Applications of Prestressing Steel Bars (PSB Bars) in Hydropower Stations

Here’s an overview of the applications of Prestressing Steel Bars (PSB Bars) / Thread Bars in hydropower stations, presented in English:

Applications of Prestressing Steel Bars (PSB Bars) in Hydropower Stations

Prestressing Steel Bars (PSB Bars), also commonly known as Thread Bars or High-Strength Threaded Bars, are crucial high-strength tension elements extensively used in hydropower projects due to their unique properties. Their primary applications include:

1. Rock and Soil Anchoring for Dams & Structures:
Dam Stability: Anchoring dam foundations and abutments into stable bedrock to prevent sliding or overturning under immense water pressure and seismic loads.
Slope Stabilization: Securing excavation slopes around powerhouses, intake structures, penstocks, and tailraces to prevent landslides and ensure construction safety.
Tunnel & Cavern Support: Providing permanent or temporary rock support in headrace tunnels, surge chambers, powerhouse caverns, and transformer halls using rock bolts and systematic rock anchors.
Cutoff Walls & Diaphragm Walls: Anchoring deep concrete cutoff walls or diaphragm walls used for seepage control around dams and foundations.

2. Post-Tensioning of Concrete Structures:
Penstocks:Anchoring and post-tensioning the concrete lining or the surrounding reinforced concrete support structures of high-pressure penstocks to withstand internal water pressure and prevent cracking/leakage.
Spiral Casings & Turbine Embedded Parts: Anchoring the massive spiral casing that directs water onto the turbine runner, and other large embedded parts within the powerhouse concrete structure.
Thrust Blocks: Securing massive concrete thrust blocks that counteract the hydraulic thrust generated by bends in high-pressure penstocks.
Large Concrete Monoliths & Walls: Post-tensioning large, thick concrete sections like powerhouse walls, intake structures, or spillway piers to improve crack control and structural integrity under heavy loads.

3.Lifting and Securing Heavy Equipment:
Turbine & Generator Installation: Used as lifting anchors for the precise placement of massive turbine components (runner, shaft, generator stator/rotor) and transformers during installation.
Permanent Restraints:Providing permanent restraint systems for critical equipment against seismic or operational movement.

4. Gates and Hoist Systems:
Gate Anchorage:Anchoring large radial gates, spillway gates, stoplogs, and intake gates to their supporting structures (pier concrete, embedded frames).
Hoist Tie-Downs:Serving as tie-down anchors for gate hoist machinery.

5. Temporary Works & Construction:
Formwork & Falsework Tiebacks: Anchoring large formwork systems for massive concrete pours (like dam lifts).
Excavation Bracing:Used in tieback systems for deep excavation support walls during construction of powerhouses or intake structures.
Cofferdam Stability:Anchoring sheet pile or cellular cofferdams used during construction in the riverbed.

Why PSB Bars are Preferred in Hydropower

High Tensile Strength: Can withstand enormous tensile forces (common grades: PSB785, PSB830, PSB930, PSB1080) crucial for anchoring and post-tensioning.
Threaded Ends: Enable direct connection to anchor heads, couplers, bearing plates, or other fixtures using nuts, eliminating the need for welding on site and allowing for precise tensioning/adjustment.
Controlled Prestressing: Allow for accurate application of high preload forces (via hydraulic jacks) to actively stabilize rock, compress concrete, or secure structures.
Corrosion Resistance:Typically supplied hot-dip galvanized or epoxy-coated (or both) to withstand aggressive, wet environments common in hydropower.
Durability & Long Service Life: Essential for critical, hard-to-access structures designed for decades of operation.
Versatility: Available in long lengths (often requiring couplers) and large diameters (commonly 25mm to 75mm, even larger), suitable for massive loads.
Groutability: Can be installed as “grouted anchors” where the bar is bonded to the surrounding rock/soil/concrete via cement grout injected into the drill hole annulus, providing excellent load transfer and corrosion protection.

In summary, PSB bars are fundamental for the stability, safety, and longevity of hydropower structures. They provide the high-strength, adjustable, and durable tensile elements needed to anchor massive concrete and rock masses, post-tension critical water-retaining structures, secure heavy equipment, and support construction activities in the challenging environments of hydropower projects.


Post time: Jul-28-2025