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          p 245
        
        
          
            Chapter 3
          
        
        
          Hydraulically-Driven Push Piers
        
        
          
            CHAPTER 3
          
        
        
          HYDRAULICALLY-DRIVEN PUSH PIERS
        
        
          
            3.11 PP288 Flush-Mount
          
        
        
          
            Push Pier Installation
          
        
        
          The PP288 flush-mount bracket system may be
        
        
          used for applications where poured concrete
        
        
          elements such as a foundation wall, column,
        
        
          pile cap or grade beam have adequate strength,
        
        
          thickness and vertical dimensions to allow proper
        
        
          attachment of the bracket. PP288 flush-mount
        
        
          system capacities are provided in Appendix 3A
        
        
          for systems using either expansion or adhesive
        
        
          anchors.
        
        
          
            Step 1 Concrete Preparation
          
        
        
          • Excavation may be necessary to expose the
        
        
          vertical face of the concrete. If the bracket
        
        
          is mounted on a foundation wall or column
        
        
          above a spread footing, the concrete footing
        
        
          would have to be cored through or removed
        
        
          entirely to allow for advancement of the pier
        
        
          tube sections. The vertical face of the concrete
        
        
          to receive the bracket should be smooth of
        
        
          surface irregularities and free of structural
        
        
          cracks. A thin layer of leveling compound
        
        
          could be considered to create a smooth flat
        
        
          surface prior to mounting the bracket.
        
        
          Safety precautionsmust be followed prior to
        
        
          and during excavation. Locate underground
        
        
          utilities prior to excavation activities and
        
        
          perform excavations at a distance away
        
        
          from utilities as mandated by the utility
        
        
          owner. Follow OSHA guidelines for trench
        
        
          safety during excavation and installation
        
        
          activities.
        
        
          
            Step 2 Mounting the Bracket
          
        
        
          • The flush-mount bracket is secured to the
        
        
          concrete vertical face using eight (8) -inch
        
        
          diameter anchors. Rather than attempting
        
        
          to position and hold the bracket in place, a
        
        
          template of the bracket bolt holes could be
        
        
          considered to mark the anchor locations.
        
        
          
            Steps 3 - 7
          
        
        
          • The remaining steps for flush-mount push
        
        
          pier installation are similar to those for the
        
        
          under-footing system described in Section 3.10.
        
        
          
            3.12 PP288 Slab Push Pier
          
        
        
          
            Installation
          
        
        
          The PP288 slab push pier system is used to lift
        
        
          and/or stabilize settling concrete floor slabs.
        
        
          Monometer survey equipment, a laser level, a
        
        
          zip level, or other suitable equipment should be
        
        
          used to identify low areas in the slab. Slab piers
        
        
          should be located at these identified low points.
        
        
          Slab piers should also be considered either
        
        
          centered on or on alternating sides of significant
        
        
          floor cracks to ensure an even lift. Voids beneath
        
        
          a stabilized and lifted slab should be filled with
        
        
          suitable material such as a cement grout or
        
        
          PolyLEVEL
        
        
          ®
        
        
          polyurethane foam.
        
        
          
            Step 1 Slab Preparation
          
        
        
          • Mark the slab pier locations with consideration
        
        
          to possible underground utilities, overhead
        
        
          obstructions, maximum pier spacing, existing
        
        
          floor cracks and lift requirements. Small paper
        
        
          plates may be used to mark preliminary slab
        
        
          pier locations since the plates can be easily
        
        
          moved around the slab
        
        
          (Figure 3.12.a)
        
        
          . Slab pier
        
        
          Figure 3.12.a
        
        
          Marking slab pier locations