El tunel que une a europa con asia

Exploring the Underwater Engineering Marvel in Istanbul

Introduction to the Project

• The speaker introduces Istanbul, highlighting its historical significance as the capital of three ancient empires and the ambitious engineering project underway: a railway tunnel connecting Asia and Europe.

• The challenges faced include strong currents, high pressure, dangerous earthquakes, and mysteries from the past.

Diving into Construction Challenges

• The speaker admits to being a novice diver despite claiming experience from a brief course taken years ago.

• Istanbul is described as unique for its geographical position; millions commute daily across continents via bridges or ferries, leading to traffic congestion.

Engineering Solutions

• A submerged metro line is proposed as a solution to alleviate traffic by connecting both continents underwater.

• Each section of the tunnel is likened to large Lego pieces that are constructed on land, then floated and submerged into place.

Risks Involved in Construction

• The Bosphorus Strait is noted as one of the most dangerous construction sites due to its unpredictable waters and historical shipwrecks.

• An expert engineer compares their work environment's unpredictability with nature's duality—water can be both friend and foe.

Technical Aspects of Tunnel Sections

• The speaker describes a floating concrete box that serves as part of the tunnel structure, emphasizing its waterproof design.

• A humorous moment occurs when discussing descending into an 8-meter deep tube while expressing concerns about safety.

Structural Integrity Under Pressure

• Inside the submerged section, there’s confidence that trains will eventually operate between Asia and Europe despite current water barriers.

• Emphasis on structural integrity under pressure reveals that every 10 meters increases atmospheric pressure significantly; thus, construction must be flawless to prevent catastrophic failures.

Earthquake Preparedness Measures

• Discussion includes proximity to active fault lines; engineers have implemented seismic joints for flexibility during potential earthquakes.

Construction of an Indestructible Underwater Tunnel

Overview of the Tunnel Construction Process

• The construction of a robust underwater tunnel begins at El Astillero de Turla, spanning 32 kilometers. Each section measures 6 meters in height and 120 meters in length, with one section already positioned and another being lowered into place.

• The new railway tunnel requires nine sections to be completed within a year. Once finished, the tube will be submerged 55 meters underwater, with a sealing wall preventing water from entering and ensuring worker safety.

• Workers are currently using tensioning equipment to align the separating wall piece accurately. A metal piece that was initially thought to obstruct is actually crucial for holding the wall in place during installation.

• An acetylene torch is used to cut away the metal obstruction, allowing for proper sealing. Concerns about safety arise as pieces fall unexpectedly during this process.

• The goal is to ensure that when submerged at 45 meters deep, no water can penetrate the seal. After several adjustments and teamwork, the wall is successfully placed and ready for welding and waterproof joint installation.

Steps in Reinforcing Tunnel Sections

• The initial step involves constructing a steel tube measuring 135 meters long. This includes placing L-shaped steel bars followed by securing them properly before adding more metal bars.

• Over a thousand tons of these bars are required for each section's construction, resembling a bird's nest structure that supports vertical walls while preparing for cement application.

• Each section is reinforced with approximately 18,000 tons of cement and metal once all steel bars are installed. This ensures structural integrity before moving on to formwork placement.

• Formwork is essential; it shapes the concrete ceiling into a U-shape initially before transitioning to flat roofing once removed. This process prepares for cement pouring effectively.

• After installing five pieces of formwork today, workers prepare for further installations tomorrow while reflecting on their progress towards completing sections necessary for tunneling under the Bosphorus Strait.

Safety Measures and Structural Integrity

• Safety harnesses are mandatory on-site not due to personal importance but rather because some workers may lack experience in wearing them correctly.

• Once formwork is secured against sections using rods, it helps create well-aligned vertical walls essential for maintaining structural stability throughout construction phases.

• Tomorrow’s plan includes placing additional formwork pieces followed by pouring concrete which will solidify into one complete section ready for further processing downwards into the tunnel system.

Final Preparations Before Submersion

• Despite its unappealing appearance at first glance—resembling just concrete and tunnel parts—the facility serves as an advanced manufacturing plant dedicated to submerged tunnels designed to withstand significant seismic activity (up to magnitude 7.5).

• Cementing processes involve filling both lower and upper parts of each section sequentially before they are transported via pontoon vessels prepared for submersion operations efficiently.

• Approximately 18,000 tons of materials can be processed annually per project timeline; however, lifting these massive structures poses challenges requiring innovative solutions like utilizing large bathtubs filled with water allowing buoyancy effects during transport preparations.

The Challenges of Underwater Tunnel Construction

Initial Observations and Issues

• The speaker describes the situation with a stuck valve, indicating that water will soon burst out forcefully once opened.

• Attempts to use brute force to move the stuck mechanism fail, leading to a decision to cut it open instead.

Water Pressure and Flow

• As the first valve is removed, boiling water begins to flow out, highlighting the immense pressure behind the wall.

• With two valves removed, water enters at an average rate of 250 cubic meters per hour; in 36 hours, it will fill a dry dock with 8,000 cubic meters of water.

Historical Context of Istanbul

• Istanbul's historical significance as a capital for three empires is noted; its strategic location on trade routes between Asia and Europe is emphasized.

• Over 40,000 ships pass through the Bosphorus Strait annually, complicating tunnel construction due to heavy maritime traffic.

Ferry Operations and Traffic Management

• Ferries conduct over 300,000 trips yearly across the Bosphorus; this makes ferry travel one of the fastest ways to cross until tunnel completion.

• The speaker discusses navigating through congested waters while managing various types of vessels including ferries and cargo ships.

Engineering Challenges Beneath Istanbul

• The need for careful navigation around larger vessels like oil tankers is highlighted; larger ships have priority in narrow straits.

• Engineers face significant challenges from both modern traffic above ground and ancient structures below during tunnel excavation.

Archaeological Discoveries Impacting Construction

Discovery of Ancient Sites

• Excavation efforts are halted upon discovering one of the world's most important archaeological sites beneath Istanbul—an ancient port.

• Archaeologists emphasize that timelines for excavation depend on discoveries made during digs rather than predetermined schedules.

Shipwreck Findings

• A significant discovery includes remains from a storm that sank numerous ships centuries ago; so far, 23 shipwrecked vessels have been found.

• One well-preserved merchant ship from the late 9th century measures about 13 meters long and was designed for heavy cargo transport.

Preservation Efforts During Excavation

The Urgency of Preserving Historical Shipwrecks

The Condition of the Ships

• Due to moisture at the docking site, ships have not deteriorated significantly; however, exposure to heat and sunlight will accelerate decomposition, risking valuable details.

• A team is preparing to extract a piece from one of the ships, emphasizing careful handling to maintain structural integrity.

Extraction Process

• The extraction involves coordinating multiple people to ensure that the piece remains intact during removal; there are approximately 2,000 pieces left on this ship alone.

• Excavation processes typically take about four months for each ship, including final steps after discovery.

Preservation Techniques

• Once extracted, wooden pieces are submerged in a chemical solution to prevent decay; this process is crucial given the age and condition of the wood.

• So far, 23 ships have been discovered in an area where construction for a tunnel was taking place.

Engineering Challenges in Underwater Operations

Testing New Sections

• Engineers conduct rigorous tests on new sections intended for underwater installation while inspecting equipment controlling descent into marine environments.

• Ballast systems are critical; they consist of ten rubber-lined containers that can be precisely filled with water to control buoyancy.

Control Mechanisms

• The section's movement can be finely adjusted by managing water levels in ballast tanks; this precision is vital for successful deployment underwater.

Navigating Water Currents

• Operators must adapt their strategies based on surface currents when lowering large structures like tunnel sections into deeper waters.

Ensuring Safe Deployment

Test Release Procedures

• A test release involves letting go of cables holding a section above its intended position; success means it will float correctly without additional support.

Importance of Pre-deployment Checks

• Thorough checks before deployment are essential due to unpredictable currents in the Bosphorus Strait which could complicate operations significantly.

Managing Competing Currents

• Two opposing currents present challenges as they could disrupt control over heavy structures being lowered into the water.

Final Preparations for Divers

Preparing for Diver Operations

• After flooding a dry dock, divers prepare for their next challenge: removing bolts from a gate that holds back water and allows access to submerged sections.

Safety Considerations

Diving into the Unknown: Underwater Construction Challenges

Preparing for the Dive

• Discussion about visibility underwater, with a mention of using a breathing tube to see better despite limited visibility.

• Concerns about jellyfish stings and their potential danger; personal experiences shared regarding encounters with jellyfish.

• Excitement builds as preparations are made for diving and underwater welding, highlighting the unusual nature of this task.

Safety Measures and Equipment

• Emphasis on safety equipment, including an air mask that covers the entire face and has communication capabilities.

• Explanation of using large tanks for extended periods underwater, contrasting it with normal diving practices.

The Experience Underwater

• Description of the challenging conditions underwater, including poor visibility and difficulty in breathing due to pressure differences.

• Introduction of specialized divers who can work at significant depths; mention of cutting bolts holding pieces together using high-temperature torches.

The Heavy Lifting Begins

• Observations on different types of wetsuits used by divers; acknowledgment of personal limitations compared to professional divers.

• Completion of welding tasks under water; anticipation builds as heavy machinery prepares to lift submerged structures.

Final Steps in Construction

• Description of lifting a massive 15-ton piece from the water, showcasing engineering feats involved in construction.

• Confirmation that one section is successfully lifted out, marking progress in the project.

Coordination and Execution

• Enthusiasm expressed over successful lifting operations; comparison made between construction efforts and other large-scale projects.

• Reflection on weeks of hard work culminating in this momentous occasion where a major tunnel section is ready to be moved into place.

Transporting the Tunnel Section

• Details about transporting a massive tunnel section from dry dock into open waters; likened to walking a dog but on a grand scale.

• Coordination among multiple boats during transport emphasizes teamwork required for such large operations.

Conclusion: A Historic Engineering Achievement

• Dramatic imagery comparing the structure being transported to iconic objects like "the Death Star," underscoring its significance.

• Anticipation builds as plans are laid out for connecting continents through this engineering marvel.

Exploring Section 11: A Journey Below the Bosphorus

Accessing Section 11

• The access well is located directly beneath, allowing entry into Section 11. It resembles a giant straw with stairs inside, and there are no currents felt while descending.

• As one descends, the surrounding water exerts significant pressure. Upon reaching the section, it feels like being inside an abandoned submarine due to the high water pressure.

The Descent Experience

• The descent begins with feelings of claustrophobia as sunlight fades away. At this point, they have descended about 10 meters and can hear water on the other side of a steel plate.

• They note that at around 10 to 12 meters deep, the steel structure becomes increasingly robust to withstand potential impacts from above, such as collisions with ships.

Entering Section 11

• Upon entering Section 11 from the access well, they acknowledge walking on the seabed of the Bosphorus for the first time—a significant moment for both individuals involved.

• Inside this section, which rests on the sea floor like a sunken submarine, there is only a thick layer of steel separating them from vast amounts of water.

Reflections on Engineering

• The speaker expresses pride in being part of a project that has been envisioned for 146 years and emphasizes its importance in helping Turkey achieve its goals.