Q&A: What are the unique engineering challenges for the Sutter Health CPMC project on Cathedral Hill?

CPMC Van Ness and Geary, located in the bottom left of the image, is on Cathedral Hill in San Francisco, CA

CPMC Van Ness and Geary (bottom left of the image) is on Cathedral Hill in San Francisco, CA.

The Sutter Health CPMC Van Ness and Geary Campus is highly visible: it is located in the heart of city, considered to be a future flagship medical center, and involves demolitions, deep excavations, and constructing an underground tunnel. This year, our geotechnical and environmental engineers focused heavily on the hospital excavation and the tunnel construction underneath one of San Francisco’s most congested and centrally located roadways, U.S. Highway 101/ Van Ness Avenue.

Closing down the road for the initial stage of the tunnel construction was the foremost challenge, but it was a necessary component. Earlier this year, the development team obtained the City and County of San Francisco’s approval and coordinated extensively with Caltrans to close down Van Ness between Geary and Post for three 72-hour periods, from Friday at 12:01 a.m. to Sunday at 11:59 p.m. The first two closures were completed last spring and the final closure will occur later this year.

During the first two closure periods, our field staff worked around-the-clock in rotating eight-hour shifts to help ensure that every necessary task was completed within the allotted time frame. Soldier beams were installed on either side of the tunnel to provide temporary excavation support and also to support temporary, traffic-rated decking atop them. During the first two closure periods, the construction team installed all soldier piles and completed an excavation of about 5 feet below Van Ness Avenue. As the excavation progressed, timber lagging boards were installed between the soldier piles. The tunnel excavation work then moved to the hospital side, where hand-digging equipment is being used to complete the tunnel, which will bottom approximately 25 feet below Van Ness Avenue.

Construction on the CPMC Van Ness and Geary site in San Francisco, CA

Construction on the CPMC Van Ness and Geary site in San Francisco, CA

The entire project team, including architects, engineers, contractors, and subcontractors, has also been dedicated to sustainability. For example, an estimated 51,000 tons of concrete and 5,000 tons of steel were recycled from the hotel demolition. The team is aiming for LEED Silver certification for this project, which will make Sutter Health CPMC Van Ness and Geary one of the largest LEED-certified hospital campuses in the world and only the fourth LEED-certified hospital in California.

Bringing this extraordinary project to fruition has required close coordination, efficient project integration, and creative problem solving. Our focus has been highly responsive and we have completed tasks on, or ahead of, schedule. We are eager to see this project come to life and serve the community.

Answer provided by Cary E. Ronan, PE, GE
Cary has over 18 years of experience performing and managing geotechnical investigations and construction observation services for numerous projects throughout the San Francisco Bay Area. She provides project management and supervision services during investigations for commercial, retail, and residential developments, including high-rise developments as well as healthcare, school, university, and museum facilities.

Cary directs subsurface investigations, designs and evaluates foundations systems, performs engineering analyses, and directs field and office personnel. She has performed engineering analyses to determine settlement behavior of soil under loading, bearing capacity for shallow foundations, lateral and vertical capacity for deep foundations, and evaluated slope stability and seismic hazards including liquefaction potential.

Photography: ©2015 Brian Haux – SkyHawk Photography

Q&A: How do ground improvement techniques affect infrastructure in areas with highly-compressible soils?

Earthwork diagram illustrating the amount of fill and adjustments for compaction and settlement.

Earthwork diagram illustrating the volumes of fill needed for a project.

As major cities in Latin America grow and evolve, land developers are looking to complex and challenging sites to meet their development needs. In general, existing conditions such as low-quality soil present various development challenges. For example, sites in low-lying areas with highly-compressible, saturated clays complicate the development process. In these cases, ground improvement solutions such as wick drains combined with temporary surcharge facilitate development by significantly accelerating the time frame in which total and differential settlement would otherwise occur gradually over an extended period of time before reaching the required clay consolidation suitable for development. These accelerated ground improvement time periods are critical to developer schedules.

Prefabricated vertical wick drains

Prefabricated vertical wick drains

Depending on the wick drain spacing and the thickness of the clay stratum, ground improvements in these areas become necessary to properly support low-rise buildings and infrastructure. Storm drainage, sanitary sewer, potable water, and roadway systems constructed in improved soils minimize the risk of critical infrastructure failure by addressing and resolving issues related to differential settlement that could affect the overall performance of the infrastructure system.

About Ing. Aurelio Escalona 
Aurelio has over 20 years of diversified experience in land development engineering projects involving utility improvements, permitting, earthwork, hydraulics and hydrology, roadways, storm drainage, potable water systems, and sanitary sewer systems. As an associate at Langan he manages the firm’s regional office in Panama City, Panama and serves as the practice leader for hospitality, residential, and mixed-use projects in Latin America and the Caribbean.

Q&A: What are the unique engineering challenges for San Francisco’s burgeoning downtown area?

706 Mission, San Francisco, CA

706 Mission, San Francisco, CA

Background Information

Langan Treadwell Rollo is performing engineering services for several new high-rise residential developments in downtown San Francisco: 706 Mission Street, Transbay Blocks 6/7 and Block 8, 201 Folsom Street, and 41 Tehama Street, among others. These projects address both the city’s lack of land space (only 7 miles wide by 7 miles long) and desire for smaller units (an estimated 38% of residents are single occupants). According to the San Francisco Planning Department’s 2014 Housing Inventory Report, the production of new housing has increased by 50% from 2013.

What makes all this interesting — and challenging — to an environmental scientist is these projects focus on sky-high vertical growth built on land that our ancestors extended horizontally.

Solutions to Challenges
As a result of the 1906 earthquake and subsequent fire and the preceding Gold Rush era, many of the new downtown developments exist on, or are close to, infill. Rubble, wreckage, old wharves and piers, and abandoned ships can be within these infills.

Boat

Remnants of an old ship found during an excavation in downtown San Francisco.

Given the nature of infill, we recognize that contamination and historical concerns will likely result in additional costs for soil handling and disposal. San Francisco’s infill is the reason why the city created the Maher Ordinance (Article 22A of the San Francisco Health Code), regulated by the city’s Department of Public Health (SFDPH). This city code mandates stricter protocols, including site history, soil sampling, and site mitigation, which SFDPH oversees and approves.

Another challenge we face when excavating is the discovery of potential artifacts. These areas within the excavation are then left undisturbed so archaeologists can investigate. While this process can delay a project, it can be quite interesting. During recent excavations, we encountered remnants of an old ship as well as a lighter boat that originated from New England. Our construction crews have discovered items of interest that were as deep as 60 feet below ground so they likely existed several thousand years ago. Some of these artifacts are now displayed in museums. This is why I like the more complex projects: the more challenges we face, the more fascinating these projects become.

Answer provided by Peter J. Cusack
Peter Cusack is an environmental scientist who has worked on San Francisco and other Bay Area projects for the last 26 years. He manages and implements hazardous waste characterization and remediation projects. His experience includes pre-acquisition site assessments, site investigations, underground storage tanks removal, Phase II investigations, soil and groundwater sampling and remediation, development of soil management plans, aquifer pumping tests, contractor oversight, and field inspection for numerous construction projects. His work is often done in coordination with our geotechnical practice. He has extensive experience in site investigations and regulatory agency interaction prior to new construction/development.

Q&A: What are some major seismic design challenges in the Middle East?

As with most regions of the world, the challenge to evaluating seismic hazards is proper quantification of seismicity of the region of interest. Because of the Middle East’s tremendous size, spanning from Western India to North Africa and Turkey and Central Asia to the Southern Arabian Peninsula, it encompasses a region of very different seismic environments. Not only is the seismicity in the region tremendously varied from the highly seismic region of Turkey, Armenia, Azerbaijan, and Iran to low seismicity in the Southern Gulf region, but the cultural and language barriers provide unique challenges for projects in the region.

Langan provided seismic hazard assessments for the structures at Basrah Sports City in Iraq.

Langan provided seismic hazard assessments for the structures at Basrah Sports City in Iraq.
(Rendering courtesy of HOK)

With the high rate of signature developments in the Middle East and the prevalence of Performance-Based Design, appropriately quantified site-specific seismic criteria is imperative for effective and efficient design. Proper quantification of seismic load demands on structures provides the best value engineering that Langan can provide. As such, understanding of the geology and seismic histories of the particular region of interest is critical in seismic evaluations. Another equally important factor is quality, quantity, and appropriateness of locally developed subsurface information used in the development of site-specific seismic design criteria. It is critical to provide seismic recommendations that properly evaluate geologic, geotechnical, and seismologic conditions, that are appropriate, and not overly conservative.

Langan completed a geotechnical earthquake engineering study for Abu Dhabi Media Zone.

Langan completed a geotechnical earthquake engineering study for Abu Dhabi Media Zone.

 

About Ramin Golesorkhi, PhD, PE, GE
Dr. Golesorkhi, with over 28 years of experience in international seismic analysis and foundation engineering, is the director of seismic engineering services at Langan. He has developed seismic and geotechnical design criteria appropriate for industrial, residential, private and government office buildings, hospitals and healthcare facilities, bridges, elevated freeways and viaducts, structures with energy dissipation systems such as base-isolators and dampers, tunnels, and seismic strengthening of existing structures.

Langan Participates in Shell Safety Day 2015

Achieving Goal Zero Because We Care!

Langan will participate in its inaugural Shell Safety Day 2015 on Wednesday, May 6th with activities centered in the Langan Irvine Office. Langan understands and values that on Shell Safety Day all employees and contractors are encouraged to engage with one another on the topic of safety, and has put together activities to support this objective. Shell Safety Day at Langan will be a forum to get together and share ideas and good practices, to work together on plans to deliver continuous improvement in safety performance, and to reflect on our personal and collective commitment to safety.

This year Langan has identifed road safety as the primary focus area, and put together an agenda to include learnings on “Why We Care About Road Safety,” “How to Improve Your Intervention,” “Distracted Driving,” and “Driver Fatigue Management.”

Langan’s participation in Safety Day reinforces our commitment to providing a healthy and safe work environment and our goal of staying accident free every day.

Q&A: What technical challenges did the Langan Treadwell Rollo team overcome on Avaya Stadium?

 

Avaya Stadium during a San Jose Earthquakes Game

Avaya Stadium during a San Jose
Earthquakes Game

Background Information

Home to the Major League Soccer’s San Jose Earthquakes, Avaya Stadium is a soccer-specific stadium that opened in early 2015. Formerly the site of an FMC Corp. facility, the stadium is located just two miles from downtown San José and is next to San José International Airport. Langan provided geotechnical, seismic, environmental, and construction monitoring services for the project. Our team observed and tested mass grading, installation of foundations, preparation of sub-grade for slab-on-grade, and backfill of underground utility trenches and pre-existing concrete obstructions. Langan also assisted the construction team to comply with the Department of Toxic Substances Control’s (DTSC) approved Soil Management Plan, and evaluated potential vapor intrusion risks from residual volatile organic compounds.

Solutions to Challenges

Langan was a key member of the project team, working closely with Magnusson Klemencic Associates and Devcon Construction. The project had two significant challenges.

The first challenge we encountered was the weak compressible layers in some areas of the site. To address these subsurface conditions, we developed design criteria for an economically efficient foundation system that could adequately perform under the design loads with acceptable settlements.

The largest outdoor bar in North America at Avaya Stadium.

The largest outdoor bar in North America
at Avaya Stadium.

We faced our second challenge during the grading and installation of the underground utilities: buried, pre-existing obstructions. These obstructions consisted primarily of old concrete footings, drilled piers, pier caps, and below grade basement structures. Due to the lack of information regarding these obstructions, our team thought outside the box to come up with effective measures to deal with them without adversely impacting the construction progress. 

Underground obstructions are common – but not to the degree and depth that we found in this project. There were numerous obstructions, with many extending below the groundwater table. We implemented appropriate grading requirements to properly place and compact fill in the openings after removing the obstructions.

Our environmental team also had to ensure the project complied with DTSC’s Soil Management Plan. To that end, we evaluated potential vapor intrusion risks from residual volatile organic compounds, coordinated with DTSC on the plan’s implementation, and observed and documented construction activities to assure compliance with DTSC’s requirements.

We overcame these challenges by being flexible in our approach and innovative in our solutions. One of our favorite moments was seeing the tall sections of the structural steel being placed—verifying our successful work underneath. Another great moment was watching the Earthquakes’ first game at the inaugural soft opening event—it was great to see such a wonderful landmark structure become reality.

Answer provided by Scott Walker, PE, GE
Scott provides project management, engineering analysis, construction observation, and subsurface investigation services for various projects throughout California and southwestern Montana. His experience includes performing geotechnical services as well as staff supervision during investigations and construction for schools, hospitals, residential and commercial buildings (including high rise structures), sports facilities, industrial projects (including bridges, roadways, utilities), and resort development.

Q&A: How are civil engineering and master planning evolving in the Middle East?

Ege Yapi Mixed-Use Development

Ege Yapi in Istanbul, Turkey is an 800,000-square-meter mixed-use development featuring residential and retail space, a five-star hotel, a high school, office buildings, and parking facilities.

 

I believe 2015 and beyond will mark the progression of sustainable and smart master planning for real estate development in the Middle East. Governments and developers will continue to emphasize perfecting the art of efficiently engineered and architecturally sustainable real estate development projects. This is a breath of fresh air from the “design-and-build as fast as you can” days of old for which the Middle East was known. We are already witnessing the time and effort spent on preliminary planning and forward thinking of the projects revolving around the Dubai Expo 2020 and the Qatar 2020 World Cup. Both events are a driving force for new and smarter developments in the Middle East, and have shown the need for sustainable and long-term building solutions.

I strongly believe that the emphasis on planning will become the norm for future projects as all stakeholders will continue to benefit from the results of carefully planned real estate development. Langan has been involved with a number of initial planning projects, working closely with the master planners/architects, and has seen first-hand the positive impact of extensive planning before the project even gets underway. Our recent projects include large master planned developments in Saudi Arabia, the UAE, Russia, and other CIS countries which have been successful due to the involvement from the site/civil engineer from the beginning planning stages, and the preliminary planning on the part of the architect and developer.

Estidama (UAE's sustainability initiative) certified Dubai Silicon Oasis (DSO) Data Center - Dubai, United Arab Emirates

Estidama (UAE’s sustainability initiative) certified Dubai Silicon Oasis (DSO) Data Center – Dubai, United Arab Emirates

 

About Can Karayel, PE, LEED AP

Can has over 16 years of design and project management experience in the Middle East, Europe, CIS, and the US, specializing in civil and land development engineering. He has successfully designed and managed numerous land development projects within the retail, office, residential, industrial, school, and government sectors.