Through Wall Tie System

Through Wall Tie System is a full‑penetrating matched hardware assembly widely used in cast‑in‑place concrete wall construction. The system includes through tie rods, fastening nuts, pressure bearing plates, positioning cones, plastic sleeves and water‑stop plates for waterproof working conditions. Each component undertakes independent mechanical functions. All accessories cooperate with formwork panels to realize formwork tensioning, wall‑thickness positioning and seepage blocking without modifying main formwork structures. High‑strength carbon steel serves as primary raw material. According to engineering requirements, it is divided into ordinary through wall tie system and waterproof through wall tie system. Ordinary type is applied for common non‑waterproof wall structures. Waterproof type is fitted with fully welded water‑stop plate on the middle rod body to block water seepage channels along the tie rod penetration path. Two main structural forms are integral one‑piece style and segmented assembled style. Integral through wall tie rod runs through the whole wall and is permanently embedded inside concrete for one‑time use. Assembled structure consists of fixed middle embedded section and detachable outer threaded segments. Outer threaded segments can be unscrewed and recovered after concrete hardening. Thread sections are processed by thread rolling technology, improving thread‑tooth surface hardness and wear resistance to adapt to frequent assembly, disassembly and cyclic turnover. Fastening nuts are produced by forging craft to keep stable clamping force under lateral hydrostatic pressure from fresh concrete. Welding quality of water‑stop plates is strictly inspected to guarantee anti‑seepage effect for basement, water tank and other water‑bearing structures. Positioning cones and plastic sleeves precisely control wall‑thickness dimension and reduce post‑construction surface repair workload. Custom‑made sizes are available according to project drawing specifications.

Multiple surface anti‑corrosion treatments are optional for metal components of through wall tie system. Hot‑dip galvanizing forms compact zinc‑iron alloy protective layers covering rod bodies, thread teeth and welding seams. This treatment delivers stable resistance against rainwater, humid air and salt‑fog erosion, suitable for long‑term outdoor, coastal and underground construction projects. Electro‑galvanizing generates relatively thin zinc layer on steel surface, applicable for short‑cycle construction projects with low corrosion risk. Black oxide finish is suitable for temporary dry‑condition construction sites without high anti‑corrosion requirements. Paint coating is seldom used on threaded parts, as paint layers tend to peel off under thread friction and concrete impact. Through wall tie system bears expanding lateral force generated during concrete pouring, fixes clearance between two sides of formwork panels, restrains formwork bulging, offset and deformation, and ensures dimensional stability of cast‑in‑place concrete wall members.

Core dimensional parameters determine practical mechanical performance of the whole system. Rod body diameter is a critical tensile‑load indicator, larger diameter corresponds to higher ultimate tensile capacity. Effective total length shall match designed wall thickness plus formwork panel thickness and on‑site operating space. Thread specifications of tie rods and nuts must remain fully consistent to avoid poor meshing, insufficient clamping force and component slipping. For waterproof‑type assemblies, dimension and welding quality of water‑stop plates shall satisfy anti‑seepage requirements under designed water head. Specification mismatch of positioning accessories will cause concrete dimension deviation. This system enjoys good compatibility with timber formwork, steel formwork and various combined formwork assemblies. Dimensional tolerances of all components comply with corresponding international technical specifications to achieve reliable fitting and stable force transmission during on‑site assembly.

Prior to construction deployment, visual inspection and sampling mechanical tests shall be carried out for through wall tie system. Visual examination covers rod‑body bending deformation, surface cracks, welding discontinuity, thread‑tooth damage and anti‑corrosion‑layer peeling. Recycled outer threaded segments require stricter inspection standards. Even with intact outward appearance, invisible metal fatigue may accumulate after repeated load cycles and cannot be judged merely through surface observation. Sampling tensile tests verify ultimate bearing capacity and anti‑deformation performance. Components with permanent bending, thread slipping, incomplete welding and structural cracks must be screened out and prohibited for site usage. Secondary destructive modification including arbitrary cutting, welding and hole‑drilling on finished system components is forbidden. Unauthorized alteration will change original steel section characteristics and weaken tensile performance or waterproof reliability of the whole assembly.

Partial components in through wall tie system support cyclic turnover usage. After concrete reaches design strength and formwork dismantling, detachable outer threaded segments, reusable nuts and pressure‑bearing accessories shall be disassembled in standard construction sequence. Concrete mortar, dust and foreign residues attached to thread grooves and fitting surfaces need thorough cleaning before next application. Impurities trapped in matching joints will cause jamming and interfere with normal assembling and clamping effect in subsequent service cycles. Finished components shall be stored in dry and ventilated surroundings, sorted and stacked by specification grade, avoiding long‑term rain soaking and direct contact with damp soil. Improper on‑site operations include mixed use of mismatched accessories, insufficient tightening of nuts, adoption of damaged parts and applying load exceeding rated capacity. These misoperations may trigger formwork bulging, component fracture, concrete dimension deviation or wall‑body water seepage risks. As an important penetrating fastening solution for concrete formwork engineering, raw‑material quality, processing craftsmanship, component‑matching accuracy and welding performance of through wall tie system directly affect construction safety, concrete forming quality and long‑term anti‑leakage performance of wall structures, and constitute essential preconditions for cast‑in‑place concrete wall construction.