What were the geotechnical challenges of working on the One South Market project?

20131022_100822_resized_1

One South Market site during construction

One South Market is one of the latest high-rise buildings to fill the skyline of downtown San Jose in the last few years. In the past, the City of San Jose has encountered difficulty attracting developers to bring new tall building projects into downtown.  Due to downtown’s close proximity to the aircraft flight path to Mineta San Jose International Airport, the San Jose 2040 General Plan states that all new tall building heights be subject to maximum building height limitations as mandated by Federal Aviation Administration regulations.

In order to make the project economically feasible with the building height limitations, the developer of One South Market conceived a plan that included a 23-story tower of luxury condominiums and a six-story parking structure located next to the tower.  The tower was constructed at-grade, while the parking structure was constructed with a three-level basement.  Langan worked with the design team to evaluate the settlement compatibility between the two buildings and optimize the foundation system to support both structures.

img_1871

One South Market

Challenges for this project included installation of temporary shoring to support the 38-foot excavation for the parking structure. The temporary shoring protected surrounding buildings and city streets and allowed for management of the dewatering of the shallow groundwater during construction. The temporary shoring consisted of soldier-pile and lagging with tieback anchors; however internal steel beam walers and rakers were used for a nearby historic building. Installation of soldier piles included vibrated-in piles and drilled piles near existing structures to reduce vibration impacts.

It was very rewarding to be part of this project team, assist with the design and building’s LEED silver certification and to be a part of the future growth of downtown San Jose.

 

Answer provided by Gabriel Alcantar, PE, Project Engineer
Gabe is experienced in performing geotechnical evaluations and managing construction projects throughout the San Francisco Bay Area.  As a project engineer, he works on projects involving shoring systems, mass grading, installation of deep and shallow foundational systems, and  ground improvement. Additionally, he performs probabilistic hazard seismic analyses for projects within California and internationally.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s