High Tensile Bond Anchorage for Post-tensioning Bar Tendon Systems

Bond anchorages fixed at the passive side with cement based products are commonly used for bar tendons in geotechnical applications. Today's construction and strengthening projects demand short anchorage solutions for supplementary or additionally placed anchorages where the passive side is neither accessible nor enough space for placing an anchor plate can be provided. Therefore, DYWIDAG-Systems International (DSI) developed a chemical anchoring system based on a water-repellent two-component high strength epoxy resin named DYWIPOX (R). The resin itself offers a high performance in compression and tensile strength. Derived from strengthening applications where DYWIPOX (R) was developed to securely fill improperly injected tendon ducts and to eliminate remaining moisture, the resin was continuously enhanced for anchoring applications. In combination with a defined mix ratio with special quartz sand the resin generates a strong grain structure with high compression strength, low relaxation and very high bond properties. For tendons placed in defined drilling bore holes the anchorage length can be significantly reduced and short high strength tendon solutions in combination with DSI post-tensioning bar tendons can be realized for new construction projects as well as for the strengthening of existing concrete and hybrid structures. This chemical bond anchorage allows tensioning up to the maximum overstressing force acc. to EN 1992-1-1 (0,95 x F-p0,F-1k) and provides in long term tests similar well-tempered relaxation properties like common mechanical anchorages. Based on several reference projects successfully executed within the last five year DSI can revert to a profound knowledge base and developed a design, installation and quality control system for the application of DYWIPOX (R) bond anchorages that can be easily adopted to the project related requests.