STRUCTURAL TECHNOLOGIES’ external post-tensioning systems utilize high strength prestressing cables, strands and steel bars, and are used to increase or restore load-carrying capacity to a variety of structures. Post-tensioning is ideal for situations that require significant load capacity increases or deflection and/or crack control.
Our external post-tensioning systems for strengthening of existing structures feature the same proven VSL post-tensioning products used in new construction. VSL products have been used as the industry standard for post-tensioning throughout the world. These systems have been used to repair, and strengthen bridges, buildings, parking structures, tanks and special structures.
STRUCTURAL TECHNOLOGIES designs these versatile systems to reduce tensile stresses, cracking and deflection. External P-T is an active strengthening system - which immediately engages in load sharing and transfer. By creating uplift or offset deflections, significant load capacity increases can be achieved while also minimizing and controlling crack formation.
Unbonded Monostrand Systems
VSL Monostrand Systems are coated with grease as a permanent corrosion inhibitor and sheathed in extruded plastic to provide double corrosion protection, as well as prevent any bonding between the strands and the surrounding concrete. In aggressive environments, special sleeves are used to join the sheaths to the anchorages, and each anchorage includes a protective cap. Available in diameters of 0.5" (13mm) and 0.6" (15mm), these light, flexible monostrands can be easily and rapidly installed.
VStrand™ Heat Resistive Tendons
VSL’s innovative VStrand™ heat resistive tendons, have been developed to mitigate the detrimental thermal effects of a fire on the strength of the prestressing steel. These tendons are specially designed to promote fire protection for strengthening systems used in bridges, parking garages, and other structures where the risk of a potential fire is a concern.
Bonded Multistrand Systems
VSL Bonded Multistrand Systems, used typically in bridges and transportation structures, have been successfully installed by VSL in commercial building construction and retrofit. A single multistrand tendon can hold up to 55 strands that are encased in HDPE plastic or steel duct and then encapsulated using a high performance grout.
STRUCTURAL TECHNOLOGIES' external post-tensioning systems feature VSL® branded products - known worldwide as the products of choice for both new and repair post-tensioning applications. Structural Technologies, LLC is the exclusive licensee of VSL® Post-Tensioning Systems in the United States.
VSL® is the registered trademark of VSL International Ltd.
Specialized Engineering Services for Structural Strengthening
STRUCTURAL TECHNOLOGIES’ Strengthening Team provides highly specialized engineering and technical support services. Our team integrates with owners, engineers and builders to evaluate multiple strengthening options in order to produce the best, most comprehensive solution.
Strengthening Engineering Team Leader
Tarek Alkhrdaji, PhD, PE, is Vice President of Engineering with Structural Technologies, Hanover MD. He received his Masters and Ph.D. degrees at the Missouri University of Science and Technology. Dr. Alkhrdaji has experience in structural repair and strengthening and full scale load testing of concrete structures. He has been involved in more than 400 projects involving structural repair and strengthening and was involved in numerous repair and strengthening projects that received awards from The American Concrete Institute (ACI), the Post-Tensioning Institute (PTI), and the International Concrete Repair Institute (ICRI). Dr. Alkhrdaji also has experience in design, planning and execution of full-scale load testing of structures for strength evaluation and performance verifications. such as ACI, ASCE, AWWA, SEA, PTI, and ICRI. Dr. Alkhrdaji is currently an active member of He is also an active member of ACI Committee 437 (Strength Evaluation of Existing Concrete Structures), ACI Committee 562 (Concrete Repair Code), a member of ASCE (American Society of Civil Engineers), ICRI (International Concrete Repair Institute) and AWWA (American Water Works Association).
Dr. Alkhrdaji has written more than 40 papers and articles on structural strengthening of structures including buildings, bridges, silos, tanks and concrete pipes. He has made many technical presentations at major industry events, professional organizations seminars and conferences and was the past Chair of ACI Subcommittee 440F (FRP Repair & Strengthening).
STRUCTURAL TECHNOLOGIES' licensed engineering services are provided by Structural Technologies StrongPoint, LLC - A Structural Group Company, or through other licensed engineers.
STRUCTURAL TECHNOLOGIES provides construction phase support services to ensure that the strengthening systems are installed properly and will carry out their intended functions. We coordinate with builders to provide project-specific oversight, quality assurance and quality control.
Turnkey Investigate – Design – Build Solutions
When paired with Structural Group's specialty contracting companies—we provide our clients with a full range of strengthening design support, construction, and maintenance services from a single source of accountability. Together, we seamlessly deliver customized, cost-effective, and long-lasting solutions for structural challenges.