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Residential Alkali Silica Reaction Distress Investigation

CA investigated a residential concrete foundation slab where the interior finished concrete floor exhibited visible distress consisting of exudations on the surface of the concrete. These exudations included some consisting of clear, sticky gel and others consisting of hardened, opaque-white deposits. CA completed a condition survey, elevation survey, and concrete core sampling on site. The condition survey showed concentrated distress at and immediately around the grade beams where the vapor barrier was discontinuous and little distress in the slab areas between grade beams. The petrographic examination of the cores found that the observed distress in the cores extracted from the distressed areas was the result of alkali‑silica reaction (ASR). In this case, the aggregate near the surface exuded the gel to the surface of the concrete. Due to the site grading in combination with the discontinuous vapor retarder, moisture was being transmitted through the concrete at the grade beams resulting in the ASR distress. The lack of ASR in the slab areas between the grade beams indicated that with adequate under-slab moisture-proofing, the concrete was performing adequately.

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Residential Soil-Driven Foundation Movement Investigation

CA evaluated claims of poor foundation performance and distress caused by foundation movement at thirty-eight (38) residences in a development in Heber, CA. CA’s investigation consisted of document review and background research, site visits and inspections, data analysis and summary of findings. While on site, CA performed a detailed visual condition assessment of the residences and relative elevation surveys of the post‑tensioned slab‑on‑grade foundations. Distress, in the form of stucco and drywall cracking, was observed in the residences. CA determined that the distress was not caused by foundation movement but rather by one or a combination of shrinkage of the stucco during curing, seasonal expansion and contraction of the stucco and wood framing due to seasonal variation in temperature and humidity. The foundation system was performing as intended exhibiting little to no differential settlement and swell.

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Forensic Engineering Investigation & Analysis of Bridge Overlay Failure

The Pulaski Skyway Bridge Project consisted of a steel truss bridge supporting a concrete bridge deck with repairs where the top 1.5 inches of concrete bridge deck was replaced with a latex modified concrete topping along the entire length. Shortly after, the repairs began to exhibit premature failure in the form of reflective cracking around the perimeter of the repaired area, then debonding, followed by cracking of the patch repair material causing eventual potholes in the bridge deck. CA’s investigation involved, among others, review of daily log reports, expert reports, and other relevant documents, and a site visit during which a visual condition survey was performed to determine the cause(s) of the observed premature patch repair failures in the bridge deck.

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Repair and Rehabilitation of Cooling Basin

A cooling basin constructed as an addition to an existing co-generation cooling system consisted of cast-in-place concrete with walls approximately 60 ft. tall. Shortly after the cooling basin was constructed, the owner expressed concerns that the basin was leaking. CA was retained to observe the repairs performed to the basin walls by a third party hired and to certify that all repairs were performed according to industry standards of practice. CA’s activities included numerous site visits, non-destructive testing, evaluation of existing conditions, and observed on-site testing by other parties. CA provided the client with additional repair options and procedure recommendations.

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Concrete Materials Consulting & Structural Analysis for Christopher Columbus Statue in Puerto Rico

Located atop a hillside on the northern shores in the city of Arecibo, Puerto Rico, a Christopher Columbus Statue is being erected and is projected to be completed by late summer of 2015. The Statue consists of over 2,000 exterior pieces of copper and bronze connected to an interior structural steel frame for a total weight of over 600 tons. The structure was originaly designed by Russian sculptor Zurab Tsereteli in 1991 to commemorate the 500th anniversary of Columbus’ 1492 arrival to the Western Hemisphere. CESG’s contribution to the project included consulting services in regards to the mat concrete foundation consisting of the structural design, project specifications’ development, material condition assessments, and construction management. In addition, CESG’s project involvement also included the development of the concrete mixture proportions, concrete placement sequencing, quality control, temperature and maturity monitoring, and implementation of early age protection to the mass concrete elements. Over 1,500 cubic yards of concrete were placed in approximately 8 hours of which all concrete loads were accepted, there was no evidence of cracking with in the mat foundation mass concrete elements, and all the concrete compression strength tests exceeding the 28-day specified design strength in 7 days.

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Tennis Court Complex Forensic Engineering Investigation

CA was retained to perform a structural investigation and determine the cause(s) of the distress in two tennis court facilities located at a junior high school and high school in South Texas. To accommodate construction on expansive soil conditions, the structural system of the tennis courts was comprised of precast concrete hollow core planks (HCP) with a 3 inch concrete topping slab supported by cast-in-place reinforced concrete piers. Shortly after construction the owner noticed distress in the form of cracking and spalling along joints in the playing surface of the tennis courts. It was determined that the cracking was reflective cracking propagating from the longitudinal and transverse joints between HCPs which also resulted in localized spalling of the topping slab. CA’s investigation into the problem consisted of, among others, review and evaluation of construction related documents, review of third party repair options, review of expert reports, review of plans and drawings, detailed condition survey and elevation surveys, exploratory coring to assess the details of the jointing between HPCs, structural analysis of the tennis court system, design of a repair alternative, as well as several site visits to the structures. Through the forensic engineering investigation, CA was able to determine the cause(s) of the distress and provide the client appropriate remediation procedures.

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Foundation Crack Repair of High School in Texas

CA was retained to determine if the alleged movement of the reinforced concrete slab-on-grade foundation at a high school was the result of construction related activities and to develop recommendations for restoring the facility. Shortly after the school’s completion, the owner reported deficiencies including, but not limited to, movement of the slab-on-grade foundation which caused distress consisting of cracking and/or separation of drywall panels, out-of-plumb doorways, and out of level floors. CA’s investigation included the review and evaluation of construction related documents, multiple site visits including a detailed condition survey and relative elevation surveys of the school. Through the investigation, CA was able to determine the cause(s) of movement and develop a mitigation procedure to minimize any future movement and restore functionality of the facility.

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Structural Engineer Expert Witness: Sports Car Speedway

In January of 2012, a barrier wall at a race track near Houston, Texas was struck by a vehicle resulting in injuries to a spectator. Carrasquillo Associates (CA) conducted a forensic investigation into the structural integrity of the barrier wall. CA’s investigation and litigation support included review of depositions, photographs, drawings, expert reports and industry standards for vehicle barrier design. In addition, CA performed a structural analysis on the as-built barrier wall and after a site investigation to identify distress and the as-built condition of the wall. CA’s investigation culminated in an expert report where CA was able to determine the injuries to the spectator were attributable to the structural deficiencies in the barrier wall and poor safety practices at the facility. The case was settled in favor of CA’s client.

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Warehouse Slab-on-Grade Distress Investigation

A 160,000 square foot warehouse located in Austin, TX was exhibiting distress of the finished concrete floor in the form of aggregate exposure, distress, surface wear, and joint deterioration of both control joints and construction joints in the cast-in-place slab-on-grade. In addition, several areas were identified as containing cold joints and poor quality concrete within the cast-in-place slab-on-grade. CA was retained to perform a detailed condition survey to identify and determine the cause(s) of the defects within the slab and to develop concrete repair recommendations. CA’s condition survey included photographic documentation, distress mapping, non-destructive testing using ground penetrating radar, concrete core sampling, and petrographic examination. The investigation also included an assessment of the equipment and use of the facility as well as an evaluation of the specifications, plans, drawings and construction related documents. CA determined the cause of distress in the concrete and provided the client with a repair plan to prevent future distress that would have otherwise been caused by the existing defects within the slab-on-grade.  CA also aided in the litigation for this project by participating in mediation proceedings.

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Concrete Distress Investigation at a Suburban Shopping Center

The concrete parking lot at a Dallas, TX suburban strip mall housing a national electronics retailer and other popular chain stores was exhibiting various forms of distress in the concrete pavement including cracking, faulting, heaving, aggregate pop-outs, and relative joint displacement. In addition, CA observed that the brick facade of the concrete tilt-wall panels of the structure was delaminating and spalling at localized areas. CA was retained by the owner to perform an investigation into the cause(s) of the distress which included evaluation of the construction practices, plans, and drawings and a detailed condition survey of the both the concrete pavement and tilt-wall panels, numerous relative elevation surveys, and non-destructive testing, including the use of ground penetrating radar (GPR). Sampling and testing also included petrographic examination of the concrete pavement and stabilized base materials. CA was able to determine the cause of the distress in both the concrete pavement and tilt-wall panels and provided the owner with a cost efficient solution that could be implemented without disrupting everyday operations at the strip mall plaza.