Temporary Structural Shoring at Ferry Building

Joe Lazzaretti
Oct 12
7 min read

Updated: 2 days ago

The Ferry Building in San Francisco underwent temporary structural shoring to address critical foundation issues while preserving its historic charm and ensuring safety. The project focused on stabilizing the building during repairs, meeting earthquake safety standards, and maintaining operations for tenants and visitors. Key efforts included:

Foundation Stability: Addressed uneven sinking, rusted steel, and cracked brickwork.
Safety Measures: Installed temporary supports and monitored structural shifts with advanced sensors.
Preservation: Retained the building's historic design by reinforcing existing features like tie-rods and buttresses.
Efficient Planning: Scheduled work during low tides and off-peak hours to minimize disruptions.
Collaboration: Coordinated with tenants to align construction with business needs.

This case highlights the importance of balancing safety, functionality, and historical preservation in retrofitting projects.

Structural Shoring with Scaffolding Extraordinary Uses with Ordinary Inventory

Basic Structure Issues and First Checks

The project found many deep structure problems, not just common repair issues. Solving these got special fixes to keep the building strong and keep its old look. A deep check made way to add needed support.

Structure Woes at the Ferry Building

The main trouble was with the foundation sinking and weak spots from shaking that got worse over time. Uneven sinking made tight stress points, adding more pressure on the structure.

The old mix of brick and steel had its own trouble. Steel parts got rust from being wet for long, while cracks in the brick made it tough for walls to hold up weights well.

To meet California's new shake rules and save the old look, adding support was key. The first design did not have side braces, so they had to put in brief supports before lasting fixes could be set.

How Experts Checked the Structure

Experts were very careful, using tests that did not break things and close looks at the structure. Radar that could see into the ground checked the base, while sound waves checked the hidden steel parts.

Making holes to take soil from the edge gave clues on the soil and how well it could hold weight, showing changes in how steady it was over time.

Weight tests showed the building could take daily use, but added support was needed for shake safety. Top-end 3D pictures showed stress spots, helping put brief support to keep things safe and working.

Keeping the Building Open While Fixing

To keep the building in use, experts used a step-by-step, area by area fix plan. Work was done when fewer people were around to cut down on the mess.

Brief paths and safe bars were set up to change where people walked. This let them keep going to main spots while keeping everyone safe. Sensors worked all the time to watch for any bad structure moves and gave quick warnings if something was off.

Talking often with renters made sure the fix times matched with business tasks, cutting waits and keeping things safe. These smart plans let the work go on while the building stayed open to all, getting ready for the next steps in adding support and making it strong.

How They Held Up the Building

The Ferry Building job needed well-made shores to back up underdeck concrete jobs in a tide zone. These plans made sure the tough spot by the water got the help it needed and kept the old look of the building safe. Here's more on the shores, how workers put them in, and the stuff they picked to make the project work.

Types of Shores Used

The job was all about keeping the underdeck concrete in good shape[1]. Teams put up work spots on the water using boats. This smart move let them fix things well, even with the water going up and down[1].

How They Put Up the Shores

Time was key for this job. Shores went up when the water was low. This tight plan cut hold-ups and made sure other needed work went smoothly with fixing[1].

Picking Stuff and Meeting Needs

Each thing used was picked with care to hit top quality and to honor the old feel of the building. The aim was to make fixes last and not mess with the day-to-day of folks and renters[1].

Building Steps and Time Plan

The work on the Ferry Building needed careful planning to keep every day work going smooth while fixing important parts of the structure. The team at Power Engineering Construction Co. made a time plan that kept work going and met the needs of being near water. This step-by-step approach faced the building issues directly while keeping things exact and causing little bother.

Step-by-Step Building Plan

The building work was split into clear parts to keep things running with no stops. All concrete pouring and putting on shotcrete were set for night times, cutting down on the effect on day-to-day stuff. Tasks linked to the sea, like setting up platforms and taking out concrete, were planned for times when the tide was low. This let workers reach the area under the deck by boat[1].

"Our commitment to delivering high-quality work while respecting the site's historical significance, its daily visitors, and tenants was foremost. This often meant flexibility in work hours to maximize low tides, and validated our approach!" - Power Engineering Construction Co.[1]

Project Outcomes and Future Uses

The strong plan for support in this project built a solid base for real results and gave good tips for future work in keeping old buildings safe.

Key Results from the Ferry Building Project

The short-term support work at the Ferry Building showed how engineering can blend well with saving old, important places in areas that get earthquakes. By using well-thought-out, gentle support methods, the project took on the building's tough parts without hurting its old, earthquake-safe bits like tie-rods and buttresses. These parts have helped the building last a long time. The work showed that short-term support can keep things safe right away and care for the building's old style in the long run.

Tips for Similar Old Building Projects

Make clear goals from the start. Before putting up support, say what you want the building to stand up to after shakes. Look past basic building checks and think about what the place needs. While rules focus on keeping people safe, owners should say what they want from the building after shakes, as the bare minimum in rules might not be enough.
Talk with owners about risks. Get the building's owners in on talks early to figure out what level of shaking risk is okay. Talking openly about the give-and-take between keeping old parts and adding new strong parts can stop surprises during building and set true hopes.
Use what's already there. Many old buildings have parts that can deal with quakes, like tie-rods and buttresses, that have lasted. Short-term support should make these features better, not swap them out.
Plan for regular upkeep. Short-term support setups should be easy to keep up without big changes. Choices that don't need much work help keep old buildings safe for a long time while keeping trouble low.

End thoughts: Keeping Safe While Saving History

The Ferry Building work shows how smart design and good planning can keep a place both safe and full of old charm. By going over the building's own form, engineers made plans that made it more firm without losing the original look.

Planning was key, too. The group put a lot of work into knowing what the building needed - like handling people walking by, following its build limits, or working in a busy market. This careful setup kept problems away and made sure things went smoothly.

Talking together helped a lot, too. Talking early and clear with the owners set firm goals for both safety and keeping the past look, which guided every choice in the work.

This story shows that short-term supports do more than hold up a place at once. The setups used not only helped during building but also helped keep the building safe for the long run, making sure its story goes on.

The Ferry Building work stands as a strong show of how new build ways can work well with saving old values. It reminds us of the need to make special plans for each old place, using new ways with a strong care for history.

FAQs

What challenges arise when retrofitting the historic Ferry Building to meet modern earthquake safety standards?

Retrofitting the historic Ferry Building to comply with modern earthquake safety standards is a delicate balancing act. The goal is to strengthen the structure against seismic threats - like lateral spreading and seawall instability - while safeguarding its iconic architectural features.

To achieve this, engineers rely on advanced methods such as base isolators and shear walls. These techniques bolster the building's stability without compromising its historic character. The real challenge lies in seamlessly incorporating these safety upgrades into a landmark situated in a high-risk seismic area, ensuring both its resilience and its historical essence remain intact.

What is temporary structural shoring, and how is it used to stabilize historic buildings like the Ferry Building?

Temporary structural shoring involves setting up supports - like props, beams, or braces - to stabilize a building during construction, repairs, or renovations. For historic landmarks such as the Ferry Building, this process is essential to ensure safety while preserving the structure's original design and character.

Some of the main techniques include dead shoring (vertical supports that carry weight), raking shores (angled braces that provide lateral support), and horizontal bracing (used to prevent movement or shifting). Materials like timber, steel, and concrete are commonly used because of their strength and ability to stabilize without compromising the historic structure.

How did the team ensure the Ferry Building stayed open for tenants and visitors during structural repairs while minimizing disruptions?

The project team kept the Ferry Building open by meticulously planning construction schedules and organizing the work in phases to minimize disruptions. They used temporary scaffolding and protective coverings to ensure tenants and visitors could safely access the building during the entire process.

Through close collaboration with stakeholders and a strong focus on safety, the team managed to carry out essential repairs while maintaining the building's daily operations and safeguarding its historic charm.