

levels of engineering.

GEI experts knew they had to limit the total number of

site access, adjacent buildings, and neighboring elevated

the tank creates a balancing liquid force against the structure

piles and that the piles needed to be as strong as possible.

roadways, the site was too crowded to support a land-based

to keep the narrow building from drifting. As the building drifts

They also recommended minimizing the number of digs. The

crane with a reasonable reach. A tower crane could not lift

over, the water in the tank has inertia and wants to stay in

initial 400-kip micropiles were re-engineered to increase the

the bulb tees, which required as much as 128,000 lb. of lifting

one place, i.e., it creates a balancing liquid force against the

strength. Over the course of nearly four months, more than

capacity. With no space for a crane on site, a floating platform

building. As the building moves one way, the water stays

100, 600-kip micropiles-the highest-capacity piles ever

system was developed that allowed use of a massive barge-

and pushes up against the opposing wall, helping to hold the

installed in Chicago-were sunk between the tracks.

mounted Manitowoc 888 Ringer crane. This required close

building back. The water tanks also serve as city-approved

For the tower foundation, MKA designed 16 fully

coordination with the U.S. Coast Guard, the Army Corps of

fire-protection water.

reinforced caissons, each with a 10-ft. dia. They were drilled

Engineers, and the Metropolitan Water Reclamation District.

Using tanks to manage drift is the first time this has

6 ft. into bedrock. The team also pre-planned the foundation-

The Clark team sequenced the work to ensure that

been done in the world. While tanks have been used to

reinforcement design so that a floor could be added to the

structural elements were properly installed, with a particular

manage acceleration numerous times, they have not been

building midway through construction at the developer's

focus on the progression of work in the building's signature

used to manage drifts and keep cladding joints from getting

request.

lobby. For the tower and plaza construction to meet at the

overstressed due to story drift.

COMMERCI A L A RCHI T EC T URE

MARCH 2018

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Table of Contents for the Digital Edition of Commercial Architecture March 2018