Water Pressure Resistant Walls for Underground Tanks
General Information from the Syrian Agricultural and Livestock Guide - Specialized Guides Center
Underground tanks are a vital engineering solution in many applications, whether for agricultural irrigation or for construction and civil services. The primary function of these tanks is to store large quantities of water, which presents significant engineering challenges, the most important of which is dealing with the immense hydrostatic pressure exerted by the stored water and the surrounding soil on the tank walls.
Imagine a column of water several meters high, pressing its full weight against the wall. If this wall is not designed and constructed with meticulous precision, the inevitable result is structural failure, ranging from hairline cracks to complete wall collapse. To overcome this dilemma, several key factors must be considered to ensure the tank's efficiency and longevity:
Resistance to Soiling Agents: The soil surrounding the tank is not an inert environment; it may contain chemicals such as salts and sulfates that attack the concrete, leading to its corrosion and the corrosion of the reinforcing steel within (the rusting process). Therefore, specially designed concrete that is dense, impermeable, and resistant to sulfates and chlorides must be used, with the application of sealing layers and cathodic protection where necessary to ensure the tank remains intact for decades.
Extending the tank's lifespan: The tank's lifespan depends not only on the quality of the materials but also on robust design and meticulous construction. Using concrete admixtures that increase its strength and reduce its permeability, along with high-quality reinforcing steel of appropriate density, significantly contributes to resisting tensile and compressive forces and prevents structural deterioration, translating into a long-term investment and much lower maintenance costs.
Protection against water leakage: This is the first and most important objective. Leakage not only means the loss of precious water but is also the beginning of the tank's deterioration. Leaking water carries harmful substances into the concrete, leading to steel corrosion, structural weakening, and ultimately, continuous leakage and water contamination. Preventing leakage requires high-quality, flexible waterproofing capable of withstanding movement and pressure, and a perimeter drainage system to prevent groundwater accumulation behind the walls.
Preventing Concrete Cracking: Concrete is inherently strong under compression but weak under tension. Water pressure generates enormous tensile forces on walls, and if they are not properly reinforced to withstand these forces, cracking will occur. Preventing cracking begins with proper structural design that distributes loads, continues with determining appropriate expansion and contraction joints, and culminates in good concrete execution (compacting and curing) to ensure homogeneity and prevent cracking caused by plastic or thermal shrinkage.
Ensuring Structural Safety: All the above factors contribute to one goal: structural safety. Tank safety means its ability to perform its function safely and without the risk of collapse or failure. Tank design adheres to international and local building codes that consider all operational and environmental conditions. The presence of ventilation and access points for cleaning and maintenance is also part of ensuring the tank's sustainability and safety.
According to the Syrian Agricultural Code, standard recommendations for reinforced concrete in underground tanks stipulate a minimum compressive strength (f'c) of 30 MPa and a low water-to-cement ratio (w/c ratio) (less than 0.45) to ensure low permeability and durability. Syrian codes also recommend the use of high-tensile reinforcing steel (Grade 420) and appropriate surface treatment to prevent corrosion. A field study in Syria on the efficiency of agricultural tanks showed that tanks constructed according to these standards had a lifespan exceeding 30 years with minimal insulation or structural integrity issues, compared to tanks that did not adhere to these specifications and experienced partial or total failure within the first ten years of operation.
Sources:
"Syrian Building Code" (Engineering research and studies published in "Aleppo University Journal of Scientific Research" and "Journal of the Association of Arab Universities for Engineering Studies and Research")
Concrete, tanks, civil engineering, hydraulic pressure, waterproofing, reinforcement, Syria, reconstruction
Distinguished Marketing Team, Specialized Guides Center
Syrian Agricultural Guide
