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LEED Certification at LCRA Red Bud Center

CA provided sustainable construction consulting services to the general contractor for the construction of the LCRA Red Bud Center’s architectural concrete elements including textured exposed architectural concrete walls. CA’s consulting work included the review and evaluation of the concrete specifications, plans, and drawings.  CA then developed recommendations for the concrete mixture proportions, formwork, and concrete placement, in particular consolidation practices to meet the project requirements and most importantly the architect’s vision and aesthetic value of the exposed concrete. The architecturally exposed concrete walls were required to exhibit a textured form finished pattern and appearance similar to that observed in the Tom Miller Dam adjacent to the LCRA Red Bud Center built over 60 years ago. CA was also involved in the evaluation and concrete repair of the finished concrete walls. The design requirements incorporated the implementation of sustainable construction strategies and practices required to meet the standards of the United States Green Building Council. The facility achieved USGBC LEED® Gold Certification and Four-Star Rating from the Austin Energy Green Building Program.

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Structural Evaluation and Testing of a Parking Structure

Work performed on a parking structure located in Plano, Texas, encompassed a two phase investigation. Phase I consisted of investigating the cause of cracking occurring in the precast, prestressed double tee beams which resulted in the repair or replacement of several double tees. The forensic structural engineering investigation included a condition assessment of the parking garage structure, evaluation of the double tees removed from the structure, sampling of the concrete, non-destructive testing, petrographic examination, and analytical testing. Phase II consisted of investigating the cause of distress in the architectural precast concrete elements by performing a condition assessment and evaluation of the architectural precast elements in-place. It involved determining the adequacy of the erection details, connections, and the overall structural integrity of the precast architectural members.  CA’s forensic consulting work on this project involved performing a structural analysis, sampling, testing, and petrographic examination of the concrete, the review of concrete production and construction practices, and the development of recommendations for rehabilitation and maintenance of the parking garage structure.

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Texas Children’s Hospital Mass Concrete Placement

The project consisted of the construction of a 5,000 cubic yard mass concrete mat foundation for a medical facility in Houston, TX. CA’s work consisted of working with the Structural Engineer of Record, General Contractor, Concrete Sub-Contractor, Independent Testing Laboratory, and the Ready-Mixed Concrete Supplier to develop a construction plan for the placement, curing, and protection of the mass concrete to ensure the quality of the concrete in-place. CA developed a plan for the preparation and placement of the mass concrete including monitoring internal concrete temperatures after several meetings with all parties involved in the construction; review of plans, drawings, and specifications; developing mixture proportions using fly ash as the supplementary cementitious material; casting and evaluating the performance of a mock-up; and field testing. CA’s work also included developing the quality control program for accepting the fresh concrete delivered to the job, temperature monitoring plan, concrete specifications, curing methods, and early age protection to prevent distress in the fly ash concrete. Through daily monitoring of the ambient and internal concrete temperatures, CA was able to provide the General Contractor with guidelines for proceeding with construction as quickly as possible while ensuring that the concrete did not experience any thermal cracking.

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Heat Flow Analysis of Mass Concrete

CA has conducted heat flow analyses of mass concrete structures. These have included evaluating the effect of the concrete placement sequence, structural specifications, ambient conditions, and concrete materials and their mix proportions on the cumulative heat generation and internal temperature of the mass concrete construction and thus, on the quality of the in-place concrete. The heat flow analysis and the predicted temperature profiles were later confirmed by field measurements during actual construction. The information developed by CA was instrumental in determining the concrete curing, early age protection, and form removal practices followed by the contractor in the job. CA has also investigated the cause(s) of cracking as a result of thermal induced stresses in other facilities such as mass concrete foundations and precast/prestressed concrete highway structures.

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Concrete Materials Consulting for the Modern Art Museum of Ft. Worth

In May of 1997, the world renowned architect, Tadao Ando, was selected as the architect for the Modern Art Museum’s building in Fort Worth, Texas. The Museum’s 150,000 square foot building sits on an 11-acre property. CA provided concrete materials consulting services for the production and construction of the architectural concrete structure including, among others, material selection, concrete mix proportions, batching, quality control, formwork, and consolidation. Notable features of the building included a natural setting utilizing existing major trees on site augmented by additional trees; shrubs and plant materials native to North-Central Texas; three gallery pavilions that appear to float above a shallow reflecting pond to the north and west; double skin or envelope inner structural walls of cast concrete to protect interior gallery spaces and support large projecting roof planes above; outer glass and metal panel walls to provide public circulation areas from which to view the museum’s landscaped exterior and reflecting pond; and immense concrete roof overhangs, supported by Y-shaped columns on the east side to help shade interior spaces surrounded by 36 foot glass curtain walls constructed with energy efficient insulated glass units.

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Quality Control of Mass Concrete: UT MDA Mat Foundation

The project consisted of the construction of a 22,000 cubic yard mass concrete mat foundation for a medical facility in Houston, TX. CA’s work consisted of working with the Structural Engineer of Record, General Contractor, Concrete Sub-Contractor, Independent Testing Laboratory, and the Ready-Mixed Concrete Supplier to develop a construction plan for the placement, curing, and protection of the concrete to ensure the quality of the concrete in-place. CA developed a plan for the preparation and placement of the mass concrete including monitoring of internal concrete temperatures.  This plan was based upon several meetings with all parties involved in the construction, review of plans, drawings, and specifications, evaluation of the concrete mixture proportions, and prior experience with mass concrete. CA’s work also included developing the quality control program for accepting the fresh concrete delivered to the job, temperature monitoring plan, concrete specifications, curing methods, and early age protection to prevent distress of the concrete. Through daily monitoring of the ambient and internal concrete temperatures, CA was able to provide the General Contractor with guidelines for proceeding with construction as quickly as possible while ensuring that the concrete did not experience any cracking due to thermally-induced stresses.

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Non-Destructive Testing Services at Dos Hermanos Bridge

The Dos Hermanos Bridge structure, built in 1981, is one of the two ground-level links between the Islands of San Juan and Puerto Rico. As a result of the severe marine environment exposure conditions, a few years after its completion, the bridge showed signs of early deterioration including severe corrosion of the concrete reinforcement in both the cast-in-place and the precast, prestressed structural members. CA performed a field condition survey and assessment of the structural integrity and safety of the structure including, among other things, destructive and non-destructive concrete testing, chloride ion content testing to determine the chloride ion penetration into the concrete, and cover meter scanning to determine the location of existing reinforcement. Furthermore, a service life cost estimate analysis and predicted service life expectancy was prepared based on various modeling techniques considering the in-service conditions, the implementation of different concrete restoration and rehabilitation techniques, and the actual properties, characteristics, and performance of the concrete.

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Concrete Finish Discoloration

The investigation consisted of determining the cause(s) of discoloration in the hard-troweled finished surface of the elevated structural slab in a high rise building. CA performed a visual inspection of the facility, extracted samples from the concrete surface, and performed a petrographic examination. The discolorations were found to be very shallow. The concrete samples did not indicate the presence of any deficiencies in the concrete requiring any further action other than the removal of the discoloration through very light polishing in order to restore consistency in the appearance of the finish of the elevated slab.

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Architectural Concrete Quality Control and Quality Assurance Program at the Mexican-American Cultural Center

This project was a joint effort between the City of Austin and Desarrollo Integral de Inmuebles, S.A. de C.V. in Mexico. Construction consisted of white precast architectural concrete panels produced in Mexico and white cast-in-place architectural concrete cast in Austin, Texas. Initially, CA was retained to investigate the cause of concrete cracking and failure of some architectural precast panels upon delivery and/or erection of the panels in the project. CA determined that the cause of the cracking was related to the reinforcement and anchorage details associated with the lifting hooks. CA evaluated and tested the anchorage detail and visited the contractor in Mexico to help implement changes. In addition, CA worked with the owner in the development and implementation of the quality control and quality assurance procedures during the construction of the project. CA was also retained to determine the cause of inconsistencies in the color and appearance of the cast-in-place architectural concrete. CA developed recommendations to achieve the specified quality of the architectural concrete construction restoring the uniformity within the architectural concrete in the project in addition to facilitating the progress of the construction activities. Of great significance, CA’s work resulted in alternatives and recommendations to adequately fabricate and install the architectural precast panels meeting the needs of the contractor to achieve the specified project requirements.

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Calgary Ring Road High Performance Concrete Design

The northeast portion of the Calgary Ring Road project consisted of 13 miles of new four and six lane roadway around Calgary, Canada, which included 23 bridge structures and 6 interchanges. CA was retained to provide structural engineering consulting services to assist the general contractor in the fabrication of the precast, prestressed concrete girders under severe cold weather concreting conditions. Among others, work included an assessment and evaluation of the production of the high performance concrete, calibration of the batch plant, and the implementation of quality control procedures and concrete placement procedures.  CA provided recommendations for the production of the high performance concrete during cold and hot weather conditions. During several site visits, CA evaluated the construction needs, quality control procedures, and casting bed and curing facilities available at the casting yard. CA also evaluated concrete production practices, batch plant setup, and mixture proportions. Most importantly, the work included providing recommendations for curing and early age protection of the precast girders thus allowing their fabrication to meet the contractual requirements while ensuring the quality, strength, durability, and long term performance of the concrete in service. Field work also included several trial mixes for adjusting the mixture proportions and providing recommendations for batching high performance concrete. CA’s comprehensive plan for the curing and early age protection and production of high performance concrete resulted in significant benefits to the construction schedule and allowed for the production of precast concrete girders during the severe winter months.