Construction Manager Pro

  Building Failure  My Geotechnical Firm performed a Geoforensic investigation of a recently built Police Station in the Houston area. They noticed floor cracks and wall damage throughout. The original design required the footers to be constructed 6’6” below the finish floor elevation. During their pit investigations, they found that the footers were only constructed to a depth of 40” instead of the designed depth of 55”. They also found that there were no void boxes under the grade beams as shown in the design. Void boxes are used in areas of expansive soil to allow the soil to swell into the voids instead of lifting the foundation. They also found that the soil under the slab was highly expansive with a PI of 33 to 44. Through their soil investigation, they determined that the PVR was 1.9”. This is the total movement under wetting conditions of the foundation. In their estimation, spread footers were an inadequate design.   Negative drainage was found ...

  A Concrete Pump overturns on a construction site and kills one worker in the Houston area My geotechnical firm investigated the soil conditions under the crane and the timber that was placed under the outriggers.    They conducted a geotechnical investigation of the soil. The soil conditions under the crane were sufficiently compacted for the weight of the crane. Based on their calculation, the soil bearing capacity was 2,100 psf for a safety factor of 3. They measured and analyzed the support timbers under the crane’s outrigger and found that they were insufficient in size.    Based on the results of the field explorations, laboratory testing, and engineering analysis, it was the Geotechnical opinion that the potential causes of the concrete pump truck outrigger failure are as follows: 1)      The concrete pump truck outrigger failure occurred at the rear outrigger leg. 2)     The significant presence of plastic trash ...

Building Failure  My Geotechnical Firm performed a Geoforensic investigation of a School in South Texas. Drilled piers were to be built according to the above design. All piers would be constructed at a depth of 13’. They dug investigation holes at several of the piers and found that they were not constructed according to the design. Pier depths were measured at 10’6” instead of the design depth of 13’. The Bell size was constructed at 36” instead of the design of 78”. The Shaft diameter was constructed at 18” instead of the design of 30”. They also found that the fill under the slab was highly expansive with a PI (Plastic Index) of 32-40. In their review of the expansive soil, they determined that the PVR (Potential Vertical Rise) is 3.6”. Therefore, the original design of a 13’ depth was not sufficient to resist the uplift loads due to the expansive soils. The minimum depth should have been a minimum of 25’. They also found negative drainage on the east and west sides of ...

  A concrete crane collapses at the Texas Medical Center project and injures one worker.   My Geotechnical firm investigated the soil conditions under the crane. They found a loose sandy soil that was not compacted. They determined that the soil bearing capacity was 1,000 psf. The actual loading of the crane and the concrete container was 5,000 psf. They also discovered that the outrigger area of the crane was 2.25 SF, and the wood outrigger was also only 2.25 SF. The outrigger base was too small and therefore insufficient. A summary of the collapse. 1)      Insufficient bearing capacity of the soil underneath the crane. 2)     Outrigger pads are too small 3)     Settlement of the soil under the crane. Perform a bearing capacity check by a geotechnical engineer for any crane or concrete pump truck outrigger used on the project. Meet with your crane operator and review a lifting plan before work commences.  ...