Construction Fails: When Projects Go Wrong
The B1M・2 minutes read
San Francisco's Millennium Tower is sinking and leaning due to soil compaction, with a plan to install new piles to stabilize it and prevent further sinking, despite concerns of worsening the lean if measures are not taken. The tower situation highlights construction challenges but also showcases modern engineering's robustness in addressing structural issues.
Insights
- The Millennium Tower in San Francisco is sinking and leaning due to soil compaction, with a plan to install new piles to stabilize it and prevent further sinking, showcasing the impact of construction practices on structural integrity.
- Jeda Tower's construction faced political, labor, and financial challenges, leading to delays and an unfinished state, emphasizing the complex nature of large-scale projects and the need for robust planning and execution to overcome obstacles.
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Recent questions
What is causing the Millennium Tower in San Francisco to sink and lean?
The Millennium Tower in San Francisco is sinking and leaning due to soil compaction caused by nearby construction work and water clearing during its construction. This has led to the tower sinking over 45 cm and leaning 60 cm to the west and 20 cm to the north, with ongoing tilting of 7 cm north and 2 cm west annually.
How is the Millennium Tower's tilt being corrected?
The tilt of the Millennium Tower is being corrected by installing additional piles under the building. Initially, a plan to install 52 piles was proposed, but concerns about worsening the tilt led to a new plan with only 18 piles. The decision on this plan is pending in March 2022, with a potential cost increase to $500 million.
What challenges did the construction of Jeda Tower face?
The construction of Jeda Tower faced political crackdowns, labor issues, and delays, leading to its current unfinished state. Despite securing $1.2 billion in funding in 2015 and completing 63 stories by 2017, various issues halted the construction, highlighting the challenges faced in completing such a massive project.
What safety concerns led to the halt in construction of the new Harbor Bridge in Texas?
The new Harbor Bridge in Texas faced a halt in construction due to five key safety concerns identified in an independent study in 2021. These concerns led to a pause in construction on the main span, with issues ranging from foundation system problems to uplift issues at piers, necessitating modifications to ensure structural integrity.
What obstacles have slowed down the progress of the high-speed rail line project in California?
The high-speed rail line project in California has faced slow progress due to various obstacles, including setbacks, delays, and challenges in securing funding. Despite the approval of the plan in 2008 and ongoing construction on the Midway section, doubts about the project's viability have hindered private investors and the federal government from committing fully to the project.
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Summary
00:00
Millennium Tower: Sinking Skyscraper Needs Stabilization
- San Francisco's Millennium Tower, a new skyscraper, is sinking and leaning due to soil compaction, with a revised plan to install new piles to stabilize it.
- The tower has sunk over 45 cm and leans 60 cm to the west and 20 cm to the north, with ongoing tilting of 7 cm north and 2 cm west annually.
- Despite efforts to correct the issue, the tower could lean over a meter, affecting its functionality, with a plan to install new piles to prevent further sinking.
- Construction work on a nearby site and water clearing during the tower's construction are blamed for the soil compaction causing the leaning issue.
- The tower's sinking and tilting have led to cracks in the sidewalk, walls, and sidewalks, with water seepage and crumbling walls in the garage.
- A plan to correct the tilt involves installing 52 additional piles under the building, but the stabilization efforts were halted due to concerns of worsening the tilt.
- A new plan proposes installing only 18 piles to stabilize the tower, with a decision pending in March 2022, potentially increasing the fix cost to $500 million.
- Millennium Tower's current tilt is less than 0.2 degrees, with engineers claiming it's safe but needing stabilization to prevent plumbing and elevator issues.
- The building's tilt could render it uninhabitable if it reaches 100 cm, with a new plan proposed by engineer Ron Hamburger to stabilize the tower.
- The Millennium Tower's situation highlights the challenges in construction projects, emphasizing the robustness of modern engineering in dealing with such issues.
17:01
"Jeda Tower: Unfinished Icon of Innovation"
- Jeda Tower, standing at 1,000 meters, was intended to surpass the Burj Khalifa and position Jeda as a global city.
- Construction of Jeda Tower began in 2013, with a core structure and 270 concrete piles drilled 105 meters into the ground.
- The tower's design includes a hexagonal core reinforced with three y-shaped walls to counteract extreme lateral wind loads.
- The tower's construction faced political crackdowns, labor issues, and delays, leading to its current unfinished state.
- The project secured $1.2 billion in funding in 2015, with 63 stories completed by 2017 before halting due to various issues.
- The tower's design features a tapering peak and a crowning open-air observation deck on the 157th floor.
- Engineers utilized a jump form system for concrete pouring and a butress core design to support the tower's height.
- The tower's extreme height poses challenges in managing wind loads, requiring innovative solutions like carbon fiber elevator ropes.
- The tower's location in the desert necessitates durable coatings to withstand sandstorms and automatic cleaning systems.
- Despite challenges, there are plans to restart construction on Jeda Tower, with utilities and roadways already in place at the site.
34:33
Challenges and Delays in Texas Bridge Construction
- The new Harbor Bridge in Texas connects directly to pylons or towers, unlike a suspension bridge where cables spread out across a suspender between towers.
- Construction of the new Harbor Bridge began in 2016 and was initially set to finish by 2020 but faced delays, with construction still ongoing in 2023.
- Work on the bridge was suspended twice, first in 2019 following a pedestrian bridge collapse in Florida due to design errors by fig Bridge group, the same engineers working on the Texas bridge.
- An independent study in 2021 found five key safety concerns in the new Harbor Bridge design, leading to a halt in construction on the main span.
- The project's budget increased from around $800 million to nearly a billion due to the delays and safety concerns.
- Issues with the foundation system of the bridge were identified, leading to the extension of foundations and addition of more drilled shafts below each tower to hold more weight.
- Problems with foundation caps on the towers necessitated creating more space underground to prevent bending and slipping of piles.
- The Delta frame design lacked necessary reinforcement, risking cracking, so engineers roughened concrete surfaces and added rebar for strengthening.
- Uplift issues at two piers caused the structure to rise instead of transferring weight down, leading to modifications to prevent loosening connections.
- Placement of cranes during construction exposed the bridge deck to twisting from high winds, prompting the addition of counterweights and modifications to prevent potential movement.
50:46
California High-Speed Rail Faces Financial Challenges
- The construction of a building is facing financial challenges as prospective buyers have withdrawn, leading to uncertainty about its completion.
- A high-speed rail line project in California aims to connect major cities, boost the economy, and reduce emissions, but progress has been slow due to various obstacles.
- The plan for the high-speed rail network in California was approved in 2008, with over $1 billion in bonds issued for planning and construction.
- Construction is ongoing on the Midway section of the rail line, but setbacks and delays have pushed the estimated cost to over $100 billion, with completion now expected in 2029.
- Funding for the project has been a challenge, with private investors and the federal government hesitant to commit due to doubts about the project's viability.
- Despite the numerous setbacks and criticisms, the completion of the high-speed rail line in California could have significant benefits, including reducing car travel and aiding in achieving climate change targets.
