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Foundation Movements and Welding Defects in Precast Parking Garage

Carrasquillo Associates (CA) was retained in 2013 to investigate alleged construction defects in a precast parking garage supported by drilled piers near Austin, TX. As part of CA’s investigation, welds were inspected at broken precast connections, relative elevation surveys were performed near distressed areas, cracking was mapped throughout the structure, and a comprehensive finite element method (FEM) model was created for the garage. The FEM model allowed CA to analyze the effect of the measured support settlements to evaluate the cause(s) of the observed distress. Using this information, CA also evaluated the repair scheme being implemented to address the distressed areas throughout the structure.

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Causes and Ramifications of Distress in Post-Tensioned Multimodal Transit Facility

Carrasquillo Associates (CA) was retained in 2016 to investigate distress in a multimodal transportation hub located in the northeast United States.  The cast-in-place structure consisted of a slab on ground and two elevated slabs supported by a concrete frame. The elevated slabs as well as the concrete beams and girders were post-tensioned (PT). CA investigated concerns related to cracking in the concrete slab and frame, reinforcement cover, and concrete durability. As part of the investigation, CA made a site visit to the structure and also reviewed numerous documents including, among others, design drawings, specifications, photographs, shop drawings, expert reports, testing reports, and communications between parties. CA’s investigation helped to identify the causes and ramifications of the observed distress which allowed the parties to come to an agreement regarding the damages.

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Crane Rail Wear and Misalignment

Carrasquillo Associates (CA) was retained in 2014 to investigate unusual wear on crane rails in a steel processing plant in Pennsylvania. CA conducted an on-site investigation to measure the severity of the crane rail wear and to determine its cause. Custom crane rail measuring devices were fabricated at a machine shop in Austin, TX for this purpose. In addition, CA reviewed numerous surveying reports to verify dimensional compliance between laser surveys, project specifications and industry standards. Life cycle estimates of the crane rails were made based on the information collected during the site visit and research conducted by the US DOT.

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Forensic Evaluation of a Rigid Pavement

Several new warehouses for an oil drilling equipment manufacturing company were constructed in 2012 in Houston, TX.  The warehouses were surrounded by three large reinforced concrete drive lanes utilized for delivery and pick-up of large-size oil equipment parts.  Shortly after construction, the reinforced concrete pavement exhibited distress in form of spalled joints at dowel locations, pumping, and localized panel failures.  CA was retained to determine the cause(s) of the distress and provide repair recommendations.  CA’s field work included soil sampling and testing, non-destructive testing of the concrete pavement, including the use of ground penetrating radar, and relative elevation surveys to verify surface drainage patterns.  In addition to the field work, CA also performed an analysis of the pavement design to determine its structural adequacy as-designed.  Ultimately, the cause(s) of the distress was determined and a repair plan was recommended.

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Alkali-Silica Reaction (ASR) in Pier Structure

Carrasquillo Associates (CA) was retained in 2012 to investigate concerns about the structural integrity and long term performance of a pier structure in Honduras and to determine the deterioration mechanisms affecting the durability, the structural safety and useful life of the structure. The investigation into the structure included visual inspection, crack monitoring, concrete sampling, petrographic examination, chloride testing, structural analysis, and half-cell testing among other items. Based on the testing performed, the internal concrete expansion damage mechanism was identified and the remaining service life of the structural performance of the structure was assessed. Further, several alternatives for restoring the service life and the facility were evaluated. This allowed the client to better understand the cause of the distress that was being observed and what needed to be done to allow the structure to continue to operate safely moving forward.

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Slab-On-Grade Distress Investigation and Analysis

The project consisted of two aircraft assembly hangars consisting of 8 in. thick cast-in-place slabs-on-grade with 0.5 in. wide and 2 in. deep joints.  The facilities were constructed during the period from 2004 to 2005.  CA was retained to conduct an investigation and determine the cause(s) of the distress occurring at the joints that consisted of the joint sealant protruding up to a 0.5 in. above the surface of the slab-on-grade.  CA’s investigation consisted, among others, of several site visits, concrete core sampling at the joint sealant locations, shore hardness testing, evaluation and different joint sealant, test program, and condition surveys.  CA determined the cause(s) of the distress and provided recommendations for remediation of the distress including material selection and installation procedures and recommendation for joint detailing for future construction.

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Alkali-Silica Reaction Residential Home

CA was retained in order to investigate the long term performance and possible remediation alternatives for the cast-in-place concrete slab-on-grade foundation at the residence affected by alkali-silica reaction (ASR). Shortly after placement, the foundation exhibited signs of ASR by exuding the slippery gel product throughout the slab causing a safety hazard for the owners. CA was tasked with determining the extent of the damage as well as provide a set of guidelines for repair. CA’s investigation consisted of document review of concrete delivery records, photographic evidence of the site, litigation documents, concrete sampling,  petrographic examination, and three site visits to the residence.

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NDT Assessment, and Repair of Concrete Basement Wall

Carrasquillo Associates (CA) assessed the condition of a 22 in. thick reinforced concrete basement wall and pilasters during construction after irregularities were observed on the surface of the concrete wall. CA determined the extent of the deficiencies and developed a repair protocol for the wall. CA’s investigation of the wall included a visual survey, non-destructive testing (NDT) using ultrasonic echo 3D tomography, and concrete core sampling for visual examination and compressive strength testing. CA non-destructively scanned the wall using ultrasonic echo 3D tomography, a method that uses ultrasonic shear waves to locate internal defects, reinforcement, and the back surface of the concrete. The majority of the NDT testing data did not indicate the presence of internal defects within the wall. Verification cores and compressive strength testing from several of these areas confirmed the absence of internal defects and/or low strength concrete. At CA’s recommendation, the project team approved the repair of the wall.

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NDT Assessment, and Repair of Cast-in-Place Concrete Framing

Carrasquillo Associates investigated deficiencies observed on the surface of the concrete for the second floor cast-in-place concrete framing, which consisted of conventionally reinforced beams, girders, column tops, and the second floor slab. CA reviewed the condition of the cast-in-place concrete to determine the extent of the deficiencies, to develop a repair protocol, and to selectively observe and document the repair work. CA’s investigation included a visual condition survey, non-destructive testing (NDT) using Ultrasonic Pulse Velocity (UPV) equipment, and concrete core sampling. CA’s visual condition survey identified several types of possible deficiencies. These included surface honeycombing, poor consolidation, internal voids, and visible lift lines and/or cold joints. CA demonstrated that the majority of the observed deficiencies were near surface and did not impact the structural integrity of the concrete structure. Based on CA’s recommendations, the project team decided that all of the observed deficiencies could be repaired.

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Ground Penetrating Radar Scanning for Artwork Design and Construction

Carrasquillo Associates (CA) performed work related to ground penetrating radar (GPR) scanning for artwork to be installed at ABIA. Prior to construction, CA scanned and mapped areas around the perimeter and approximately 900 sq. ft. of the art zone’s interior to determine appropriate places for through drilling between double tee stems and embedded anchors in double tee stems. After reviewing available construction documents, drawings, and project related material, CA completed extensive scanning of the parking deck using high resolution GPR equipment. CA mapped the location of precast double tee stems and embedments in the parking deck. Embedments and items found on the underside of the slab were identified as “no drill zones” and the extents of the double tee stems were also mapped. The project was a great success with over 900 sq. ft. scanned, and only one drilled hole encountering an unforeseen embedment.