Located at a pharmaceutical plant in Lafayette, Indiana, the overall construction project involved a 6” deep post-tensioned slab on grade with 36” thick edge beams, CMU external and internal walls, and steel columns and roof trusses. The foundation portion of the project consisted of a 23,000 square foot slab-on-ground.

The engineer-of-record hired VSL to design the slab-on-ground post-tensioning system. In general, the design requirements specified that the concrete slab-on-ground would not crack. Post-tensioning was selected as a means to meet these strict requirements. The VSL two-strand VSLAB+® bonded slab post-tensioning tendon system was used for the slab, and a multistrand bonded post-tensioning system incorporating the VSL ES5-12 Anchorage System with PT+ plastic duct was used in the edge beams. VSL’s design resulted in the VSLAB+® tendons being spaced at 24” on-center in each direction and two 0.5” diameter 12 strand tendons in each edge beam.

The second phase of the project awarded to VSL was the material fabrication, supply and installation portion of the foundation. VSL provided an experienced site supervisor and project engineer onsite to oversee preparation, installation, stressing and grouting. VSL also executed a detailed Quality Assurance / Quality Control Plan to ensure work in the field met the demanding project specifications. This plan entailed the systematic procedures and actions necessary to produce a facility that conformed to the specified requirements and met the intended purpose.

The unique 2-strand VSLAB+® ram was utilized on this project to place an initial stress of 26 kips within 36 hours of concrete placement to prevent any initial shrinkage cracks in the slab. This phase was very important to perform as soon as possible in order to meet the project requirements for crack control. The tendons were fully stressed to 66 kips when concrete strength reached 4000 psi. VSL’s low bleed VGrout™ was also utilized on this project to produce a bonded, fully encapsulated system.